Drought adaptation mechanisms: the beneficial interaction of photosynthesis and respiration in Nicotiana sylvestris

Abstract

More frequent drought events will impair plant carbon balance and thus primarily affect photosynthesis and respiration. Due to their close interconnection, an improved plant adaptation to drought and survival may be derived from the beneficial interactions of photosynthetic and respiratory processes. Nicotiana sylvestris plants were grown under different environmental conditions (indoors & outdoors), subjected to severe drought stress by withholding water and thereafter re-watered until photosynthesis recovered. In vivo photosynthetic and respiratory pathway activities, as well as related leaf compounds were determined. The response to drought and re-watering was similar under all growth conditions, while the rate of decline in net photosynthesis and respiration differed among them. Moreover, mitochondrial respiratory pathway activities were different in outdoors and indoors experiments, most likely to adjust ATP supply for maintained cell functioning. Additional data on mitochondrial complex I mutants (CMSII) support the essential role of respiratory ATP supply during drought-inhibited photosynthesis. Further implications on photosynthetic limitations and the rate of recovery are discussed.