植物生态学报 ›› 2014, Vol. 38 ›› Issue (5): 452-459.DOI: 10.3724/SP.J.1258.2014.00041

• 研究论文 • 上一篇    下一篇

高寒退化草地狼毒种群不同海拔花大小-数量的权衡关系

张茜,赵成章(),董小刚,马小丽,侯兆疆,李钰   

  1. 西北师范大学地理与环境科学学院, 甘肃省湿地资源保护与产业发展工程研究中心, 兰州 730070
  • 收稿日期:2013-12-02 接受日期:2014-03-11 出版日期:2014-05-01 发布日期:2014-05-13
  • 通讯作者: 赵成章
  • 基金资助:
    国家自然科学基金(91125014);国家自然科学基金(409710- 39);甘肃省科技支撑计划(1011FKCA157);甘肃省生态学重点学科项目

Trade-off between the biomass and number of flowers in Stellera chamaejasme along an elevation gradient in a degraded alpine grassland

ZHANG Qian,ZHAO Cheng-Zhang(),DONG Xiao-Gang,MA Xiao-Li,HOU Zhao-Jiang,LI Yu   

  1. Research Center of Wetland Resources Protection and Industrial Development Engineering of Gansu Province, College of Geography and Environmental Science, Northwest Normal University, Lanzhou 730070, China
  • Received:2013-12-02 Accepted:2014-03-11 Online:2014-05-01 Published:2014-05-13
  • Contact: ZHAO Cheng-Zhang

摘要:

权衡关系是植物生活史对策理论的基础, 花大小-数量的权衡关系对理解花的生物量分配具有重要的意义。该文利用实验生态学方法, 研究了祁连山北坡高寒退化草地4个不同海拔狼毒(Stellera chamaejasme)种群花大小与花数量间的关系。结果表明: 随着海拔升高, 草地群落的高度、密度和地上生物量均呈先升高后降低的倒U型分布, 狼毒花大小呈逐渐增大的趋势, 而花数量呈相反的变化趋势; 不同海拔样地狼毒花大小与花数量间的相关性存在差异, 海拔2700、2900和3000 m样地狼毒花大小和花数量之间均存在极显著的负相关关系(p < 0.01), 海拔2800 m样地二者之间存在显著的负相关关系(p < 0.05), 狼毒植株分配给花大小与花数量的资源间存在着“此消彼长”的权衡关系; 海拔2800 m样地是狼毒植株花大小与花数量权衡关系由低海拔的花数量多而单花生物量低向高海拔的花数量少而单花生物量高转变的区域。狼毒植株通过合理权衡花数量和花大小的资源配置, 以补偿在海拔梯度上不利因素对种群繁衍带来的影响, 从而实现种群的繁殖成功, 反映了毒杂草对异质性生境的表型可塑性机制。

关键词: 高寒退化草地, 海拔, 花大小, 花数量, 狼毒, 权衡关系

Abstract:

Aims Trade-offs are the basis of the theory on plant life-history strategies, and the trade-off between flower size and flower number is an important determinant of flower biomass allocation. Our objective was to study the changes in the relationship between flower size and flower number in Stellera chamaejasme populations with elevation in Northwest China.
Methods The study site was located in a degraded alpine grassland on the northern slope in Qilian Mountains, Gansu Province, China. Survey and sampling were carried out at four elevations at intervals of 100 m from 2700 m to 3000 m; a GPS was used to determine the elevation. Community traits were investigated and 45 individuals of S. chamaejasme were collected randomly at each elevation. The samples were cleaned and divided into different organs, and their biomass were then measured after being dried at 80 °C in an oven.
Important findings With increasing elevation, the height, density, and aboveground biomass of the plant communities displayed a pattern of initial increase and then followed by a subsequent decline; the flower biomass in S. chamaejasme increased with increasing elevation, while the flower numbers decreased. The flower size was negatively correlated with the flower number, but the relationship varied along the elevation gradient; there was a highly significant negative correlation (p < 0.01) between the flower size and the flower number at elevations 2700, 2900, and 3000 m, whereas the correlation only reached a significant level (p < 0.05) at the elevation of 2800 m, indicating that there is a trade-off between the flower size and flower number. The elevation of 2800 m appeared to be a switching point where the S. chamaejasme individuals with more but smaller flowers at the lower elevations were transformed into ones with fewer but bigger flowers with increasing elevation. Consequently, a change in the reproductive strategy with a trade-off between flower size and flower number ensures successful reproduction of the S. chamaejasme populations in adverse environments.

Key words: degraded alpine grassland, elevation, flower number, flower size, Stellera chamaejasme, trade-off