Photosynthetic and Chloroplast Ultrastructural Consequences of Manganese Deficiency in Soybean

Abstract

Soybean plants (Glycine max ‘Harasoy’) grown in horticultural perlite with a manganese-deficient nutrient solution, developed typical deficiency symptoms of interveinal chlorosis and necrosis. A decrease in photosynthetic rate, dry leaf weight, leaf area, chlorophyll content, and chloroplast number was observed in plants displaying the deficiency. Transmission electron microscopy of manganese-deficient leaf tissue revealed disorganization in the chloroplast lamellar network, nonhomogeneous distribution of the stroma, and a reduction in quantities of starch, which became increasingly more acute from nodes three to five in plants 28 days postgermination. The data suggest that manganese functions both as a requirement in the photosynthetic apparatus and as a structural component in the lamellar membrane.