|Title||Fine root respiration in mature eastern white pine (Pinus strobus) in situ: the importance of CO2 in controlled environments.|
|Publication Type||Journal Article|
|Year of Publication||1999|
|Authors||Clinton, BD, Vose, JM|
We measured seasonal fine root respiration rate in situ while controlling chamber temperature and [CO2]. Atmospheric [CO2] ([CO2]a) and measured soil [CO2] ([CO2]s) were alternately delivered to a cuvette containing intact fine roots of eastern white pine (Pinus strobus L.). Respiration rates were consistently higher in [CO2]a than in [CO2]s and were almost three times higher during midsummer. Respiration rates were immediately reversed after returning to the alternate [CO2] (i.e., [CO2]a a [CO2]s a [CO2]a, and vice versa) suggesting a direct effect of elevated [CO2] on apparent respiration. Soil [CO2]-based respiration rates decreased with increasing [CO2] on a dry mass and tissue [N] basis. We conclude that estimates of soil CO2 flux and soil carbon budgets may be improved by more completely accounting for the rhizosphere microclimate (i.e., soil temperature and [CO2]s) during measurement of fine root respiration.