二氧化碳加富对大豆叶片光系统II功能的影响

 本文研究了长期CO2加富对大豆叶片光系统Ⅱ(PSⅡ)功能的影响。结果表明,CO2加富能促进大豆叶片PSⅡ潜在活性和原初光能转化效率,以及电子传递量子产量的提高;增加荧光光化学淬灭组分,降低荧光非光化学淬火组分。CO2加富对大豆叶片PSⅡ功能的改善,可能是CO2加富条件下,大豆叶片光合速率的提高和产量增加的重要原因之—。     

Effects of Doubled CO2 on Contents of Photosynthetic and on Kinetic Parameters of Fluorescence Induction in Different Genotypes of Soybean

Effects of doubled C02 on photosynthetic characteristics of soybean ( Glycine max L. ) Bragg (wild type) and its different monogene mutation strains--Nts 382 (supemodulation mutant) and Nod 49 (non-nodulation mutant) were studied. The experimental results showed that the contents of chlorophyll and carotenoid of Bragg, Nts 382 and Nod 49 were increased under doubled CO2, respectively, although to different extent. The determination results of fluorescence induction kinetic parameters showed that PS Ⅱ activity, the efficiency of primary conversion of light energy of PS Ⅱ and the efficiency of potential photosynthetic quantum conversion of a leaf from Bragg and its mutants were raised in doubled CO2. Fluorescence photochemical quenching coefficient and the overall photochemical quantum yield of PS Ⅱ were raised and non-photochemical quenching coefficient was reduced with CO2 enrichment; such changes were bigger in Nts 382 than those in Bragg and Ned 49. It might be that atmospheric N2 was more effectively utilized by Nts 382 than by Bragg and Ned 49.     

施氮和大气CO2浓度升高对小麦旗叶光合电子传递和分配的影响

采用开顶式气室盆栽培养小麦,设计2个大气CO2浓度(正常:400 μmol.mol-1;高:760 μmol·mol-1)、2个氮素水平(0和200 mg·kg-1土)的组合处理,通过测定小麦抽穗期旗叶氮素和叶绿素浓度、光合速率(Pn)-胞间CO2浓度(C1)响应曲线及荧光动力学参数,来测算小麦叶片光合电子传递速率等,研究了高大气CO2浓度下施氮对小麦旗叶光合能量分配的影响.结果表明:与正常大气CO2浓度相比,高大气CO2浓度下小麦叶片氮浓度和叶绿素浓度降低,高氮处理的小麦叶片叶绿素a/b升高.施氮后小麦叶片PSⅡ最大光化学效率(Fv/Fm)、PSⅡ反应中心最大量子产额(Fv'/Fm')、PSⅡ反应中心的开放比例(qr)和PSⅡ反应中心实际光化学效率(φPSⅡ)在大气CO2浓度升高后无明显变化,虽然叶片非光化学猝灭系数(NPQ)显著降低,但PSⅡ总电子传递速率(JF)无明显增加;不施氮处理的Fv'/Fm'、φPSⅡ和NPQ在高大气CO2浓度下显著降低,尽管Fv/Fm和qp无明显变化,JF仍显著下降.施氮后小麦叶片JF增加,参与光化学反应的非环式电子流传递速率(Jc)明显升高.大气CO2浓度升高使参与光呼吸的非环式电子流传递速率(J0)、Rubisco氧化速率(V0)、光合电子的光呼吸/光化学传递速率比(J0/Jc)和Rubisco氧化/羧化比(V0/Vc)降低,但使Jc和Rubisco羧化速率(Vc)增加.因此,高大气CO2浓度下小麦叶片氮浓度和叶绿素浓度降低,而增施氮素使通过PSⅡ反应中心的电子流速率显著增加,促进了光合电子流向光化学方向的传递,使更多的电子进入Rubisco羧化过程,Pn显著升高.     

