Water use efficiency by alfalfa: Mechanisms involving anti-oxidation and osmotic adjustment under drought
Water use efficiency by alfalfa: Mechanisms involving anti-oxidation and osmotic adjustment under drought
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苜蓿的水分利用效率：干旱条件下的抗氧化和渗透调节机制
DOI：
10.1134/s1021443712020033
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发表时间：
2012-05-01
影响因子：
1.4
通讯作者：
Yang, H.
中科院分区：
文献类型：
--
作者：
He, Sh.;Liu, G.;Yang, H.
以紫花苜蓿（Medicago sativa L.）为研究材料，研究了水分利用率降低条件下植物的水分利用及其渗透调节和抗氧化机制。采用温室盆栽试验，测定了3个紫花苜蓿品种在3种土壤水分有效度条件下的水分利用效率、丙二醛和脯氨酸含量及抗氧化酶活性。用水效率通过判别碳同位素组成间接测定。水分利用效率随水分亏缺程度的增加而增加。在所有审查的水制度下，cv。在50%的土壤田间水量下，陇东的WUE值最大，生物量产量减少最少。气孔密度随水分亏缺量的增加而增加，气孔导度降低。这表明水分胁迫可以通过改变气孔对CO2同化速率和水分损失率之间平衡的调节来提高水分利用效率。叶片生理功能和水分状态的维持表明，紫花苜蓿在水分亏缺时具有维持细胞功能的机制。干旱条件下MDA含量的增加表明细胞膜在一定程度上的损伤是不可避免的，而其他结果显示脯氨酸和可溶性糖含量以及超氧化物歧化酶、过氧化物歧化酶和过氧化氢酶活性的增加表明细胞功能可能在一定程度上得到维持，从而导致更高的水分利用效率。紫花苜蓿在水分利用效率方面表现出不同品种的差异，水分亏缺条件下细胞功能的维持与抗氧化和渗透调节有关。
Water use and mechanisms relating to osmotic adjustment and anti-oxidation were investigated in alfalfa (Medicago sativa L.) plants under reduced water availability. Water use efficiency (WUE), MDA and proline contents, and antioxidant enzyme activities were measured in three alfalfa cultivars under three levels of soil water availability in a greenhouse pot experiment. WUE was determined indirectly using discriminating carbon isotope composition. WUE increased with the severity of water deficit. Under all water regimes examined, cv. Longdong showed the greatest WUE values and the least reduction in biomass production under a 50% soil field water capacity. Stomatal density increased with increasing water deficit, but stomatal conductance decreased. This suggests that water stress can increase WUE by modifying stomatal regulation of the balance between the rates of CO2 assimilation and water loss. The maintenance of leaf physiological function and leaf water status suggests that alfalfa has some mechanisms to maintain cell function when the plant is subjected to water deficit. The increase in the MDA content under drought conditions indicates that some degree of damage to cell membranes is unavoidable, whereas other results showing increases in the contents of proline and soluble sugars and activities of superoxide dismutase, peroxide dismutase, and catalase indicate how cell function may be to some extent maintained to result in the higher WUE. Alfalfa is shown to exhibit cultivar-specific differences in WUE with the maintenance of cell function under water deficit being related to anti-oxidation and osmotic adjustment.