Mississippi State University
Reddy, K. Raja
Baldwin, Brian S.
Lang, David J.
Reddy, Krishna N.
Date of Degree
Graduate Thesis - Open Access
Master of Science
College of Agriculture and Life Sciences
Department of Plant and Soil Sciences
Influence of nitrogen (N) deficiency on castor cv. ‘Hale’ growth, physiology, and leaf reflectance properties were investigated. Treatments imposed were complete Hoagland’s nutrient solution (control, 100N), reduced N to 20% of the control (20N) and withheld N from the solution (0N) from 34 to 66 days after sowing (DAS) in 12-L pots grown out doors. N deficiency significantly reduced leaf area, chlorophyll and photosynthesis resulting lower total biomass. Leaf and stem growth rates were more sensitive to leaf N concentration than photosynthesis and leaf addition rates. N deficiency stress increased leaf reflectance at R555 and R715 nm and caused a red-edge shift to shorter wavelengths. Reflectance ratios of R455/R605 and R505/R605 nm was highly correlated with leaf N on weight (r2 = 0.93) and area-based (r2 = 0.90) estimations, respectively. Similarly, reflectance ratio R635/R505 was highly correlated with chlorophylls (r2 = 0.94). The N-specific wavebands and functional relationships between leaf N and growth and developmental processes would be useful for rapid and non-destructive estimation of leaf N and growth rates of castor.
Matcha, Satyasai Kumar, "Effects Of Nitrogen Deficiency On Plant Growth, Leaf Photosynthesis, And Hyperspectral Reflectance Properties In Castor (Ricinus Communis L.)" (2007). Theses and Dissertations. 1770.