Chickpea, a Common Source of

International journal of Agronomy and Plant Production. Vol., 4 (1),94-97, 2013Available online at ISSN 2051-1914 ©2013 VictorQuest PublicationsEffects of water supply on field performance of chickpea(Cicer arietinum L.)cultivarsKazem Ghassemi-Golezani*, Saeid Ghassemi and Ali BandehhaghDepartment of Plant Eco-Physiology, Faculty of Agriculture, University of Tabriz, Iran;*Corresponding Author Email:golezani@AbstractIn order to investigate the effects of water supply (I1, I2, I3 and I4: irrigation after 70, 100,130 and 160 mm evaporation from class A pan, respectively) on yield and yieldcomponents of three chickpea(Cicer arietinum L.)cultivars (Azad, Arman and Jame), asplit plot experiment (using randomized complete block design) with three replicationswas conducted in 2012.Pods per plant, grains per plant, 100 grains weight, biologicalyield, grain yield and harvest index decreased with decreasing water supply. Azad was asuperior cultivar in grains per pod, 100 grain weight, plant biomass, grain yield andharvest index, compared with Arman and Jam. The superiority of Azad in grain yield wasmore evident under normal irrigation conditions.Differences between Arman and Jam ingrains per pod, 100 grains weight and biological yield were not significant. Therefore,yield and yield components of chickpea can be reduced under water stress, dependingon the severity of stress and cultivar.Keywords:Chickpea, Grain yield, Plant biomass, Water stressIntroductionChickpea is an important grain legume in the world and constitutes 20% of the pulses production (FAO, 2004).It is traditionally cultivated in marginal areas (Rao et al., 2002) and grown in semi-arid regions(Labidi et al., 2009).Major producing countries include India, Pakistan and Iran (FAO, 2010).Drought is a major abiotic stress that severely affects food production world-wide. It was reported that water deficit results in nearly 50% of the variation in chickpea production caused by both biotic and abiotic stress factors (Saxena, 1987).Water deficit is an important factor limiting growth and productivity of the crops in a large part of the agricultural areas in the world (Borsani, et al., 200; Micheletto, et al., 2007).Drought stress is a serious problem in Iran, because rainfalls are poorly distributed over the growing season and stop before plant growth completion and chickpea is traditionally planted towards the end of the rainy season and generally grown on progressively declining soil moisture residual and increasing temperature (Ganjeali et al., 2011).Photosynthesis and cell growth are the primary processes which are affected by water stress (Munns et al., 2006).The flowering and pod setting stages appear to be the most sensitive stages to drought (Nayyar et al., 2006). Water stress during flowering and grain filling caused 50-80% reductions in grain yield due to restrictions in photosynthesis (Leport et al., 1999). Chickpea is more sensitive to water stress during reproductive stages and consequently experiences substantial yield loss (Turner et al., 2001; Nayyar et al., 2005). Water limitation at these stages leads to flower abortion, poor pod set and formation of infertile pods (Davies et al., 1999).The effect of drought stress on growth and yield depends on function of genotype, duration of stress, weather conditions, growth and developmental stages of crops (Robertson and Holland, 2004). Moderate to high drought stress reduced plant biomass, number of pods and seeds, days to maturity, harvest index,grain yield and grain weight in common bean (Ghassemi-Golezani and Mardfar, 2008), soybean (Demirtas et al., 2010) and pinto bean (Ghassemi-Golezani et al., 2010). Mensah et al. (2006) and Hong et al.(1985) reported that drought stress resulted in stunted growth and reduced grain yield of sesame(Sesamum indicum L.).This research was carried out to evaluate the extent of the effects of water limitation on yield and yield components of three chickpea cultivars.Materials and MethodsThis research was conducted in 2012 at the Research Farm of the Faculty of Agriculture, University of Tabriz, Tabriz, Iran (Latitude 38° 05ʹN, Longitude 46° 17ʹE, Altitude 1360 m above sea level)to evaluate effects of water supply (I1, I2, I3 and I4: irrigation after 70, 100, 130 and 160 mm evaporation from class A pan, respectively) on yield and yield components of three chickpea(Cicer arietinum L.)cultivars (Azad, Arman and Jam).The climate is characterized by mean annual precipitation of 245.75 mm per year and mean annual temperature of 10°C.The experiment was arranged as split plot on the basis of randomized complete block design in three replicates, with the irrigation treatment (I1, I2, I3 and I4:irrigation after 70, 100,130 and 160 mm evaporation from class A pan, respectively) in main plots and chickpea cultivars (Azad, Arman and Jam) in sub plots. Each plot had 6 rows of 5m length, spaced 25 cm apart. Seeds were treated with Benomyl at a rate of 2 g/kg before sowing. The seeds were then sown by hand on 14 May 2012 in 4 cm depth of a sandy-loam soil. All plots were irrigated immediately after sowing, but subsequent irrigations were carried out according to the treatments. Weeds were controlled by hand during crop growth and development as required.At maturity, 10 plants from each plot were harvested and pods per plant, grains per pod,grains per plant, 100 grain weight, grain yield, biological yield and harvest index were determined.Analysis of variance appropriate to the experimental design was conducted, using MSTATC software. Means of each trait were compared according to Duncan multiple range test at p≤0.05. Excel software was used to draw figures.Results and DiscussionAnalyses of variance of the data for grain yield, yield components and harvest index showed that pods per plant, grains per plant, 100 grain weight, biological yield, grain yield and harvest index were significantly affected by irrigation and cultivar. Grains per pod did not differ significantly among irrigation treatments, but it was significantly varied among cultivars. The interaction of irrigation × cultivar was only significant for grain yield per unit area (Table 1).Table 1. Analyses of variance of the data for grain yield, yield components and harvest indexof chickpea cultivars under different irrigation treatmentsSource df Pods perplantGrainsper podGrains perplant100 GrainsweightBiologicalyieldGrain yieldHarvestindexReplication286.3700.225660.72320.4395865.551026.493 3.925 Irrigation(I)3254.261**0.124ns231.464*105.131*13471.779**19961.108**378.155** Ea625.6850.25746.06516.3461358.922116.758 6.634 Cultivar(C)2650.138**0.876**252.361**41.922**12583.496**8428.530**46.374** I*C611.652ns0.051ns14.775ns8.790ns256.444ns215.456* 1.716nsEb1615.0510.0397.182 3.738600.33276.914 1.771CV%12.3614.229.197.42 5.22 3.65 2.62*,** Significant at p≤0.05 and p≤0.01, respectivelyPods per plant, grains per plant, 100 grains weight, biological yield, grain yield and harvest index decreased with decreasing water supply (Table 2). Similar result in chickpea was report by Ghassemi-Golezani et al. (2012).Reduction in grain number was due to a decrease in pod formation and an increase in pod abortion (Fang et al., 2009; Ghassemi-Golezani et al.,2012). Irrigation disruption at pod filling can decrease grain filling duration (Ghassemi-Golezani et al., 2009) and photosynthate mobilization to grains, thereby decreasing grain weight (Sadeghipour, 2008).Decreasing grain yield per unit area due to water deficit was attributed to reductions in pods and grains per plant, biological yield and 100 grain weight (Table 2).These results confirm previous field studies with chickpea that water deficit reduces biological and grain yields (Behboudian et al., 2001;Ghassemi-Golezani et al., 2008;Bahavar et al., 2009; Niari-Khamssi et al., 2010, 2011).Silvius et al. (1977) stated that the effects of water stress on soybean yield appeared to be related to limited availability of photosynthate and nitrogen for translocation to developing seed.Azad was a superior cultivar in grains per pod,100 grain weight, plant biomass, grain yield and harvest index, compared with Arman and Jam (Table 2).Azad produced less, but larger grains,leading to higher grain yield per unit area under all irrigation treatments. The superiority of Azad in grain yield was more evident under well-watering than under limited irrigation conditions (Figure 1).Differences between Arman and Jam in grains per pod, 100grains weight and biological yield were not significant.Grains per pod only varied among cultivars and water stress had no significant effect on this trait (Table 2). Therefore,environmental factors had little effect on grains per pod and it is mainly influenced by genotypes. Similar result was reported by Ghassemi-Golezani et al. (2012) for chickpea.Table 2. Means of the grain yield, yield components and harvest index of chickpeafor irrigation treatments and cultivarsTreatment Pods per Plant Grains per pod Grains per plant 100 Grains weight (g)Biologicalyield (g m -2)Grain yield(g m -2)Harvest Index (%)IrrigationI 137.61a1.530a35.04a29.04a518.4a286.2a55.16aI 233.76ab1.499a31.33ab28.37a475.4b258.7b54.36aI 328.36bc1.319a26.81b25.16ab459.3bc240.5c52.36aI 425.80c1.288a23.48b21.59b425.2c175.4d41.21bCultivars Azad 24.26c 1.583a 24.26c 28.18a506.6a 270.3a 52.94a Arman 38.96a1.122b33.34a24.73b446.3b220.3c49.10cJam30.92b1.254b29.90b25.21b456b 230.1b50.28bDifferent letters in each column indicate significant difference at P I 1, I 2, I 3, I 4: Irrigation after 70, 100, 130 and 160 mm evaporation from class A pan,respectively.a b c g cd ef f h cdefh50100150200250300350400I1I2I3I4G r a i n y i e l d (g )Irrigation levelsAzadArmanFigure 1.Mean grain yield of chickpea cultivars under different irrigation treatmentI 1, I 2, I 3, I 4: Irrigation after 70, 100, 130 and 160 mm evaporation from class A pan,respectivelyConclusionWater limitation reduces grain yield in chickpea cultivars due to reductions in grains per plant and grain weight.Pods per plant, grains per plant, 100 grains weight, biological yield, grain yield and harvest index of chickpea can be reduced under water stress, depending on the severity of stress and cultivar. 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Ann Bot. 89(5): 563-570.Robertson MJ, Holland JF. 2004. Production risk of canola in the semi-arid subtropics of Australia .Aust J Agri Res. 55: 525-538.Sadeghipour O. 2008. Effect of withholding irrigation at different growth stages on yield and yield components of mungbean (Vicia radiata L.) varieties. Amer Eur J Agric Environ Sci. 4: 590-94. Saxena NP. 1987. Screening for adaptation to drought: case studies with chickpea and pigeonpea. In: Adaptation of Chickpea and Pigeonpea to Abiotic Stresses. Proceedings of the Consultation Workshop , ICRISAT, Patancheru, India, pp 37–63.Silvius JS, Johnson RR, Peters DB. 1977. Effect of water stress on carbon assimilation and distribution in soybean plants at different stages of development. Crop Sci. 17: 713-716.Turner NC, Wright GC, Siddique KHM. 2001. Adaptation of grain legumes (pulses) to water-limited environments. Adv Agron. 7: 194-23.。

