酵母多糖处理提高樱桃番茄抗冷性的机制分析

探讨酵母多糖诱导"佳西娜"樱桃番茄果实抗冷的部分机制,并明确在其诱导的番茄果实抗冷过程中NO的作用。用蒸馏水、0.5 g/L酵母多糖、0.5 g/L酵母多糖+0.5 mmol/L亚甲基蓝、0.5 g/L酵母多糖+0.5 mmol/L一氧化氮合酶抑制剂N-硝基-L-精氨酸甲酯(N’-nitro-L-arginine-methyl ester hydrochloride,L-NAME)、0.5 g/L酵母多糖+0.5 mmol/L L-NAME+0.1 mmol/L硝普钠5种不同方法处理樱桃番茄,浸泡20 min后用聚乙烯保鲜袋包装(不封口),置于(2±1)℃、相对湿度85%~95%的环境中贮藏,研究各组处理对番茄采后冷害情况以及生理生化品质的影响。结果表明:低温贮藏过程中,酵母多糖提取物处理能显著抑制樱桃番茄冷害的发生,延缓冷害引起的膜质过氧化反应和各品质指标的下降;诱导番茄果实内源NO的积累和抗氧化酶活性的升高可能是其主要的抗冷机制;通过NO清除剂和L-NAME的使用,进一步明确了酵母多糖诱导的NO在番茄抗冷过程中的作用。

Mechanism Underlying the Improvement of Cold Resistance in Cherry Tomato Treated with Yeast Saccharide

This study aimed to reveal the mechanism by which yeast saccharide reduces chilling injury of cherry tomato
and to examine the effect of nitrite oxide (NO) induced by yeast saccharide N’-nitro-L-arginine-methyl ester hydrochloride
(L-NAME) on cold resistance. Cherry tomato samples were soaked in distilled water, 0.5 g/L yeast saccharide (YS), 0.5 g/L
YS + 0.5 mmol/L MB-1, 0.5 g/L YS + 0.5 mmol/L L-NAME and 0.5 g/L YS + 0.5 mmol/L L-NAME + 0.1 mmol/L sodium
nitroprusside (SNP) for 20 min, respectively before being packaged in polyethylene plastic bags (unsealed) and stored
at (2 ± 1) ℃ and relative humidity (RH) of 85%?95%. The results showed that yeast saccharide treatment was effective
in restraining chilling injury, slowing down membrane lipid peroxidation and the decline of quality indexes. Induction
of endogenous NO accumulation and increased activities of antioxidant enzymes may be the main mechanism of cold
resistance. At the same time, the effect of NO induced by yeast saccharide on cold resistance in cherry tomato was further
confirmed by the use of NO scavenger and nitricoxide synthase inhibitor.