采后水分和营养胁迫对西兰花未成熟衰老中相关酶活性的影响

Effect of Water Stress and Nutrition Stress on Premature Senescence-related Enzyme Activity in Harvested Broccoli

摘要:

本研究以西兰花（Brassica oleracea）花蕾为试材，研究了采后水分胁迫和营养胁迫对西兰花贮藏过程中色值变化、叶绿素含量、抗坏血酸（Vitamin C，Vc）含量、呼吸强度、超氧化物歧化酶（Superoxide Dismutase，SOD）、过氧化物酶（Peroxidase，POD）、过氧化氢酶（Catalase，CAT）活性和丙二醛（Malondialdehyde，MDA）含量以及总抗氧化能力的影响。结果表明，西兰花在采后贮藏过程中花蕾出现黄化现象，采后水分和营养胁迫加速了西兰花叶绿素、Vc的降解。采后12 h，对照、水处理、聚乙二醇（polyethylene glycol，PEG）处理、PEG加营养液处理和营养液处理的花球Vc含量为8.84 mg/100g，12.16 mg/100g，PEG 24.44 mg/100g，PEG 30.68 mg/100g，27.56 mg/100g。采后水分和营养胁迫均可导致西兰花花蕾POD活性下降，CAT活性峰值升高，两者同时发生时，延缓了西兰花花蕾总抗氧化性的上升。SOD、POD、CAT活性和总抗氧化性相比较可以看出，总抗氧化能力比单纯的某一种抗氧化酶更能反映西兰花的抗衰老能力。

Abstract:

The effects of post-harvest water stress and nutrition stress during storage on broccoli (Brassica oleracea) florets were studied based on changes in color, chlorophyll content, ascorbic acid (vitamin C, Vc) content, respiratory rate, superoxide dismutase (SOD) activity, peroxidase (POD) activity, catalase (CAT) activity, malondialdehyde (MDA) content, and the total antioxidant capacity. The broccoli florets showed yellowing during storage. Water stress and nutrition stress accelerated the degradation of chlorophyll and Vc. The Vc contents of the control sample and samples subjected to water treatment, polyethylene glycol (PEG) treatment, PEG + nutrition treatment, and nutrition treatment of 12 h post-harvest were 8.84 mg/100 g, 12.16 mg/100 g, 24.44 mg/100 g, 30.68 mg/100 g, and 27.56 mg/100 g, respectively. Post-harvest water stress and nutrition stress can both result in reduced POD activity and increased CAD activity. When these two stresses occur simultaneously, the increase in the total antioxidant capacity is delayed in broccoli florets. Therefore, the total antioxidant capacity could reveal the anti-senescence capacity better than a single antioxidase in broccoli, based on comparisons of SOD, POD, and CAT activities with the total antioxidant capacity.