Effects of altitude on seed size on the eastern Qinghai-Tibetan Plateau

Abstract

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, R²=0.029, P<0.001), in accord with previous studies; 2) The decline in seed size with altitude was significant within grasses(n=512,R²=0.026,P<0.001), but not within shrubs(n=72, R²=0.004, P=0.616), or trees(n=16, R²=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.

CLC Number:

S315.7

GUO Shu-qing, QI Wei, WANG Yu-lin , MA Xiong, CHEN Xue-lin, DU Guo-zhen. Effects of altitude on seed size on the eastern Qinghai-Tibetan Plateau[J]. Acta Prataculturae Sinica, 2010, 19(1): 50-58.

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