草酸预处理对辣椒叶片抗热性的影响

研究了 40℃热胁迫下辣椒叶片中膜透性、膜脂过氧化、抗坏血酸 (ascorbate,As A)和还原态谷胱甘肽(glutathione,GSH)含量以及过氧化物酶、草酸氧化酶活性的变化 .在热胁迫处理前 3d用草酸溶液 (p H6 .5 )喷洒叶片 .结果表明 :草酸预处理能减轻热胁迫对细胞膜的伤害 (以电解质渗漏表示 ) ,在一定程度上能抑制丙二醛(malondialdehyde,MDA)和 H2 O2 的产生 ;草酸预处理能使辣椒叶片在 40℃热处理下保持较高水平的 As A、GSH含量和过氧化物酶活性 (peroxidase,POD) ;在常温下 ,草酸预处理能诱导 POD活性 ,但是对草酸氧化酶活性没有影响 .这些结果提示 ,草酸预处理能增强辣椒叶片的内在抗热性 ,但与草酸氧化酶活性无关

Effects of Oxalate Pretreatment on the Thermotolerance of Pepper Leaves

The alterations of membrane permeability (relative electrolyte leakage), lipid peroxidation, levels of ascorbate (AsA) and glutathione (GSH), and activities of peroxidase (POD) and oxalate oxidase were studied during heat stress of pepper (Capsicum annuum ) leaves at 40℃. The pepper leaves were sprayed by oxalate solution (pH6.5) for 3 days before heat stress treatment. The results showed that oxalate pretreatment can alleviate the damage of membrane (indicated by relative electrolyte leakage), and decrease the production of malondialdehyde (MDA) and hydrogen peroxide, to some extent. Oxalate pretreatment enabled the leaves to keep relatively higher levels of AsA and GSH, and higher POD activity under heat stress than the control. Furthermore, oxalate pretreatment can induce the increase in POD activity under normal temperature, but has not any effect on the induction of oxalate oxidase activity. These results suggested that oxalate pretreatment enhance the intrinsic heat tolerance of pepper leaves. This enhancement is not associated with oxalate oxidase.