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以番茄 (Lycopersiconesculentum)品种‘丽春’为试验材料研究了果实采后多聚半乳糖醛酸酶 (PG)和脂氧合酶 (LOX)的活性变化与果实硬度的关系 ,并观察了细胞超微结构的变化。结果表明 ,随着果实采后呼吸强度和乙烯释放量不断增加 ,PG和LOX活性迅速增加 ,而果实硬度逐渐下降。呼吸强度和LOX活性高峰出现在发白期 (BR) ,而乙烯释放量高峰延迟至转色期 (TU)。PG活性随着果实的成熟逐渐增加 ,而LOX活性在发白期之后保持较高水平。分别用外源LOX和LOX加底物处理番茄组织切片 ,发现组织细胞的衰老进程加速 ,进而导致细胞膜瓦解、胞壁纤维松弛以及细胞器空胞化。PG和LOX都与果实的后熟软化有关 ,LOX与衰老的启动有关
The effect of polygalacturonase (PG) and lipoxygenase (LOX) activity changes on the fruit firmness was investigated by using Lycopersicon esculentum cultivar ’Lichun’ as test material. The effects of ultrasonication Microstructure changes. The results showed that the PG and LOX activity increased rapidly with the increase of respiration rate and ethylene release, while the fruit firmness decreased gradually. The peak of respiration and LOX activity appeared in the whitening period (BR), while the peak of ethylene release was delayed to the color change period (TU). PG activity gradually increased with fruit maturity, while LOX activity remained high after the whitening period. The sections of tomato tissue were treated with exogenous LOX and LOX, respectively. The results showed that the senescence of tissue cells accelerated, leading to cell membrane disintegration, cell wall fiber relaxation and organelle cell decellularization. Both PG and LOX are related to the ripening and softening of fruit. LOX is related to the initiation of aging