Keeping a positive carbon balance under adverse conditions: responses of photosynthesis and respiration to water stress

Drought and salinity (i.e. soil water stress) are the main environmental factors limiting photosynthesis and respiration and, consequently, plant growth. This review summarizes the current status of knowledge on photosynthesis and respiration under water stress. It is shown that diffusion limitations to photosynthesis under most water stress conditions are predominant, involving decreased mesophyll conductance to CO 2 , an important but often neglected process. A general failure of photochemistry and biochemistry, by contrast, can occur only when daily maximum stomatal conductance ( g s ) drops below 0.05–0.10 mol H 2 O m −2 s −1 . Because these changes are preceded by increased leaf antioxidant activities ( g…

• UD
  Universitat de les Illes Balears