| Ca2＋对镉胁迫下玉米幼苗生长、光合特征和 PSⅡ功能的影响 |
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| 引用本文： | 王玉萍,常宏,李成,梁延超,卢萧.Ca2＋对镉胁迫下玉米幼苗生长、光合特征和 PSⅡ功能的影响[J].草业学报,2016,25(5):40-48. |
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| 作者姓名： | 王玉萍 常宏 李成 梁延超 卢萧 |
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| 作者单位： | 甘肃农业大学园艺学院，甘肃 兰州 730070;甘肃省作物遗传改良与种质创新重点实验室，甘肃省干旱生境作物学重点实验室，甘肃农业大学，甘肃 兰州 730070;甘肃省种子管理总站,甘肃 兰州,730000;甘肃省作物遗传改良与种质创新重点实验室，甘肃省干旱生境作物学重点实验室，甘肃农业大学，甘肃 兰州 730070 |
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| 基金项目： | 国家自然科学基金(31060063，31260094)，甘肃省财政厅高等学校基本科研业务费资助。 |
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| 摘 要： | 为探究钙(Ca~(2+))对玉米镉(Cd)胁迫的缓解作用,采用盆栽试验,研究了根部施加外源Ca~(2+)对Cd胁迫下玉米幼苗生长、光合特征及叶绿素荧光参数等生理指标的影响。结果显示,与对照(CK)相比,100mg/L的Cd处理显著降低了玉米幼苗株高、根、地上部生物量以及玉米叶片叶绿素a、叶绿素b和总叶绿素含量。同时,净光合速率(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)、电子传递速率(ETR)、PSⅡ激发能捕获效率(F_v′/F_m′)、光化学淬灭系数(qP)和PSⅡ实际光化学效率(Φ_(PSⅡ))显著下降,而非光化学淬灭系数(NPQ)和胞间CO_2浓度(C_i)较CK显著上升。外源施加Ca~(2+)可以有效增加镉胁迫下幼苗生物量的积累,明显提高叶绿素a、叶绿素b和叶绿素总量,升高P_n,G_s,T_r,F_v/F_m,ETR,F_v′/F_m′,降低NPQ和C_i,增加幼苗生物量积累,Ca~(2+)浓度为7.5~10.0mmol/L时各指标变化幅度最明显,缓解胁迫的效果最佳。研究结果表明,Cd胁迫使玉米幼苗叶片PSⅡ原初光能转化效率降低,电子传递受到抑制,净光合速率降低。适宜浓度的外源Ca~(2+)能有效缓解Cd对光合机构的伤害,增强幼苗叶片对光的捕获能力,促进光合作用,增加幼苗的生物量,增强玉米幼苗对Cd胁迫的抗性。
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| 关 键 词： | 镉胁迫 玉米 钙 光合特性 PSⅡ 功能 |
| 收稿时间： | 2015-05-12 |
Effects of exogenous Ca2+ on growth,photosynthetic characteristics and photosystem II function of maize seedlings under cadmium stress |
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| WANG Yu-Ping,CHANG Hong,LI Cheng,LIANG Yan-Chao,LU Xiao.Effects of exogenous Ca2+ on growth,photosynthetic characteristics and photosystem II function of maize seedlings under cadmium stress[J].Acta Prataculturae Sinica,2016,25(5):40-48. |
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| Authors: | WANG Yu-Ping CHANG Hong LI Cheng LIANG Yan-Chao LU Xiao |
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| Abstract: | To investigate how calcium relieves cadmium toxicity in maize,the effects of exogenous Ca2 + on growth properties,photosynthetic characteristics and chlorophyll fluorescence parameters of maize seedlings under cadmium stress were studied in a pot experiment.A treatment with 100 mg/L of cadmium obviously in-hibited the growth of maize seedlings,decreased the biomass of plants,and decreased the contents of chloro-phyll a,b and a+b of leaves.At the same time,the net photosynthetic rate (P n ),stomatal conductance (G s ), transpiration rate (T r ),the maximal PSⅡ efficiency (F v/F m ),photosynthetic electron transfer rate (ETR), the efficiency of excitation energy capture by open PSⅡ centers (F v′/F m′),photochemical quenching coeffi-cient (qP ),and the actual PS Ⅱ efficiency (ΦPSⅡ )were reduced whereas the intercellular CO2 concentration(C i )and non-photochemical fluorescence quenching coefficient (NPQ)were increased under cadmium stress.Supply of exogenous Ca2 + under cadmium stress promoted the growth of seedlings,increased the biomass ofplants and raised the contents of chlorophyll a,b and a+b of leaves.At the same time,P n ,G s ,T r ,F v/F m ,ETR,F v′/F m′,qP andΦPSⅡ of leaves tended to be increased with increased exogenous Ca2 + concentration,but C i and NPQ were reduced.Among different Ca2 + application rates,7 .5 to 1 0.0 mmol/L Ca2 + had the greatestalleviation of Cd toxicity effects.It is suggested that Cd stress led to a decrease in the photochemical efficiencyof PSⅡ,reduction in electron transfer,and reduction in net photosynthetic rate.Exogenous Ca2 + at appropriatecon centrations had favorable effects on seedling growth,including enhanced performance of the photosyntheticapparatus and capture of solar energy,effectively ameliorate Cd-induced depression of photosynthesis and enhancingthe resistance of maize seedlings to Cd stress. |
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| Keywords: | cadmium stress maize (Zea mays ) calcium photosynthesis characteristics PSⅡ function |
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