小学上册英语第一单元测验试卷英语试题一、综合题(本题有100小题，每小题1分，共100分.每小题不选、错误，均不给分)1.The ocean is a source of ______ for many organisms.2.In a chemical equation, the products are shown on the _____ side.3.They are having a ______ (party) this weekend.4.The cat is very _______ (可爱).5.What do we call a person who is trained to help sick people?A. NurseB. DoctorC. ParamedicD. All of the above6.My sister loves to watch ______ (鸟) in the garden.7.What is the name of the famous music festival held in California?A. CoachellaB. LollapaloozaC. BonnarooD. GlastonburyA Coachella8.The ______ is very cold. (water)9.The _______ of a balloon can change when it is heated.10.What do we call the science of numbers?A. ChemistryB. PhysicsC. MathematicsD. BiologyC11.My sister is good at __________ (跳舞).12.The ancient Greeks are famous for their _______ and philosophy.13.What is the name of the toy that can spin?A. Yo-yoB. KiteC. BallD. PuzzleA Yo-yo14.The chemical symbol for arsenic is _______.15. A reaction that absorbs heat is called an ______ reaction.16.can Revolution was influenced by Enlightenment ________ (理念). The Amer17.Which body part do you use to hear?A. EyesB. NoseC. EarsD. MouthC18.I like to ______ my friends' birthdays. (celebrate)19.My cat enjoys climbing up on ______ (家具).20.My cat has sharp ______ (爪子).21.The country of Italy is shaped like a __________.22.The ancient Greeks established the concept of ________ (民主).23.Which planet is known as the Red Planet?A. EarthB. MarsC. VenusD. JupiterB24.The __________ (绿色空间) is essential for health.25.We will have _____ (fun/work) at the fair.26.The ______ (植物的生长速度) can vary based on conditions.27.Have you ever seen a _____ (考拉) in Australia?28.What is a common animal found on a farm?A. TigerB. PigC. ElephantD. LionB29.How do you say "mountain" in Spanish?A. MontañaB. MontC. MontagneD. Moutain30.I see a _____ (car/bike) on the road.31.The country known for its fashion is ________ (以时尚闻名的国家是________).32.The Great Red Spot on Jupiter is a permanent ______.33.I wear _____ (shoes/socks) to school.34.The ______ helps with the detection of temperature changes.35.Which animal is known for its long neck?A. ElephantB. GiraffeC. ZebraD. KangarooB36.The chemical formula for ammonium sulfate is _______.37.The solid part of a solution after filtration is called ______.38. A _____ (生态平衡) is essential for a healthy environment.39.ts are __________ (有毒的) and should be handled carefully. Some pla40.I found a _______ (小蛇) in the grass.41.My brother loves to play __________. (篮球)42.What do we call a young kangaroo?A. CalfB. JoeyC. KidD. Pup43. A chemical change can result in a change in ______.44.The _____ (园艺技巧) can enhance your gardening skills.45.The process of making sugar involves _______.46.What is the capital of Norway?A. OsloB. BergenC. StavangerD. Trondheim47.In the garden, we have many ________ (树) and flowers that attract ________ (蜜蜂).48.ts can survive in very ______ (干燥) conditions. Some pla49.The main components of air are nitrogen and _____.50.My favorite season is ______ (春天) because of the flowers.51.What is the name of the famous American author known for "The Grapes of Wrath"?A. John SteinbeckB. Ernest HemingwayC. F. Scott FitzgeraldD. Mark Twain52.The _____ (植物繁荣) occurs in favorable conditions.53.What is the capital of Norway?A. CopenhagenB. StockholmC. OsloD. HelsinkiC54.Liquids have a definite __________ but no fixed shape.55.The chemical formula for glucose is ________.56. A ______ (温暖的天气) encourages plant growth.57.The party is at my ________.58. A frog's tongue is fast and ______ (黏).59.My uncle is a ______. He works with computers.60.I love to explore ________ (国家公园) during vacations.61.He is ___ his homework. (finishing)62.The ______ is important for clean air.63.The book is ________ and interesting.64.What is the name of the famous clock tower in London?A. Big BenB. Eiffel TowerC. Leaning Tower of PisaD. Burj Khalifa65.I like to __________ (动词) with my __________ (玩具名) after school.66.The ______ (老虎) has stripes and is very powerful.67. A thunderstorm can be very ______ (可怕).68.We are going to ___ dinner. (eat)69.The __________ were fierce warriors from Scandinavia. (维京人)70.The antelope is quick on its ____.71.What do we call a type of poetry that tells a story?A. LyricB. EpicC. OdeD. Sonnet72.I like to ______ my grandparents during holidays. (visit)73.Wildflowers grow without ______ (照顾).74.The bird builds a nest in the _______ (鸟在_______中筑巢).75.I like _______ (观察) the stars at night.76.What is the name of the famous ancient city in Peru?A. TenochtitlanB. Machu PicchuC. PetraD. Angkor WatB77.What do you call a group of stars?A. GalaxyB. UniverseC. ConstellationD. Solar SystemC78.The first female aviator to fly solo across the Atlantic was _______ Earhart.79.My teacher is _______ (友好的).80.The ____ is known for its incredible speed and agility.81.My dad enjoys fixing ____ (electronics).82. A telescope makes distant objects appear ______.83.The movie was ______ (really) entertaining.84.What is the longest river in the world?A. NileB. AmazonC. MississippiD. Yangtze85.What is the main ingredient in hummus?A. BeanB. ChickpeaC. LentilD. PeaB86.He is very _____ (善于沟通) in meetings.87. A chemical reaction that absorbs heat is called _______.88.What is the main purpose of the Hubble Space Telescope?A. To study the EarthB. To study the MoonC. To observe distant galaxiesD. To communicate with aliens89.The main use of sulfuric acid is in _____.90.My mom loves to _______ (动词) to relax. 她觉得这个很 _______ (形容词).91.The ancient Romans believed in many _______. (神灵)92.What do you call the action of preparing food for a meal?A. CookingB. BakingC. RoastingD. GrillingA93.What is the capital of the Dominican Republic?A. Santo DomingoB. SantiagoC. Puerto PlataD. La RomanaA94.My cousin is very __________ (活跃的) in school clubs.95.The __________ (历史的多样性) highlights richness.96.My brother loves to play ____.97.My favorite food is ________ (意大利面) with sauce.98.What is the weather like when it rains?A. DryB. WetC. SunnyD. ColdB99.The cake is _____ with candles. (decorated)100.The __________ can reveal patterns in sedimentation and erosion over time.。

