高羊茅和钝叶草对土壤缓慢水分胁迫的响应差异

Response differences to water stress of Festuca arundinacea and Stenotaphrum secundatum

以草坪草高羊茅(Festucaarundinacea)和钝叶草(Stenotaphrumsecundatum)为材料,研究了盆栽条件下2种草的叶片和根系的质膜透性、抗氧化酶活性及膜脂过氧化产物丙二醛(MDA)含量等生理性状对土壤缓慢干旱胁迫(生长60d,覆盖率达95%以上后断水处理)的响应。结果表明,在干旱胁迫下,高羊茅的土壤含水量下降比钝叶草更为迅速,相对电导率和MDA含量的增加幅度也相应高于钝叶草。SOD、POD、CAT3种抗氧化酶活性均表现出先升后降的变化,高羊茅抗氧化酶活性的下降时期出现的比钝叶草早。在相同程度的干旱胁迫下,由于植物失水速度差异所引起的植物细胞受伤害程度、体内膜脂过氧化物含量及活性氧保护酶活性出现下降时期上的差异可能是2种草坪草抗旱性机制差异的一个重要原因。

Changes in the plasma membrane permeability, the activity of three kinds of antioxidant enzymes, and the malondialdehyde (MDA) content of leaves and roots under slowly increasing water stress (plant watering stopped after plant coverage reached 95% or above) were studied for the cool-season turfgrass, Festuca arundinacea cv Houndog and warm-season turfgrass, Stenotaphrum secundatum cv Bitter blue grown in pots. The results showed that under water stress, the soil volumetric water content of tall fescue decreased more quickly than that of S.secundatum, and the plasma membrane permeability and MDA content of F.anundinacea had greater increase. SOD, POD and CAT all showed an increase in activity in the early phase after watering was stopped and then a decrease in activity with further increase in water stress, and the activity decrease occurred sooner for F.anundinacea than S.secundatum. It is suggested that under the same level of water stress, differences in speed of plant water loss affecting the level of cell damage, MDA content, and differences in the times of activity decrease of SOD, POD and CAT, may be an important reason for the differences between the drought resistance mechanisms of the two turfgrasses.