【摘要】 采用红外气体分析法(IRGA)原位测定了长汀重建生态系统2个先锋树种马尾松(Pinusmassoniana)和木荷(Schima superba)冬季树干CO2释放速率(stem CO2efflux rates,FCO2),同时测定了气温、空气相对湿度、树干温度及树干液流密度.结果表明:2个树种冬季南面FCO2日变化呈单峰型模式,峰值分别出现在18:00和20:00;北面FCO2日变化呈S型,最高值出现在18:00到2:00之间;但它们的最低值均出现在8:00前后.冬季马尾松FCO2在0.71~1.56μmol.m-2.s-1之间,木荷在1.57~2.98μmol.m-2.s-1之间,极显著高于马尾松(P<0.01).树干温度和树干液流密度是影响长汀重建生态系统冬季马尾松和木荷冬季FCO2的重要因素,FCO2与树干温度显著相关(P<0.05),树干南、北面的Q10马尾松分别为1.86和1.57,木荷为1.77和1.82.白天树干液流出现峰值时,马尾松和木荷树干呼吸产生的CO2分别有19.72%~29.12%和20.68%~29.83%溶解于木质部液流中,并被向上运输.因此,通过FCO2估计树干呼吸速率(stem respiration rates,RS)的方法可能低估了长汀重建生态系统冬季马尾松和木荷白天的RS.更多还原

【Abstract】 In this paper,infra-red gas analyzer(IRGA)method was used to measure in situ the stem CO2 efflux rates(FCO2)in winter of Pinus massoniana and Schima superba in the restoring ecosystem,Changting county.Meanwhile,air temperature and relative humidity in the forest,stem temperature and sap flow density were measured.The tendencies in diurnal FCO2 of Pinus massoniana and Schima superba in winter showed single peak pattern in the south stem face,with the maximum at 18:00,2:00 for Pinus massoniana and Schima superba respectively;and the diurnal variation were in a ’S’ curve in the north stem face,with the peak occurring between 18:00 and 2:00;the minimum FCO2 of 2 tree species were at around 8:00.FCO2 of Pinus massoniana ranged from 0.71 to 1.56 μmol·m-2·s-1,significantly lower than those of Schima superba ranged from 1.57 to 2.98 μmol·m-2·s-1.FCO2 of Pinus massoniana and Schima superba in winter in the restoring ecosystem,Changting county were affected by stem temperature and sap flow density.FCO2 had significantly correlation with stem temperature(P<0.05),the Q10 of Pinus massoniana was 1.86 in the south and 1.57 in the north,and was 1.77 in the south and 1.82 in the north for Schima superba.Under high rates of sap flow,the internal transport flux represented 19.72%～29.12% and 20.68%～29.83% of stem respiration in Pinus massoniana and Schima superba,respectively.It is concluded that FCO2 may underestimate stem respiration rates(RS) during daytime.更多还原