Responses of stem anatomical structure of a lakeside dominant plant Zizania latifolia to simulated warming in Napahai wetland of Northwestern Yunnan

Abstract

Lakeside plants of plateau wetland show strong functional responses to climate warming, one of the main phenomena of global change. Anatomical traits are closely related to the ecological function in plants. In order to explore the influences of climate warming on stem anatomical structures of wetland plants, the effects of simulated temperature increase on the stem anatomical structure of Zizania latifolia, an emergent plant in the lakeside zone of the Napahai wetland in the northwest of Yunnan Province, were studied by using an open-top chamber. The results were as follows: (1) In the temperature-increasing range of 4℃, the aboveground stem of Z. latifolia responded to warming mainly by increasing the thickness of the epidermal structure to increase the epidermal water loss. The response strategy of the underground stem was the same as that of the aboveground stem when the temperature was increased by 2℃, while the response to the temperature increase was mainly through reducing the sizes of the vascular structure to reduce the risk of cavitation when the temperature were increased by 4℃. (2) Annual maximum temperature(MAX) and nighttime accumulated temperature(NAT) were the key factors affecting the stem anatomical structure of Z. latifolia, but both of which only have significant effects on the sieve tube size of the underground stem (R2=0.838, P<0.01). (3) The thickness of inner epidermal cells was the main traits of the aboveground stem in response to the warming, and was significantly and positively correlated with temperature factors. The sizes of the vessel and sieve tube were the main traits of the underground stem response to the warming, and they were negatively correlated with temperature factors. The results indicate that there are differences in response strategies of the aboveground stem and underground stem of Z. latifolia to the temperature increase, which provides a scientific basis for revealing the response laws of plateau wetland plants to climate warming and ecological adaptation strategies. Based on the current climate warming context, we need to further investigate and supplement the ecological response processes and laws of more plateau wetland plants with more scientific experimental methods in the future.

Keywords

• climate warming
• plateau wetland
• plant functional traits
• emerging plant
• incremental temperature