ResearchCrop Genetics and Breeding—ReviewAphanomyces euteiches :A Threat to Canadian Field PeaProductionLongfei Wu a ,Kan-Fa Chang b ,Robert L.Conner c ,Stephen Strelkov a ,Rudolph Fredua-Agyeman b ,Sheau-Fang Hwang b ,⇑,David Feindel baDepartment of Agricultural,Food and Nutritional Science,University of Alberta,Edmonton,AB T6G 2P5,Canada bCrop Diversification Center North,Alberta Agriculture and Forestry,Edmonton,AB T5Y 6H3,Canada cAgriculture and Agri-Food Canada,Morden Research and Development Centre,Morden,MB R6M 1Y5,Canadaa r t i c l e i n f o Article history:Received 2February 2018Revised 2May 2018Accepted 8June 2018Available online 17July 2018Keywords:Field peaAphanomyces euteiches Root rotPathogenicity variability Quantitative trait locia b s t r a c tField pea (Pisum sativum var. arvense L.) is an important legume crop around the world. It produces grains with high protein content and can improve the amount of available nitrogen in the soil. Aphanomyces root rot (ARR), caused by the soil-borne oomycete Aphanomyces euteiches D rechs. (A. euteiches ), is a major threat to pea production in many pea-growing regions including Canada; it can cause severe root damage, wilting, and considerable yield losses under wet soil conditions. Traditional disease manage-ment strategies, such as crop rotations and seed treatments, cannot fully prevent ARR under conditions conducive for the disease, due to the longevity of the pathogen oospores, which can infect field pea plants at any growth stage. The development of pea cultivars with partial resistance or tolerance to ARR may be a promising approach to analyze the variability and physiologic specialization of A. euteiches in field pea and to improve the management of this disease. As such, the detection of quantitative trait loci (QTL) for resistance is essential to field pea-breeding programs. In this paper, the pathogenic characteristics of A. euteiches are reviewed along with various ARR management strategies and the QTL associated with partial resistance to ARR.Ó 2018 THE AUTHORS. Published by Elsevier LTD on behalf of Chinese Academy of Engineering and Higher Education Press Limited Company. This is an open access article under the CC BY-NC-ND license1.IntroductionField pea (Pisum sativum var.arvense L.),along with common bean (Phaseolus vulgaris L.),faba bean (Vicia faba L.),soybean (Gly-cine max (L.)Merr.),chickpea (Cicer arietinum L.),and lentil (Lens culinaris Medik.),belongs to the family Fabaceae.The interaction between pea and Rhizobium bacteria leads to the formation of root nodules,which enable pea roots to fix nitrogen directly from the atmosphere,thereby benefiting production of the pea and subse-quent crops.Pea seeds have a high protein content,are rich in starch,dietary fiber,vitamins,minerals,and polyphenols,and provide a protein-rich food source for both humans and livestock [1].Garden peas are processed for canning or freezing by the food industry,while field pea is one of the most widely cultivated crops for human consumption and livestock feed on the Canadian Prairies,with an export market value of 1.2billion CAD in 2016[2].World grain pea production peaked in 1990at 1.66Â107t;by 2014,it had decreased by 5.5Â106t due to a reduction in pea cultivation in Europe [3,4].Since then,European pea cultivation has once again increased as a result of new Common Agricultural Policy (CAP)greening measures [5].Pea cultivation was introduced to Canada more than a century ago [6],first in limited areas in East-ern Canada in the late 1800s.In 1985,there were only 8.05Â104hm 2of field peas seeded in Canada.There was a significant increase in pea cultivation in North America (i.e.,Canada and the United States)starting in the 1990s.Because of its adaptation to cool climates and its nutritional value for human and livestock consumption,field pea has become increasingly popular as a cash crop to meet demand for the export market in Canada.By 2014,Canada had become the largest field pea producer in the world,which now accounts for 21%of global production [4].At present,Aphanomyces root rot (ARR)is one of the major limitations to pea production worldwide.This disease is caused by Aphanomyces euteiches Drechs.(A.euteiches ),which is distin-guished from most other soil-borne pathogens by the formation of thick-walled oospores [7].It can cause severe root damage at all growth stages of its host.The longevity of A.euteiches oospores,⇑Corresponding author.E-mail address:sheau-fang.hwang@gov.ab.ca (S.-F.Hwang).combined with the absence of fully resistant pea genotypes, makes the management of ARR difficult.This review describes pathogenic variability in A.euteiches,and the application of tradi-tional management strategies and partial resistance to control ARR infield pea.Pea root rot complex(PRRC)has been reported to be a serious problem infield pea production in Canada[8]and worldwide[9]. When root rot is severe,yield reduction can be as high as70% [10,11].A number of soil-borne pathogens have been reported to be involved in PRRC,including A.euteiches,Fusarium spp., Pythium spp.,Phytophthora spp.,and Rhizoctonia solani Kühn [12–15].Fusarium solani(Mart.)Sacc.(F.solani)was the most common causal agent of pea root rot worldwide[16].In addition to Fusarium spp.,A.euteiches has been reported to occur in certain countries in North America and Europe,as well as in Japan,Aus-tralia,and New Zealand[17].Yield losses due to infection by Pythium ultimum and A.euteiches were reported in the United States[18,19].An estimated loss of2.4Â104t offield pea caused by PRRC occurred in Southern Ontario in1983[10].F.avenaceum (Corda ex.Fr.)Sacc.was reported to be the main cause of Fusarium root rot in pea crops in Alberta and Manitoba,account-ing for as much as80%of the isolates collected fromfield samples [20,21].Hwang and Chang[22]reported that PRRC was prevalent in the Canadian province of Alberta.Tu[23]noted that the amount of damage tofield pea caused by Fusarium spp.is influ-enced by soil compaction,temperature,and moisture levels, which may also impact the relative prevalence of F.solani[16] and F.avenaceum[20].Infection by PRRC is associated with seed decay,damping-off, seedling blight,root rot,and wilt;however,the identity of the causal organisms cannot be determined solely by examining the symptoms[24].This increases the difficulty of predicting and controlling pea root rot in western Canada and elsewhere.Direct invasion of the seeds by any of the fungi involved in the PRRC complex,but most often by Pythium spp.,is usually the cause of seed decay[25,26],which results in a soft,mushy appearance of the seeds and in their rapid deterioration.Damping-off and seedling blight reduce seedling emergence and plant density, limit pea growth,delay canopy closure,and therefore increase weed competition.All of these factors may cause yield reductions [27].Root rot also restricts the transport of water and nutrients in infected roots,and reduces canopy density and the uniformity of crop maturity[28].Root rot may also destroy rhizobial nodules,leading to a reduction in nitrogenfixation in the roots[29].2.ARR caused by A.euteichesA.euteiches belongs to the class Oomycota(oomycetes),which comprises a large group of eukaryotes that includes the most diverse,important,and earliest-known water molds[30].Oomy-cetes resemble fungi in morphology(i.e.,mycelial growth)and many are parasitic.Unlike true fungi,oomycetes produce motile, biflagellate zoospores[30,31].Cytological and biochemical studies indicate additional differences that distinguish oomycetes from fungi[32–34].At the vegetative stage,the mycelia of oomycetes consist of a coenocytic thallus that remains diploid[33](Fig.1 (a)).The formation of haploid nuclei only occurs through meiosis for gamete formation.At this stage,fungal thalli produce septate cells,each of which carry one haploid nucleus.In addition,in con-trast to fungal cell walls,which are composed mainly of chitin (acetylglucosamine polymers),along with glucans,polysaccha-rides,mucopolysaccharides,waxes,and pigments,the cell walls of oomycetes contain cellulose,b-glucans and hydroxyproline, but no chitin[35].The genus Aphanomyces includes a number of water molds that are saprophytes or parasites offish,crayfish,and plants[36].There are about40described species of Aphanomyces[37].Most have a wide range of hosts belonging to different families,although there are a few exceptions such as A.cochlioides Drechs.,which only affects sugar beet(Beta vulgaris L.)[37]and A.iridis Ichitani et Tak.Kodama,which only affects iris(Iris spp.)[36].Although A. euteiches has a broad host range within the family Fabaceae,it causes the greatest economic damage to pea and lentil crops [38–40].This parasite has been isolated from pea,alfalfa(Medicago sativa L.),snap and red kidney bean(Proteus vulgaris L.),faba bean, red clover(Trifolium pratense L.),white clover(Trifolium repens L.), lentil,and several weed species[38,41].Nevertheless,its occur-rence and degree of pathogenicity may differ from one host to another.Pea-infecting strains and alfalfa-infecting strains of A. euteiches from the United States and France have been identified, and some strains can infect both pea and alfalfa[39,42,43].Papavi-zas and Ayers[38]reported that infection by A.euteiches caused large economic losses in pea and alfalfa crops in North America and Europe.The wide host range of A.euteiches,combined with its long-lived oospores,makes the management of ARR with crop rotation difficult.Since it wasfirst described by Jones and Drechsler[44]and extensively reviewed by Papavizas and Ayers[38], A.euteiches has been considered to be one of the most damaging soil-borne pathogens of legumes.At present,A.euteiches has been reported in all of the main pea cultivation regions of the world[17].In France,it affects pea crops in the northern regions of the country [41].In North America,it causes severe yield losses in the Great Lakes region in both Canada and the United States,as well as in the Northeastern[25]and the Pacific Northwest[45]regions of the United States.A high incidence and severity of pea root rot caused by A.euteiches was recently reported in Alberta[46].Yield losses caused by this parasite can be as high as86%in heavily infested peafields[47].2.1.Favorable conditionsSymptoms of ARR can develop within7–14days afterfirst infection,depending on soil moisture,temperature,and the concentration of oospores[38,47].High inoculum densities of A.euteiches increase the incidence and severity of ARR.Chan and Close[7]observed a positive correlation between the num-ber of oospores per100g of soil and root rot severity.Oospores can form germ tubes,which directly penetrate the cortex of the pea roots.Soil moisture levels influence the formation of sporangia and the release of zoospores,and allow theflagellated zoospores to travel to the plant roots in the moisturefilms sur-rounding soil particles[48,49].Zoospore infection also facilitates the leakage of metabolites from pea roots[50],which stimulates the germination of oospores and attracts more zoospores[9]. High rainfall favors ARR outbreaks,and only a short period is required for the completion of the infection process by A.euteiches[25].The minimum level of soil moisture needed for the initiation of ARR is about30%of the water-holding capacity of the soil[51,52].ARR may occur over the same wide soil-temperature range that is conducive for pea growth[25];however,the optimal tempera-tures for infection are about16°C,and20–28°C for disease devel-opment[53,54].High temperatures may accelerate pea root decay following infection by A.euteiches,since severe infection further limits water and nutrient movement withinfield peas[55].Gaulin et al.[56]reported that A.euteiches can infect legume hosts at any growth stage,while others have suggested that infection occurs most commonly at the seedling stage[57,58].L.Wu et al./Engineering4(2018)542–5515432.2.Life-cycle of A.euteichesThe life-cycle of A.euteiches includes both asexual and sexual stages,which allow for its efficient dissemination via zoospores and its survival as oospores during harsh winter conditions [41].The oospores are 18–25l m in diameter,have a thick protective wall,and contain energy reserves in the form of a large oil globule [9,38].They can survive in the soil for over ten years [47]and may be spread over long distances by the transportation of infested soil and/or infected plant residue [38].When adjacent to pea roots,the oospores germinate under con-ducive temperature and moisture conditions,and form either a mycelium or a zoosporangium.The zoosporangium,which forms as long tubes on the oospores,may release a large number of zoos-pores [59].The biflagellate motile zoospores are attracted to a suit-able host by chemical signals in the root exudates [60],and encyst within minutes on the rhizoplane (Fig.1(a)).The resulting cysts germinate and penetrate the host cortical cells within hours [38].Once an infection site has been established,coenocytic hyphae develop rapidly in the intercellular spaces of the host root tissue and the pathogen spreads from the roots to the stem (hypocotyls and epicotyls),eventually colonizing the entire root system.The infected roots become soft and water-soaked,and take on a honey-brown or blackish-brown coloration,which turns orange-brown or blackish-brown during the later stages of disease devel-opment (Fig.2(b)and (c)).Within a few days of infection,A.euteiches may enter its sexual stage with the formation and fusion of haploid antheridia and oogonia [59](Fig.1(a)and (d)).Subsequently,thick-walled oos-pores are formed,which ensure the long-term survival of the pathogen and serve as the primary source of inoculum for new infections in subsequent years [61](Fig.1(e)).The parasite may progress from first infection of the roots to formation of oospores in as few as 10–14days [62].The translocation of water and nutrients within infected plants can be restricted by severe root rot [63](Fig.2(a)and (f)).Infectedplants may become stunted during the early growth stages and then start to wilt,resulting in premature death [64](Fig.2(d)).Moreover,ARR may severely delay pea maturity,reduce pod size and seed number,and decrease seed quality [64](Fig.2(e)and (g)).2.3.Variability and physiological specialization in A.euteiches Information on pathogenic variability and physiologic speciali-zation in A.euteiches is limited.Given the absence of completely resistant or immune pea genotypes,it is difficult to create a differ-ential set to distinguish races,and the races identified by the limited differential genotypes may exhibit atypism [38].Nonethe-less,differences among isolates have been detected based on zoos-pore and oospore size,the time required for sporulation and the ability to produce zoospores,growth rate on culture media,and the production of pectinolytic and cellulolytic enzymes [38].Physiological specialization in A.euteiches was first examined by King and Bissonnette [65],who indicated that isolates of the parasite differed in their virulence patterns on various pea culti-vars in Minnesota.Carlson [55]tested ten isolates of A.euteiches ,which were isolated from infested soil from Minnesota,New York,and Wisconsin,by inoculating the root tips of tolerant and suscep-tible pea cultivars,and reported considerable differences in the ability of the isolates to infect plants and produce oospores.Vari-able virulence and growth characteristics on culture media were also observed among seven single-zoospore isolates obtained from germinated oospores [48].Beute and Lockwood [66]inoculated six differential cultivars with 15A.euteiches single-zoospore isolates,and identified two races based on their virulence on those pea cul-tivars (Table 1)[66–70].The two races displayed a different disease reaction pattern on the six pea cultivars,based on disease severity.Employing the same differentials as Beute and Lockwood [66],Sundheim and Wiggen [67]confirmed the existence of four physiological races of A.euteiches in a collection of 14isolates from four counties in Norway.Sundheim and Wiggen [67]evaluated resistance by counting the number of dead plants ten daysafterFig.1.Structures of A.euteiches .