外源NO处理对采后鲜莲子品质及乙烯代谢的影响

Effects of Exogenous NO Treatment on the Postharvest Quality and Ethylene Metabolism of Fresh Lotus Seeds

摘要:

为探讨一氧化氮（NO）处理对采后鲜莲子乙烯代谢的影响，本研究首先采用不同浓度NO处理新鲜“太空莲36号”莲蓬，在（25±1）℃下进行贮藏，通过分析莲蓬和莲子色差及表型，筛选出适宜的NO处理浓度。在此基础上，研究了NO处理对鲜莲蓬呼吸作用，鲜莲子品质变化和乙烯代谢的影响。结果表明，0.25 mmol/L的NO处理可有效保持莲蓬及莲子品质，减缓贮藏期间莲子可溶性糖和淀粉含量的下降，抑制2~4 d的莲蓬呼吸速率及4 d后莲子的乙烯释放量19.93%以上，以及莲子中1-氨基环丙烷-1-羧酸（ACC）含量，同时抑制了莲子4 d后的ACC合成酶（ACS）46.72%以上，和2~4 d的ACC氧化酶（ACO）活性14.79%以上；并保持其较高的蛋氨酸（Met）含量(但对S-腺苷蛋氨酸（SAM）含量影响并不显著), 从而延缓了莲蓬及莲子常温货架期2~3天。综上所述，NO处理能够有效保持莲子品质及其抑制乙烯的合成，从而延缓了莲蓬及莲子的衰老，本研究对莲蓬及莲子的采后保鲜提供了理论和技术的支持。

Abstract:

In order to investigate the effects of nitric oxide (NO) treatment on ethylene metabolism in postharvest fresh lotus seeds, the fresh “Space Lotus No. 36” lotus seedpods were treated firstly with different concentrations of NO, before storage at (25±1) ℃. The optimal concentration of NO was screened through analyzing the color difference and phenotype of lotus seedpods and seeds. On this basis, the effects of NO treatment on the respiration of fresh lotusseed pods, and the quality and ethylene metabolism of lotus seeds were studied. The results showed that the treatment with NO at 0.25 mmol/L significantly maintained the qualities of lotus seedpods and seeds, significantly slowed down the decreases of soluble sugar and starch in the lotus seeds, and inhibited the respiration rate of lotus seedpods from the 2nd to 4th day (while enabling the release of ethylene over 19.93% after 4 days) inhibited the accumulation of 1-aminocyclopropane-1-carboxylic acid (ACC) in lotus seeds. Meanwhile this NO treatment inhibited the activities of ACC synthetase (ACS, over 46.72% after 4 days) and ACC oxidase (ACO, over 14.79% during day 2~4) in the lotus seeds, while maintaining a relatively high methionine (Met) content in lotus seeds (but exerting insignificant effect on the content of s-adenosine methionine (SAM)). Therefore, this NO treatment prolonged the shelf life of lotus seedpods and seeds by 2~3 days. In conclusion, NO treatment can inhibit effectively preserve the quality of lotus seeds and inhibit the synthesis of ethylene in lotus seeds, thereby delaying the senescence of lotus seedpods and seeds. This study provides theoretical and technical support for the postharvest preservation of fresh lotus seedpods and seeds.