Photosynthetic responses to Solar UV radiation of Gracilaria lemaneiformis cultured under different temperatures and CO_2 concentrations

为了研究不同温度及CO2浓度下培养的大型海藻对紫外辐射的生理学响应,选取龙须菜(grACIlArIA lEMAnEIfOrMIS)作为实验材料。实验设置两个温度梯度(20℃和24℃),两种CO2浓度(390μl/l和1000μl/l)以及3种辐射处理,即可见光(PAr)处理(滤除紫外线A(uV-A)、紫外线b(uV-b),400—700 nM)、可见光加紫外线A(PA)处理(滤除uV-b,320—700nM)、PAb处理(全波长辐射280—700 nM)。结果表明,酸化、升温以及紫外辐射处理都未影响大型经济红藻龙须菜的叶绿素A和类胡萝卜素的含量。然而紫外辐射处理显著降低了龙须菜的有效光化学效率,其抑制水平在酸化处理的藻体中更为显著,并且随着温度的上升而进一步加剧;酸化与温度耦合使藻体对紫外辐射的敏感性增加,导致其较低的修复速率以及较高的损伤速率。The marine red macroalga Gracilaria lemaneiformis( Bory) Weber-van Bosse( Gigartinales,Rhodophyta) is an economically important species for cultivation in China.The cultivation of this species has been extensively spread which could be found in both northern and southern parts of China.This species could support as food resources for both human beings and aquaculture,and could also be commonly used in agar industry and biofuel production.The growth condition of G.lemaneiformis in natural environment varied frequently( especially the temperature,light intensity and quality,pCO2),which would potentially affect the physiology and photosynthetic production.Though the physiological and ecological effects induced by these environmental variations have been extensively concerned and studied,multi-factor coupling effects to marine macroalgae are still less documented up to now.To study the physiological responses of G.lemaneiformis to multiple stressors of ocean acidification,rising temperature and Ultraviolet( UV) radiation,the thalli of G.lemaneiformis cultured under different temperature( 20 ℃ as control,and high temperature group where it was increased by 4 ℃ to 24 ℃) and different CO2concentrations( ambient atmosphere CO2concentration,390 μL / L,and elevated CO2concentration set at1000 μL / L which expected attain in the end of this century according to IPCC report of A1F1 scenario) for two weeks,and then the algae were treated with three levels of radiations( Photosynthetically active radiation,PAR,400—700 nm;Photosynthetically active radiation+Ultraviolet A,PA,320—700 nm; Photosynthetically active radiation +Ultraviolet A +Ultraviolet B,PAB,280—700 nm) respectively,in the short-period.The photosynthetic pigments and chlorophyll fluorescene characteristics of the thalli of G.lemaneiformis were determined.The results showed that ocean acidification,rising temperature and UV irradiance alone did not affect the concentrations of chlorophyll a and carotenoid of G.lemaneiformis,and also no interactive effects were found among the treatments.Elevated CO2in culture generally did not have a significant effect on the value of maximum relative electron transport rates( rETR max).Temperature had no effect on the photosynthetic light-use efficiencies for thalli of G.lemaneiformis.However,exposure to UV radiation strong reduced the values of light-use efficiencies.Moreover,exposure of UV radiation significantly lowered the effective quantum yield in both G.lemaneiformis thalli grown 20 and 24 ℃,with the inhibition rate being more pronounced in the algae grown under high CO2condition together with increased temperature than the algae grown at control conditions( ambient CO2concentration and 20 ℃).Combine effects of ocean acidification and rising temperature enhanced the sensitivity of G.lemaneiformis to UV radiation,which could be reflected by the increased damage rate( k),decreased repair rate( r),and finally decreased ratio of repair to damage( r / k) in the thalli grown at high CO2concentration together with increased temperature.Taken together,we proposed that under the background of global change,intensified UV radiation( ozone hole continue exist),increased surface seawater temperature and enhanced ocean CO2absorption( ocean acidification) will synergistically exert negative effects on photosynthetic performance of G.lemaneiformis,and could thereby potentially decrease the yield and affect the aquaculture of this species.国家海洋863项目(2012AA10A411); 国家自然科学基金(41106093); 科技部农业科技成果转化资金项目(2012GB2E000340

Atomic structures of enterovirus D68 in complex with two monoclonal antibodies define distinct mechanisms of viral neutralization

