Miao Bo, Meng Ping, Zhang Jin Song, He Fang Jie, Sun Shou Jia
Key Laboratory of Tree Breeding and Cultivation of State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing 100091, China.
Co-Innovation Center of Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing 210037, China.
Ying Yong Sheng Tai Xue Bao. 2017 Jul 18;28(7):2111-2118. doi: 10.13287/j.1001-9332.201707.037.
The water sources and transpiration of poplar trees in Zhangbei County were measured using stable hydrogen isotope and thermal dissipation method. The differences in water relationships between dieback and non-dieback poplar trees were analyzed. The results showed that the dieback trees mainly used shallow water from 0-30 cm soil layer during growing season while the non-dieback trees mainly used water from 30-80 cm soil layer. There was a significant difference in water source between them. The non-dieback trees used more water from middle and deep soil layers than that of the dieback trees during the dry season. The percentage of poplar trees using water from 0-30 cm soil layer increased in wet season, and the increase of dieback trees was higher than that of non-dieback trees. The contributions of water from 30-180 cm soil layer of dieback and non-dieback trees both decreased in wet season. The sap flow rate of non-dieback trees was higher than that of dieback trees. There was a similar variation tend of sap flow rate between dieback and non-dieback trees in different weather conditions, but the start time of sap flow of non-dieback trees was earlier than that of dieback trees. Correlation analysis showed that the sap flow rate of either dieback or non-dieback poplar trees strongly related to soil temperature, wind speed, photosynthetically active radiation, relative humidity and air temperature. The sap flow rate of die-back poplar trees strongly negatively related to soil temperature and relative humidity, and strongly positively related to the other factors. The sap flow rate of non-dieback poplar trees only strongly negatively related to relative humidity but positively related to the other factors. The results revealed transpiration of both poplar trees was easily affected by environmental factors. The water consumption of dieback trees was less than non-dieback trees because the cumulative sap flow amount of dieback trees was lower. Reduced transpiration of dieback trees couldn't help to prevent poplar forest declining due to shallow water source.
采用稳定氢同位素和热扩散法测定了张北县杨树的水源和蒸腾情况。分析了枯死杨树和未枯死杨树水分关系的差异。结果表明，枯死杨树在生长季主要利用0-30厘米土层的浅层水，而未枯死杨树主要利用30-80厘米土层的水。它们的水源存在显著差异。在旱季，未枯死杨树比枯死杨树更多地利用中深层土壤的水。在雨季，利用0-30厘米土层水的杨树比例增加，且枯死杨树的增幅高于未枯死杨树。雨季枯死和未枯死杨树30-180厘米土层水的贡献均降低。未枯死杨树的液流速率高于枯死杨树。在不同天气条件下，枯死和未枯死杨树的液流速率变化趋势相似，但未枯死杨树液流开始时间早于枯死杨树。相关性分析表明，枯死或未枯死杨树的液流速率均与土壤温度、风速、光合有效辐射、相对湿度和气温密切相关。枯死杨树的液流速率与土壤温度和相对湿度呈极显著负相关，与其他因素呈极显著正相关。未枯死杨树的液流速率仅与相对湿度呈极显著负相关，与其他因素呈正相关。结果表明，两种杨树的蒸腾作用均易受环境因素影响。枯死杨树的耗水量低于未枯死杨树，因为枯死杨树的累计液流量较低。枯死杨树蒸腾作用降低无助于防止杨树林因水源浅而衰退。
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