Growth and Eco-Physiological Performance of Cotton Under Water Stress Conditions

Available online at www.sciencedirect.comAgricultural Sciences in ChinaScienceDirect2007. 6(8); 949-955August 2007Growth and Eco-Physiological Performance of Cotton Under Water StressConditionsWANG Chun-yan.3, Isoda Akihiro, LI Mao -song.3 and WANG Da-longl.3Instiute of Environment and Sustainable Development for Agriculture, Chinese Academy of Agricultural Sciences, Beijing 100081, P.R.China2 Faculty of Horticulture, Chiba University, Matsudo, Chiba 271-8510, Japan3Key Laboratory of Agro-Enviroment & Climate Change, Ministry of Agriculture, Bejing 100081, P.R.ChinaAbstractA cotton cultivar Xinluzao 8 was grown under four levels of water stress treatments (normal irrigation, slight, mild andsevere water stress) from the initial reproductive growth stage in Shihezi, Xinjiang, China, in 2002, to evaluate the growthand eco-physiological performances. Under water stress conditions, the transpiration ability decreased while the leaftemperature increased. Although the relative leaf water content decreased as water stress increased, the differencesamong the treatments were small, indicating that cotton has high ability in maintaining water in leaf. The stomatal densityincreased as water stress increased, while the maximum stomatal aperture reduced only in the severest stressed plants.The time of the maximum stomatal aperture was delayed in the mild and severe stressed plants. When severe stressoccurred, the stomata were kept open until the transpiration decreased to nearly zero, sugesting that the stomata mightnot be the main factor in adjusting transpiration in cotton. Cotton plant has high adaptation ability to water stressconditions because of decrease in both stomatal conductance and hydraulic conductance from soil-to-leaf pathway. Theactual quantum yield of photosystem II (PS II) decreased under water stress conditions, while the maximum quantumyield of PS II did not vary among treatments, suggesting that PS II would not be damaged by water stress. The total dryweight reduced as water stress increased.Key words: cotton, eco-physiological performance, water stress, transpiration, stomatal apertureconsidered as the response of transpiration to waterINTRODUCTIONstress (Mott and Parkhurst 1991). Under water deficitcondition, the transpiration decreases and the leafCotton is known as a well-adapted crop in arid areatemperature increases. The reduced transpiration might(Peterson et al. 1992). In arid condition the leafbe attributed to the decrease in stomatal conductivityconductance in cotton reduces less as compared withand/or in hydraulic conductance from soil-to-leafother crops. It has been reported that soybean adaptedpathway (Sperry and Pockman 1993; Lovisolo andto arid conditions by the combination of paraheliotropicSchubert 1998; Hubbard et al. 2001). On the otherleaf movement and reduction in transpiration (Isoda andhand, in agronomic aspects, growth of cotton wouldWang 2001). As cotton leaves move diaheliotropically,be highly constrained by water stress. However,the response of cotton to water stress actually could bemech中国煤化工8 growth of cottonTYHCNMHGReceived 2 June, 2006 Accepted 21 December, 2006WANG Chun-yan, Ph D, E-mail: chunyanyrx@yaboo.com.cn02007.CAS. Artrgnosrnd Putholbyboeorerere950WANG Chun-yan et al.was less reported. Thus, the objectives of this studytime by T-type thermocouples, humidity sensors (CHS-were, on water stress conditions, to evaluate theAPS, TEAC, Japan) and a P.AR sensor (LI-190S-1, LI-adaptation mechanisms of cotton in terms oCOR, USA), respectively. The data were collected attranspiration and leaf temperature, to find the role of1-minute interval by data loggers (Thermodac E, Etostomata in regulating the transpiration in cotton, and to Denki Corp, Japan) connected with personalassess the growth.computers. The data used in this article were averagedat 5-minute interval. The data were collectedMATERIALS AND METHODScontinuously for