11月5日，《自然》子刊《自然•微生物学》（Nature Microbiology）在线刊出了我校夏宁邵教授团队发表的题为“Atomic Structures of Enterovirus D68 in Complex with Two Monoclonal Antibodies Define Distinct Mechanisms of Viral Neutralization”的研究论文。这是夏宁邵教授团队在《自然•通讯》（Nature Communications，2017）、《科学•进展》（Science Advances，2018）上发表手足口病重要病原体CVA6、CVA10研究论文之后的又一项关于肠道病毒的重要研究成果。该研究通过解析肠道病毒D组68型（EV-D68）不同类型病毒颗粒及其免疫复合物的高分辨率结构，系统阐明了EV-D68病毒的生活周期及各时期的病毒中和机制，进一步完善了小RNA病毒的吸附入胞及感染机制理论，为EV-D68新型疫苗、抗病毒治疗药物的研发提供重要的理论指导。该研究依托电镜技术平台，解析了EV-D68病毒生活周期中的三种代表性颗粒成熟颗粒、脱衣壳中间态和前体病毒衣壳的近原子分辨率结构，阐明了三种病毒颗粒间的结构差异，以及成熟颗粒转变为脱衣壳中间态的分子机制。夏宁邵教授、李少伟教授、程通副教授和美国国立卫生研究院（NIH）高级研究员Barney Graham博士为该论文的共同通讯作者。郑清炳工程师、博士生朱瑞、博士后徐龙发、博士生何茂洲和美国加州大学圣地亚哥分校颜晓东博士为该论文共同第一作者。【Abstract】Enterovirus D68 (EV-D68) undergoes structural transformation between mature, cell-entry intermediate (A-particle) and empty forms throughout its life cycle. Structural information for the various forms and antibody-bound capsids will facilitate the development of effective vaccines and therapeutics against EV-D68 infection, which causes childhood respiratory and paralytic diseases worldwide. Here, we report the structures of three EV-D68 capsid states representing the virus at major phases. We further describe two original monoclonal antibodies (15C5 and 11G1) with distinct structurally defined mechanisms for virus neutralization. 15C5 and 11G1 engage the capsid loci at icosahedral three-fold and five-fold axes, respectively. To block viral attachment, 15C5 binds three forms of capsids, and triggers mature virions to transform into A-particles, mimicking engagement by the functional receptor ICAM-5, whereas 11G1 exclusively recognizes the A-particle. Our data provide a structural and molecular explanation for the transition of picornavirus capsid conformations and demonstrate distinct mechanisms for antibody-mediated neutralization.This work was supported by a grant from the National Science and Technology Major Projects for Major New Drugs Innovation and Development (no. 2018ZX09711003-005-003), the National Science and Technology Major Project of Infectious Diseases (no. 2017ZX10304402-002-003), the National Natural Science Foundation of China (no. 81401669 and 81801646) and the Natural Science Foundation of Fujian Province (no. 2015J05073). This work was supported in part by funding by the National Institutes of Health (grants R37-GM33050, GM071940, DE025567 and AI094386). We acknowledge the use of instruments at the Electron Imaging Center for Nanomachines supported by UCLA and by instrumentation grants from the NIH (1S10RR23057 and 1U24GM116792) and NSF (DBI-1338135 and DMR-1548924). 该研究获得了国家自然科学基金、新药创制国家科技重大专项、传染病防治国家科技重大专项和美国国立卫生研究院基金的资助

Identification of antibodies with non-overlapping neutralization sites that target coxsackievirus A16

