一氧化氮延缓草莓成熟衰老的生理效应

 以硝普钠（SNP）为一氧化氮（NO）供体，研究了不同浓度NO对丰香草莓采后果实乙烯产生、呼吸强度、维生素C（Vc）、可溶性蛋白、失水腐烂和相对电导率，以及超氧物歧化酶（SOD）、过氧化氢酶（CAT）和过氧化物酶（POD）活性的影响。结果表明，5 μmol·L-1 SNP释放NO可以抑制草莓果实乙烯的产生和呼吸强度，延缓乙烯产生和呼吸高峰的出现，并推迟了果实固酸比、Vc和可溶性蛋白含量下降时期，抑制果实腐烂失水和相对电导率升高；使果实CAT活性显著增强，SOD活性在后期高于对照，但POD活性低于对照。10 μmol·L-1 SNP对果实产生轻微毒害作用，1 μmol·L-1 SNP延迟草莓衰老的效果不明显。证明了NO抑制果实衰老与其浓度的相关性，揭示了NO保护细胞膜结构完整的作用机理。

Effects of Nitric Oxide (NO) on Ripening and Senescence of Strawberry

Using sodium nitroprusside (SNP) as a nitric oxide (NO) donor, the effects of different concentrations of nitric oxide treatment on physiological index of post-harvest strawberry (Fengxiang), including ethylene production rate, respiration rate, vitamin C (Vc), soluble protein, the rate of water loss, rot and relative conductivity, and the activities of relevant enzymes from the fruit, including SOD, CAT and POD, were investigated. The results showed that NO resulting from 5 μmol·L-1 SNP aqueous solution obviously inhibited ethylene production rate, respiration rate, the increase of rot rate and relative membrane permeability and delayed the decrease of the ratio of soluble solids/acids, vitamin C and soluble proteins. The activity of CAT obviously increased during the storage and the decrease of activity of SOD was delayed during the later storage for the strawberry treated with 5 μmol·L-1 SNP aqueous solution. But the activity of POD from strawberry after treatment was lower than that of control fruit. NO resulting from 10 μmol·L-1 SNP aqueous solution injured slightly the fruit. The effect of NO from 1 μmol·L-1 SNP aqueous solution on delaying senescence of strawberries was not distinct. These have proved the relationship between inhibition of NO on senescence of fruit, and opened up the mechanism that NO protected the structural integrity of cell wall.