a few days. The data of the day withthe most stable weather condition (17 July) were adopted.The experiment was conducted in the experimental fieldOn the same day, leaf water content, actual quantumof Shihezi Agricultural and Environmental Institute foryield of photosystem II (PS II), and stomatal densityArid Areas in Central Asia, Shihezi, Xinjiang, China,and stomatal aperture were measured at 3-hour intervalduring the growing season in 2002. Cotton cultivarfrom 8 a.m. The uppermost fully expanded leaves ofXinluzao 8 was sown in four concrete framed fieldsstem were measured with the measurements mentioned(5 mx 15 m with 1.5 m in depth) with a population ofearlier. Leaves from each treatment were taken and18.5 plants m2 on 28 April 2002. The organic manuresealed immediately in plastic bags. The leaves werewhich was made from fowl dropping containing N,oven-dried for 24 h. The weights before and after dryingP20, K,0 at rates of 240, 300 and 195 kg ha',were measured and the relative water content of eachrespectively, was applied in a ratio of 10 Mg ha' beforeleaf was calculated. The actual quantum efficiency ofsowing. From 20 June (the initial blooming stage),PS II (OF/Fm) was measured using a pulse amplitudefour levels of imigation (normal rrigation, slight, mild,modulation chlorophyll fluorometer (PAM-2000, Waltz,and severe water stress, assigned as T1, T2, T3 andEffeltrich, Germany). Three leaves from each treatmentT4, respectively) were carried out (Table 1). Theand five places of each leaf were measured. Theirrigation quantity of Tl was designed according to themaximum quantum yield of PS II (Fv/Fm) wasneighboring commercial cotton field where water stressmeasured at 4 a.m. The method of stomatal datawould not occur. T3 and T4 plots were covered withcollection was according to Hirose et al, (1992). Aclear plastic flms for the greenhouse when raining fromcover glass with a small drop of fast sticking adhesive25 June. T4 obtained only 1.4 mm of water from rainfallwas attached to the abaxial surface of leaf and lastedbefore being covered with the flms.for about 30 seconds. Three leaves were taken fromOn 17 July (when the leaves of the plants in T4 wiltedeach treatment and three samples were taken from eachat noon), the leaf temperatures of four uppermost fullyleaf. The stomata were measured through a computerexpanded leaves were measured with the T-typecontrolled digital microscope (Axioplan 2 Imaging, Carlthermocouples. The thermocouples were fixed at theZeiss Corp. Germany). Three good samples wereabaxial side of the leaves. The flow rates of stem sapchosen for each treatment and three pictures were taken(FRSS) of two plants for each treatment were measuredfor every sample. Stomatal lengths and widths of fiveby sap flow gauges (Dynagage, Dynamax Inc., USA).stomata of each picture were measured at 400 XThe sap flow gauges were attached at the base of themagnification. Stomatal aperture (A) was calculatedstem. Air temperature, humidity and photosyntheticallyfrom length and width using the equation A=rab, whereactive radiation (PAR) were also recorded at the samea and b are 1/2 length and 1/2 width, respectively (WiseTable 1 Amount of irigationo of 4 teatments (mm)Treatment6/206/307/8/16Total?T40.030.030140.3 (10.3)T220.07.55.0中国煤化工75.3 (10.3)0.033.9(.4)MYHCNMHG_1.4(1.4)”The numbers in the brackets indicatc the quantity of pecipiatio.o02007,CAAS. Alnghtg reerd tnebererdrGrowth and Eco-Pbysiological Performance of Cotton Under Water Stress Conditions951et al. 2000). Stomatal quantity was counted at 100xincreased (Fig.4). However, in T3 and T4, leafmagnification. The quantity of each treatment wastemperature in the moring was lower than that in thecalculated as the average of all samplings at differentafternoon at same values of FRSS, suggesting that thetimes.leaf temperature could not be regulated only byTen plants from each treatment were harvested ontranspiration at the mild or serve water stress condition.19 June, and 6 and 23 July. The