植物生活史型的多样性及动态分析

主要阐述了植物生活史型的基本定义和基本模式。根据植物的生态幅（Ｅｃｏｌｏｇｉｃａｌ　ａｍｐｌｉｔｕｄｅ）、适合度（Ｆｉｔｎｅｓｓ）和能量分配格局将植物生活史型划分出Ｖ生活史型、Ｓ生活史型和ｃ生活史型３个基本类型以及ＶＳ生活史型、ＳＶ生活史型、ｃＳ生活史型、Ｓｃ生活史型等６个具有混合特征的过渡类型。文中分析了权衡（丁ｒａｄｅ—ｏｆｆ）植物生活史各阶段的能量需求，使之合理地进行能量分配，进而使植物生活史型获得最佳的繁殖和存活效益以及最大的适合度的重要性，指出韧生代谢和次生代谢增值物生活史型及其生活史型之间相互转换的密切关系。韧生代谢物质主要用于营养生长，次生代谢物质主要用于促进繁育和拮抗环境胁迫。植物生活史型在特定时空中依生境的连续变化而发生相互转换，呈现出具动态特征的植物生活史型诺。提出了植物生活史型的形成机制，即生境中的资源状况和干扰程度构成了环境筛的径度，进而形成选择压力，以使植物按需分配能量，合成初级代谢产物或次级代谢产物来应对选择压力，形成自身的生态幅和适应对策，最终与生境相互作用过程中表现出的适合度来表征相应的生活史型。还提出了植物生活史型之间相互转化的机制，即每一种植物生活史型均有与该生活史型相对应的生境类型、选择压力、代谢物质和生活史对策，由于时空的连续变化，生境类型也发生过渡性变化，形成过渡类型（ＥＤ、ＤＥ、ＤＦ、ＦＤ），因而导致选择压力、代谢物质、生活史对策也发生过渡性变化，形成过渡类型ＬＭ、ＭＬ、ＭＨ、ＨＭ、ＫＲ、ＲＫ、ＲＴ、ＴＲ、ＢＰ、ＰＢ、ＰＡ、ＡＰ，最终通过ＶＳ、ＳＶ、ＳＣ、ＣＳ等过渡类型的形成而实现植物生活史型之间的相互转换。文中以高山红景天（Ｒｈｏｄｉｏｌａ　ｓａｃｈａｌｉｎｅｎｓｉｓ）等５种植物生活史型谱为例，分析了各植物生活史型谱的动态特征并指出：Ｖ生活史型的植物因营养体较为发达、寿命较长，且能通过正常的有性生殖繁衍后代，通常都能产生稳定种群；以Ｓ生活史型为主的植物，因台子中含有来自双亲的两套基因，故有性生殖过程能产生较多遗传性不同的后代，使种群的适应环境变化的能力加强，因而容易形成爆发种群；以ｃ生活史型为主的植物，其遗传物质与母体完全相同，故种群适应环境变化的能力较弱，因而容易导致种群濒危。

Dynamic Analysis and Diversity of Plant Life Cycle Forms

This paper mainly discussed the basic definition and types of plant life cycle form. According to the plant ecological amplitude, fitness and energy allocation patterns, plant life cycle form could be classified as three basic forms (V form: vegetative growth form; S form: sexual reproduction form and C form: clone reproduction form) and six transitional forms (VS form, SV form, CS form and SC form, VC and CV form) which combine features of three basic forms. By trading off the energy allocation among different plant cycle phases, plants optimize their energy utilization and adopt a specific plant life cycle form with the characteristics of best reproductive and survival benefits as well as maximum fitness to habitats. Moreover, our results indicate that primary metabolism and secondary metabolism might be closely correlated with plant life cycle forms and their transformation between forms. Generally speaking, primary metabolite is mainly used in vegetative growth, but secondary metabolite may be mainly used to promote propagation and over come environmental stress. The plant life cycle form of one specific species could transform from one form to another to adapt to the changing environment. This transformation process is characterized as a dynamic process and form the spectrum of plant life cycle forms of this species. The developing mechanism of plant life cycle form is also discussed in this paper. The size of an environmental sieve (resource status and disturbance degree of habitat) results in the selective pressure. According to the pressure intensity, plants optimize their energy allocation with regard to the need of their different organs by way of producing primary and secondary metabolites, These result in the adaptive strategy and ecological amplitude of one specific species. Finally, fitness manifested by the interaction between the habitat and the adaptive strategy can be characterized as plant life cycle form. Furthermore, this paper also discusses the transformation mechanism between the plant life cycle forms. Because each species has its specific habitat type, selective pressure, metabolite and adaptive strategy, habitat also has a transformational change with the continuous change in spatial and temporal scales. These result in the formation of transformation types of habitat. These kinds of habitat enhances the transformational changes in selective pressure, metabolite and adaptive strategy, which form their transformation types, respectively. As a result, the inter|transformation processes of plant life cycle forms (so|called transformation types) were observed. The spectrums of plant life cycle forms of five species including Rhodiola sachalinensis were exemplified to analyze the dynamic features of these spectrums and their possible correlation to the community characteristics. Our results indicated that: First,plants mainly with a V life cycle form generally have a stable population because of their relative big vegetative body, long lifespan and offspring production by normal sexual reproduction. Second, plants with a S life cycle form easily form a eruption population because their diversified genetic message, which is inherited from double genomes of their parent through sexual reproduction, could induce their strong ability to acclimate to the changing environment; Finally, plants with a C life cycle form easily form an endangered population because their gene message is just duplicated from one parent through clone reproduction, which is uniform and have a relative weak ability to acclimate to the changing environment.