荒漠植物几种主要附属结构的抗逆功能及其协同调控的研究进展

Uptates on Stress Tolerance of Main Accessory Structures and Their Synergetic Interaction in Desert Plants

荒漠植物常生长于盐、旱、强光照、高低温等胁迫生境。为应对复杂、严酷的荒漠环境,荒漠植物的形态结构与功能产生一系列响应并形成特殊的抗逆机制。盐腺、表皮毛、角质层及表皮蜡质纹饰等是荒漠植物常见的附属结构,在其抗逆过程中起重要作用。盐腺包括双细胞盐腺、多细胞盐腺及盐囊泡等,是荒漠盐生植物的特殊泌盐结构,与细胞内离子平衡以及离子通道调节机制密切相关;表皮毛是植物地上部分表皮组织延伸产生的特殊毛状结构,包括腺毛与非腺毛,对寒、旱、高温、强辐射等逆境以及病虫害侵染均有防御作用;角质层是角质聚合物和蜡质组成的连续性疏水层,是旱生荒漠植物在表皮细胞外形成的趋同适应结构,在控制非气孔水份损失和防止病虫害等方面起关键作用。对荒漠植物抗逆分子机制的研究显示:ABA信号途径与盐腺、表皮毛以及角质层等附属结构直接或间接相关联,从而实现协同抗逆功能。本文基于目前对以上方面的研究进展,从荒漠植物几种主要附属结构及其生理生化和基因调控等方面进行综述,并对附属结构之间的相互联系进行了讨论,以期对荒漠植物抗逆机制研究提供参考。

Desert plants usually grow in extreme environments which include salt,drought,strong illumination,high or low temperature and other stress conditions,and it results in evolution of these plant species with different strategies to adapt to such harsh conditions.The accessory structures,e.g.salt gland or salt bladder,trichome,cuticle,epidermal waxy ornamentation,etc.are universal and crucial to stress tolerance of desert plants.Salt glands mainly include bicellular gland,multicellular gland and salt bladder,which are the special salt secretory structure of desert plant,and associate with ionic equilibrium and ionic channel regulation.Trichomes include gland and non-gland trichomes,which locate at the surface of epidermal cell,and have the protective effect to low and high temperature,drought,strong illumination and diseases and insect pests attack.Cuticle is a continuous hydrophobic layer consisted of wax and cutin which covers the outer surface of aerial part of plant,it may protect plant from non-stoma water losing.Thick cuticle is usually presented as a convergent adaptation manners in desert plants.Evidence reveals that ABA（abscisic acid） signal transduction pathway associates directly or indirectly with the development and regulation of the salt gland,trichome,cuticle and other accessory structures,and suggests the synergetic interaction among them in stress tolerance.This paper reviewed a large number of references on accessory structures of desert plants in aspects of morphological characteristics,physiological and biochemical functions,and gene regulations,and discussed the association among different accessory structures,which is expected to supply evidence for understanding of stress tolerance mechanism of desert plants.