甜菜碱对果实采后冷害调控及其机制研究

冷害是限制冷敏性果实低温贮藏的主要问题，甜菜碱具有提高果实抗冷性的作用，但其作用机制尚不明确。本项目以冷敏性果实桃、枇杷为试材，围绕果实采后冷害调控这一科学问题，从甜菜碱合成代谢及其生物学功能入手，研究外源甜菜碱处理对果实冷害、品质指标、活性氧代谢、内源甜菜碱含量、甜菜碱醛脱氢酶活性与表达、细胞膜结构、脂肪酸组分和细胞程序性死亡的影响。此外，研究热处理和低温预贮对冷敏性果实桃、枇杷内源甜菜碱代谢的影响。通过这些研究明确甜菜碱对果实细胞膜稳定性和细胞程序性死亡的调控机制，以揭示甜菜碱对果实采后冷害调控的机理。本项目的研究成果可丰富果实采后冷害调控的生物学理论，为控制我国冷敏性果实冷藏期间冷害劣变提供理论依据，对降低我国果品采后损失、增强我国果品在国际市场上的竞争力，都具有重要的现实意义。

Chilling injury (CI) is a major problem, which limits the application of cold storage in cold-sensitive fruits. Glycine betaine (GB) play an important role in enhancing cold tolerance of postharvest fruits, however, its mechanism is not clear. This study focused on the scientific issue of CI of postharvest fruits, and commenced from metabolism of GB and its physiological and biological function. The effect of exogenous GB treatment on CI, quality parameters, active oxygen radical metabolism, endogenous GB metabolism, activity and expression of betaine aldehyde dehydrogenase, cell membrane structure and lipid content, and programmed cell death (PCD) were investigated in cold-sensitive fruits including peaches and loquats. In addition, heat treatment and low temperature conditioning were applied on peaches and loquats, and the metabolism of endogenous GB was also evaluated. Thus, this study is supposed to illuminate the regulation and mechanism of GB improving membrane integrated and inhibiting PCD, and explain the mechanism of GB alleviating CI in cold-sensitive fruits. Moreover, the results of this study can enrich the theory of CI regulation in postharvest biology, provide theoretical principle in controlling CI and deterioration in cold-sensitive fruits during cold storage, and enhance competitive strength of China's fruit industry in the global market.