巴西橡胶树排胶机制研究进展

橡胶树是世界上商业用天然橡胶最主要的来源,排胶是天然橡胶生产的最后关键环节,为了安全高效的获取胶乳产量,橡胶树排胶机制的研究一直受到人们的重视。橡胶树中的乳管是天然橡胶合成和储存的组织,人们通过割胶收集从乳管中流出的胶乳用作提炼天然橡胶。胶乳的排出速度及排胶持续时间是决定天然橡胶产量的重要因素,是排胶动力和排胶阻力共同作用的结果。笔者对与排胶相关的乳管细胞学基础、排胶主要初动力的乳管膨压、排胶继动力的乳管胶乳水分稀释效应以及乳管排胶阻力的形成及其调控机制等研究进行了归纳,主要分析了乳管伤口堵塞物的形成和影响排胶阻力的多种因素,指出乳管堵塞在胶乳的停排中起重要作用。针对目前排胶机制的研究进展缓慢这一现状,我们提出有必要从以下几点展开深入研究：（1）乳管膨压形成相关的树皮木质素合成和调控;（2）水分运输相关的水通道蛋白基因表达和活性分析;（3）停排相关的乳管伤口末端堵塞物的形成和调节。这些研究将为全面解析橡胶树排胶机制奠定基础,也可为分子辅助育种-选育排胶通畅的种质提供依据。

The Latex Flow Mechanism in Rubber Tree (Hevea brasiliensis Muell. Arg.): A Review

Rubber tree is the most important source for commercial natural rubber in the world, and latex flow is the last key step in the production of natural rubber. In order to obtain the latex output safely and efficiently, the study on the mechanism of latex flow has always been paid attention to. Laticifer is a tissue specific for natural rubber biosynthesis and storage in rubber tree. Usually, latex from laticifer is collected to refine natural rubber by tapping. The velocity and duration of latex flow after tapping are the crucial factors that determine the rubber yield, and are decided by the motivator and barrier from laticifer. In this paper, the cytological basis of laticifer, turgor pressure of laticifer as the primary driving force of latex flow, the water dilution reaction of latex as the relay driving force, and the formation and regulation of latex flow barrier in laticifer were summarized. The paper mainly analyzed the plug formation in laticifer and the main factors to regulate the plugging, and proposed that the laticifer plugging played a vital role in the cessation of latex flow. In view of the slow progress of present research, several topics were proposed: (1) the biosynthesis and regulation of bark lignin that related to the laticifer turgor pressure; (2) the gene expression and activity analysis of aquaporin that related to the water transportation; (3) the formation and regulation of the laticifer wound plug that related to the cessation of latex flow. The study will lay a foundation for illuminating the mechanism of latex flow and further provide valuable reference for selecting the fluent latex flow germplasm by molecular assisted breeding.