减压对果实采后能量形成及调控机制研究

Fruits and vegetables easily senesce and deteriorate after harvest, which reduces commercial value and becomes the major problem of the industry, resulting in huge economic losses every year. The energy availability is a fundamental feature and becomes the focus of research in fruits and vegetables during senescence in recent years. However, the role of energy status in the senescence of harvested fruits and vegetables needs to be further elucidated. Hypobaric storage is a new technology and demonstrated to significantly inhibit postharvest senescence and quality deterioration, thus extending shelf life in various fruits and vegetables. However a picture of the sequence of the role of hypobaric storage in senescence and quality deterioration of harvested fruits and vegetables is still unclear. Particularly, there is little information of energy production and metabolism in relation to biochemical and physiological activities in fruits and vegetables during hypobaric storage. This study is to use peach as samples, which are the typical respiratory climacteric fruits, respectively. The relationship between energy metabolism and senescence and quality deterioration, the role of energy status on senescence, and effects of changes of energy production on reactive oxygen species (ROS) production is to be investigated when peach will be kept with hypobaric pressure treatment. The aim of the project is to explore the relationship of energy production, quality deterioration and ROS production of fruits and vegetables during hypobaric storage. The results will help us to understand the effect of hypobaric storage on energy synthesis and regulation metabolism of fruits and vegetables after harvest and provide theoretical guidance for the hypobaric storage technology applications.

减压贮藏能显著抑制果蔬采后衰老劣变，是未来保鲜技术的重要发展方向，国内外关于减压贮藏有较多研究，主要集中在压力参数比较和对不同果蔬保鲜效果的研究上，对减压技术的作用机理还知之甚少，制约了减压技术的发展和应用。果蔬的衰老劣变与能量代谢有着密切的关系，能量形成特性和调控机制是近年来的研究热点，但减压对果蔬能量代谢的影响研究还未见报道。本课题拟以跃变型果实桃为对象，研究减压对果实能量代谢的影响，明确果实中能量水平与衰老劣变发生的关系；研究减压处理对调节能量供给和活性氧代谢的作用；重点探明减压下组织能量代谢、活性氧代谢和衰老劣变三者之间的相互作用关系。本项目的成果，将填充减压技术对果实采后能量代谢调控机制的研究空白，从能量角度阐明减压的保鲜作用机制。

本课题以跃变型果实桃为对象，研究了减压对果实能量代谢的影响，明确果实中能量水平与衰老劣变发生的关系；研究减压处理对调节能量供给和活性氧代谢的作用；重点探明减压下组织能量代谢、活性氧代谢和衰老劣变三者之间的相互作用关系。研究了（10±5）kPa、（80±5）kPa 2个不同减压压力处理及常规冷藏对水蜜桃贮藏期间能量相关物质三磷酸腺苷（ATP）、二磷酸腺苷（ADP）、磷酸腺苷（AMP）含量和能荷以及 H+-ATPase、Ca2+-ATPase、琥珀酸脱氢酶（SDH）、细胞色素氧化酶（CCO）等线粒体呼吸代谢相关酶活性变化。结果表明，本研究表明减压能使贮藏过程中较好地保持SDH、CCO、H+-ATPase和Ca2+-ATPase等酶活性，使ATP 含量和能荷在整个贮藏期间均维持在较高水平；采用（10±5）kPa压力处理更有利于维持采后贮藏的能量水平并保持相关酶活性。这些结果表明减压技术在采后保鲜上的作用与能量代谢相关。同时研究了不同减压压力处理及常规冷藏对水蜜桃贮藏期间褐变指数、呼吸途经、活性氧和相关酶活性变化的影响。结果表明，减压处理可有效减少果肉丙二醛的含量，减轻膜脂过氧化，减缓果肉褐变的发生。减压处理果实中的超氧阴离子产生速率低于对照，而H2O2含量在减压贮藏中保持稳定。减压处理的交替氧化呼吸途经在贮藏中后期得到增强，并有效保持APX、POD酶活性，说明减压处理在减少活性氧生成的同时，有利于活性氧的清除。采用10±5kPa压力处理更有利于维持采后贮藏的活性氧代谢能力。这些结果表明减压技术在采后保鲜上的作用与活性氧代谢相关。本项目的成果，从能量角度阐明减压的保鲜作用机制，填充了减压技术对果实采后能量代谢调控机制的研究空白。