盐胁迫对裸果木幼苗光合特性的影响  

Effects of salt stress on photosynthetic characteristics of Gymnocarpos przewalskii seedlings

作　　者：周晓瑾 黄海霞[1] 张君霞[1] 马步东 陆刚 齐建伟 张婷[1] 朱珠 ZHOU Xiao-jin;HUANG Hai-xia;ZHANG Jun-xia;MA Bu-dong;LU Gang;QI Jian-wei;ZHANG Ting;ZHU Zhu(College of Forestry,Gansu Agricultural University,Lanzhou 730070,China)

机构地区：[1]甘肃农业大学林学院,甘肃兰州730070

出　　处：《草业学报》2023年第2期75-83,共9页Acta Prataculturae Sinica

基　　金：甘肃农业大学学科建设专项基金(GSAU-XKJS-2018-110);甘肃农业大学学科建设专项基金(GSAU-XKJS-2018-100)资助;甘肃省自然科学基金项目(17JR5RA144)。

摘　　要：本研究以一年生裸果木幼苗为材料,采用盆栽育苗方式,设计7个不同浓度Na Cl溶液(CK、0.2%、0.4%、0.6%、0.8%、1.0%和1.2%)模拟盐分胁迫,测定分析了其叶片气体交换参数、光响应曲线及叶绿素荧光参数的变化规律。结果表明:随着盐浓度的增加,叶片净光合速率(P_(n))、气孔导度(G_(s))和蒸腾速率(T_(r))均呈下降趋势,NaCl浓度≥0.4%时,各处理P_(n)、G_(s)和T_(r)均显著低于CK;气孔限制值(L_(s))和瞬时水分利用效率(WUE)随盐浓度增加呈先升后降趋势,胞间CO_(2)浓度(C_(i))呈相反趋势,NaCl浓度为0.4%时,L_(s)达到最大值,而C_(i)达到最小值,说明P_(n)下降以气孔限制因素为主,而当Na Cl浓度≥0.6%时,以非气孔限制为主要因素。随着盐胁迫程度的增大,最大净光合速率(P_(nmax))、暗呼吸速率(R_(d))、光饱和点(L_(SP))、表观量子效率(A_(QY))逐渐降低,光补偿点(L_(CP))逐渐增加,表明盐分抑制了幼苗对光的吸收、利用和转换能力。叶片PSII潜在活性(F_(v)/F_(0))、原初光能转化效率(F_(v)/F_(m))、实际光化学效率(ΦPSII)、电子传递速率(ETR)和光化学猝灭系数(q_(p))随着盐浓度的增加呈下降趋势;非光化学猝灭系数(NPQ)在≤0.4%NaCl处理下较CK显著增加,盐浓度≥0.8%时,NPQ显著下降。基质的Na Cl浓度在0.2%和0.4%时,裸果木叶片P_(n)、F_(v)/F_(0)、F_(v)/F_(m)下降不显著,WUE有所提高,PSII系统可以通过耗散过剩的光能保护光合机构,表现出一定的耐盐性;但盐浓度超过0.6%时,光合生态幅变窄,光合机构受到明显破坏,显著抑制了光合作用能力。This research examined the effect of salt stress on photosynthesis responses in potted seedlings of the annual plant Gymnocarpos przewalskii.Salt stress was simulated using seven Na Cl solutions of different concentrations(CK,0.2%,0.4%,0.6%,0.8%,1.0% and 1.2%)and changes in leaf gas exchange parameters,light response curves and chlorophyll fluorescence parameters were determined and analyzed.It was found that with increasing salt concentration,leaf net photosynthetic rate(P_(n)),stomatal conductance(G_(s))and transpiration rate(T_(r))all showed a downward trend.At Na Cl concentrations≥0.4%,P_(n),G_(s)and T_(r)were all significantly lower than in CK plants.Stomatal limit value(L_(s))and instantaneous water use efficiency(WUE)showed an initial upward with a maximum value in the 0.4%NaCl treatment,and then a downward trend at higher NaCl concentrations.Intercellular CO_(2)concentration(C_(i))showed the opposite trend,reaching its minimum value when the NaCl concentration was less than or equal to 0.4%.The decrease in P_(n)was mainly due to non-stomatal limitation when the NaCl concentration was equal to or greater than 0.6%,at lower Na Cl levels,stomatal limitation was the main factor.As the degree of salt stress increased,the maximum net photosynthetic rate(P_(nmax)),dark respiration rate(R_(d)),light saturation point(L_(SP))and the apparent quantum efficiency(A_(QY))all gradually decreased,while the light compensation point(L_(CP))gradually increased,indicating salt inhibits the ability of seedlings to absorb,utilize and convert light.Leaf PSII potential activity(F_(v)/F_(0)),light energy conversion efficiency(F_(v)/F_(m)),actual photochemical efficiency(ΦPSII),electron transfer rate(ETR)and photochemical quenching coefficient(qp)all showed decreases with increasing salt concentration.The non-photochemical quenching coefficient(NPQ)was significantly increased compared with CK at NaCl concentrations≤0.4%,but was significantly decreased when the salt concentration was≥0.8%.At NaCl concentrations in the seedli

关 键 词：裸果木 光合作用 光响应曲线 叶绿素荧光参数 

分 类 号：Q945.78[生物学—植物学]