plants were separatedinto roots, stems, leaves, squares and bolls, and driedDiumal changes in relative leaf water contentat 80°C for 72 h. Number of bolls per plant wascounted. Leaf area was measured with an automaticThe leaf relative water conteat (water contained by perleaf area meter (AMM-7, Hayashideno Inc., Japan).unit leaf dry weight) was much higher in T1 as comparedwith other treatments (Fig.5). T2 had larger valuesRESULTS .than the other two severer treatments. There was noDiumal changes in leaf temperature FRSSAir temperatureFig.1 shows the diurmal changes in PAR and humidity40-observed on 17 July 2002. It was a typical day in Julyin the local area. Peak values of leaf temperatures wereobserved at 10, 11, 12 and 14 h for T1, T2, T3 and T4,30个at 32°C, 37°C, 42°C and 40°C, respectively (Fig.2).Leaf temperatures were higher from 9 h in all thetreatments as compared with air temperature and20dropped to lower than air temperature at 11, 15, 17 and18 h for T1, T2, T3 and T4, respectively. Leaftemperature of T4 was lower in the morning as4 681012141618 20compared with T2 and T3.Loceal time (h)Peak values of FRSS were 5.8, 4.5, 3.3 and 2.0 gdm2d:l at 14, 12, 11 and 10h for T1, T2, T3 and T4,Fig. 2 Diurnal changes in leaf temperature of treatments.respectively (Fig.3).In general, FRSS increased as leaf temperature三势VPDPAR- Airbumidityl.02000.81000|300 t0.640.4:00tr0.24681012141618 20中国煤化工18 20Local time (h)FHCNMHGFig. 1 Diumal changes in photosyteically active radiation (PAR)and air humidity on 17, July.Fig 3 Diurnal changes in flow rate of stem sap (FRSS) of treatments.02007,CAAS.Alngyts reeve laleyelererde.95WANG Chun-yan et aldifference between T3 and T4. The leaf relative waterlarge differences in stomatal density among treatments.contents were higher in the morning than those in theThe stomatal density increased as water stress increased.afternoon in T1, though diurnal changes did not varylargely in the other treatments.Diumalchanges inactual quantumyield(AF/Fm)and maximum quantum yield (Fv/Fm)Diurnal changes in stomatal aperture size anddensityAF/Fm' in T3 and T4 was lower as compared with thatin T1 and T2 except for 11 h (Fig.7), however,The stomata kept opening largely at 11 and 14 h, whiledifference in Fv/Fm was not found among treatments,no difference was observed in the other sanpling timesuggesting that PS II was not damaged by the water(Fig.6). The maximum stomatal aperture was smallerstress despite lower eficiency in PS II.in T4 as compared with the other treatments throughout量升-毋口the daytime. However, there were no large differences-0-T460「in the average aperture among treatments. There were40自120fab I田00ofaq通一用b三30b出01720”Local time (b)012Fig. 6 Diumal changes in stomatal aperture size among treatments.FRSS (gm2 d)Stoma1 density (num. mm2):T1 (312c). T2 (347 b).T3 (367 a).T4 (358 ab). The same letters indicate noignificantdfference atFig. 4 Relationship between leaf temperature and flow rate of stem0.05 level.'sap (FRSS).0.7 [世3.5 r0.6θT4/用0.3.0眼25 tmbQ0.2°.18202.0L14Local time (间)Local time ()Fig. 7中国煤化Iyied QvFm) amtreatmi-TI (0.74 a), T2 (0.73Fig. 5 Diurnal changes in relative leaf water content (RLWC).a),T3:YHC N M H Gindiate a0 sgticintThe same letters indicate no significant difference at 0.05 level.difference at 0.05 level.Growth and Eco-Physiological Performof Cotton Under Water Stress Cond953Changes in dry weight accumulation and growth00 -口Boll . Square四Leaf Slerm 口 Roorparameters|T2|T400 |There are large differences in dry matter accumulation400-among treatments (Fig.8). As stress became stronger言and advanced, the total dry matter reduced. At the00 tinitial phase (9 July), plants under water stress conditionpartitioned more dry matter to reproductive organs,619 79 723 619 79 723 619 79 71236/19 79 7/23especially to square (Fig.9). However, there were noDate (mon'd)large differences in partition percentages amongtreatments at advanced stress phase (23 July).Fig. 8 Changes in dry matter accumulation of treatments atThe growth parameters are shown in Fig.10. Thedifferent sampling dates.increase of LAI became less as stress became stronger.