盐胁迫下CO2加倍对春小麦一些光合功能的影响

 研究了在盐胁迫下CO2浓度加倍对春小麦(Triticum aestivum)青323光合色素含量和一些光合功能的影响。结果表明,盐胁迫降低春小麦叶片单位鲜重叶绿素(Chl)和类胡萝卜素(Car)的含量、叶绿体对光能的吸收能力,Mg2+对两个光系统(PSⅡ和PSⅠ)之间激发能分配的调节能力,以及荧光猝灭速率(△FV/T)。然而,CO2加倍有提高上述各参数的作用,表明高CO2浓度能减轻盐胁迫对光合功能的不利效应。     

施氮和大气CO2浓度升高对小麦旗叶光合电子传递和分配的影响

采用开顶式气室盆栽培养小麦,设计2个大气CO₂浓度（正常：400 μmol·mol^-1;高：760 μmol·mol^-1）、2个氮素水平（0和200 mg·kg^-1土）的组合处理,通过测定小麦抽穗期旗叶氮素和叶绿素浓度、光合速率（P_n）-胞间CO₂浓度（C_i）响应曲线及荧光动力学参数,来测算小麦叶片光合电子传递速率等,研究了高大气CO₂浓度下施氮对小麦旗叶光合能量分配的影响.结果表明：与正常大气CO₂浓度相比,高大气CO₂浓度下小麦叶片氮浓度和叶绿素浓度降低,高氮处理的小麦叶片叶绿素a/b升高.施氮后小麦叶片PSⅡ最大光化学效率（F_v/F_m）、PSⅡ反应中心最大量子产额（F_v′/F_m′）、PSⅡ反应中心的开放比例（q_p）和PSⅡ反应中心实际光化学效率（Φ_PSⅡ）在大气CO₂浓度升高后无明显变化,虽然叶片非光化学猝灭系数（NPQ）显著降低,但PSⅡ总电子传递速率（J_F）无明显增加;不施氮处理的F_v′/F_m′、Φ_PSⅡ和NPQ在高大气CO₂浓度下显著降低,尽管F_v/F_m和q_P无明显变化,J_F仍显著下降.施氮后小麦叶片J_F增加,参与光化学反应的非环式电子流传递速率(J_C)明显升高.大气CO₂浓度升高使参与光呼吸的非环式电子流传递速率(J₀)、Rubisco氧化速率（V₀）、光合电子的光呼吸/光化学传递速率比（J₀/J_C）和Rubisco氧化/羧化比（V₀/V_C）降低,但使J_C和Rubisco羧化速率（V_C）增加.因此,高大气CO₂浓度下小麦叶片氮浓度和叶绿素浓度降低,而增施氮素使通过PSⅡ反应中心的电子流速率显著增加,促进了光合电子流向光化学方向的传递,使更多的电子进入Rubisco羧化过程,P_n显著升高.     

Interactive Effects of Drought Stresses and Elevated CO2 Concentration on Photochemistry Efficiency of Cucumber Seedlings

To reveal and quantify the interactive effects of drought stresses and elevated CO2 concentration [CO2] on photochemistry efficiency of cucumber seedlings, the portable chlorophyll meter was used to measure the chlorophyll content, and the Imaging-PAM was used to image the chlorophyll fluorescence parameters and rapid light response curves (RLC) of leaves in two adjacent greenhouses. The results showed that chlorophyll content of leaves was reduced significantly with drought stress aggravated. Minimal fluorescence (Fo) was increased while maximal quantum yield of PSII (Fv/Fm) decreased significantly by severe drought stress. The significant decrease of effective quantum yield of PSll (Y(Ⅱ)) accompanied by the significant increase of quantum yield of regulated energy dissipation (Y(NPQ)) was observed under severe drought stress condition, but there was no change of quantum yield of nonregulated energy dissipation (Y(NO)). We detected that the coefficient of photochemical quenching (Qp) decreased, and non-photochemical quenching (NPQ) increased significantly under severe drought stress. Furthermore, we found that maximum apparent electron transport rate (ETRmax) and saturating photosynthetically active radiation (PPFDsat) decreased significantly with drought stress aggravated. However, elevated [CO2] significantly increased FvlFm, Qp and PPFDsat, and decreased NPQ under all water conditions, although there were no significant effects on chlorophyll content, Fo, Y(Ⅱ), Y(NPQ), Y(NO) and ETRmax. Therefore, it is concluded that CO2-fertilized greenhouses or elevated atmospheric [CO2] in the future could be favorable for cucumber growth and development, and beneficial to alleviate the negative effects of drought stresses to a certain extent.     

