大连市黑松树木水分利用效率的环境响应

以生长于大连城区的黑松为研究对象,建立了1951—2010年间的树木径向生长、树轮稳定碳同位素比率(δ¹³C)和水分利用效率的时间序列,研究了三者的变化特点及其与主要气候因子的关系.结果表明: 1980年以来,黑松树木径向生长有减缓趋势,δ¹³C值降低,但是水分利用效率显著增加(P<0.05).年轮宽度、稳定同位素比率和水分利用效率的变化均受气候因素的影响,并随季节波动:夏季温度与树木径向生长呈负相关,而冬季则呈正相关;6月降水和相对湿度的波动与年轮宽度变化基本呈正相关;3—9月各月温度与δ¹³C和水分利用效率呈弱正相关,其他月份基本呈弱负相关;全年降水和相对湿度分别与δ¹³C和水分利用效率基本呈负相关.快速暖干化的城市气候环境促进了树木水分利用效率的提高.

Environmental response of intrinsic water use efficiency of Pinus thunbergii in Dalian City,China.

Based on Pinus thunbergii growing in Dalian City, we developed the time series of tree radial growth, tree-ring stable carbon isotope ratio (δ¹³C) and intrinsic water use efficiency (WUE_i) in the period of 1951-2010, and studied their variation and the climate related significance. Radial growth of the pines showed a decrease trend, tree-ring δ¹³C decreased slightly, but WUE_i increased significantly (P<0.05) after 1980. Climate factors affected tree-ring width, δ¹³C and WUE_i of the pines, and the effects showed seasonal variation. Temperatures respectively showed positive and negative correlations with radial growth of the pines in summer and winter, while monthly precipitation and relative humidity in June had positive correlations with tree-ring width in general. Monthly temperature had weakly positive correlations with δ¹³C and WUE_i in March-September, and slightly negative correlation during the rest months of a year. Precipitation and relative humidity respectively had negative correlations with δ¹³C and WUE_i in general. The rapid warming environment in the city contributed to the WUE_i increase of urban trees.