(a)Coenocytic hyphae with no septa;(b)encysted zoospore losing both flagella;(c)oogonium of A.euteiches ;(d)antheridium and oogonium of A.euteiches during the sexual stage;(e)thick-walled oospore for survival in unfavorable conditions.544L.Wu et al./Engineering 4(2018)542–551inoculation.The method of race identification described by Sund-heim and Wiggen [67]was questioned by Manning and Menzies [68],who suggested that the irreversibly wilted plants 10d after inoculation could not fully reflect the virulence spectrum of A.euteiches.The inconsistencies between these studies underscore the difficulties associated with race identification in A.euteiches .Malvick and Percich [69]developed a new differential set (con-sisting of the pea genotypes MN313,MN314,90-2079,WI-8904,Little Marvel,Saranac,and Early Gallatin)to evaluate pathogenic diversity among 114A.euteiches isolates from the United States (Table 1),and also examined genetic variation via random ampli-fied polymorphic DNA (RAPD)analysis.All isolates were patho-genic on one or more pea cultivars,and 18%and 14%were pathogenic on alfalfa (Saranac)and bean (Early Gallatin),respec-tively.Malvick and Percich [71]concluded that A.euteiches popula-tions were genotypically (based on the RAPD analysis)and phenotypically variable in the central and western United States.In a subsequent study,four virulence groups were identified,in which a disease severity of greater than 3.0(i.e.,>90%of the roots brown or yellow,but no symptoms present on the epicotyl or hypocotyl)was used as the threshold for a clear pathogenic inter-action [72].Fig.2.Symptoms of pea ARR caused by A.euteiches.(a)Yellowing and stunting of pea stems in the field;(b)comparison of healthy (left)and diseased (right)plants;(c)discoloration and water-soaking of diseased pea rootlets;(d)wilted pea plants in the field near harvest;(e)comparison of healthy (left)and diseased (right)pods;(f)Seedling blight in a low area of a field after heavy rainfall;(g)bleaching of leaflets and premature ripening of the pod.Table 1Studies on pathogenic variability and physiological specialization in A.euteiches isolates from pea using various sets of differential pea genotypes.MethodDifferential genotypesIdentified race/virulence type Isolate region Ref.Race identification Miragreen;Early Perfection;PI 175232;PI 169604;PI 180693;PI 166159Races 1and 2United States [66]Race identification Miragreen;Early Perfection;PI 175232;PI 169604;PI 180693;PI 166159Races 1–4Norway [67]Race identification Miragreen;Early Perfection;PI 175232;PI 169604;PI 180693;PI 166159Race 5New Zealand [68]Pathogenic variability MN313;MN314;90-2079;WI-8904;Little Marvel;Saranac;Early GallatinVirulence groups I–IV United States[69]Pathogenic variabilityBaccara;Capella;90-2131;MN313;552;PI 180693Virulence types I–XINorth America,Europe,and Oceania[70]L.Wu et al./Engineering 4(2018)542–551545Later,Wicker and Rouxel[70]examined109isolates of A.eute-iches from France,Denmark,Sweden,Norway,the United States, Canada,and New Zealand on another differential set(Baccara, Capella,90-2131,MN313,552,and PI180693)and identified11 virulence types(Table1).In that study,the isolates belonging to virulence type I,which caused severe ARR symptoms on all of the differentials,were predominant and the most aggressive. Wicker and Rouxel[70]also calculated a disease severity index (DSI)based on the mean of the individual disease severity ratings (0–5),and regarded a DSI<1as indicative of resistance.In a later study,Wicker et al.[17]indicated that the differential pea genotypes used by Malvick and Percich[69]were inadequate to distinguish French strains of A.euteiches.To more accurately evaluate the virulence of the pathogen from different countries, Wicker et al.[17]evaluated33pea lines and thefive differentials originally described by Wicker and Rouxel[70].The resistance detected in the differential pea genotypes in these studies has been used in the development of commercial pea cultivars with ARR resistance[17].Wu[73]conducted greenhouse screening of eight A.euteiches isolates from Alberta and Manitoba on the same differ-ential set as Wicker and Rouxel[70].Most strains were classified as virulence type I,although one strain was identified as virulence type III.Further testing of additional isolates from other Canadian regions with more differential breeding lines is still needed in order to better understand physiological specialization in this pathogen.2.4.Isolation of A.euteichesThe isolation of A.euteiches strains is difficult.Pea root and root-let samples easily slough off infected tissue into the soil[74]. Numerous fungi also interfere with the isolation of A.euteiches [75].Manning and Menzies[75]successfully isolated A.euteiches on potato dextrose agar(PDA)plates using soil baiting.To increase the isolation success rate,metalaxyl-benomyl-vancomycin(MBV) [25]medium has been widely used to isolate A.euteiches,since it suppresses the growth of Pythium spp.,Phytophthora spp.,and most bacteria.Wu[73]used both direct isolation from infected root samples and soil baiting.For direct isolation,root and soil samples were collected at2–3weeks after seeding,when roots were not yet com-pletely infected by PRRC.The soil samples were later used for pathogen baiting with susceptible pea cultivars[68].The tips were cut from water-soaked pea roots and examined under a micro-scope for the presence of oospores.The root tips were surface-sterilized in1%NaClO for30s,rinsed in sterilized water,and plated on MBV medium.However,A.euteiches was detected in <0.1%of the samples,based on the results of a real-time poly-merase chain reaction(PCR)assay described by Vandemark et al.[76].2.5.Inoculation methodsZoospores are the most common form of A.euteiches inoculum employed in greenhouse experiments[17,43,70,77–83],while oospore-based inoculum has also been used in both greenhouse andfield trials[38,73].The zoospore-based inoculum has been used widely for the detection of partial resistance to ARR infield pea[77–83].Zoospore inoculum is usually produced in a broth made from corn kernels,maltose-peptone,and oat(Avena sativa L.),or from pea seeds suspended in water,which are inoculated with A.euteiches and incubated for5–7d in the dark at room tem-perature[84].The resulting mycelial mats are placed in a mineral salt solution and aerated overnight to produce a zoospore suspen-sion of3Â105–8Â105zoospores per milliliter.The zoospores are usually used to precisely inoculate seven-day-old pea seedlings,before the seedlings are transplanted into pots in a green-house,with a determined zoospore concentration,thus eliminating the undesirable effect of nutrient substances in the media.Oospore inocula have been produced on autoclaved rolled oats with sand,cornmeal,and water.This substrate is inoculated with A.euteiches and incubated in the dark for30days at room temper-ature[38].Wu[73]modified this method by replacing cornmeal with oat grain.The grain-sand inocula were often used infield trials,as well as in greenhouse experiments,which need intensely infected disease conditions.Thygesen et al.[85]incubated A.euteiches in an oatmeal broth at20°C in the dark for4–8weeks; the broth was homogenized in a blender and thenfiltered and washed with a mineral salt solution.The suspension was mixed with sterilized sand,dried at room temperature,and stored at 4°C.The oospore suspension also provides a precise inoculation for both the pea seedlings and pea seeds,which could continuously release zoospores in a greenhouse experiment.3.Traditional disease managementARR has been recognized as one of the most damaging root diseases offield pea for almost a century[86].The options for management of this disease,however,are limited.Pea cultivars completely resistant to ARR are not available[25,87]and only partial resistance and/or tolerance has been reported in several studies[80,81,88].Some studies have focused on the efficacy of fungicidal seed treatments at the seedling stage,which have been shown to improve plant health[89,90].At present,the most widely recommended method to manage ARR is avoidance via crop rotation and evaluation of infestation levels in thefield prior to seeding[91].Biological control,including seed and soil treatments,has also shown promise at the experimental stage [9,92].3.1.Cultural practicesCrop rotation is one of the oldest and most fundamental meth-ods to manage diseases caused by soil-borne pathogens,although its effectiveness directly coincides with the length of rotation [93].A positive relationship exists between the frequency of pea crops and root rot severity[86].Rotation with non-host crops can therefore reduce the density of A.euteiches in the soil and thereby reduce the severity of ARR.Long-term crop rotations can reduce A.euteiches inoculum density in the soil,but they are not always effective in eradicating the disease[94].Nonetheless,the practicality and effectiveness of crop rotation as a method to manage ARR is questionable,because the oospores can survive for10–15years in the absence of a host[95].Furthermore,many alternative hosts,including chickpea,lentil,alfalfa,and weedy species,can sustain inoculum levels in the absence of pea[38]. Hossain et al.[96]recommended a crop rotation interval of6–8 years.Williams-Woodward et al.[97]examined the effect of oats as a rotation crop with pea,and observed that oat residues improved ARR suppression.Therefore,increased crop diversity may represent a good long-term strategy for disease management [98].Soil conditions can be suppressive or conducive to ARR[99]. Heyman et al.[100]observed a strong negative correlation between calcium concentration and disease development,which indicated that free calcium was a major variable in the degree of soil suppression of A.euteiches.Thisfinding led to the suggestion that calcium might play a role in the inhibition of zoospore produc-tion from the oospores[100].Residues from two plant families,the Brassicaceae—such as cabbage(Brassica oleracea L.),mustard(Brassica nigra L.),turnip546L.Wu et al./Engineering4(2018)542–551(Brassica rapa L.),and rapeseed(Brassica napus)[7,8,63,101–103]—and the Poaceae—such as oats,rye(Secale cereale L.),and maize (Zea mays L.)[8,97,104–108]—can reduce the severity of ARR.Soil compaction can exacerbate the development of ARR, causing pea yield losses as high as63%[107].In contrast,the yield of pea plots covered with oat shoots and residues increased by48% relative to plots planted without residues,suggesting that oat residues provide a promising method for the cultural control of pea ARR.Allmaras et al.[87]confirmed the effect of oats as a pre-crop in the suppression of ARR,and pointed out that excessive compaction related to tillage and traffic management may impair internal soil drainage and thus reduce the effectiveness of oat residues in controlling the disease.Field indexing by sampling soils to determine the A.euteiches inoculum potential can be an effective method to manage ARR of field pea prior to seeding.Studies have identified and distinguished heavily infestedfields from non-infested or lightly infestedfields under greenhouse conditions[109,110],and this method of prior land selection can be an economical and dependable practice for avoiding ARR[111].Real-time PCR analysis has also been used to measure populations of A.euteiches infield soil.Vandemark et al. [112]and Armstrong-Cho et al.[113]demonstrated that a positive relationship existed between ARR severity and the DNA concentra-tion of several isolates of A.euteiches in pea roots.3.2.Disease prediction and molecular detection of A.euteichesMolecular markers are useful tools for the identification of fungal and oomycete plant pathogens.The testing of soil or plant samples for the presence of A.euteiches DNA by PCR analysis with species-specific primers has been widely used[76].Chatterton et al.[46]and Armstrong-Cho et al.[113]detected A.euteiches in peafields in Alberta and Saskatchewan,respectively,based on a PCR assay.A number of commercial kits have also been used to identify A.euteiches efficiently[46,76,112].Nonetheless,informa-tion on the use of molecular markers for the identification of specific races or pathotypes of A.euteiches is still limited and preliminary.Malvick and Percich[69]conducted RAPD analyses to evaluate genotypic diversity among strains of A.euteiches in the United States,but none of the76polymorphic RAPD markers were associ-ated with pathogenic variation.In another study,the same researchers successfully distinguished one major group and two closely related minor groups in a collection of114isolates from four locations in the United States,based on a pathogenicity test offive pea genotypes and RAPD analysis[69].Sauvage et al. [111]used two sets of markers,136F/136R and11F/280R, to amplify different-sized PCR products from105isolates of A.euteiches.They demonstrated a close relationship between the quantity of soil inoculum and ARR severity.3.3.Seed and soil treatmentsCertain soil fungicides for ARR control are prohibited in some regions,including much of Europe[96].In addition,the cost and adverse environmental effects of treating the soil with chemicals makes this approach impractical and undesirable across the broad area over which pea crops are grown[114,115].Seed-coating treat-ments such as hymexazol can effectively improve seedling emer-gence[116].However,Tu[106]pointed out the limitations in the control of pea root rot using Captan(N-trichloromethylthio-4-cyclohexene-1,2-dicarboximide).Furthermore,A.euteiches is resis-tant to some of the fungicides that are registered for the control of other oomycetes.For example,metalaxyl is active against most oomycetes,but not against Aphanomyces.It is the main ingredient of the selective medium used to isolate A.euteiches[25].Neither the systemic acylalanine-type of oomycete fungicides,such as met-alaxyl,nor the ethyl phosphonates,such as fosetyl-Al or cymoxanil, effectively control ARR[117].Some chemicals effectively suppress A.euteiches under controlled conditions,but have limited benefi-cial effects infield trials[89,90].Tachigaren(hydroxyisoxazole or hymexazol)was reported to reduce root rot severity and increase yield under experimentalfield conditions[116];this compound is available commercially in Japan for the control of the Pythium and Aphanomyces diseases of sugar beets[117].The effectiveness of Tachigaren for the control of ARR,however,was variable in other studies[118–120].A recent study determined that Intego Solo (ethaboxam)(Valent,Guelph,ON,Canada),BAS516F,and BAS 720F reduced disease severity under greenhouse conditions,but not underfield conditions[73].At present,ethaboxam is the only fungicide registered for Pythium root rot control and the suppres-sion of seed rot caused by Phytophthora spp.and Aphanomyces spp.in legumes in Canada.3.4.Biological controlAntagonistic microorganisms applied to the seeds or soil may help to protect pea plants from infection by fungal and oomycete pathogens.The spores of arbuscular mycorrhizal(AM)fungi and some spore-forming bacteria,which were applied as seed coatings to control ARR in peafields,significantly suppressed the develop-ment of ARR in afield trial[121].The application of isothiocyanate, a compound produced by members of the Brassicaceae in shoot tis-sues,has also been shown to have potential for the management of ARR due to its toxic effects on A.euteiches under controlled condi-tions[96].Biocontrol and fungicide treatments are often integrated into seed treatments.Recent studies have demonstrated that some fun-gal and bacterial strains,such as Gliocladium roseum(Clonostachys rosea(Link)Schroers),Pseudomonasfluorescens(Flügge)Migula, and species involved in the Burkholderia cepacia(Palleroni and Holmes)Yabuuchi et plex,which are formulated for seed coat application in combination with a fungicide,improved seed-ling emergence infields infested with A.euteiches to a greater extent than treatments in which only a fungicide was applied [17,18,90].Xue[90]evaluated a seed treatment consisting of the fungal strain ACM941(Clonostachys rosea)and a fungicide(Thiram 75WP(thiram)or Apron FL(metalaxyl)),and found that a seed coating with ACM941+fungicide improved pea seed germination in an A.euteiches-infestedfield.AM fungi have also been proven to increase the seedling emergence of peas when inoculated with A.euteiches in greenhouse experiments,but they were not always effective in thefield[85,122].Several studies indicated that solar-ization was effective for the control of pea root rot in temperate regions,when used in combination with green manure crops,lower dosages of chemicals,or biological control organisms[123,124]. 4.Genetic resistance to A.euteiches4.1.Partial resistance to ARRGenetic resistance to ARR infield pea could be the most economical and effective strategy for managing this disease.A number of pea-breeding lines with partial resistance or tolerance to ARR have been developed,and are used to prevent yield losses in some pea-producing regions[78,79,88,125].Some differential pea genotypes,such as Capella,MN144,MN313,MN314, 90-2131,90-2079,552,and PI180693,have been reported to be partially resistant to certain races of A.euteiches[17,72,125].The differentials PI180693and552have drawn considerable attention due to their high level of stable partial resistance to ARR[17,126].L.Wu et al./Engineering4(2018)542–551547。