口Roou已 Slem■ Lear 口 Square: BollThe differences among treatments became larger as619stress advanced, The same trend was also found inspecific leaf area (SLA). The ratio of root dry weight80一to LAI (Root/LAI) increased as stress advanced,sosuggesting that leaves of stronger stressed plant mighthave more root for extracting water. The crop growthrate (CGR) became lower as stress became stronger.The net assimilate rate (NAR) decreased as stressTI↔12T3T4↔TIτ2T3T4↔πI↔T2T3T4increased at initial stress stage, however, differenceswere not found among treatments at the advance stage.TreatmentsAs stress advanced, the single boll weight (SBW) wasFig. 9 Changes in dry matter partition percentage of treatments athigher despite less bolls remaining per plant (BN).D田0-二胃9H手120110-告6/[7919/23-719 -723oDate (mon/d)周一届s-& 20田田-下0 T46/19 79 7/23中国煤化工YHCNMHGFig. 10 Changes in growth parameters among treatments.02007.,CAS.Alnyts reretishedbelehererertet954_WANG Chun-yan et al.DISCUSSIONassimilates partitioned to reproductive organs was mainlyfrom the reduced leaf. The photochemical activity wasTranspiration in cotton became lower as water stressaffected by water stress as the actual quantum yieldincreased. Under non-stress or slight water stressreduced under water stress conditions. However, thecondition, leaf temperature in cotton were mainlyeffect did not vary much at different stress levels. Thereregulated by transpiration, while under mild or severeis also no difference in maximum quantum yield of PSstress condition, the less active diaheliotropic leafII among treatments, revealing that the photochemicalmovement could also avoid heat stress by reducingapparatus was not damaged by the stress. Thisradiation location. Lower leaf temperature in the mormingsuggested that PS II in cotton was quite resistant tounder severe stress condition might also suggest thatwater deficit, which was similar to those in other reportsthe less active diaheliotropic leaf movement was(Lu and Zhang 1998; Saccardy et al.1998; Shangguanperformed. This was associated with what waset al.2000). On the other hand, photosynthesis mightobserved in soybean that soybean adapted to aridnot be reduced by insufficient CO, since stomata wereconditions by the combination of paraheliptropic leafnot closed under water stress condition. Moreover,movement and reduced transpiration (Isoda and Wangthe maximal stomatal aperture size delayed as water2001), though cotton performed diaheliotropic leafstress increased and did not depend on the maximummovement.FRSS, suggesting that the stomatal aperture might beAlthough the largest stomatal aperture during theadjusted for maintaining photosynthetic ability. Thus,daytime reduced significantly only in the severe stressthe reduced dry matter production under water stresscondition (T4), there was no large difference amongcondition might be due to the reduced photosyntheticthe other treatments. Ackerson et al. (1977) alsoarca (leaf).reported that stomata were not closed under droughtThe root/LAI became higher as stress becamecondition in filed grown cotton. On the other hand, theseverer, suggesting that leaves of stressed plants mightrelative leaf water content was kept nearly unchangedhave more root to extract water from soil. This mightamong the slight, mild and severe water stressbe an agronomic adaptation of cotton in water stressconditions. It has been reported that stomatalcondition. On the other hand, under water stressconductivity might be affected by leaf water statuscondition new boll producing ceased earlier and more(Cochard et al. 2002; Hubbard et al. 2001; Saliendrabolls shed. However, faster developing of remainedet al.1995). The stable values of leaf relative waterbolls could obviously reduce the growing period. Thecontent under water stress conditions in this study mayreduced growing period might be considered as anotheravoid