中文摘要：

采用气室-红外气体分析法（IRGA）原位监测西双版纳热带季节雨林优势树种番龙眼（Pometia tomentosa）和玉蕊（Barringtonia macrostachya）（雨季），以及人工种植的经济树种三叶橡胶（Hevea brasiliensis）（干季、雨季）树干呼吸的日变化，同时监测了林内空气和1cm深树干温度。结果表明，三者树干呼吸雨季呈双峰模式，三者首个呼吸高峰都在15：00前后，番龙眼和玉蕊第二个呼吸高峰在凌晨1：00前后，三叶橡胶在凌展5：00前后。干季三叶橡胶树干呼吸为单峰模式，呼吸高峰在19：00前后，午后出现明显的呼吸下降现象。番龙眼和玉蕊雨季树干呼吸速率在1．814—3．167μmol／（m^2·s）之间，三叶橡胶在8．824—10．364μmol／（m^2·s）之间，显著高于同时期的番龙眼和玉蕊，三叶橡胶干季在3．424—4．110μmol／（m^2·s）之间，显著比雨季小。三者Q10在1．60-2．58之间，三种树的平均Q10为1．77。

英文摘要：

Stem respiration is an important component of the carbon budget of forest stands. There are some data for temperate and boreal zones, but measurements of stem respiration in tropical rain forest remainsparse, We made in situchamber measurements of the stem respiration for 3 tropical tree species （ Pometia tomentosa, Barringtonia macrostachya and Hevea brasiliensis） in Xishuanghanna, by using an infra-red gas analyzer （IRGA） method in dry and rainyseasons. LI -820 CO2gas analyzer was the main equipment which connected a custom-built polyvinyl chloride （PVC） chamber. The chamber sealed to the stem using thin neoprene gaskets was fastened on the stem surface with a strap at sampling time. The stem respiration rates of Pometia tomentosa and Barringtonia macrostachya, the dominant tree species in tropical rain forest of Xishuanghanna, were measured in the south and north sections at 1.3 m height on September 12 - 13, 2005 （wet season） and Hevea brasiliensis, a planted economic tree species in Xishauanghanna, was measured in the south and north sections at 1.3 m and 2.0 m height on March 29 - 30 （ dry season） and August 30 - 31, 2005 （wet season）, respectively. Meanwhile, the temperature insidethe stems at 1 can depth and air temperature in the forests were recorded. The tendencies in diurnal stem respiration of 3 tree species at all sections in the wet season showed clear double-peak patterns. The first respiration peak of 3 tree species occurred around 15：00, and the second peak of Pometia tomentosa and Barringtonia appeared at 1：00 ,while that of Hevea brasiliensis at 5：00. The minimum stem respiration rates of all 3 tree species were at 7：00. The stem respiration tendencies of Hevea brasiliensis in the dry season were remarkable single-peak patterns, different from that in the wet season. The stem respiration rate of Hevea brasiliensis in the dry season decreased after 13：00 with the air temperature above 28℃. The stem respiration rates of Pometia tomentosa and Barringtonia, rang