US EPA

3410027 

Journal Article 

Carbon dioxide diffusion across stomata and mesophyll and photo-biochemical processes as affected by growth CO2 and phosphorus nutrition in cotton 

Singh, SK; Badgujar, G; Reddy, VR; Fleisher, DH; Bunce, JA 

2013 

Yes 

Journal of Plant Physiology
ISSN: 0176-1617 

Elsevier B.V., P.O. Box 100537 Jena D-07705 Germany 

170 

9 

801-813 

10.1016/j.jplph.2013.01.001 

WOS:000320681300002 

Nutrients such as phosphorus may exert a major control over plant response to rising atmospheric carbon dioxide concentration (CO sub(2)), which is projected to double by the end of the 21 st century. Elevated CO sub(2) may overcome the diffusional limitations to photosynthesis posed by stomata and mesophyll and alter the photo-biochemical limitations resulting from phosphorus deficiency. To evaluate these ideas, cotton (Gossypium hirsutum) was grown in controlled environment growth chambers with three levels of phosphate (Pi) supply (0.2, 0.05 and 0.01 mM) and two levels of CO sub(2) concentration (ambient 400 and elevated 800 mu mol mol super(1)) under optimum temperature and irrigation. Phosphate deficiency drastically inhibited photosynthetic characteristics and decreased cotton growth for both CO sub(2) treatments. Under Pi stress, an apparent limitation to the photosynthetic potential was evident by CO sub(2) diffusion through stomata and mesophyll, impairment of photosystem functioning and inhibition of biochemical process including the carboxylation efficiency of ribulose-1,5-bisphosphate carboxylase/oxyganase and the rate of ribulose-1,5-bisphosphate regeneration. The diffusional limitation posed by mesophyll was up to 58% greater than the limitation due to stomatal conductance (g sub(s)) under Pi stress. As expected, elevated CO sub(2) reduced these diffusional limitations to photosynthesis across Pi levels; however, it failed to reduce the photo-biochemical limitations to photosynthesis in phosphorus deficient plants. Acclimation/down regulation of photosynthetic capacity was evident under elevated CO sub(2) across Pi treatments. Despite a decrease in phosphorus, nitrogen and chlorophyll concentrations in leaf tissue and reduced stomatal conductance at elevated CO sub(2), the rate of photosynthesis per unit leaf area when measured at the growth CO sub(2) concentration tended to be higher for all except the lowest Pi treatment. Nevertheless, plant biomass increased at elevated CO sub(2) across Pi nutrition with taller plants, increased leaf number and larger leaf area. 

Acclimation; Carboxylation; Down regulation; Fluorescence; Quantum yield