葡萄休眠解除过程中冬芽组织活性氧与抗氧化系统的变化特征

摘要

以酿酒葡萄‘赤霞珠’(红)和‘霞多丽’(白)为试材,通过考察其自然休眠过程和打破休眠(单氰胺处理)过程中冬芽组织活性氧及抗氧化系统的变化,探讨葡萄休眠机制.结果表明:(1)在陕西杨陵地区,早熟品种‘霞多丽’在12月20日左右进入深度休眠,第2年1月29日进入休眠解除阶段；晚熟品种‘赤霞珠,在1月9日左右达到深度休眠,2月18日左右进入休眠解除阶段；单氰胺处理可促进葡萄休眠的解除.(2)葡萄休眠过程中,活性氧O2和H2O2含量在休眠初期逐渐增加,深度休眠时含量最高,休眠解除过程中含量降低,从而促进休眠的解除；超氧化物歧化酶(SOD)活性在休眠中一直降低,休眠解除后活性上升；过氧化物酶(POD)活性在体眠前期较低,随后活性上升,休眠解除过程中活性又降低；过氧化氢酶(CAT)活性在休眠过程中持续上升,随后维持在较高水平；抗坏血酸-还原态的谷胱甘肽(ASA-GSH)循环在休眠前期较弱,休眠解除过程中逐渐增强.研究发现,葡萄进入休眠后,其冬芽抗氧化能力逐渐降低,至深度休眠时抗氧化能力降至最低,随着低温积累需冷量得到满足,活化了抗氧化系统进而抗氧化能力迅速提高,休眠被解除.%This study aimed to investigate the bud dormancy mechanisms of wine grape during natural and breaking dormancy from the following physiological and biochemical aspects; water status, active oxygen and ant-oxidation system,phenols and the related enzymes. The results show that: (1)Chardonnay which is an early maturity variety comes into deep dormancy on Dec. 20th,and bud dormancy starts to release gradually from Jan. 29th; the late Cabernet Sauvignon's deep dormancy stage is from Jan. 9th to Feb. 18th and bud dormancy starts to release gradually. Cyanamid treatment enhanced dormancy release. (2)The contents of active oxygen species O2- and H2O2 had a gradual increase in the early dormancy stage,reaching the peak value at the deep end-dormancy,then decreased after bud dormancy release. SOD activity decreased steadily during the whole period of end-dormancy, and then increased after the dormancy release. POD and CAT ac- tivities kept increasing during the early dormancy stage,then the POD value started to drop after the dormancy release and CAT maintained a high activity until bud sprouting. ASA-GSH cycle was relatively weak at the early stage of end-dormancy,and then it was activated gradually during the dormancy release. During the breaking dormancy,the content of active oxygen,the activities of anti-oxidation system enzymes and the contents of antioxidants are changed,all of these are better for dormancy releasing.