Fine root respiration in mature eastern white pine (Pinus strobus) in situ: the importance of CO₂ in controlled environments.

Abstract

Clinton and Vose measured seasonal fine root respiration rate in situ while controlling chamber temperature and [CO₂]. Atmospheric and [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] [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 ® [CO₂]_s ® [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. The authors 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.

Citation

Clinton, Barton D.; Vose, James M. 1999. Fine root respiration in mature eastern white pine (Pinus strobus) in situ: the importance of CO₂ in controlled environments. Tree Physiology. 19: 475-479.