同源四倍体青甘韭叶片气体交换特征对不同温度的响应

Polyploidy is a major force of driving plant evolution, even about 70% of flowering plants have experienced one or more times polyploidization process in nature, and usually there is a clear differentiation in their habitats between polyploid and its diploid. In order to study the physiological and ecological mechanisms of polyploid and its diploid plant in habitat differentiation, the gas exchange parameters of autotetraploid and diploid Allium przewalskianum Regel leaf were measured under 18 C, 24 C and 30 C. The results showed that almost all the leaf gas characteristic parameters of autotetraploid were higher than its diploid in three temperature treatments, especially under 24 C, the net photosynthetic rate (Pn), stomatal conductance (Gs), intercellular CO2 concentration (Ci) and transpiration rate (E) were the highest, however, the instantaneous water use efficiency (WUEi) decreased with increasing temperature, and saturated water vapor pressure deficit (VPDL) on the contrary. Meanwhile, at the same temperature change the leaf gas exchange parameters variation in autotetraploid significantly less than its diploid, especially the changes of the autotetraploid significantly was less than their ancestral diploid when the temperature lower 6 C. In summary, both at a specific temperature or in the same temperature ranged the leaf gas exchange parameters of autotetraploid A. przewalskianum were significantly higher than its diploid and the sensitivity to temperature changes of autotetraploid were lower than its diploid, indicating that autotetraploid A. przewalskianum can adapt to the low temperature and large temperature unstable habitats, contribute to its distribution, growth and survival in the high-altitude extreme environment.