植物种子二形性(多形性)研究进展  

Advances in plant seed dimorphism (or polymorphism) research

作　　者：李伟强[1] 刘小京[1] 毛任钊[1] 安萍[2] 乔海龙[1] 黄玮[1] 李志刚[1] 

机构地区：[1]中国科学院遗传与发育生物学研究所农业资源研究中心,石家庄050021 [2]日本国鸟取大学干燥地研究中心,鸟取6800001

出　　处：《生态学报》2006年第4期1234-1242,共9页Acta Ecologica Sinica

基　　金：河北省"十五"农业资助项目;中国科学院知识创新资助项目(KZCX2405和KZCX3SW428)~~

摘　　要：植物种子的二形性(多形性)是指在同一棵植株上生长有形态结构、生理、生态学特性等方面有很大差异的两种(多种)种子。这种现象在自然界中比较普遍,特别是菊科、藜科、禾本科、十字花科中最为常见。二形性种子可分为有扩散结构和没有扩散结构(如冠毛和表皮毛状体)两种。如菊科的边花种子一般不具有扩散结构、个体较大,具有休眠特性和对光、温度、水、盐分等环境因子的敏感特性;而中间花种子一般具有扩散结构,个体较小,不具有休眠特性。具有休眠特性和对环境因子比较敏感的种子是形成土壤种子库的主要成分。二形性种子产生的幼苗在前期形态大小上都有差异,但生长后期有些差异不显著(70daysoldforHedypnoiscretica),有些仍很显著(AtriplexSagittata)。这二形性幼苗所产生的后代同样也具有二形性现象。二形性种子产生的比例受环境因素的影响,例如:水、盐、养分和密度胁迫等。遗传因素也影响二形性种子的比例,其遗传率一般在0.2～0.5之间,是一种数量遗传性状,受多个基因控制。为了解释二形性种子产生的原因,从生态学和个体发育的角度提出了两个模型:生态进化模型(两面下注策略或高低风险策略)和个体发育模型。不同植物的二形性(多形性)种子在结构、发芽休眠特性、对环境因子的反应、幼苗特性、两者的比例受遗传和环境因素的影响不尽相同。种子二形性(多形性)是植物本身的遗传特性和环境因素共同作用产生的现象,是植物适应环境的一种生理、生态机制,是植物长期进化的结果。总之,二形性种子的形成机理非常复杂,目前还不是很清楚。对以下4个方面的研究进行了展望:采用生物技术的手段研究种子二形性的遗传机制;二形性种子激素等化学物质含量的差异;目前各种环境因素对植物生长的生理生态学意义;二形性植物生活史�Seed dimorphism （polymorphism） can be defined as the production of two （ or more than two） different types of seeds by a single individual. The seeds may be different in morphological and/or physiological aspects. Seed dimorphism or polymorphism is found in many plant species of Asteraceae, Poaceae, Brassicaceae and Chenopodiaceae. Dimorphic seeds typically differ in the presence/absence of dispersal structures （e. g., pappus, trichomes）. In members of Asteraceae, peripheral achenes are persistent, large, dormant and sensitive to light, temperature, water and salt; while central archenes are dispersible, small and non-dormant. Dormant seeds or the seeds which are sensitive to environmental factors are an essential part of a seed bank. Seedlings from dimorphic seeds differ at the early stage （40 days old for Hedypnois cretica）, but the difference decreases quickly for H. cretica（no difference at 70 days old）, while the difference persists during the life cycle for Atriplex Sagittata. Both kinds seedlings produce dimorphic seeds in next generation. Environmental factors such as water, salt, nutrient and density stress affect the ratio of dimorphic seeds quantitative genetic character Genetic factors also affect this ratio with a heritability factor of 0.2 ～ 0.5. Seed dimorphism is a and is under the control of more than two genes （locus）. In order to explain the causes of seed dimorphism, two models are proposed based ecological and ontogenetic constraints： bet-hedging （high risk/low risk） strategy and ontogenetie model. Dimorphie seeds from different individuals of the same species differ considerably in their structure, germination/dormancy characters, responses to environmental stresses, early seedling growth and genetic aspects. Generally, seed dimorphism （polymorphism） is a consequence of long-term （evolutionary） interactions between environmental and genetic factors-an ecological adaptation to variable environment. The underlying mechanisms of seed dimorphism are very c

关 键 词：种子二形性 多形性 进展 发芽 扩散 两面下注策略 

分 类 号：Q944.3[生物学—植物学] Q945.79