我爱吃汉堡的作文英语Here is an English essay on the topic "I Love to Eat Hamburgers" with more than 1000 words, as requested:I have always been a big fan of hamburgers ever since I was a child. There is something about the combination of a soft bun, juicy patty, and flavorful toppings that just speaks to my taste buds. Whether I'm enjoying a classic cheeseburger or getting a little adventurous with specialty toppings, a good hamburger is one of my all-time favorite foods.One of the things I love most about hamburgers is the sheer variety that exists. You can find them served in fast food joints, gourmet burger restaurants, and even high-end eateries. The classic hamburger with lettuce, tomato, onion, and pickles is a timeless favorite, but the possibilities for customization are endless. Adding cheese, bacon, mushrooms, avocado, or even a fried egg can transform a basic burger into something truly special.Beyond the toppings, the actual patty itself can also vary tremendously. Ground beef is the most common, but you can also find burgers made from turkey, chicken, bison, or even veggie-basedpatties. The level of doneness is another point of customization, with some people preferring their burgers well-done while others enjoy a nice pink center. The bun can also come in a variety of styles, from fluffy sesame seed buns to sturdy pretzel buns and even lettuce wraps for those looking to cut down on carbs.Hamburgers also have a long and storied history that adds to their appeal. While the exact origins are debated, it's believed that the modern hamburger as we know it today emerged in the late 19th or early 20th century. Numerous cities and towns across America have laid claim to inventing the burger, but one thing is certain – it has become an iconic American food that is beloved around the world.What I find particularly fascinating about the hamburger is how it has evolved and adapted to different cultures and cuisines. In the United States, the burger is a staple of diner and fast food menus, often served with fries and a milkshake. But in other parts of the world, you'll find hamburgers that incorporate local flavors and ingredients. In Japan, for example, you might find a burger topped with teriyaki sauce and pickled ginger, while in India, a vegetarian version made with spiced chickpea patties is common.Personally, I love exploring the different variations of hamburgers that exist. I'm always eager to try new and creative takes on this classic dish, whether it's a burger topped with peanut butter andbacon or one that features a blend of beef and chorizo. I find that each new burger I try offers a unique flavor profile and cooking technique that keeps me coming back for more.Beyond the taste, I also really enjoy the social and cultural aspects of hamburgers. They are a quintessential food for gatherings, whether it's a backyard barbecue, a tailgating party, or a casual dinner out with friends. There's something about biting into a juicy burger that just seems to bring people together and create a sense of shared enjoyment.I also love how hamburgers have become a symbol of American culture and cuisine. They are a staple at county fairs, state fairs, and community festivals, where people come together to indulge in this beloved food. Hamburgers have even become a source of national pride, with different regions and states laying claim to having the "best" burgers in the country.At the end of the day, I think my love of hamburgers comes down to the simple pleasure of enjoying a delicious and satisfying meal. There's just something about that first bite of a perfectly cooked patty, with the flavors of the toppings and bun all coming together in perfect harmony. It's a taste that never gets old, and one that I will continue to seek out and savor for years to come.Whether I'm grabbing a quick lunch at a fast-food joint or sitting down for a gourmet burger experience, I always approach the experience with the same level of excitement and anticipation. I love the ritual of carefully constructing my ideal burger, adding just the right amount of condiments and toppings to create the perfect flavor balance. And when I take that first bite, it's like a little piece of heaven on earth.Of course, my love of hamburgers isn't without its occasional downsides. I'm well aware of the health concerns that can come with consuming too many burgers, particularly those from fast-food chains that use lower-quality ingredients. But I try to keep things in moderation and seek out healthier, more sustainable options when I can.Overall, I believe that a good hamburger is one of life's simple pleasures that should be celebrated and enjoyed. It's a food that has the power to bring people together, spark nostalgia and fond memories, and simply provide a delicious and satisfying eating experience. And for me, that's more than enough reason to keep coming back for more.。