tissue dehydration and might be the reason foradaptation of cotton plant to water deficit in agronomicstomatal aperture despite low transpiration. It has beenaspect.reported that when water stress increased to a certaindegree, the hydraulic conductance from soil-to-leafAcknowledgementspathway might become one of limitation for transpirationThe research is supported by National 863 Program of(Hubbard et al. 2001; Lovisolo and Schubert 1998).China (2006AA100215, 2006AA100202) and theThe transpiration under water stress conditions in ourNational Science and Technology Planning Projectexpriment might reduce as decreasing in hydraulicContract Research, China (2006BAD04B07). Theconductance from soil-to-leaf pathway, since theauthors are grateful to all members of the Shihezistomata did not close.Agricultural and Environmental Institute for Arid AreaCotton plants transported more assimilates to in Central Asia, Shihezi, Xinjiang, China, for theirreproductive organs at the initial water stress. At thecooperation in data collection.advanced stress phase, however, there was ncdifference in partition percentages and NAR amongRefer中国煤化工treatments, suggesting that water stress affect thAckersoYHCNMHGgN.1977.Efctsofassimilate partition mainly in early stage. The increasedplant water on stomatal activity, photosynthesis, and nitrateGrowth and Eco-Physiological Performance of Cotton Under Water Stress Conditions955reductasc activity of field grown cotton. Crop Science, 17,Mott K A, Parkhurst D F. 1991. Stomatal responses to bumidity81-84.in air and helox. Plan,; Cell and Environment, 14, 509-515.Cochard H, Coll L, Roux X L, Ameglio T.2002. Uaraveling thePerterson K L, Fuchs M, Moreshet s, Cohen Y, Sinoquet H.effects of plants bydraulics on stomatal closure during water1992. Computing transpiration of sunlit and sbaded cottonstress in walnut. Plant Physiology, 128, 282-290.foliage under variable water stress. Agronomy Journal, 84,Cornic G. 2000. Drought stress inhibits photosynthesis by91-97. .decreasing stomatal aperture not by afecting ATP synthesis.Saccardy K, Pineau B, Roche O, Cormic G.1998. PhotochemicalTrends in Plant Science, 5, 187-188.efficiency of photosystem II and xantophyll cycleHirose T, Izuta T, Miyake H, Totsuka T.1992. A stomatalcomponents in Zea mays leaves exposed to water stress andimpression method using a fast- sticking adhesive. Japanesehigh light. Photosynthesis Research, 56, 57-66.Jourmal of Crop Science, 61, 159-160.Saliendra N Z, Sperry J s, ComstockJ P.1995. Influence of leafHubbard R M, Ryan M G, Siller V, Sperry J s.2001. Stomatalwater status on stomatal response to humidity, hydraulicconductance and photosynthesis vary linearly with plantconductance, and soil drought in Betula occidentalis. Planta,hydraulic conductance in ponderosa pine. Plant, Cell and196, 357-366.Environment, 24, 113-121.Shangguan z, Shao M, Dyckmans J. 2000. Effect of nitrogenIsoda A, Wang P. 2001. Effects of leaf movement on leafnotrition and water deficit on net photosynthetic rate andtemperature, transpiration and radiation interception inchloropbyll fluorescence in winter wheat Jourmal of Plantsoybean under water stress conditions. Technology BulletinPhysiology, 156, 46-51.of Faculty of Horiculrure of Chiba University,55, 19.Sperry J s, Pockman W T. 1993. Limitation of transpiration byLovisolo C, Schubert A.1998. Effectes of water stress on vesselhydraulic conductance and xylem cavitation in Betulasize and xylem hydraulic conductity in Vitis vinifera L.occidentalis. Plan, Cell and Environment, 16, 279-287.Joumal of Experimental Botany, 49, 693-700.Wise R R, Sassenrath-Cole G F, Percy R G. 2000. A comparisonLu C, Zhang J.1998. Effects of water stress on photosynthesis,of leaf anatomy in field grown Gossypium hirsutum and G.chlorophyl fluorescence and photoinhibition in wheat plants.barbadense. Annals of Botany, 86, 731-738.Australia Jourmal of Plant Physiology, 25, 883-892.(Edited by ZHANG Yi-min)中国煤化工MYHCNMHG02007,CAAS. Alny reve Pulilhnedby Baenverud