水分胁迫对云锦杜鹃抗氧化系统和脂类过氧化的影响

 以盆栽年生云锦杜鹃苗木为材料, 分别设对照、轻度胁迫、中度胁迫、重度胁迫个处理,研究土壤水分胁迫对云锦杜鹃叶片脂类过氧化及抗氧化系统的影响。结果表明与对照和轻度胁迫相比,中度和重度胁迫导致了活性氧产生速率、丙二醛含量、脯氨酸含量、质膜透性和过氧化物酶活性显著升高谷胧甘肤含量、类胡萝卜素含量和过氧化氢酶活性显著降低。而抗坏血酸含量、超氧化物歧化酶活性和抗坏血酸过氧化物酶活性则在中度水分胁迫下上升, 重度水分胁迫下下降。过度水分胁迫导致脂类过氧化严重, 对云锦杜鹃生长造成一定的伤害。

Effects of Water Stress on Antioxidant System and Lipid Peroxidation in Leaves of Rhododendron fortunei

Rhododendron fortunei is one of the famous ornamental flowers in China, but its water condi- tions for growth are less known. Effects of soil water stress on antioxidant system and lipid peroxidation in the leaves of R.fortunei were investigated by using 5-year-old pot-cultured seedlings as experimental materials and exposing them to different levels of water stress. Twelve pots of plant seedlings with a similar growth were di- vided into 4 groups: no stress(control), light stress, moderate stress and heavy stress. In comparison with no stress and light water stress, the moderate stress and heavy stress resulted in significant increases in the malon- dialdehyde(MDA)content, generating rate of superoxide anion(O_2),proline content, peroxidase(POD) activity and membrane permeability of leaf cells and significant decreases in glutathione(GSH)contents, ca- rotenoid content and catalase(CAT)activity. However, the content of ascorbic acid(AsA),activities of su- peroxide dismutase(SOD)and ascorbate peroxidase(APX)exhibited another trend, i.g. increased under moderate water stress, but declined under heavy water stress. The present conclusion is that R. fortunei growth can be inhibited through enhancing lipid peroxidation under heavy water stress.