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.