Respiration of field-grown loblolly pine roots as influenced by temperature and root type

Abstract
Respiration was determined manometrically for 136 samples of field-grown loblolly pine [Pinus taeda] roots collected over a period of several months. Mean QO2 [oxygen uptake] values ranged from 0.028-3.68, depending upon root size, type, mycorrhizal condition and temperature. Roots with vigorous, active mycorrhizae respired more than twice as fast, on a dry weight basis, than roots with less vigorous mycorrhizae or no mycorrhizae. Unsuberized root-tip meristems respired several times faster than roots of any other type.