不同干旱胁迫下欧李光合及叶绿素荧光参数的响应

采用人为控制土壤含水量的方法对欧李进行轻度和重度干旱的处理,测定叶片的气体交换和叶绿素荧光参数的日变化。结果表明,干旱胁迫下欧李叶片净光合速率、蒸腾速率、水分利用效率、气孔导度、PSII最大光化学效率、光化学量子效率显著下降,但胞间CO2浓度、非光化学猝灭系数以及叶黄素循脱环氧化状态（Z＋0.5A）/（V＋A＋Z）和Z含量升高。两干旱处理植株的影响程度存在差异。这表明在长时间干旱条件下,欧李叶片光合作用的降低受到气孔与非气孔因素的双重影响,叶黄素循环的启动增加了胁迫条件下的热耗散能力以保护光合机构免受干旱胁迫的进一步伤害。     

玉米全生育期黄化材料的光合性能分析

通过对玉米(Zea mays L.)黄化材料和2份正常自交系的光合特性、光响应曲线及荧光动力学参数进行分析,结果表明,黄化材料yglm1的净光合速率(Pn)、气孔导度(Gs)和胞间CO2浓度(Ci)均显著低于正常自交系Mo17和RP128,而蒸腾速率(Tr)却显著高于正常自交系;黄化材料的光补偿点、光饱和点、暗呼吸速率及表观量子效率均高于正常自交系Mo17和RP128,但其净光合速率却低于正常自交系;黄化材料的荧光动力学参数初始荧光(Fo)、最大荧光(Fm)、PSⅡ原初光能转换效率(Fv/Fm)、PSⅡ原初光能捕获效率(Fv'/Fm')、PSⅡ光下实际光化学效率(ΦPSⅡ)、光化学猝灭系数(qP)均显著低于正常自交系Mo17和RP128,非光化学猝灭系数(qN)显著高于正常自交系。相对于正常自交系,黄化材料具有较低的电子传递潜力、原初光能捕获效率和转换效率、光能分配及利用率,这可能是导致其净光合能力降低的根本原因。     

外源ATP对NaCl胁迫下菜豆叶片叶绿素荧光特性的调节

盐胁迫是影响植物生长的主要逆境因子之一,外源ATP被发现可作为信号分子参与植物对逆境胁迫生理反应的调节。为了探明外源ATP在植物盐胁迫响应中的作用,以增强植物对土壤盐渍化的耐性,更好地应用于土壤盐渍化修复。该研究以菜豆( Phaseolus vulgaris)为材料,通过叶绿素荧光技术探讨了外源ATP 对菜豆叶片在NaCl胁迫下叶绿素荧光特性的变化规律。结果表明：在NaCl胁迫下,叶片光系统Ⅱ( PSⅡ)潜在最大光化学量子效率( Fv/Fm)、光适应下最大光化学效率( Fv′/Fm′)、PSⅡ光适应下实际光化学效率[ Y (Ⅱ)]、光化学荧光猝灭( qP)、电子传递速率( ETR)与对照组相比均有显著性下降,而非光化学猝灭( NPQ)和( qN)较对照组有显著性增加,这表明NaCl胁迫导致菜豆叶片光系统Ⅱ光化学效率的下降和光能耗散的增加。而外源ATP(eATP)的处理能有效缓解NaCl胁迫所造成的Fv/Fm、Fv′/Fm′、Y(Ⅱ)、qP、ETR下降和NPQ、qN的上升。该研究结果表明在NaCl胁迫下外源ATP可以有效地提高菜豆幼苗光系统Ⅱ( PSⅡ)的光化学反应效率。     

杂种杨无性系的光系统Ⅱ放氧活性、光合色素及叶绿体超微结构对光胁迫的响应

 用氧电极仪、红外CO2气体分析仪及叶绿素荧光仪,结合透射电镜技术对几个杂种杨无性系在光胁迫下的光系统Ⅱ活性、光合色素及叶绿体超微结构进行了测定。随着预处理光强的增加,各无性系叶片的净光合速率和光系统Ⅱ放氧活性明显下降。二倍体无性系B11的光系统Ⅱ最大光化学效率（Fv/Fm）及实际光化学效率［(Fm′-F)/Fm′］高于两个三倍体无性系B346和B342。强光下三倍体无性系B346的非光化学淬灭远高于B342和二倍体无性系B11。叶绿素含量和光合速率没有明显的线性关系,叶绿素a/b含量在自然光胁迫下存在季节变化,受强光胁迫2个三倍体无性系的叶绿素a/b增大。预处理光强PFD超过3 000 μmol photons·m-2·s-1,各无性系的基粒类囊体片层结构遭到破坏,但二倍体无性系的类囊体片层结构受破坏程度较三倍体无性系轻。叶绿体蛋白合成抑制剂（硫酸链霉素,SM）可加剧叶绿体超微结构的破坏。     

