Submitted to: Journal of Agronomy and Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/19/2013
Publication Date: 7/23/2013
Publication URL: http://handle.nal.usda.gov/10113/58020
Citation: Singh, S.K., Badgujar, G.B., Reddy, V., Fleisher, D.H., Timlin, D.J. 2013. Effect of phosphorus nutrition on growth and physiology of cotton under ambient and elevated carbon dioxide. Journal of Agronomy and Crop Science. 199(6):436-448. Interpretive Summary: Phosphorus is a major plant nutrient and essential for plant growth and development. The atmospheric carbon dioxide (CO2) concentration is projected to be doubled by the end of the 21st century. In general, plant growth and productivity increases under high CO2 environment. However, the availability of phosphorus in the soil controls the overall beneficial effect of high CO2 on plants. Therefore, it is important to study the combined effect of phosphorus deficiency under current and project CO2 concentrations on cotton growth. Results showed that the beneficial effects of high CO2 on cotton growth and development were reduced or highly suppressed under severe phosphorus deficiency. Phosphorus deficiency led to over 77 percent reduction in total cotton biomass across CO2 concentrations. This work illustrated that the cotton growth will be more sensitive to phosphorus deficiency under CO2 enriched atmosphere and increased CO2 may not benefit cotton growth under severe phosphorus deficient soils. The results will benefit researchers and cotton growers by highlighting the importance of better soil phosphorus management to maximize cotton yield under the current and projected CO2 enriched atmosphere.
Technical Abstract: Phosphorous deficiency in soil limits crop growth and productivity in the majority of arable lands worldwide and may moderate the growth enhancement effect of rising atmospheric carbon dioxide (CO2) concentration. To evaluate the interactive effect of these two factors on cotton (Gossypium hirsutum L.) growth and physiology, plants were grown in controlled environment growth chambers with three levels of phosphate (Pi) supply (0.20, 0.05 and 0.01 mM) under ambient and elevated (400 and 800 µmol mol-1, respectively) CO2. Phosphorus stress caused stunted growth and resulted in early leaf senescence with severely decreased leaf area and photosynthesis. Phosphate stress led to over 77% reduction in total biomass across CO2 levels. There was a below-ground (roots) shift in biomass partitioning under Pi-stress. While tissue phosphorus (P) decreased, tissue nitrogen (N) content tended to increase under Pi deficiency. The CO2 x Pi interactions were significant on leaf area, photosynthesis and biomass accumulation. The stimulatory effect of elevated CO2 on growth and photosynthesis was reduced or highly depressed suggesting an increased sensitivity of cotton to Pi deficiency under elevated CO2. Although, tissue P and stomatal conductance were lower at elevated CO2, these were not the main causes of cotton unresponsiveness to elevated CO2 under severe Pi-Stress. The alteration in the uptake and utilization of N was suggested due to a consistent reduction (18 to 21%) in the cotton plant tissue N content under elevated CO2.