多年生黑麦草对干旱-低温交叉适应的生理响应

草坪草在冬季的时候常常面临着干旱和低温的双重胁迫,严重影响着春季返青时草坪草的质量。为了探讨多年生黑麦草的干旱-低温胁迫交叉适应的生理机制,以多年生黑麦草“爱神特(Accent)”为植物材料,设置3个水分梯度,土壤相对含水量分别为30%(重度胁迫)、60%(中度胁迫)、100%(良好浇水)。处理5 d后在人工气候箱中进行低温处理(2℃)15 d。低温胁迫使多年生黑麦草的叶片相对含水量、叶绿素含量显著降低,电解质渗漏、脯氨酸、可溶性总糖、抗氧化酶的含量增加。3种水分处理条件下,经过中度干旱处理后的多年生黑麦草的叶片相对含水量、叶绿素含量的降低幅度减小,但脯氨酸、可溶性糖、抗氧化酶的含量增加显著。实验结果表明多年生黑麦草对干旱-低温胁迫具有交叉适应能力。适当地进行干旱处理有利于提高多年生黑麦草对低温胁迫的适应能力。但值得注意的是,严重的干旱处理会造成过度伤害,致使植株更快死亡。

Cross adaptation under drought and low temperature stress in perennial ryegrass

Turfgrass suffers from both drought and cold stress in winter which degrades turf quality in the following spring. In order to investigate the physiological mechanism of cross adaptation to drought and low temperature stress in perennial ryegrass “Accent” turf ryegrass was subjected to three watering regimes (30%, 60% and 100% of requirements) for 5 days and then exposed to 2℃ temperatures day and night for 15 days. The results showed that low temperature stress decreased the relative water content (RWC) and chlorophyll (Chl) content but increased electrolyte leakage (EL), proline, soluble sugar and antioxidant enzymes. Mild drought stress before exposure to cold stress produced a significantly lower reduction in RWC and Chl content but increased osmotic adjustment and antioxidant enzymes. It was concluded that moderate drought prior to exposure to low temperatures helped perennial ryegrass adapt to low winter temperatures but severe drought caused considerable damage to plants.