夜间高温胁迫对水稻叶片光合机构的影响

The net photosynthetic rate (Pn), the apparent quantum yield (AQY), the photochemical efficiency of PSⅡ(Fv/Fm), the quantum yield of PSⅡ electron transport (Ф PSⅡ) and the coefficient of photochemical quenching (qp) were decreased in rice (Oryza sativa L.) leaves under high nocturnal temperature (42±1) ℃ stress, but the relative reduction state of PSⅡ (1-qp) was increased. With the increment of stress time, the chlorophyll content and the binding degree of chlorophyll-protein complex declined gradually, the O2(superoxide radical) production rate and H2O2 content in leaves elevated. The activities of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) increased for 2-3 days under high temperature stress yet decreased afterwards. The results showed that the photosynthetic efficiency declined in rice leaves under high nocturnal temperature stress with concurrent emergence of the symptom of oxidative damage. The gradual increase of the SOD, POD and CAT activities, as well as that of the ratio of Pr (photo-respiration rate) to Pr+Pn and non-photochemical quenching of chlorophyll fluorescence (NPQ) indicates that those mechanisms related to the changes of these parameters may play an important role in protecting rice leaves from oxidative damage under high nocturnal temperature stress.     

重金属对盐生草光合生理生长特性的影响

以盐生草幼苗为试验材料,分别设置0(CK)、50、100、200、400μg?g-1的Ni2+、Cu2+处理,研究重金属Ni2+和Cu2+对盐生草光合生理特性的影响.结果表明:盐生草叶片光合色素含量、净光合速率(Pn)、气孔导度Gs、蒸腾速率Tr、PSⅡ最大光化学效率Fv/Fm、非光化学猝灭系数qN及生长指标(株高、地上部干重和鲜重)在50μg?g-1的Ni2+处理时均达到最大值,后随Ni2+浓度继续增加,其叶片叶绿素a、叶绿素b、Pn、Gs、Tr、Fv/Fm、PSⅡ电子传递量子产率ΦPSⅡ、光化学猝灭系数qP、qN及各项生长指标逐步下降并低于对照水平,而细胞间隙CO2浓度(Ci)较对照呈增加趋势.在50μg?g-1的Cu2+处理时,盐生草叶片光合色素含量、Pn、Gs、Tr、Ci、Fv/Fm、ΦPSⅡ、qP、qN及各项生长指标均达峰值;在100μg?g-1Cu2+处理时,光合色素含量、Pn、Gs、Tr、Fv/Fm、ΦPSⅡ、qN及各项生长指标较对照仍有增加,而后随Cu2+浓度继续增加,其叶绿素a、叶绿素b、各光合参数、叶绿素荧光参数及生长指标均逐步降低并低于对照.可见,盐生草Pn在Ni2+胁迫下的下降主要是由非气孔限制所致,而Cu2+胁迫下的下降主要是由气孔限制所致;低浓度Ni2+和Cu2+对盐生草生长具有一定促进作用,过高浓度Ni2+和Cu2+则会通过抑制盐生草叶片叶绿素合成,影响其光合作用,从而抑制植株生长.     

水华鱼腥藻生长与光合作用对大气CO2浓度升高的响应

 为了探讨大气CO2浓度升高对水华藻类的影响,利用水华鱼腥藻(Anabena flos_aquae)作为实验材料,研究了大气CO2浓度加倍对其生长和光合作用的影响,结果显示大气CO2浓度升高导致水华鱼腥藻的生物量、光饱和光合速率、光合效率和光系统II的光化学效率（Fv/Fm）明显提高,但对暗呼吸速率和光饱和点没有明显影响。CO2加倍条件下藻细胞光合作用对无机碳的亲和力降低,表明其利用HCO-3的能力受到抑制。     

