Does Respiration Reduce Crop Yields?
Plant respiration can consume an appreciable amount of the carbon fixed each day during photosynthesis over and above the losses due to photorespiration (see textbook, Chapter 8). To what extent can changes in a plant′s respiratory metabolism affect crop yields? Attempts to establish a quantitative relationship between respiratory energy metabolism and the various processes going on in the cell have led to a break-up of respiration into two components (Lambers 1985). In growth respiration, reduced carbon is processed to bring about the addition of new biomass. The other component, maintenance respiration, is needed to keep existing, mature cells in a viable state. Utilization of energy by maintenance respiration is not well understood, but estimates indicate that it can represent more than 50% of the total respiratory flux. Although numerous questions remain regarding these issues, there are several empirical examples of relations between plant respiration rates and crop yield. In the
