中国东部沿海互花米草种群生活史特征的纬度变异与可塑性  

Variation and phenotypic plasticity in life history traits of Spartina alterniflora along the east coast of China

作　　者：张亦默[1] 王卿[2] 卢蒙[1] 贾昕[1] 耿宇鹏[1] 李博[1] 

机构地区：[1]生物多样性和生态工程教育部重点实验室、复旦大学生物多样性科学研究所,上海200433 [2]上海市环境科学研究院,上海200233

出　　处：《生物多样性》2008年第5期462-469,共8页Biodiversity Science

基　　金：国家重点基础研究发展计划(2006CB403305);国家自然科学基金项目(30670330)

摘　　要：互花米草(Spartina alterniflora)于20世纪70年代被引入中国,目前已在东部沿海盐沼湿地中广泛分布,成为海岸带盐沼中危害严重的入侵植物之一。为了研究互花米草在中国入侵区中的适应机制,揭示遗传分化和表型可塑性在该物种成功入侵中的作用,本研究沿纬度梯度在南起广东(22°N)、北至天津(39°N)的沿海样带上采集了10个种群的样本,通过同质园实验比较了不同纬度来源的种群在生活史和生长特征方面是否存在遗传分化,并平行设置高低两个水位处理以比较互花米草对水位变化(不同高程生境条件)的可塑性反应。结果表明,在所研究的互花米草17个性状中有12个存在显著的种群间差异。其中,平均开花日期和相对生长率(植株高度)表现出显著的纬度梯度变异:随着纬度的升高,开花时间提前,相对生长速率(植株高度)趋于增加。同时17个性状中有9个在不同水位处理之间存在显著差异。这些结果表明,遗传分化可能是互花米草能够快速占据广阔分布区的重要原因之一,而表型可塑性可能对互花米草在小尺度上占据不同高程环境的过程有重要作用。Spartina alterniflora, native to North America, is invasive in salt marshes worldwide. Its geographic distribution in China has expanded to include most eastern coastal areas since it was introduced in 1970s. Genetic differentiation and phenotypic plasticity are two major strategies in adaptation to varying environments. To investigate the mechanisms of the range expansion of S. alterniflora in China, we collected samples from ten populations on the east coast of China along a latitudinal gradient from Guangdong （22°N） to Tianjin （39°N）. We grew plants singly in pots placed in an outdoor garden under either low or high water levels to explore plastic responses to varying elevation in the field. Twelve of 17 traits measured demon- strated considerable variation among populations. In particular, mean date of blossoms and the relative growth rate of height （RGRH） showed clinal variation with latitude. Our results suggested that Chinese populations of S. alterniflora might have experienced genetic differentiation. Furthermore, 9 of 17 traits showed remarkable plasticity in response to different water levels. S. alterniflora at high water level was more prolific and produced its first ramet earlier. Therefore, the successful invasion of S. alterniflora in China might have resulted from both genetic differentiation and phenotypic plasticity. The former might have facilitated its rapid range expansion on a regional scale, and the latter might have played an important role in local adaptations to habitats along an elevational gradient.

关 键 词：SPARTINA alterniflora 表型可塑性 入侵种 水位 遗传分化 

分 类 号：Q948[生物学—植物学]