交替呼吸途径对CuCl2胁迫下菜豆叶片光系统Ⅱ的保护作用

以“农普”12号菜豆幼苗为材料,采用1mmol·L^-1的水杨基氧肟酸（SHAM）抑制交替呼吸途径活性,探讨了在CuCl₂胁迫下交替呼吸途径对菜豆幼苗叶片光系统Ⅱ的保护作用。结果表明,随着CuCl₂胁迫浓度的增加,菜豆幼苗叶片潜在最大光化学效率F_v/F_m、光适应下叶片的最大光化学效率F_v'/F_m'、PSⅡ的实际光化学效率Y（Ⅱ）以及光化学猝灭系数qP、叶绿素含量均呈下降趋势,而非光学猝灭系数NPQ和交替呼吸途径的容量水平则呈上升趋势。较之在CuCl₂处理下的菜豆幼苗,用交替呼吸途径抑制剂预处理后的菜豆再置于CuCl₂的胁迫下,则会导致F_v/F_m、F_v'/F_m'、Y（Ⅱ）、qP以及叶绿素含量的进一步下降和NPQ的进一步上升。上述观察表明,在CuCl₂胁迫下交替呼吸途径可以缓解PSⅡ光化学效率的下降、维持PSⅡ反应中心的开放程度、减少天线色素的热耗散以及缓解叶绿素含量的降低,从而保护菜豆叶片光系统Ⅱ免受CuCl₂胁迫的伤害。     

An Analysis of the Mechanism of the Low-wave Phenomenon of Chlorophyll Fluorescence

The low-wave phenomenon, i.e., the transient drop of yield of modulated chlorophyll fluorescence shortly after application of a pulse of saturating light, was investigated in intact leaves of tobacco and Camellia by measuring fluorescence, CO(2) assimilation and absorption at 830 nm simultaneously. Limitations on linear electron flow, due to low electron acceptor levels that were induced by low CO(2), induced the low waves of chlorophyll fluorescence. Low-wave amplitudes obtained under different CO(2) concentrations and photon-flux densities yielded single-peak curves when plotted as functions of fluorescence parameters such as PhiPS II (quantum yield of Photosystem II) and qN (coefficient of non-photochemical quenching), suggesting that low-wave formation depends on the redox state of the electron transport chain. Low waves paralleled redox changes of P700, the reaction center of Photosystem I (PS I), and an additional electron flow through PS I was detected during the application of saturating pulses that induced low-waves. It is suggested that low waves of chlorophyll fluorescence are induced by increased non-photochemical quenching, as a result of the formation of a trans-thylakoid proton gradient due to cyclic electron flow around PS I.     

外源GSH对NaCl胁迫下番茄幼苗光合特性及碳同化关键酶基因表达的影响

对NaCl胁迫下番茄幼苗叶片分别喷施还原型谷胱甘肽(GSH)、氧化型谷胱甘肽(GSSG)和谷胱甘肽合成抑制剂(BSO)构建不同氧化还原水平的番茄植株,研究外源GSH介导的氧化还原状态对NaCl胁迫下番茄幼苗光合作用的影响.结果表明: 外源喷施GSH诱导NaCl胁迫下番茄幼苗叶片的还原力水平提高,叶片净光合速率(P_n)、气孔导度(g_s)、蒸腾速率(T_r)及最大光化学效率(F_v/F_m)、实际光化学效率(Ф_PSⅡ)、光化学猝灭系数(q_P)、非光化学猝灭系数(NPQ)值均提高,核酮糖-1,5-二磷酸羧化酶/加氧酶(Rubisco)活性及大亚基(RbcL)、小亚基(RbcS)和Rubisco活化酶(RCA)的基因表达水平上调,从而有效保护了光合系统,促进了(光系统Ⅱ)PSⅡ光化学反应活性、降低了NaCl胁迫对光合暗反应的抑制,缓解了NaCl胁迫对番茄植株的危害.喷施GSSG显著降低了NaCl胁迫下番茄幼苗叶片还原力水平,造成叶片光损伤和光抑制加剧,但RbcS和RbcL的基因表达水平上调可能是导致NaCl+GSSG处理下叶片P_n未下降的原因.喷施BSO对NaCl胁迫下番茄幼苗叶片氧化还原状态、CO₂传导能力和PSⅡ反应中心无显著影响,但BSO上调碳同化关键酶Rubisco初始活性、总活性及RCA和RbcS表达水平是导致P_n提高的原因.     

