硅酸钠处理对厚皮甜瓜果实采后病害的控制及活性氧代谢的作用

【目的】研究硅酸钠处理对厚皮甜瓜果实采后病害的控制和活性氧代谢的作用。【方法】以‘玉金香’厚皮甜瓜为试材，用100 mmol?L-1硅酸钠常温浸泡处理10 min，处理后12 h接种粉红单端孢（Trichothecium roseum），测定处理对果实采后病害及活性氧代谢的影响。【结果】硅酸钠处理可显著降低果实损伤接种T. roseum的病斑直径(P＜0.05)和果实的自然发病率；诱导果实过氧化氢（H2O2）的积累和超氧阴离子（ ）产生速率的提高，增加了果肉组织过氧化氢酶（catalase, CAT）的活性，抑制了前期果肉组织超氧化物歧化酶（superoxide dismutase, SOD）的活性，促进了丙二醛（malondialdehyde, MDA）的产生，降低了果肉组织细胞膜的完整率。接种后硅酸钠处理果实可进一步诱导果肉组织产生更多的H2O2和 ，提高了CAT活性，维持了SOD活性，促进果肉组织产生了较多的MDA。【结论】采后硅酸钠处理可通过调节果实活性氧的代谢来提高厚皮甜瓜果实对采后病害的抗性。

Control of Postharvest Diseases and Potentiation of Reactive Oxygen Species Metabolism in Muskmelon (Cucumis melo L.) Fruits Treated by Sodium Silicate

【Objective】Dipping treatment with sodium silicate on control of postharvest diseases and potentiation of reactive oxygen species metabolism in muskmelon fruits was investigated in this paper.【Method】Muskmelon(Cucumis melo L.cv.Yujinxiang) fruits were dipped at 100 mmol.L-1 of sodium silicate for 10 min,and inoculated with Trichothecium roseum 12 h after treatment.Effect of sodium silicate treatment on postharvest diseases and reactive oxygen species metabolism in muskmelon fruits was determined.【Result】Sodium silicate significantly decreased(P<0.05) the lesion diameter of fruits inoculated with T.roseum,and the natural incidence of fruits during storage at room temperature.Sodium silicate induced the accumulation of hydrogen peroxide(H2O2),and promoted the generation rate of superoxide anion().Furthermore,sodium silicate increased the catalase(CAT) activity,but inhibited the superoxide dismutase(SOD) activity in the earlier period.Sodium silicate promoted the accumulaition of malondiadehyde(MDA),however,decreased the cell membrane integrity in muskmelon fruits.Inoculation sodium silicate treated fruits enhanced the generation of H2O2 and and CAT activity,and maintained SOD activity.Sodium silicon-treatment also induced higher production of MDA.【Conclusion】Sodium silicate treatment decreased postharvest diseases of muskmelon fruits by regulating reactive oxygen species metabolism.