模拟增温对川西亚高山林线交错带绵穗柳生长、叶物候和叶性状的影响

采用开顶式生长室(open-top chamber, OTC)模拟增温的方法,研究了模拟增温对川西亚高 山林线交错带绵穗柳生长和叶性状的影响.结果表明：与对照样地相比,OTC内日平均气温(地上12 m)在植物生长季中增加2.9 ℃,而5 cm土壤温度仅增加0.4 ℃；温度升高使绵穗柳芽开放时间明显提前、落叶时间明显推迟,叶寿命延长；OTC内绵穗柳叶面积和侧枝生长速率明显加快,比叶面积明显增加,而叶氮浓度却显著下降；OTC内绵穗柳的气孔导度、净光合速率、光呼吸速率和暗呼吸速率总体上呈增加趋势.综上所述,绵穗柳适应增温效应的能力较强,在未来气候变化背景下,其分布的海拔高度有可能上升.

Effects of simulated warming on the growth, leaf phenology, and leaf traits of Salix eriostachya in sub-alpine timberline ecotone of Western Sichuan, China.

By using open-top chamber (OTC), the effects of simulated warming on the growth , leaf phenology, and leaf traits of Salix eriostachya in sub-alpine timber line ecotone of Western Sichuan were studied. The results showed that comparing with the control, the mean air temperature at 12 m above the ground through out S. eriostachya growth season in OTC increased by 29 ℃, while the soil temperature at the depth of 5 cm only increased by 04 ℃. The temperature inc rease in OTC made S. eriostachya budding advanced and defoliation postpon ed obviously, and the leaf life-span longer. The leaf and branch growth rates a s well as the specific leaf area in OTC increased obviously, whereas the leaf ni trogen concentration decreased significantly. In OTC, the stomata conductance, n et photosynthetic rate, photorespiration, and dark respiration rate of S. erio stachya all exhibited an increasing trend. It was suggested that S. eriostac hya had stronger capability to adapt to warming, and, under the background of future global climate change, the elevation of S. eriostachya distribution i n the timberline ecotone would be likely to ascend.