Abstract
Studies showed that the most important assimilatory organ in the development of the cotton boll is the main stem leaf subtending the sympodium. In the first leaf of the first reproductive branch soluble sugars decreased, starch decreased first and increased at the end. Protein content was maintained and nitrate reductase decreased with age till 20 days after flowering. In the third sympodium the youngest leaf, farther away from the stem, had the highest protein and starch contents and the lowest nitrate reductase activity, for the first and second leaves, protein content decreased from the first to the fifth reproductive branches and was accompanied by sharp decreases in soluble sugars and starch, with small increases in the younger branches. Development imposes an increased stress on cotton leaves which changes their composition and assimilatory potential.
