内蒙古中东部草原不同生境克氏针茅（Stipa krylovii Roshev.）种群的形态差异分析

对内蒙古中东部草原分布的克氏针茅进行了种群内和种群间的形态差异分析。结果表明：（1）种群内不同的形态性状存在不同程度的差异；（2）种群间生殖枝中的一部分形态性状以及营养枝高度和营养枝干重均存在较大差异；（3）每穗小花数、每穗籽粒数、每穗小穗数、生殖枝高、穗干重、生殖枝干重、每穗种子重、种子重/生殖枝重比等性状的变化趋势相同，均表现为随生境条件变差而增加，即在生殖上投入增加以增大适合度；（4）主成分分析表明穗长、种子重/生殖枝重比、每穗小花数、每穗籽粒数、生殖枝高、基盘长、第二芒柱长、营养枝高、千粒重、芒针长是不同种群差异的主要指标。这些形态性状的差异可以看作克氏针茅对不同生境的适应性表现。

Morphological Variations of Stipa krylovii Roshev. in Middle and Eastern Inner Mongolia Steppe

In this paper four populations of Stipa krylovii in Inner Mongolia steppe, collected from Xinhot, West Xilinhot, East Xilinhot, Bayanwula, respectively, were used for the study of their morphological variations. (1)The variation of some morphological characters was greater than that of other characters within the same population. (2)Among all populations some of the reproductive traits varied much more than others, and in the vegetative traits, dry matter weight per reproductive shoot had greater variation than height of vegetative shoot.(3) Most reproductive traits, including the number of florets per panicle, seeds per panicle, spikelets per panicle, height of reproductive shoot, dry matter weight per panicle, dry matter weight per reproductive shoot, seed weight per panicle and the ratio of seed weight/ reproductive shoot weight varied in a similar pattern, and their values increased with their habitats worsening. This suggested that S. krylovii could increase the allocation of the photosynthetic assimilate to sexual reproduction so as to respond to the adverse habitat. (4) The principal component analysis revealed that ten morphological traits were mainly responsible for the variations among populations. The ten traits included the length of panicle, ratio of the dry matter weight between seeds and reproductive shoot, the number of spikelets per panicle, the number of seeds per panicle, height of the reproductive shoot, height of vegetative shoot, weight of 1 000 seeds, length of awn apex, length of callus and length of the second segment of awn. The variation of these traits might have resulted from adaptability of S. krylovii to different habitats.