Abstract:
The objective of this study was to quantitatively determine and to separate the efftcts of potassium deficiency on growth and development of a maize plant. Maize varieties Vi (Sadaf) and Vi (Sultan) were grown in a sand culture. When the coleoptile leaf was fully expanded, three level of K supply i-e Ko = 8 mM; KM - 4 mM and KZBRO = 0 mM were established by varying K concentration in the Long Ashton nutrient solution. The supply of respective nutrient media was maintained from coleoptile leaf stage through silking. A thermal time in growing degree days (GDD) was calculated to characterize the thermal environment of the corn plants. The leaf area was estimated daily non-destructively as a measure of growth of a maize plant. Number of leaves per plant, irrespective of a leaf size and the number of leaves per plant in Haun scale were used as a measure of development of a plant and were also recorded on daily basis. There was straight-line linear relationship between the number of leaves of Vi and Vi and the thermal time since sowing for each level of K supply. The development rat of Vi and Vi in KZERO level was 10 and 15%, respectively slower than that in Ko level. . At leaf stage 11, the leaf area in KZBKO was about 46% less than the leaf area in Ko ; and the leaf area in KM was about 25% less than the leaf area in Ko supply. At the stage of tasseling, the leaf area in Kziso was
about 37% less compared to Ko and 26% less than the leaf area in KM. The differences established in the size of leaf area by the differential supply of K at the tasseling stage were maintained at the silking stage.