手足口病（Hand, Foot and Mouth Disease，HFMD）是一种由人肠道病毒引起的全球性传染病，主要发生于5岁以下的婴幼儿。2月5日，我校夏宁邵教授团队在《细胞》子刊《细胞•宿主与微生物》（Cell Host & Microbe）上在线发表题为“Identification of antibodies with non-overlapping neutralization sites that target coxsackievirus A16”的研究论文。该研究首次揭示了手足口病主要病原体柯萨奇病毒A组16型（CVA16）三种衣壳颗粒形式与三种不同类型的治疗性中和抗体的全面相互作用细节和非重叠的中和表位结构信息，阐明了CVA16成熟颗粒是疫苗候选主要保护性免疫原的理论基础，建立了可指导疫苗研制的免疫原特异检测方法，为CVA16疫苗及抗病毒药物研究提供关键基础。我校夏宁邵教授、李少伟教授、程通副教授和美国加州大学洛杉矶分校纳米系统研究所Z. Hong Zhou（周正洪）教授为该论文的共同通讯作者。我校博士生何茂洲、徐龙发博士后、郑清炳高级工程师、博士生朱瑞和尹志超为该论文共同第一作者。【Abstract】Hand, foot, and mouth disease is a common childhood illness primarily caused by coxsackievirus A16 (CVA16), for which there are no current vaccines or treatments. We identify three CVA16-specific neutralizing monoclonal antibodies (nAbs) with therapeutic potential: 18A7, 14B10, and NA9D7. We present atomic structures of these nAbs bound to all three viral particle forms—the mature virion, A-particle, and empty particle—and show that each Fab can simultaneously occupy the mature virion. Additionally, 14B10 or NA9D7 provide 100% protection against lethal CVA16 infection in a neonatal mouse model. 18A7 binds to a non-conserved epitope present in all three particles, whereas 14B10 and NA9D7 recognize broad protective epitopes but only bind the mature virion. NA9D7 targets an immunodominant site, which may overlap the receptor-binding site. These findings indicate that CVA16 vaccines should be based on mature virions and that these antibodies could be used to discriminate optimal virion-based immunogens.This work was supported by grants from the Major Program of National Natural Science Foundation of China ( 81991490 ), the National Science and Technology Major Projects for Major New Drugs Innovation and Development ( 2018ZX09711003-005-003 ), the National Science and Technology Major Project of Infectious Diseases ( 2017ZX10304402-002-003 ), the National Natural Science Foundation of China ( 31670933 and 81801646 ), the China Postdoctoral Science Foundation ( 2018M640599 and 2019T120557 ), the Principal Foundation of Xiamen University ( 20720190117 ), and the National Institutes of Health ( R37-GM33050 , GM071940 , DE025567 , and AI094386 ). 该研究获得了国家自然科学基金、新药创制国家科技重大专项、传染病防治国家科技重大专项和美国国立卫生研究院基金的资助

Effects of CO_2 and UV radiation on photosynthetic performance of conchocelis of Pyropia haitanensis

为了探索大型海藻生活史丝状体阶段对于海洋酸化与紫外辐射的响应,实验选取经济海藻坛紫菜的自由丝状体作为实验材料。实验设置两个CO2浓度,正常CO2浓度(390 PPMV)和高CO2浓度(1 000 PPMV);3种辐射处理,PAr处理(仅接受可见光)、PA处理(滤除uV-b)、PAb处理(全波长辐射)。研究结果表明,高CO2显著提高了坛紫菜自由丝状体的生长速率,但高CO2处理下坛紫菜自由丝状体中藻红蛋白、藻蓝蛋白、叶绿素A、类胡萝卜素及紫外吸收物质uVACS分别降低了7.3%、9.3%、19.8%、16.5%和18.7%。高CO2处理的坛紫菜自由丝状体最大光化学效率fV/fM,光能利用效率(α)及最大相对电子传递速率(rETrMAX)都显著高于正常CO2处理。太阳模拟器下处理的坛紫菜自由丝状体,PAr与PA处理下的抑制率,正常CO2与高CO2处理间无显著差异,然而在PAb处理下,高CO2处理的抑制率要高于正常CO2处理,这可能与其体内紫外吸收物质含量下降有关。PAr处理下的抑制率,无论是在正常CO2还是在高CO2处理下,都显著低于PA及PAb处理,而PA与PAb之间无显著差异。在未来海洋持续酸化的背景下,uV辐射的增加将会影响到坛紫菜自由丝状体的光合生理及生长。To study the effects of ocean acidification and UV radiation on early life cycle stage of macroalgae,we selected the conchocelis of economic algae Pyropia haitanensis as our material.Two CO2 levels(ambient CO2,390 ppmv and high CO2,1 000 ppmv)and three irradianceswere set in the study.Results showed that high CO2 significantly enhanced the relative growth rate of conchocelis of P.haitanensis,but the contents of phycoerythrin,phycocyanin,chlorophyll a,carotenoid and UVACs were significantly reduced by 7.3%,9.3%,19.8%,16.5% and 18.7% under high CO2 condition,respectively.Maximum photochemical efficiency(Fv/Fm),light using efficiency(α)and maximum relative electron transport rate(rETRmax)were all significantly increased under high CO2 condition.When exposed to different light treatments,inhibition induced by PAR and PA had no significant differences between the thalli grown at high and ambient CO2.However,significant inhibition under PAB was found in the thalli grown at high CO2,which was closely related to the low concentration of UVACs in the thalli of conchocelis of P.haitanensis.Inhibition induced by PAR were all lower than PA and PAB in both high and ambient CO2 treatments,however,no difference was found between PA and PAB treatments.In future ocean,increased UVR would have great effects on photosynthesis and growth of P.haitanensis,especially under the background of ocean acidification.国家自然科学基金项目(41106093); 广东省科技计划项目(2010B060200010;2010B020201015); 广东省汕头市科技计划项目(2010-126;2011-161

