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利用Granier测定系统,对华南丘陵植被恢复先锋树种马占相思和木荷的树干液流分别进行4 a(2004—2007年)和5 a(2008—2012年)监测,比较不同龄级两树种的蒸腾量及其季节变化.结果表明:马占相思和木荷的年蒸腾量均随树龄增加而增大,木荷蒸腾量的增加速度更快.木荷平均整树年蒸腾量为7014.76 kg,比马占相思(3704.97 kg)高;马占相思蒸腾量的季节变异(511.46~1802.17 kg)比木荷(1346.48~2349.35 kg)大.蒸腾速率(Eh)与光合有效辐射(PAR)、水汽压亏缺(VPD)的标准回归系数随土壤湿度的增加而增大,表明土壤水分的增加提高了植物对环境响应的敏感度.偏相关分析表明,土壤湿度的季节变异是导致两树种蒸腾量季节变化的最主要因素.木荷和马占相思的最适土壤湿度分别为0.22~0.40和0.29~0.30(V/V),表明与外来树种马占相思相比,乡土树种木荷对水分胁迫有更好的适应及调节能力.
Using the Granier system, the sap flow of the pioneer tree species Acacia mangium and Schima superba in the hilly region of South China were monitored for 4 years (2004-2007) and 5 years (2008-2012) respectively. Transpiration and seasonal variation were observed.The results showed that the annual transpiration of Acacia mangium and Schima superba increased with the increase of tree age and the transpiration rate of Schima superba increased more rapidly.The annual average annual volume of M. sativa was 7014.76 kg, (3704.97 kg) than Acacia mangium (3704.97 kg). The seasonal variation of transpiration of Acacia mangium (511.46-1802.17 kg) was larger than that of Muhe (1346.48-2349.35 kg) .The transpiration rate (Eh) and photosynthetically active radiation (PAR) The standard regression coefficient of deficit (VPD) increased with the increase of soil moisture, indicating that the increase of soil moisture increased the plant’s sensitivity to environmental responses. Partial correlation analysis showed that the seasonal variation of soil moisture was the main cause of the two tree species transpiration season The most important factor for the change was the optimum soil moisture of Amomum acuminatum and Amomum acuminatum respectively ranging from 0.22 to 0.40 and 0.29 to 0.30 (V / V), indicating that compared with alien species, Acacia mangium, Better ability to adapt and adjust.