Photorespiration in Green Plants During Photosynthesis Estimated by Use of Isotopic CO2

摘要

Photosynthetic re-absorption of photorespired CO2 causes underestimation in measured photorespiration and turnover rate of the substrate for photorespiration. Actual values of photorespiration exceed the measured by a factor greater than 1 + R′w/rp + [CL]x/(rp·Lx). (R′w and rp are the partial resistances to CO2 uptake between atmosphere, mesophyll evaporating surface, and photosynthetic sink, respectively; Lx is the measured flux of photorespired CO2 and [CL]x is the ambient conc of photorespired CO2). In 8 species, 1 + R′w/r_p alone amounted to a correction ranging between 148% and 233%.