EFFECT OF SEQUENTIAL CONCENTRATIONS OF ZINC AND ITS COMBINATION WITH CALCIUM OR GLUTATHIONE ON THE GROWTH, WATER RELATIONS AND ANATOMY OF ROOTS, STEMS AND LEAVES OF PHASEOLUS VULGARIS CV. CONTENDER

Abstract

Zinc (Zn) is one of the eight essential micronutrients. It is needed by plants in small amounts, but yet crucial to plant development. A solution culture experiment was conducted to study the variation in growth, water relations and anatomy of roots, stems and leaves of Phaseolus vulgaris cv. contender   treated with 1, 200, 400, 600, 800, 1000and 1200 mMZnSO4. Maximum significant deplete in parameters of growth (Length of root and shoot; fresh and dry weights, relative growth rate; No of leaves and leaf area), stomatal index and rate of transpiration was observed with, 200, 400, 600, 800, 1000and 1200 mM ZnSO4. These effects were improved by the addition of Ca2+than the addition of glutathione at 10 mM. Moreover, there were a significant increase at low concentration (1mM) treatment. Width of root, width of cortex and width of vascular bundles were increase with increasing Zn concentrations either alone or in combination with glutathione >Ca (NO3)2. For stem, the No of vascular bundles were decreased with increase in Zn concentration alone and with Ca (NO3)2, meanwhile increase with glutathione. Width of cortex and No of its rows were decrease with increase Zn concentrations. For leaves, the thickness of leaf blade, mid rib and vascular bundle were increase with increase the Zn concentrations alone, On other hands, they records a significant decrease in combination of Zn with Ca(NO3)2 or glutathione . In general, an increase in total uptake of zinc with increasing the concentration of Zn in all treatments. However, Ca (NO3)2 decrease these amounts than glutathione.