Study on the Photosynthetic Characteristics of Bothriochloa ischaemum under Different Water and Nutrient Conditions Ⅲ. Chlorophyll Fluorescence Kinetic Parameters

本研究揭示了不同土壤养分条件下,黄土丘陵区乡土草种白羊草(Bothriochloa ischaemum L.Keng.)对土壤水分短期变化的光合生理响应及其适应性,旨在为充分发挥其光合潜力以及黄土丘陵区白羊草人工草地的建设与管理提供科学依据。采用盆栽控制试验,比较研究3种养分(CK,P和NP)处理下白羊草叶绿素荧光动力学参数对土壤短期水分胁迫和旱后复水的响应特征。结果表明:充分供水条件下,P与NP处理显著提高了白羊草叶片最大光化学效率(Fv/Fm)和实际光化学效率(ΦPSⅡ),使表观光合电子传递速率(ETR)升高,且降低了非辐射性能量耗散(NPQ)。短期干旱胁迫下,P与NP处理的Fv/Fm降幅显著低于CK处理,复水1 d后的Fv/Fm恢复水平均显著高于CK处理(P<0.05),表明P和NP营养有助于增强白羊草对短期干旱胁迫的耐旱性及复水后叶片光合功能的恢复能力

Study on the Photosynthetic Characteristics of Bothriochloa ischaemum under Different Water and Nutrient Conditions Ⅱ. Light-Response Curve

为揭示黄土丘陵区乡土草种白羊草(Bothriochloaischaemum(L.) Keng.)在不同水肥供应条件下的光合生理特征,本研究采用盆栽控制实验,比较研究了白羊草在2种水分水平(HW-80%FC和LW-40FC%)和3种养分(CK,P和NP)处理下的光合光响应曲线特征。结果表明:非直角双曲线模型能很好的拟合白羊草光响应曲线。充分供水条件下(HW),土壤NP营养提高了白羊草最大净光合速率(P′max),降低了暗呼吸消耗(Rd)并且保持较低的光合补偿点(LCP)和较高的光饱和点(LSP),表明NP营养有利于提高白羊草对光照的广幅适应能力和光合潜力。水分胁迫条件下(LW),P处理显著提高了白羊草P′max,其表观量子效率(a)和LCP也相对较高,表明施磷将有利于提高干旱条件下白羊草的光合能力

Study on the Photosynthetic Characteristics of Bothriochloa ischaemum under Different Water and Nutrient Conditions Ⅰ.Diurnal Variation of Photosynthesis

为揭示黄土丘陵区乡土种白羊草(Bothriochloa ischaemum L. Keng.)在不同水肥供应条件下的光合生理特征,本研究采用盆栽控制实验,比较研究了白羊草在2个水分水平(HW-80%FC和LW-40FC%)和3个养分(CK、P和NP)处理下的光合生理日变化特征。结果表明:HW下白羊草光合速率日变化均呈"三峰"型曲线。LW下,P和NP处理呈"双峰"型曲线,CK处理呈"三峰"型曲线,均具有明显的光合"午休"现象。不同水肥条件下白羊草叶片水分利用效率日变化均呈"L"型。HW下,白羊草光合速率日均值无肥处理显著高于其他处理(P<0.05),LW下,3养分处理间白羊草光合速率日均值无显著差异,而不同养分处理下,土壤水分胁迫均显著降低了白羊草光合速率日均值,并使光合"午休"程度加剧,水分是限制白羊草光合生理过程的首要因素

Study on the Leaf Chlorophyll Fluorescence Characteristic of Bothriochloa ischaemum under Different Water and Nutrient Conditions

采用盆栽控制试验,比较研究了四种养分(不施肥、施N肥、施P肥和施N+P肥)处理和三种水分(充分供水、轻度水分胁迫、重度水分胁迫)水平下白羊草叶片叶绿素荧光动力学参数特征。结果表明:在不施肥(CK)处理中,重度水分胁迫下白羊草叶片的Fm、Fv/Fm、ΦPSII、qP和ETR显著最小,F0显著最大,表明重度水分胁迫会显著影响其叶片PSII反应中心活性。重度水分胁迫下,施N、P和N+P肥处理的Fm、Fv/Fm、ΦPSII和ETR显著大于CK,而F0显著小于CK,表明重度水分胁迫下N肥、P肥及其配施均能有效提高白羊草叶片PSII反应中心活性、开放程度和光合电子传递。不同水分处理下,施N+P肥比单施N肥和P肥能够更大程度提高白羊草叶片ETR值,显著减小水分胁迫对其F0、Fv/Fm和ΦPSII的影响,表明氮磷配施能更有效地改善其PSII反应中心结构和功能

