Effect of external NK concentrations on the leaf content of divalent cations, their forms and fractions in capsicum plants

Capsicum plants grown under controlled conditions underwent crossed fertili zation with N (four levels) and K (three levels) totalling 12 combination o f NK dosages. The plants were sampled throughout their growth cycle and the leaves were analyzed to measure total and soluble Ca and Mg, and their fra ctions. Soluble Mg showed its lowest leaf level in the treatment N4K3, wher eas the highest value was obtained at N1K3. Total Mg has the maximum leaf l evels at N1K2, whereas the lowest levels occurred in the treatment N2K1. Th e various fractions of Mg showed different degrees of importance and in the present study the order of importance was: Pectate-Mg<Residual-Mg<Organic acid anion-Mg<Organic anion-Mg<Chlorophyll-M g. Soluble Ca showed its lowest leaf level in the treatment N2K3, whereas the highest value was obtained at N4K1. Total Ca has the maximum leaf levels at N4K3, whereas the lowest levels occurred in the treatment N1K2. The increa sing NK supply directly or indirectly affects the integration of the ionic forms of Ca in plant tissues as Ca was integrated in proportions which indi cated the growing conditions of the crop, with the following order: Oxalate-Ca > Inorganic-Ca > Pectate-Ca approximate to Residual-Ca > Phospha te-Ca.