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

• Published in: Journal of plant physiology Vol. 170; no. 9; pp. 801 - 813
• Main Authors: Singh, Shardendu K., Badgujar, Girish, Reddy, Vangimalla R., Fleisher, David H., Bunce, James A.
• Format: Journal Article
• Language: English
• Published: Germany Elsevier GmbH 15-06-2013
• Subjects: Acclimation; Acclimatization; Biomass; Carbon - metabolism; Carbon dioxide; Carbon Dioxide - pharmacology; Carboxylation; chlorophyll; Chlorophyll - metabolism; Cotton; Diffusion; Down regulation; Elevated; Fluorescence; Gossypium - drug effects; Gossypium - growth & development; Gossypium - physiology; Gossypium - radiation effects; Gossypium hirsutum; growth chambers; irrigation; leaf area; leaves; Light; mesophyll; Mesophyll Cells; nitrogen; Nitrogen - metabolism; nutrients; Nutrition; Phosphorus; Phosphorus - metabolism; Phosphorus - pharmacology; Photosynthesis; Photosynthesis - drug effects; Photosynthesis - physiology; Plant Epidermis - drug effects; Plant Epidermis - growth & development; Plant Epidermis - physiology; Plant Epidermis - radiation effects; Plant Leaves - drug effects; Plant Leaves - growth & development; Plant Leaves - physiology; Plant Leaves - radiation effects; plant response; Plant Stomata - drug effects; Plant Stomata - growth & development; Plant Stomata - physiology; Plant Stomata - radiation effects; Plant Transpiration; Plants (organisms); Quantum yield; stomata; stomatal conductance; Temperature; Cc; PAR; A; Fv′/Fm; LAER; ETR; Ci; PSII; ΦPSII; Fluorescence; ΦCO2; Rubisco; VCmax; P; Rd; C:N; RuBP; Pi; Amax; Astd; LSE; SLW; Lm; gm; Φ; Ls; aCO2; gs; Down regulation; Quantum yield; eCO2; Acclimation; DAP; Carboxylation; Jmax; Ca
• ISSN: 0176-1617; 1618-1328
• DOI: 10.1016/j.jplph.2013.01.001

Nutrients such as phosphorus may exert a major control over plant response to rising atmospheric carbon dioxide concentration (CO2), which is projected to double by the end of the 21st century. Elevated CO2 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 0.01mM) and two levels of CO2 concentration (ambient 400 and elevated 800μmolmol−1) under optimum temperature and irrigation. Phosphate deficiency drastically inhibited photosynthetic characteristics and decreased cotton growth for both CO2 treatments. Under Pi stress, an apparent limitation to the photosynthetic potential was evident by CO2 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 (gs) under Pi stress. As expected, elevated CO2 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 CO2 across Pi treatments. Despite a decrease in phosphorus, nitrogen and chlorophyll concentrations in leaf tissue and reduced stomatal conductance at elevated CO2, the rate of photosynthesis per unit leaf area when measured at the growth CO2 concentration tended to be higher for all except the lowest Pi treatment. Nevertheless, plant biomass increased at elevated CO2 across Pi nutrition with taller plants, increased leaf number and larger leaf area.