青藏高原东缘海拔对植物种子大小的影响
Effects of altitude on seed size on the eastern Qinghai-Tibetan Plateau
郭淑青 1齐威 2王玉林 1马雄 1陈学林 2杜国祯2
作者信息
- 1. 甘肃民族师范学院化学与生命科学系,甘肃,合作,747000
- 2. 兰州大学草地与农业生态教育部重点实验室,甘肃,兰州,730000
- 折叠
摘要
以青藏高原东缘600种植物种子为对象,就海拔对种子大小的影响展开系统性地研究.结果表明,1)整个区系内,植物种子大小与海拔呈极显著的负相关关系(n=600, R~2=0.029, P<0.001),并且在2 000～3 000 m海拔梯度中,种子大小有先增大后减小的趋势; 2)草本植物种子大小与海拔呈极显著的负相关关系(n=512,R~2=0.026,P<0.001),但是灌木(n=72, R~2=0.004, P=0.616)和乔木种子大小(n=16, R~2=0.005, P=0.795)随海拔虽有减小的趋势但无显著相关性;3)海拔较高地区的草本植物种子大小比同属的海拔较低的植物种子大11.5%(df=131, t=2.724, P=0.007),小于阈值±30%,草本植物属内种子大小与海拔无关.在132个草本植物种对中,与同属的低海拔物种相比,40.9%(54种)高海拔物种种子大,另外19.7%(26种)小,39.4%(52种)没有变化,由此,认为在青藏高原东缘强烈的选择压力下,海拔和系统发育综合因子对植物种子大小的影响由具体的某个属本身的特性所决定,不存在单一的海拔与属的种子大小变异模式.
Abstract
Seed size was studied in relation to altitude, growth form and phylogeny across 600 species on the eastern Qinghai-Tibet Plateau. 1) Considering the whole flora, seed size decreased with altitude(n=600, R~2=0.029, P<0.001), in accord with previous studies; 2) The decline in seed size with altitude was significant within grasses(n=512,R~2=0.026,P<0.001), but not within shrubs(n=72, R~2=0.004, P=0.616), or trees(n=16, R~2=0.005, P=0.795). 3) t-tests found that seeds of higher region species were 11.5% larger than seeds from lower region species of the same genus(df=131, t=2.724, P=0.007), but smaller than the threshold ±30%, so, there was no significant effect between seed size and altitude within a genus. This is in contrast to other studies that have found a positive correlation. Compared with seed size of species collected from lower regions in the 132 grass species-pairs 40.9%(54 species) of, higher species had larger seeds, 19.7%(26 species)had smaller, and 39.4%(52 species)had no difference. There was no uniform pattern relating seed size to altitude. In different genera, seed size responses to environment have varied over long-term ecological time.
关键词
种子大小/海拔/区系/生长型/属Key words
seed size/altitude/flora/growth form/genus引用本文复制引用
出版年
2010
国家科技期刊平台
NSTL
维普
万方数据