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采用盆栽控制试验,研究了达乌里胡枝子(Lespedeza davurica)在3种水分水平[分别为土壤田间持水量的80%(HW)、60%(MW)、40%(LW)]与2种肥料处理(P处理:纯P 0.1g.kg-1干土;对照:不施肥)下不同叶位叶绿素荧光参数特征。结果表明,P处理中,MW下旗叶F0和Fv/Fm值显著低于中叶,Fm值差异不显著,说明在轻度水分胁迫下旗叶PSⅡ反应中心受到的损伤较小,虽然旗叶和中叶电子传递没有差异,但旗叶光能转换效率比中叶高。另外,P处理显著降低了达乌里胡枝子叶片NPQ值,同时显著提高了MW下新叶和旗叶Fv/Fm值,说明施用P肥能够有效减少叶片对光能的热耗散,并提高其在一定水分胁迫下的光能利用能力,增强达乌里胡枝子对黄土丘陵区的适应能力Ａｂｓｔｒａｃｔ：Ａ　ｐｏｔ　ｅｘｐｅｒｉｍｅｎｔ　ｗａｓ　ｕｓｅｄ　ｔｏ　ｄｅｔｅｒｍｉｎｅ　ｔｈｅ　Ｃｈｌｏｒｏｐｈｙｌｌ　ｆｌｕｏｒｅｓｃｅｎｃｅ　ｃｈａｒａｃｔｅｒｉｓｔｉｃｓ　ｏｆ　ｄｉｆｆｅｒｅｎｔｐｏｓｉｔｉｏｎ　ｌｅａｖｅｓ　ｉｎ　Ｌｅｓｐｅｄｅｚａ　ｄａｕｒｉｃａ　ｕｎｄｅｒ　ｔｈｒｅｅ　ｄｉｆｆｅｒｅｎｔ　ｗａｔｅｒ　ｌｅｖｅｌ（８０％ ＦＣ，６０％ ＦＣ　ａｎｄ　４０％ ＦＣ）ａｎｄ　ｔｗｏ　ｐｈｏｓｐｈｏｒｕｓ　ｔｒｅａｔｍｅｎｔｓ（０．１Ｐｇ·ｋｇ－１　ｄｒｙ　ｓｏｉｌ　ａｎｄ　ｎｏ　Ｐ　ａｄｄｉｔｉｏｎ）．Ｔｈｅ　ｒｅｓｕｌｔｓ　ｏｆ　ｔｈｉｓ　ｓｔｕｄｙｓｈｏｗｅｄ　ｔｈａｔ　ｔｈｅ　ｉｎｉｔｉａｌ　ｆｌｕｏｒｅｓｃｅｎｃｅ（Ｆ０）ａｎｄ　ｔｈｅ　ｍａｘｉｍｕｍ　ｐｈｏｔｏｃｈｅｍｉｃａｌ　ｅｆｆｉｃｉｅｎｃｙ（Ｆｖ／Ｆｍ）ｏｆ　ｆｌａｇ　ｌｅａｖｅｓｗｅｒｅ　ｓｉｇｎｉｆｉｃａｎｔｌｙ　ｌｏｗｅｒ　ｔｈｏｓｅ　ｏｆ　ｍｉｄｄｌｅ　ｌｅａｖｅｓ　ｕｎｄｅｒ　ｍｏｄｅｒａｔｅ　ｗａｔｅｒ　ｓｔｒｅｓｓ　ａｎｄ　ｓｕｐｐｌｙ　ｐｈｏｓｐｈｏｒｕｓ，ｗｈｉｌｅｔｈｅｒｅ　ｗｅｒｅ　ｎｏ　ｓｉｇｎｉｆｉｃａｎｔ　ｄｉｆｆｅｒｅｎｃｅｓ　ｉｎ　ｍａｘｉｍａｌ　ｆｌｕｏｒｅｓｃｅｎｃｅ（Ｆｍ），ｉｍｐｌｙｉｎｇ　ｔｈａｔ　ｔｈｅ　ＰＳⅡｒｅａｃｔｉｏｎ　ｃｅｎｔｅｒ　ｏｆｆｌａｇ　ｌｅａｖｅｓ　ｗｅｒｅ　ｌｅｓｓ　ｄｅｓｔｒｏｙｅｄ　ｔｈａｎ　ｔｈｅ　ｍｉｄｄｌｅ　ｌｅａｆ　ａｎｄ　ｔｈｅ　ｌｉｇｈｔ　ｅｎｅｒｇｙ　ｔｒａｎｓｆｏｒｍａｔｉｏｎ　ｅｆｆｉｃｉｅｎｃｙ　ｏｆ　ｆｌａｇｌｅａｖｅｓ　ｗａｓ　ｈｉｇｈｅｒ．Ｔｈｅ　ｌｅａｆ　ｑｕｅｎｃｈｉｎｇ　ｃｏｅｆｆｉｃｉｅｎｔ（ＮＰＱ）ｓｉｇｎｉｆｉｃａｎｔｌｙ　ｄｅｃｒｅａｓｅｄ　ａｎｄ　ｔｈｅ　Ｆｖ／Ｆｍｖａｌｕｅｓ　ｏｆｆｌａｇ　ｌｅａｆ　ａｎｄ　ｎｅｗ　ｌｅａｆ　ｕｎｄｅｒ　ｍｏｄｅｒａｔｅ　ｗａｔｅｒ　ｓｔｒｅｓｓ　ｃｏｎｄｉｔｉｏｎ　ｗｅｒｅ　ｓｉｇｎｉｆｉｃａｎｔｌｙ　ｈｉｇｈｅｒ　ｉｎ　ｓｕｐｐｌｙ　ｐｈｏｓｐｈｏｒｕｓｔｒｅａｔｍｅｎｔ，ｉｎｄｉｃａｔｉｎｇ　ｔｈａｔ　ｔｈｅ　ｌｉｇｈｔ　ｅｎｅｒｇｙ　ｄｉｓｓｉｐａｔｉｏｎ　ｄｅｃｒｅａｓｅｄ　ａｎｄ　ｌｉｇｈｔ　ｅｎｅｒｇｙ　ｔｒａｎｓｆｏｒｍａｔｉｏｎ　ｉｎｃｒｅａｓｅｄｕｎｄｅｒ　ｗａｔｅｒ　ｓｔｒｅｓｓ　ｂｙ　ａｄｄｉｔｉｏｎ　ｏｆ　ｐｈｏｓｐｈｏｒｕｓ，ｗｈｉｃｈ　ｓｕｇｇｅｓｔｅｄ　ｔｈａｔ　ｔｈｅ　ｓｕｐｐｌｙ　ｐｈｏｓｐｈｏｒｕｓ　ｉｍｐｒｏｖｅｄ　ｔｈｅ　ａｄａｐｔｉｖｅ　ｃａｐａｃｉｔｙ　ｏｆ　Ｌ．ｄａｕｒｉｃａｔｏ　ｓｅｍｉａｒｉｄ　ｌｏｅｓｓ　ｈｉｌｌｙ－ｇｕｌｌｙ　ｒｅｇｉｏｎ

