细胞壁代谢参与乙烯作用抑制剂引起的采后番木瓜果实“橡皮化现象”的机理研究

Papaya (Carica papaya L.) is a kind of typical climacteric fruits, the problem which it is difficult to be stored and transported has greatly limited the development of papaya industry. Fruit softening is one of the important symbols of ripening and senescence, suppressing and delaying the fruit softening is very important for preservation. 1-methylcyclopropene (MCP) is a novel ethylene action inhibitor, positive effects have been found in many fruits and vegetables used with 1-MCP. However, papaya fruit can not soften normally when it is applicated with 1-MCP, and "rubbery phenomenon' is occured,it becomes the "bottleneck" of applying 1-MCP on the preservation of papaya fruits.At present,there is no much complicated study about the mechanism of "rubbery phenomenon' in the world.Therefore, focusing on "rubbery phenomenon" and basing on the cell wall metabolism, the main papaya cultivars in Hainan are used to study the relationship between cell wall metabolism and " rubbery phenomenon " from the three aspects of physiology and biochemistry, cell microstructure and gene expression regulation.The object is to reveal the possible mechanism of "rubbery phenomenon" of papaya fruits. This study could not only apply the new idea for studying the softening mechanism of climacteric fruits , but also provide a reference for preserving papaya fruits with 1-MCP.

番木瓜（Carica papaya L.）是典型的呼吸跃变型果实，其难贮运的问题极大的限制了番木瓜产业的发展。果实软化是成熟衰老的重要标志之一，抑制或减缓果实软化对于贮藏保鲜具有重要意义。1-甲基环丙烯（l-MCP）是一种新型的乙烯作用抑制剂，在多种果蔬保鲜中应用效果良好。但是，对于番木瓜果实，1-MCP可导致果实不能正常软化，出现"橡皮化现象"（ rubbery phenomenon），这成为1-MCP在番木瓜果实应用上的瓶颈。目前有关"橡皮化现象"发生的机理国内外还缺乏较深入的研究。本项目针对 "橡皮化现象"，从细胞壁代谢着手，以海南主栽番木瓜品种为材料，从生理生化、细胞显微结构和基因表达调控三个角度，研究细胞壁代谢与番木瓜果实"橡皮化现象"的关系，揭示"橡皮化现象"发生的可能机制。此研究可为进一步研究跃变型果实的软化机理提供新的思路，也为将1-MCP应用于番木瓜果实的保鲜提供参考。

番木瓜（Carica papaya L.）是典型的呼吸跃变型果实，其难贮运的问题大大的限制了番木瓜产业的发展。本项目针对 “橡皮化现象”，从细胞壁代谢入手，以海南主栽番木瓜品种为材料，从生理生化、细胞显微结构和基因表达调控三个角度，研究了细胞壁代谢与番木瓜果实“橡皮化现象”的关系，揭示了“橡皮化现象”发生的可能机制。取得了以下主要结果：（1）明确了不同品种、不同采收成熟度的番木瓜果实对不同浓度1-MCP处理的软化反应，明确了“橡皮化”果实其品质风味和软化生理的变化规律。（2）确定了番木瓜果实“橡皮化”现象的细胞壁代谢关键酶是木葡聚糖酶和半乳糖苷酶。（3）确定了“橡皮化”现象与1-MCP和外源乙烯处理及内源乙烯释放之间的相互关系；（4）明确了“橡皮化”果实与正常果实其细胞壁代谢和结构的差异。（5）从生物信息分析和基因表达调控两个方面阐明了“橡皮化”果实与正常果实其的差异。（6）发表了较高水平的学术论文4篇,申请专利2项，获得省级科研成果奖1项。（7）培养3位硕士研究生和6位本科生。（8）揭示了番木瓜果实发生“橡皮化”现象的内在机制，研究结果能为生产上科学应用1-MCP以改善番木瓜果实的风味品质提供参考，并未进一步研究跃变型果实的成熟软化奠定基础。