外源Ca2+对高温强光下西葫芦幼苗形态特征、光合特性及荧光参数的影响

选用西葫芦(Cucurbita pepo)品种“阿兰”一代为试验材料,研究了外源Ca²⁺处理对高温强光交叉胁迫下西葫芦幼苗生长特征、光合特性及叶绿素荧光参数的影响.结果表明：高温强光胁迫下,5～20 mmol·L^-1 Ca²⁺处理的西葫芦幼苗具有较高的株高和较大的叶面积,其叶绿素、类胡萝卜素含量及光合速率（P_n）、气孔导度（G_s）、蒸腾速率（T_r）、PSⅡ最大光化学效率(F_v/F_m)、PSⅡ实际光化学效率(Φ_PSⅡ)和光化学猝灭系数(q_P)均较高,而胞间CO₂浓度（C_i）和非光化学猝灭系数（NPQ）较低,其中以10 mmol·L^-1Ca²⁺处理效果最好.说明5～20 mmol·L^-1Ca²⁺处理能有效缓解高温强光对西葫芦光合机构的不可逆伤害,使其保持较快的光合电子传递速率和较高的PSⅡ电子传递活性.Ca²⁺处理浓度超过40 mmol·L^-1时对高温强光胁迫没有缓解效应.     

Studies on the Characteristics of Chlorophyll Fluorescence of Winter Wheat Flag Leaves at Different Developing Stages

The parameters of fluorescence induction kinetics and the maximal light-saturated net CO2 assimilation rate ( P sat ) of the flag leaves of four cultivars of winter wheat （Triticum aestivum L.） were compared at three different developing stages for the first time. From the blooming stage to the milky stage, the quantum efficiency of PSⅡ photochemistry ( Fv/Fm ) declined slightly only at the milk stage. The photochemical quenching co-efficient ( qP ), actual quantum yield of photosystem Ⅱ（PSⅡ）electron transport ( Φ PSⅡ) and P sat decreased substantially (>15%), while the non-photochemical quenching co-efficient ( qN ) increased significantly (>100%). There existed a linear correlation between the Φ PSⅡ and the P sat ( r =0.918). The results indicate that with the senescence of the flag leaves of winter wheat the photosynthetic efficiency including that of the energy transport and the CO2 assimilation significantly decreased.     

渗透胁迫对小麦幼苗叶绿素荧光参数的影响

用叶绿素荧光诱导动力学技术,研究模拟干旱条件对小麦幼苗叶片叶绿素荧光参数,即原初光能转化效率(F_v/F_m)、光合电子传递量子效率(φPSⅡ)、qP(光化学猝灭)、qNP(非光化学猝灭)、ETR(表观光合量子传递效率)的影响.结果表明,渗透胁迫对小麦幼苗叶绿素荧光参数影响较大.随着渗透胁迫的加剧,F_v/F_m和F_v/F_o都表现出现降低-增加-降低的趋势,在渗透胁迫2 h以前,小麦叶片内部没有发生光抑制,但随着胁迫的加剧,F_v/F_m值增加,使得小麦幼苗叶内发生光抑,导致ΦPSⅡ和ETR的下降;在渗透胁迫过程中,小麦叶片吸收光能的光化学猝灭(qP)的下降和光化学猝灭(qNP)呈现先降低后增加的趋势,说明小麦在受到干旱胁迫前期,PSⅡ反应中心的开放比例降低;在胁迫2h后,随着胁迫的加剧,qP和qNP增加有利于提高PSⅡ反应中心开放部分的比例,将更多的光能用于推动光合电子传递,提高了光合电子传递能力,同时非光化学能量耗散的提高,有助于耗散过剩的激发能,以保护光合机构,缓解环境胁迫对光合作用的影响,体现了小麦叶片的自我保护机制.两个品种相比,长武13的叶绿素荧光参数的变化幅度比陕253小,具有更强的抵御干旱胁迫的能力.     

光强转换对不同生长环境下桑树叶片光化学效率的影响

以桑树品种‘蒙古桑’为试验材料,利用叶绿素荧光技术研究了光强转换对生长在不同光强下的桑树叶片实际光化学效率(ΦPSⅡ)、电子传递速率(ETR)和非光化学淬灭(NPQ)的影响,分析了非光化学淬灭(NPQ)3个组分的变化.结果表明:当光强从黑暗或弱光转换到自然光条件下,自然光桑树叶片的光量子转化效率高于弱光叶片,ΦPSⅡ、ETR诱导平衡较快,NPQ诱导呈先升后降趋势.自然光叶片在强光下状态转换淬灭组分(qT)占NPQ的18%,而弱光叶片qT仅占NPQ的7%.与弱光桑树叶片相比,自然光桑树叶片可以通过较高的光量子转化效率和较强的调节激发能在PSⅠ和PSⅡ之间的分配能力来适应光强的变化.