Insects are a class of creatures that have fascinated humans for centuries due to their incredible diversity,unique behaviors,and vital roles in ecosystems.Here is an English essay about insects,exploring their characteristics,importance,and some of the most common species.The Marvel of Insects:A World of Tiny GiantsInsects are the most diverse group of animals on our planet,with over a million described species and many more yet to be discovered.They belong to the class Insecta within the phylum Arthropoda,characterized by a chitinous exoskeleton,a threepart body head, thorax,and abdomen,three pairs of jointed legs,compound eyes,and one pair of antennae.Characteristics of Insects1.Exoskeleton:Insects possess a hard,protective exoskeleton made of chitin,which provides structural support and protection from predators and environmental factors.2.Metamorphosis:Many insects undergo metamorphosis,a process of development that includes four distinct life stages:egg,larva,pupa,and adult.This allows for drastic changes in form and function as they grow.3.Reproduction:Insects reproduce at an astonishing rate,with many species laying hundreds or even thousands of eggs at a time,ensuring the survival of their species.4.Diversity:Insects are incredibly diverse in size,shape,and color,ranging from the tiny fairyfly to the large,colorful butterflies and beetles.Importance of Insects1.Pollination:Many insects,particularly bees,butterflies,and moths,play a crucial role in pollinating plants,which is essential for the production of fruits,vegetables,and nuts.2.Decomposition:Insects such as beetles and flies are vital in breaking down dead organic matter,recycling nutrients back into the ecosystem.3.Food Source:Insects are a primary food source for many animals,including birds, reptiles,and other insects.4.Biological Control:Some insects,like ladybugs and praying mantises,are natural predators of pests,helping to control populations of harmful insects in agriculture.Common Insect Species1.Butterflies and Moths Lepidoptera:Known for their beautiful wings and patterns,they are important pollinators and serve as a food source for many animals.2.Beetles Coleoptera:With the largest number of species,beetles are incredibly diverse, from the small ladybugs to the large,shiny scarabs.3.Ants,Bees,and Wasps Hymenoptera:These social insects are known for their complex colonies and roles in pollination and pest control.4.Flies Diptera:Although many species are considered pests,some,like the hoverfly,are beneficial pollinators.5.Dragonflies and Damselflies Odonata:These agile fliers are predators of other insects and are important for controlling mosquito populations.Conservation and InsectsInsects face numerous threats,including habitat loss,pesticide use,and climate change.It is crucial to protect their habitats and reduce the use of harmful chemicals to ensure the survival of these essential creatures.ConclusionInsects are not just a part of nature they are the backbone of many ecosystems.Their survival is intertwined with ours,and understanding their importance can lead to better stewardship of our environment.As we continue to explore the world of insects,we uncover the intricate connections that bind us all in the web of life.This essay provides a comprehensive overview of insects,their characteristics,ecological importance,common species,and the need for conservation efforts.It is a testament to the significance of these tiny creatures in the grand scheme of life on Earth.。

