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以甜瓜为材料,分析了果实发育成熟过程中生理生化变化,克隆了ABA生物合成关键酶9-顺环氧类胡萝卜素双加氧酶基因NCED的保守序列并进行表达分析,研究了ABA,NDGA、1-MCP及1-MCP+ABA对果实成熟软化的影响。结果表明:NCED基因在甜瓜果实始熟期大量表达,内源ABA高峰出现在此之后。乙烯释放量,ACC含量和ACO活性在果实成熟初期极低,其各自峰值的出现迟于ABA高峰10 d左右。外源ABA处理显著促进果实成熟和软化,各项成熟指标比对照提前8 d。NDGA处理效果相反;1-MCP和1-MCP+ABA处理与NDGA处理相似,但效果较小。ABA启动了甜瓜果实成熟,它通过诱导乙烯合成相关酶基因的表达而参与了成熟与软化过程,乙烯则主要在成熟后期,尤其是在果实固有风味形成过程中起主导作用。
The melon was used as the material to analyze the physiological and biochemical changes during fruit ripening. The conserved sequence of 9-cis-epoxy carotenoid dioxygenase gene NCED, a key enzyme of ABA biosynthesis, was cloned and analyzed. The effects of ABA, NDGA , 1-MCP and 1-MCP + ABA on fruit ripening and softening. The results showed that NCED gene was highly expressed in the ripening stage of melon fruit, and the peak of endogenous ABA appeared after this. Ethylene emission, ACC content and ACO activity were extremely low at the beginning of fruit ripening, and their peak appeared later than ABA peak about 10 d. Exogenous ABA treatment significantly promote fruit ripening and softening, the maturity indicators than the control 8 d early. NDGA treatment had the opposite effect; 1-MCP and 1-MCP + ABA treatment were similar to NDGA treatment, but the effect was less. ABA initiates melon fruit ripening, which participates in the process of maturation and softening by inducing the expression of the enzyme gene related to ethylene synthesis, while ethylene plays a dominant role mainly in the later maturing stage, especially in the formation of natural flavor of fruit.