作 者 :于顺利, 陈宏伟, 李晖
期 刊 :植物生态学报 2007年 31卷 6期 页码:989-997
Keywords:seed mass, attributes of plant species, community characteristics, ecological characteristics,
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。
Abstract: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 relations hips 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.