干旱胁迫下沙棘膜脂过氧化保护体系研究

研究了干旱胁迫下沙棘幼林苗木自由基清除系统活性与沙棘耐旱性的关系.结果表明:长期轻度及中度干旱胁迫下保护酶系统SOD、POD、CAT活性均高于正常水平,重度干旱下3种酶活性均能在胁迫初期随时间延长而上升;抗氧化物质AsA在轻度、中度干旱下高于对照,GSH含量在轻度干旱下含量与对照接近,中度及重度干旱下前、中期随时间延长趋于增加,而后期降低,表明干旱下自由基清除系统活性高,能有效减轻膜脂过氧化伤害,细胞膜透性和MDA含量增加不明显.由于沙棘保护酶体系(SOD、POD、CAT)、抗氧化物质(AsA、GSH)、细胞膜透性和MDA含量增加缓慢,重度干旱下也能在一定时间内保持稳定,这些物质是构成沙棘强耐旱性的内在基础.

Seabuckthorn Membrane-lipid Peroxidation System under Drought Stress

Relationship between the ability of scavenge system of active oxygen mechanism and the drought resistance were analyzed. The main results showed: the activity of protective enzyme system SOD,POD and CAT were higher or a little lower than those of control in a long term stress under light and medium water stress, which increased slowly or kept stable at the early days under serious water stress. Antioxidant (AsA) fell a bit under light and medium water stress. The content of GSH was close to that of control under light water stress, while it dropped under medium and serious water stress but had a tendency to gain at early and middle stage. This showed that the ability of scavenge system of active oxygen was high and can lessen the membrane lipid peroxidation injury effectively. Owing to the protective enzyme system ( SOD, POD and CAT), antioxidant (AsA and GSH) and osmotic adjustment solutes(soluble sugars, free amino acids and proline ) worked in coordination,which made solute protein decomposed in small quantities,at the same time,permeability of plasma membrane and MAD increased slowly under long light and middle drought stress and grew by a small margin in certain time even under serious water stress.So,these materials and physiological mechanism were inherent basis of superior drought tolerance of seabuckthorn.