为了解温州蜜柑果实贮藏过程中枯水指数及保护酶活性的变化规律,试验开展不同大小果实发生枯水的生理机制研究.以不同大小温州蜜柑果实为试材,研究果实大小对枯水指数、失重率及保护酶(超氧化物歧化酶SOD,过氧化氢酶CAT和过氧化物酶POD)活性的影响.结果表明,贮藏60d后果实逐渐出现枯水,枯水指数随着贮藏时间的延长而增加,大果的枯水指数明显高于中小型果；伴随着果实枯水的进行,果实的失重率逐渐增加,大果的失重率高于中小型果,贮藏120 d后,分别比中果和小果的失重率高8.3％和22.9％；果皮的SOD,CAT和POD活性显著高于果肉,在贮藏过程中,果皮和果肉中的SOD和CAT活性逐渐降低,且呈现出一致的变化规律:小果＞中果＞大果；POD活性则随着贮藏时间的延长而增加,大小为:大果＞中果＞小果.温州蜜柑果实枯水是果皮逐渐衰老的过程,果皮POD活性增加,SOD和CAT活性降低,是果实发生枯水的主要原因.大果中保护酶活性的变化幅度大于中小型果,容易发生枯水,建议在贮藏时选择中小型果实进行贮藏,以降低果实枯水的发生率.%The main purpose of this paper was to study the change of citrus fruit granulation index and activities of antioxidant enzymes, physiological mechanism of granulation in different sizes of citrus fruit, and to propose comprehensive prevention measures. Satsuma mandarin fruit with different sizes were used to study the effect of fruit size on granulation index and activities of antioxidant enzymes (superoxide dismutase SOD, catalase CAT and peroxidase POD) during storage. The results showed that fruit granulation appeared at 60 d after storage and granulation index increased as storage time prolonged. The fruit weight loss increased during storage and that of large fruit was 8. 3% and 22. 9% higher than middle fruit and small fruit respectively at 120 d after storage. SOD, CAT and POD activities in citrus peel were higher than those in citrus pulp. SOD and CAT activities in citrus peel and pulp decreased gradually during storage, which were the highest in small fruit and the lowest in large fruit among the three sizes of fruits. POD activities decreased gradually, which were the highest in large fruit but were the lowest in small fruit. Satsuma mandarin fruit granulation was a course of peel senescence. Higher POD activities and lower SOD and CAT activities in peel were the main causes for fruit granulation. Antioxidant enzyme activities of large fruit changed most among three sizes of citrus fruits during storage. As a result, it is recommended that selecting middle-size and small-size fruit to store could be regarded as an important measure to prevent Satsuma mandarin fruit granulation during storage time.
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