作物学报ACTA AGRONOMICA SINICA 2009, 35(12): 2180−2186 /zwxb/ ISSN 0496-3490; CODEN TSHPA9E-mail: xbzw@DOI: 10.3724/SP.J.1006.2009.02180鹰嘴豆锌指蛋白基因ZF1的克隆及表达分析陈晨1彭辉1高文瑞1石庆华2张桦2张巨松2李建贵2 麻浩1,*1 南京农业大学作物遗传与种质创新国家重点实验室 / 南京农业大学大豆研究所, 江苏南京210095; 2新疆农业大学农业生物技术重点实验室, 新疆乌鲁木齐830052摘要: 利用一段从PEG胁迫的鹰嘴豆幼苗叶片所构建的cDNA文库中得到的EST序列, 通过3′RACE方法克隆到一个鹰嘴豆C2H2型锌指蛋白基因ZF1, 该基因不含内含子, 编码一条244个氨基酸残基的多肽, 含有两个典型的Cys2/His2锌指结构。

其氨基酸序列含有一个可能的核定位型号, 农杆菌介导的洋葱表皮细胞GFP瞬时表达实验表明,ZF1蛋白位于细胞核内。

半定量RT-PCR分析表明, ZF1在鹰嘴豆的根、茎、叶、花、幼荚和幼胚中均有表达, 在茎和叶中表达较弱, 为组成型转录因子。

半定量RT-PCR和实时荧光定量PCR检测结果显示, ZF1不但受高温及干旱诱导, 而且还受6-苄基腺嘌呤(6-BA)、脱落酸(ABA)、乙烯利(Et)、赤霉素(GA3)、吲哚-3-乙酸(IAA)、茉莉酸甲酯(MeJA)、水杨酸(SA)和氧胁迫诱导。

这些结果表明, ZF1基因可能作为一个核调控因子参与植物的生长代谢以及多种生物与非生物胁迫的应答。

关键词: 鹰嘴豆; 锌指蛋白; 基因克隆; 胁迫; 表达分析Cloning and Expression of Zinc Finger Protein Gene ZF1 in Chickpea (Cicer arietinum L.)CHEN Chen1, PENG Hui1, GAO Wen-Rui1, SHI Qing-Hua2, ZHANG Hua2, ZHANG Ju-Song2, LI Jiang-Gui2, and MA Hao1,*1 State Key Laboratory of Crop Genetics and Germplasm Enhancement / Soybean Research Institute, Nanjing Agricultural University, Nanjing 210095, China;2 Key Laboratory of Agricultural Biotechnology, Xinjiang Agricultural University, Urumqi 830052, ChinaAbstract: Regulation of gene expression at the level of transcription controls many crucial biological processes including growth and development, stress response, signal transduction and disease resistance. A number of factors, such as C2H2 zinc finger protein,are required and factors play an important role in the transcription. Chickpea (Cicer arietinum L.) is the third important legume crop gown mainly in the arid and semi-arid regions in the world. Due to its taxonomic proximity with the model legume genomeof Medicago truncatula and its ability to grow in soil with relatively low water content, chickpea is being investigated as a model legume crop for drought tolerance studies. In our laboratory, two cDNA libraries from the PEG-treated and non-treated seedling leaves of chickpea XJ209 were constructed and many genes were found to express differentially and involved in diverse biologi-cal processes, such as metabolism, transcription, signal transduction, protein synthesis and others. According to an EST in the cDNA libraries, a zinc finger protein gene ZF1 was cloned by RT-PCR and rapid amplification of cDNA ends (RACE). ZF1 didnot include any intron, encoding a 26.33 kD protein with 244 amino acids, containing two typical C2H2 zinc finger domains. The deduced protein sequence had a potential nuclear localization signal (NLS). Meanwhile, transient expression of the ZF1-GFP pro-tein in onion epidermal cells showed that ZF1 protein was localized in cell nuclei. Semi-quantitative RT-PCR analysis showed thatZF1 expressed in root, stem, leaf, flower, immature pod, and embryo of chickpea with different expression patterns. The expres-sion of ZF1 investigated by semi-quantitative PCR had no obvious changes under stresses of cold, salt and wounding, while was increased under the treatments of heat and drought, as well as N-6-benzyl-adenine (6-BA), abscisic acid (ABA), ethephon (Et), gibberellin (GA3), indole-3-acetic acid (IAA), methyl jasmonate (MeJA), salicylic acid (SA), and H2O2. These results from semi-quantitative PCR in several treatments were further confirmed to be mainly in accord with those from real-time quantifica-本研究由国家自然科学基金项目(30860152), 国家“十一五”科技支撑计划项目(2007BAC15B06, 2006BAD09A04, 2006BAD09A08), 教育部高等学校学科创新引智计划和“全国科技支疆行动”合作项目(200991254)资助。