Effect of Different Water and Macro-Nutrient Levels on the Chlorophyll Fluorescence Kinetic Parameters of Lespedeza davurica(Laxm.) Schindl

采用盆栽控制试验,比较研究了3种水分(高水(HW-80%FC)、中水(MW-60%FC)和低水(LW-40%FC))以及4种养分(CK,N,P,NP)处理对生长旺期达乌里胡枝子(Lespedeza davurica(Laxm.)Schindl)叶绿素荧光动力学参数的影响。结果表明:不同养分处理下,随着土壤含水量的降低,达乌里胡枝子叶片Fv/Fm值降低,表明水分胁迫降低了其PSⅡ反应中心的光化学效率。HW和MW水平下,N处理的叶片F0显著高于其他养分处理(P<0.05),而Fv/Fm值则显著低于其他养分处理(P<0.05),表明氮肥对其叶片PSⅡ反应中心的活性和光能转化效率的提高作用较小;P处理的叶片ΦPSⅡ,ETR和qP显著高于其他养分处理(P<0.05),说明施磷提高了叶片PSⅡ反应中心光化学反应效率、开放程度和电子传递速率。LW水平下,4种养分处理间Fv/Fm值无显著差异,表明在重度水分胁迫条件下,施肥对提高叶片光化学效率无明显效果