[Altitudinal variation of floral organs in Saussurea przewalskii and its relationship with the number and mass of seeds]. / å¼¯é½¿é£Žæ¯›èŠèŠ±éƒ¨å™¨å®˜çš„æµ·æ‹”å˜å¼‚åŠå ¶ä¸Žç§å­è´¨é‡å’Œæ•°ç›®çš„å ³ç³».

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.

[Effects of altitude on the reproductive characteristics of Saussurea przewalskii at the eastern margin of the Tibetan Plateau, China.] / 海拔对青藏高原东缘弯齿风毛菊繁殖特征的影响.

The paper studied the effects of altitude on reproductive characteristics in 12 populations of Saussurea przewalskii at the eastern Qinhai-Tibetan Plateau, China. The results showed that the size, reproductive organ biomass, vegetative organ biomass, capitulum number, and seed number of individual plant decreased with the increasing altitude, and the capitulum mass and hundred-grain mass increased continuously. S. przewalskii could ensure its reproduction by reducing plant body size to decrease resource consumption, and increasing the allocation of limit resources to flower biomass. In order to ensure sexual reproduction, the reproductive allocation of the plants increased with increasing the altitude. There was a trade-off between capitulum number and capitulum mass, and between seed number and hundred-grain mass, which allowed the plants to maximize their fitness under stressful conditions.