| 水分胁迫和复水对紫花苜蓿幼苗叶绿素荧光特性的影响 |
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| 引用本文： | 李文娆,张岁岐,山仑.水分胁迫和复水对紫花苜蓿幼苗叶绿素荧光特性的影响[J].草地学报,2007,15(2):129-136. |
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| 作者姓名： | 李文娆 张岁岐 山仑 |
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| 作者单位： | 中国科学院水利部水土保持研究所,黄土高原土壤侵蚀与旱地农业国家重点实验室,陕西,杨凌,712100;中国科学院研究生院,北京,100039;中国科学院水利部水土保持研究所,黄土高原土壤侵蚀与旱地农业国家重点实验室,陕西,杨凌,712100;西北农林科技大学,陕西,杨凌,712100 |
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| 基金项目： | 中国科学院知识创新工程项目
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中国科学院水土保持研究所领域前沿科研专项经费资助项目 |
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| 摘 要： | 利用PEG-6000模拟水分胁迫(ψs=-0.2MPa,胁迫时间:48 h,复水48 h),研究了紫花苜蓿(Medicago sativa L)品种陇东苜蓿和阿尔冈金叶片叶绿素荧光特性和光合色素含量的变化,旨在探讨紫花苜蓿水分胁迫条件下的光合反应机制.结果表明:光化学淬灭系数(qP)和PSII线性电子传递的有效量子产额(YIELD)以及非光化学淬灭系数(qN)和表观光合电子传递效率(ETR)在胁迫前后随光合有效辐射(PAR)的变化规律分别可用公式:Y=aLn(X) b(Y:qP或YIELD,X:PAR,X≠0)和Y=aX2 bX c(Y:qN或ETR,X:PAR)来表示;在受到干旱胁迫后,PSII最大光能转化效率(Fv/Fm)、PSII潜在活性(Fv/Fo)和光合色素含量均明显低于对照,在任意光强下的qP、YIELD和ETR值也极显著低于对照的相应值,qN值则极显著高于对照的相应值;同时,和对照相比,qN和ETR光响应曲线顶点所对应的光强值在受到胁迫后亦明显下降,表明光抑制初始点的降低和最大光保护能力的减弱,甚至光抑制的提前到来.干旱胁迫使得PSⅡ反应中心结构和功能遭到破坏而部分关闭,光合电子传递受阻,光能利用与光化学转化与能力下降,吸收的光能更多的以热能形式耗散.复水后,虽然有光保护机制的存在,但除陇东苜蓿光合色素含量及阿尔冈金类胡萝卜素外,各参数均未能恢复到对照水平,因此旱后复水不能完全解除干旱对PSII反应中心所带来的伤害.紫花苜蓿幼苗对干旱胁迫较为敏感.供试品种相比,陇东苜蓿耐旱性优于阿尔冈金.
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| 关 键 词： | 水分胁迫 复水 紫花苜蓿 叶绿素荧光特性 光合色素含量 |
| 文章编号： | 1007-0435（2007）02-0129-08 |
| 收稿时间： | 2006-08-28 |
| 修稿时间： | 2006-12-04 |
Effect of Water Stress and Rehydration on the Chlorophyll Fluorescence Characteristics of Alfalfa Seedling Leaves |
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| LI Wen-rao,ZHANG Sui-qi,SHAN Lun.Effect of Water Stress and Rehydration on the Chlorophyll Fluorescence Characteristics of Alfalfa Seedling Leaves[J].Acta Agrestia Sinica,2007,15(2):129-136. |
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| Authors: | LI Wen-rao ZHANG Sui-qi SHAN Lun |
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| Institution: | 1. State Key Lab. of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources, Shaanxi Province 712100, China; 2. Northwest Sci-Tech University of Agriculture and Forestry, Yangling, Shaanxi Province 712100, China 3. Graduate School of Chinese Academy of Sciences, Beijing 100039, China |
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| Abstract: | Water stress mimicked by PEG-6000 solution (ψs =- 0.2 MPa, stress period 48 h, then rehydration 48 h) was performed on leaves of alfalfa (Medicago sativa L) varieties of Longdong and Algonquin seedlings. Chlorophyll fluorescence parameters and photosynthetic pigments concentration were measured. These measurements were used to investigate the available photosynthetic response mechanism to different water conditions. The results show that the change patterns of photochemical quenching (qP) and the effective quantum yield of PSII photochemistry (YIELD) with the increasing of the active radiation of photosynthesis (PAR) could be expressed by the equation:Y=a Ln(x)+b (Y:qP or YIELD, X:PAR,X≠0) and the change patterns of non-photochemical quenching (qN) and the relative electron transport rate (ETR) with the increasing of PAR could be expressed by the equation:Y=aX2+bX+c (Y:qN orETR, X: PAR). Significantly, the maximal photochemical efficiency of PSⅡ in the dark (Fv/Fm),potential activity of PSII (Fv/Fo)and photosynthetic pigments concentration in alfalfa leaves decreased obviously subjected to water stress. Simultaneously, the values of qP, YIELD and ETR in stress treatments were decreased significantly and the values of qN in stress treatments were increased obviously under every PAR. More particularly, the light intensities corresponding to the top point of light response curve of qN and ETR declined submitted to water stress. Compared to the controls, the initial point of photo-inhibition and the maximum photo-protection ability decreased, or photo-inhibition occurred in advance. It indicated that photosynthetic apparatuses and functions were inhibited by water stress, which weakened the light energy utilization and transform capability of PSII reaction center and light energy dissipated through heat energy mostly. After rehydration, all parameters except photosynthetic pigments concentration in Longdong and carotenoid in Algonquin partly recovered only to the level of the control though photo-protection might be triggered under water stress in alfalfa leaves. Therefore, rehydration did not countervail the damage induced by water stress in PSII reaction center completely. Alfalfa seedlings were sensitive to water stress, and the tolerance to water stress of Longdong was higher than that of Algonquin. |
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| Keywords: | Water stress Rehydration Alfalfa Chlorophyll fluorescence characteristics Photosynthetic pigments concentration |
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