摘要
作为植物生活史中的一个关键性特征,种子重量与其它许多植物性状和生态因子有关,种子重量的分异与其它一些植物性状及环境的变化关系在进化生物学上已经成为一个非常有意义的研究内容,且具有一定的实践意义。种子重量被发现与下列的一些植物学和群落学性状有关:植物的生活型、种子的散布能力、种子的散布方式、植物的高度、植物的冠幅、植物的比叶面积、植物的寿命、动物的捕食、植被中植物的数量或多度、土壤中种子的数量或多度、种子的休眠、种子在土壤中的持久性和植物的净初级生产力等,另外生态因子如降雨、温度、坡向、海拔、经度、纬度、光强和干扰等都影响种子的重量。种子的重量被认为是在大量小种子和少量大种子之间的进化折衷,在一定的能量限度内,较大重量的种子一般具有较少的数量,而较小重量的种子一般数量较多,这是种子重量和数量方面具有的一种反向关系。与其它性状相比,很多研究都表明种子重量和植物的生活型的关系密切。没有散布结构或风散布的种子比以动物和水作为散布媒介的种子重量要小。种子重量与捕食的关系现发现有3种格局。种子重量和形状与种子在土壤中的持久性的关系有4种格局。在干旱和阴暗的环境条件下,种子有变大的趋势。大重量种子比小种子赋予幼苗较优势的竞争地位,其原理尚有争论,尚不清楚是否是幼苗阶段的竞争决定了世界上大部分植被类型的物种组成。未来的研究方向主要有以下几个方面:1)种子重量与植物系统学相结合,探索种子重量的变化规律;2)调查群落三向(纬度、经度和海拔)性的种子重量谱变化规律;3)群落演替与群落种子重量谱的变化;4)种子重量与群落中植物个体和种子的数量的关系及机理研究;5)微生境、微地形如坡向、坡位和林间隙等对种子重量的影响;6)全球气候变化和种子重量变化的关系。
Seed mass is a key attribute of plant species,and study of relationships between seed mass and other plant traits and ecological characteristics has become a practical problem and an interesting topic in evolutionary biology.Seed mass（or size）is related to other plant traits and community characteristics,including seed dispersal capacity,seed dispersal mode,plant growth form,leaf area index,abundance of seeds or plant individuals in a community,seed predation,seed dormancy and seed persistence in soil seed banks,net primary productivity,etc.Variations in seed mass have been related to latitude,longitude,altitude,temperature,precipitation,slope aspect,light environment,etc.Seed mass is thought to have evolved as a compromise between seed mass and number for a given amount of energy.Many studies support that seed mass has a closer relationship with plant growth types than other characteristics.Species that establish in shade have large seeds.Three patterns were found in the relationship between seed mass and seed predation.Four patterns were found in the relationship between seed mass and persistence in soil seed banks.During establishment,seedlings from larger-seeded species are better able to survive competition from established vegetation,deep shade,defoliation,mineral nutrient shortage,burial under soil or litter,drought,etc.Among species with seeds unspecialized for spatial dispersal,seed mass is unrelated to dormancy.However,in species with wind-or animal-dispersed seeds those with heavy seeds typically have less dormancy.This is consistent with heavy seeds having better establishment success and/or suffering higher levels of herbivory.Future research should focus on relationships between seed mass ecology and 1）plant phylogeny and plant taxonomy,2）latitude,longitude and altitude,3）community succession,4）number of plant individuals and seeds,5）microhabitats or microtopography such as forest gaps and slope aspect and 6）global climate changes.
出处
《植物生态学报》
CAS
CSCD
北大核心
2007年第6期989-997,共9页
Chinese Journal of Plant Ecology
基金
国家自然科学基金面上项目(40771070和40641004)
关键词
种子重量
植物学性状
群落学特性
生态学性状
seed mass,attributes of plant species,community characteristics,ecological characteristics
