弯齿风毛菊花部器官的海拔变异及其与种子质量和数目的关系

以青藏高原东北缘的12个弯齿风毛菊居群为对象,分析花部器官随海拔的变异机制及其与种子质量和数目的关系.结果表明:当海拔在3500~4500 m时,花丝长、花药长、花柱长和花柱分支长分别为0.52~1.01、0.23~0.63、0.74~1.58和0.11~0.22 cm,且均随海拔的升高而显著增长,而花粉数量(26.5×10^4~73.5×10^4)显著下降;花粉数量与花丝长、花柱长及花柱分支长均呈显著负相关,花柱长与花丝长呈显著正相关;种子数目与花丝长、花柱长及花柱分支长均呈显著负相关,与花粉数量呈显著正相关;百粒重与花丝长、花柱长及花柱分支长均呈显著正相关,与花粉数量呈显著负相关.随着海拔的升高,弯齿风毛菊在花期选择延长花部器官的长度来增大昆虫对花粉的携带量和输入量,到果期生产出具有更强竞争优势和生存能力的大种子(质量大、数量少)来提高适合度.

Altitudinal variation of floral organs in Saussurea przewalskii and its relationship with the number and mass of seeds

We examined the variation of floral organs of Sausssurea przewalskii along altitude and its relationship with the number and mass of seeds from 12 populations in the northeastern edge of Qinghai-Tibetan Plateau, China. At the altitude of 3500-4500 m, the filament length, anther length, column length and style branch length were 0.52-1.01, 0.23-0.63, 0.74-1.58, and 0.11-0.22 cm, respectively. All the indices significantly increased with altitude, while the number of pollens (26.5×10⁴-73.5×10⁴) significantly decreased. There was a significant negative correlation between the lengths of filament, style, column branches and pollen numbers, and a significant positive correlation between column length and filament length. The number of seeds was negatively correlated with the lengths of filament, column and style branches, but positively correlated with the number of pollen. The hundred kernals weight was positively correlated with the length of the filament, column and style branches, and negatively correlated with the number of pollen. With the increases of altitude, S. przewalskii extends the length of flower organs to increase the pollen carrying capacity and input of insects in the flowering period, and produces large seeds with more competitive advantage and survival rate in fruiting stage to improve its fitness.