杏果实冷藏过程中果肉絮败与木质化形成机制及外源调控研究

Apricot fruit is a type of climacteric fruit and post-harvest losses was very important caused by rapid fruit ripening and declining disease resistance. Post-harvest decay and quality deterioration of apricot fruits could be effectively inhibited by cold storage. But chilling injury easily produced as a result of apricot fruits sensitivity to low temperature. The qualities of apricot fruit were degraded by its injury symptoms of the mealiness and leatheriness. The application of cold storage technology on the storage and transportation of apricot fruits was limited by chilling injury incidence. At Present,although some technologies such as intermittent warming, controlled atmosphere and et al were used to alleviate chilling injury of apricot fruits. But for the characteristics and mechanisms of mealiness or leatheriness are unclear, the effeets of these tecbnologies were not satisfied. The mechanism of rnealiness and leatheriness development of apricot fruits were determined through studying the effect of the cell wall metabolisms, benzene propane metabolisms, ethylene biosynthesis, active oxygen metabolism and the content change of endogenous hormone on the form of rnealiness and leatheriness basing on the change rule of qualities of apricot fruits in normal ripening and the effect of chilling temperatures and maturities on chilling injury. And effeets of SA, hot water and 1-MCP treatments on mealiness or leatheriness of apricot fruits were also studied. The objective of this study was to provide the new idea for control of chilling injury in apricot fruits during storage.

杏属于呼吸跃变型果实，采后后熟衰老迅速，抗病能力下降，腐烂损失非常严重。低温冷藏能有效抑制杏采后腐烂和品质下降, 但杏对低温环境敏感，在低温下贮藏易引起冷害，出现果肉絮败或木质化的异常质构，严重影响杏的贮藏品质。控制杏冷害的发生，已成为杏采后贮运产业中亟需解决的问题。目前虽有变温处理和气调处理等技术用于减缓杏果实冷害的报道，但由于对杏果絮败和木质化形成的特点和调控机理缺乏研究，这些处理的效果并不理想。本课题在研究杏果实正常后熟过程中品质变化和冷害温度下絮败和木质化冷害症状发生规律的基础上，系统研究了杏果实在絮败和木质化形成过程中细胞壁物质代谢、苯丙烷代谢及乙烯、活性氧和内源激素的变化特点和规律，阐明杏果实絮败和木质化两种冷害症状的形成机理，并在此基础上研究了水杨酸、热处理和1-MCP对杏果实絮败和木质化的控制效果。本课题的研究可为杏果实贮藏期间冷害的防治提供新思路。

杏属于呼吸跃变型果实，采后后熟衰老迅速，抗病能力下降，腐烂损失非常严重。低温冷藏能有效抑制杏采后腐烂和品质下降, 但杏对低温环境敏感，在低温下贮藏易引起冷害，出现果肉絮败或木质化的异常质构，严重影响杏的贮藏品质。控制杏冷害的发生，已成为杏采后贮运产业中亟需解决的问题。目前虽有变温处理和气调处理等技术用于减缓杏果实冷害的报道，但由于对杏果絮败和木质化形成的特点和调控机理缺乏研究，这些处理对减缓杏果絮败和木质化的效果并不理想。本课题在研究杏果实正常后熟过程中品质变化和冷害温度下絮败和木质化冷害症状发生规律的基础上，系统研究了杏果实在絮败和木质化形成过程中细胞壁物质代谢、苯丙烷代谢及乙烯和活性氧的变化特点和规律，阐明杏果实絮败和木质化两种冷害症状的形成机理，并在此基础上研究了油菜素内酯、1-MCP和热处理对杏果实絮败和木质化的控制效果。本课题的研究可为杏果实贮藏期间冷害的防治提供新思路。.本课题以新疆特色杏“赛买提”为试材，根据转黄率将杏果实分为成熟度Ⅰ(着色面积﹤50%)、成熟度Ⅱ(着色面积50%～80%)和成熟度Ⅲ(着色面积﹥80%)三种成熟度，然后置于25℃、4℃及0℃，RH 90-95%的条件下贮藏。研究结果表明，在4℃低温贮藏时，成熟度Ⅲ果实的冷害发病率始终高于成熟度Ⅱ和成熟度Ⅰ杏果实；在0℃低温贮藏时，成熟度越低的杏果实的冷害发病率越高，成熟度Ⅱ能使杏果在贮藏期和货架期保持较好的品质，是杏果采收的最佳成熟度。而且，不同成熟度杏果实在不同贮藏温度下，可溶性果胶、CDTA、NaCO3和NaOH溶解性果胶、木质素和纤维素含量；PG、PME、纤维素酶、β-葡萄糖苷酶、PAL、POD和PPO活性及乙烯生物合成和挥发性物质成分均表现出不同的变化规律。石蜡切片和透射电镜观察也表明，成熟度是影响杏果实发生絮败和木质化的重要因素。本研究还克隆到新疆“赛买提”杏果实中的一个新的PG和PME基因全长。杏贮藏实验表明，适宜浓度的油菜素内酯、1-MCP和热处理可有效控制杏果冷藏过程中絮败和木质化的程度。