高温处理对温州蜜柑幼果膜脂过氧化作用和乙烯生成的影响

以3年生枳砧兴津温州蜜柑盆栽苗为试材,研究高温处理对柑桔幼果细胞膜脂过氧化作用和内原乙烯水平的影响,及其与幼果脱落的关系,以探讨柑桔高温热害的生理机制.结果表明:高温处理使SOD活性下降,MDA含量增加;膜脂脂肪酸组分中亚麻酸比例减少,硬脂城比例上升;致使股脂不饱和脂肪酸指数下降;加速了内原乙烯合成;加剧了幼果脱落.细胞膜脂脂质过氧化产物MDA含量与不饱和脂肪酸指数呈极显著负相关(r=-0.8407),而与幼果累积落果率呈极显著正相关(r=0.8707).细胞膜脂过氧化作用加剧可能是高温热害加速幼果脱落的初始反应.

Effects of High Temperature Stress on Membrane Lipid Peroxidation and Ethylene Production in Fruitlet of Citrus unshiu Marc.

Three-year-old potted Citrus unshiu Marc. trees were used for the investigation of the effects of high temperature stress on membrane lipid peroxidation, fatty acid composition, and ethylene production in fruitlet for better understanding the physiological mechanism of heat stress injury. Results showed under high temperature stress the SOD activity was decreased, while the malondialdehyde(MDA) content was increased, the index of unsaturated fatty acid(UFA) of the membrane lipid was decreased due to decrease in linolenic acid and increase in stearic acid. Endogenous ethylene production was considerably accelerated and early fruit drop was enhanced. A close positive correlation between MDA content and IUFA(r= -0. 8407**)and a nagative correlation between MDA and rate of fruitlet abscission (r = 0. 8707**) were observed. It was suggested that aggravation in membrane lipid peroxidation is a initial reaction of fruitlet abscission promoted by high temperature stress.