两种春小麦幼苗光合特性对盐胁迫的响应比较

Comparison of photosynthetic characteristics of two spring wheat seedlings to salt stress

【目的】通过测定比较不同浓度盐处理下‘陇春27号’和‘陇春30号’小麦幼苗的光合色素含量及光合作用参数,研究并揭示其耐盐性,从而为甘肃盐渍化土壤的小麦增产提供理论支持.【方法】采用水培法,用不同浓度的NaCl(25、100、200 mmol/L)分别处理幼苗,6 d后利用浸提法测定光合色素含量、TPS-2光合系统测定气体交换参数、PAM-2500荧光仪测定叶绿素荧光参数等指标.【结果】25 mmol/L NaCl处理下2种小麦的干鲜质量显著升高,随后逐渐降低,且200 mmol/L NaCl处理对‘陇春27号’小麦的干鲜质量抑制较明显.25、100 mmol/LNaCl处理下2种小麦的光合色素含量逐渐增加,而200 mmol/L NaCl处理显著降低.与对照相比,不同盐处理下2种小麦的蒸腾速率(Tr)、气孔导度(Gs)、净光合速率(Pn)逐渐降低而胞间CO2浓度(Ci)逐渐升高,且‘陇春30号’小麦各项指标的变化更稳定.‘陇春27号’和‘陇春30号’小麦的光化学淬灭系数(qP)、表观电子传递速率(ETR)、实际光量子产量[Y(Ⅱ)]分别在25 mmol/L和100 mmol/L NaCl处理下达到最大值;2种小麦的非光化学猝灭系数(NPQ)和调节性能量耗散的量子产量(Y(NPQ))在25、100 mmol/L NaCl处理下均显著降低,200 mmol/L下显著升高.潜在最大光量子产量(Fv/Fm)、光系统Ⅱ潜在活性(Fv/F0)和非调节性能量耗散的量子产量(Y(qP))皆无明显变化.【结论】低浓度盐可通过提高两种小麦幼苗的光合特性促进其生长,而高浓度盐对‘陇春27号’小麦光合作用参数的的影响较大,说明‘陇春30号’小麦的耐盐性更高,更适宜种植在高浓度盐渍化土壤中.

【Objective】To study and reveal the salt tolerance of spring wheat seedlings Longchun 27 and Longchun 30 treated with different concentrations by measuring and comparing the photosynthetic pigment content and photosynthesis parameters,to provide the theoretical support for the wheat yield increased in the saline soil of Gansu province.【Method】The seedlings of Longchun 27 and Longchun 30 were treated with different NaCl concentrations(25,100,200 mmol/L)by hydroponic method.After 6 d of treatment,the photosynthetic pigment was determined by extraction,the gas exchange parameters were measured by TPS-2 photosynthetic system and chlorophyll fluorescence was analyzed by PAM-2500 fluorescence instrument.【Result】The dry weight of two seedlings treated with 25 mmol/L NaCl elevated significantly,then decreased gradually,and the 200 mmol/L NaCl treatment inhibited the dry weight of Longchun 27.The photosynthetic pigment content of two seedlings increased gradually under the treatment of 25 and 100 mmol/L NaCl,while decreased significantly under the treatment with 200 mmol/L NaCl.Compared with the control,the transpiration rate(Tr),stomatal conductance(Gs)and net photosynthetic rate(Pn)of two seedlings decreased gradually while the intercellular CO2 concentration(Ci)gradually increased,but the changes in the indicators of Longchun 30 were more stable.The maximum value of photochemical quenching coefficient(qP),apparent electron transport rate(ETR),and actual photon yield[Y(Ⅱ)]of Longchun 27 and 30 reached under 25 mmol/L and 100 mmol/L NaCl;the non-photochemical quenching coefficient(NPQ)and the quantum yield of regulatory energy dissipation(Y(NPQ))of two seedlings were significantly reduced under the treatment of 25 and 100 mmol/L NaCl,but significantly elevated at 200 mmol/L.There was no significant change in the potential maximum quantum yield(Fv/Fm),photosystem II potential activity(Fv/F0),and quantum yield of non-regulated energy dissipation(Y(qP)).【Conclusion】Low-concentration salts promoted the growth of two spring wheat seedlings by improving their photosynthetic characteristics,while high-concentration salt has greater influence on the photosynthesis parameters of Longchun 27,indicating that the Longchun 30 has higher salt tolerance and is more suitable for planting in high concentration in salinized soil.