Location: Crop Production Systems ResearchTitle: Cotton photosynthetic regulation through nutrient and water availability
Submitted to: Journal of Cotton Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/11/2015
Publication Date: 9/30/2016
Citation: Pettigrew, W.T. 2016. Cotton photosynthetic regulation through nutrient and water availability. Journal of Cotton Science. 20:237-245.
Interpretive Summary: Photosynthesis is the process where plants convert sunlight intercepted by the leaves into chemical energy used to support growth. As with all biological processes, its expression is determined by both genetic and environmental aspects. In this review article, a USDA-ARS scientist with the Crop Production Systems Research Unit at Stoneville, MS summarized the roles that the availability of two macro nutrients (nitrogen and potassium) and water have on regulating cotton crop photosynthesis, as has been documented in the scientific literature. Insufficient levels of all three factors limit photosynthesis at the canopy level by reducing overall plant height, leaf area, and the canopy’s ability to intercept sunlight. These three factors have also been shown to regulate photosynthesis at the leaf level through impacts on different aspects and phases of the photosynthetic process. The information summarized in this review article can be utilized by scientists formulating research to address various photosynthesis hypotheses, or hypotheses pertaining to the effect from varying levels of nitrogen, potassium, or water as production inputs. Crop consultants and extension personnel will be able to use the information presented in this chapter to advise their clients and stake holders how to make efficient use of the nitrogen, potassium, and water brought as inputs to their production systems.
Technical Abstract: Photosynthesis is an extremely complicated process that is fundamental to supporting plant growth. It is regulated by multiple internal and external factors. Three factors regulating photosynthesis over which cotton producers can exert some influence are the levels of nitrogen, potassium, and soil moisture. Research has shown that deficient levels of all three depress canopy photosynthesis and yield through the production of a smaller plant size with less leaf area to intercept incoming solar radiation. In addition, leaf photosynthesis is impacted by potassium at both the stomatal and non-stomatal level. Nitrogen is a component of both proteins and chlorophyll molecules and as such impacts leaf photosynthesis through effects on dark and light reaction components of photosynthesis. Stomatal factors are the dominant photosynthetic regulating influence when moisture deficit stress is severe, while non-stomatal factors predominate when the moisture deficit stress is mild. A producer can impact yield and profitability for a given field through efficient use and management of these photosynthetic regulatory inputs.