滇西北纳帕海湖滨带优势植物茭草茎解剖结构对模拟增温的响应

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

高原湿地湖滨带植物对气候变暖表现出强烈的功能响应,是全球气候变化的主要现象之一。植物解剖性状直接关系到植物的生态功能,为探讨气候变暖对湿地植物茎解剖结构的影响,该研究利用开顶式生长室分析了模拟增温对滇西北纳帕海湿地湖滨带挺水植物茭草茎解剖结构的影响。结果表明:(1)茭草地上茎在增温4℃的范围内,主要通过增加表皮结构厚度以增加表皮失水来响应增温;地下茎在增温2℃的轻度增温条件下与地上茎的响应策略相同,而在增温4℃时主要通过减小维管结构大小以降低气穴化风险来响应增温。(2)年最高温度和夜间积温是影响茭草茎解剖结构性状的关键因子,但该两个温度因子仅对地下茎筛管大小的影响达到显著水平(R^(2)=0.838,P<0.01)。(3)内表皮细胞厚度是地上茎响应增温的最主要性状,并与温度因子呈显著正相关。地下茎导管和筛管大小是地下茎响应温度升高的主要性状,二者与温度变量呈负相关关系。综上表明,茭草地上茎和地下茎对增温响应策略存在差异,为揭示高原湿地植物应对气候变暖的响应规律以及生态适应策略提供了科学依据。基于当前气候变暖的背景,建议未来采用更科学的实验方法对更多高原湿地植物的生态响应过程及规律进一步深入研究。

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(R^(2)=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.