干旱胁迫下苎麻种质的生理生化特性研究

Physiological and Biochemical Characteristics of Ramie Germplasms under Drought Stress

通过旱池试验研究干旱胁迫下三种不同根型苎麻品种和不同生长期苎麻的生理生化指标变化 ,探讨苎麻抗旱性与这些指标的关系。干旱胁迫使苎麻叶片含水量、自由水 束缚水比值、净光合强度及硝酸还原酶活性下降 ,但抗旱性品种下降较少 ;而K+ 、可溶性糖、脯氨酸、丙二醛浓度及原生质膜相对透性 (RPP)、过氧化物酶和过氧化氢酶 (CAT)活性增大。同不抗旱性品种比较 ,抗旱品种K+ 浓度增幅较大 ,而脯氨酸、丙二醛含量及RPP和CAT活性增幅较小。不同生长期、不同根型苎麻在干旱胁迫下这些指标亦存在差异。干旱下叶片含水量、RPP、丙二醛和脯氨酸含量、CAT活性和净光合强度的变化与抗旱性关系密切 。

This experiment aims to reveal the relation of ramie drought resistance with some biochemicalphysiological indices by examining the changes of the tested indices under drought stress for ramie varieties of different root-types and in different growth stage. Under drought stress, water content (WC), free water/bound water (Fw/Bw), net photosynthetic rate (Pn) and nitratase activity in leaves were decreased in comparison with CK. But these indices were decreased less in drought resistant varieties. While the concentration of K +, soluble sugar, proline and malondialdehyde (MDA), relative permeability of protoplast membrane (RPP) and activity of peroxidase and catalase were increased. But the drought resistant varieties had a greater inccrease in K + concentration, and less increase in proline, MDA, RPP and catalase activity comparing to the non drought resistant varieties. Differences were also observed for the tested indices in varieties of different root types and in different growth stages. The results revealed a close correlation of changes in WC, RPP, MDA, proline, catalase activity and Pn under drought stress with drought resistance of the tested ramie varieties. This could be used for the identification of drought resistance for ramie germplasms in early stage.