喂牡丹鹦鹉的描述英语作文Feeding the Cockatiel.The cockatiel (Nymphicus hollandicus) is a small, crested parrot native to Australia. It is a popular petbird due to its friendly and playful nature. Cockatiels are relatively easy to care for, but it is important to provide them with a healthy diet in order to keep them healthy and happy.What to Feed Cockatiels.The ideal diet for a cockatiel consists of a variety of fresh foods, including:Pellets: Pellets are a complete and balanced food that provides cockatiels with all the nutrients they need. They should make up the majority of the diet.Seeds: Seeds are a good source of protein, fat, andcarbohydrates. However, they should only be offered in moderation, as they can be high in calories and fat.Fruits: Fruits are a good source of vitamins, minerals, and antioxidants. Cockatiels enjoy eating a variety of fruits, such as apples, bananas, berries, and grapes.Vegetables: Vegetables are a good source of fiber, vitamins, and minerals. Cockatiels enjoy eating a varietyof vegetables, such as broccoli, carrots, corn, and peas.Sprouts: Sprouts are a good source of vitamins, minerals, and enzymes. Cockatiels enjoy eating a variety of sprouts, such as alfalfa sprouts, broccoli sprouts, and sunflower sprouts.In addition to these fresh foods, cockatiels also needto have access to fresh water at all times.How to Feed Cockatiels.Cockatiels should be fed twice a day, once in themorning and once in the evening. The amount of food that you give your cockatiel will depend on its size andactivity level. A good rule of thumb is to give your cockatiel about 1/4 cup of food per day.It is important to offer your cockatiel a variety of foods each day. This will help to ensure that it is getting all the nutrients it needs. You can also offer your cockatiel treats, such as millet or sunflower seeds, occasionally.What Not to Feed Cockatiels.There are some foods that you should never feed your cockatiel. These foods include:Avocado: Avocado is toxic to cockatiels and can cause vomiting, diarrhea, and respiratory problems.Chocolate: Chocolate contains theobromine, which is toxic to cockatiels.Caffeine: Caffeine is toxic to cockatiels and cancause heart problems and seizures.Alcohol: Alcohol is toxic to cockatiels and can cause liver damage and death.Salty foods: Salty foods can cause dehydration and kidney problems in cockatiels.Sugary foods: Sugary foods can cause weight gain and obesity in cockatiels.Processed foods: Processed foods are often high in fat, sugar, and salt, which can be harmful to cockatiels.If you are unsure whether or not a particular food is safe for your cockatiel, it is best to err on the side of caution and not feed it to your bird.Monitoring Your Cockatiel's Diet.It is important to monitor your cockatiel's diet toensure that it is eating a healthy and balanced diet. If you notice any changes in your cockatiel's eating habits, such as a sudden decrease or increase in appetite, it is important to consult with your veterinarian.By providing your cockatiel with a healthy diet, you can help to keep it healthy and happy for many years to come.。

食品科技鹰嘴豆水的成分功能及其在植物基食品领域的应用解　莉（南京旅游职业学院 烹饪与营养江苏省文化和旅游重点实验室，江苏南京 211100）摘　要：鹰嘴豆水指来自鹰嘴豆罐头中的液体或煮沸鹰嘴豆过程中产生的液体。

其主要成分包括碳水化合物、低分子量的蛋白质、皂素和一些美拉德反应产物。

研究发现鹰嘴豆水具有起泡、乳化和凝胶等特性，这些特性使鹰嘴豆水可以替代一些动物性原料用于食品的制作，如替代鸡蛋制作蛋白霜等。

鹰嘴豆水在植物基食品领域中的应用具有很大的前景。

关键词：鹰嘴豆水；植物基；泡沫特性；蛋白质Composition and Function of Chickpea Water and ItsApplication in Plant Based FoodXIE Li(Nanjing Institute of Tourism and Hospitality Jiangsu Key Laboratory of Cuisine and Nutrition Conferred by Jiangsu Provincial Department of Culture and Tourism, Nanjing 211100, China) Abstract: Chickpeas water refers to the liquid from the canned chickpeas or the liquid produced in the process of boiling chickpeas. Its main components include carbohydrate, low molecular weight protein, saponin and some maillard reaction products. The research found that chickpea water has the characteristics of foaming, emulsification and gel. These characteristics enable chickpea water to replace some animal raw materials for food production, such as replacing eggs to make protein cream. The application of chickpea water in the field of plant based food has great prospects.Keywords: chickpea water; plant base; foam characteristics; protein“植物基”食品是以植物为基础的食品成分和产品，鹰嘴豆水在植物性食品开发中越来越多地被应用来模仿和取代部分动物原料来源。

小学上册英语第六单元真题英语试题一、综合题(本题有100小题，每小题1分，共100分.每小题不选、错误，均不给分)1.What do we call a baby horse?A. CalfB. FoalC. KittenD. PupB2. (40) is a large city in Egypt. The ____3.The snow is ___ (melting) in spring.4.How many sides does a rectangle have?A. 2B. 3C. 4D. 5C5.I want to learn how to ______ (surf) at the beach.6.What is the primary purpose of a compass?A. Measure distanceB. Show directionC. Indicate speedD. Calculate areaB7.The __________ (生态系统) is diverse and rich.8.This __________ (玩具名) is made of __________ (材料).9.What do we call the large body of saltwater?A. LakeB. RiverC. OceanD. Stream10. A ____(community development) focuses on improving living conditions.11.The _______ (蜗牛) takes its time moving forward.12.My favorite dish is ______ (汤).13.ssance was a time of great ________ in art and science. The Rena14.The ____ is a friendly pet that loves to be around people.15.I enjoy making up stories about my ________ (玩具名称).16.What is the term for a baby deer?A. CalfB. FawnC. KidD. CubB17.ocean acidification) affects marine life. The ____18.What do you call a person who teaches students?A. DoctorB. TeacherC. EngineerD. Chef19.How many months are in a year?A. 10B. 12C. 14D. 1620.The _____ (orchard) has many varieties of apples.21.There are many ______ (countries) in the world.22.My favorite toy is ______.23.The rabbit eats ______ (胡萝卜). It is its favorite ______ (食物).24.What do we use to write?A. PaperB. PencilC. BookD. TableB25.Minerals can form from the cooling of ______.26.The sun is _______ (shining) through the trees.27.There are ______ (five) birds in the tree.28.What is the capital of the Bahamas?A. NassauB. FreeportC. Marsh HarbourD. Andros TownA29.The __________ is a large lake in Michigan. (密歇根湖)30.My teacher often says, "_______" (名言). 这让我 _______ (形容词).31.ts can survive in ______ (沙漠). Some pla32.The children are ________ in the playground.33.What do you call a place where you can watch movies?A. TheaterB. CinemaC. PlayhouseD. Both A and BD34.What do you call the art of folding paper into shapes?A. SculptureB. OrigamiC. DrawingD. PaintingB35.What is the name of the fairy tale character who kissed a frog?A. Snow WhiteB. CinderellaC. The Princess and the FrogD. Rapunzel36.We made a ________ out of paper.37.The dog is ________ at the door.38.The __________ is an area of high elevation. (高原)39.My uncle is a ____ (photographer) who takes pictures.40.Mars has the largest volcano, called ______.41.I have a ______ (big) birthday party planned.42.The ______ is a common sight in gardens.43.What is the name of the fairy tale character who had long hair?A. CinderellaB. RapunzelC. Snow WhiteD. Little Red Riding HoodB44.The city of __________ is known as the "Big Apple." (纽约)45.What do you put on a sandwich?A. SocksB. ButterC. ShoesD. HatsB46.The chemical symbol for zirconium is ______.47.What is the term for a young camel?A. CalfB. FoalC. KidD. CalfA48.The process of separating substances in a mixture is called _______.49.In photosynthesis, plants convert sunlight into _______.50.I like to ___ (eat/cook) pasta.51.I have a toy _______ that makes me giggle when I play with it.52.I like to listen to _______.53.I enjoy drinking ________ (茶) in the afternoon.54.The sun is shining ________ today.55. A ________ is a wetland area filled with plants.56.The _____ (季节) affects what plants can grow.57. A solution that contains dissolved ions is called a _______ solution.58.The ________ (河流) Thames flows through London.59.The _______ helps nourish the soil.60.I like taking care of my ______ (植物) at home. It’s rewarding to see them ______ (茁壮成长).61.听录音,按听到的顺序给下列图画标上正确的序号。