Effect of Shade on Morphological Features and Chlorophyll Content in Plants.

The effect of sunlight and low light intensity due to shading in potassium (K) applied soybean plants were evaluated in a greenhouse experiment to determine if the plants fertilized with K will have support growth in shade compared to the non fertilized plants. The experiment was divided in 4 groups of 6 replicates; group 1 as control, and group 2 with 1.75% foliar K Treatment, under full sun. The 3^rd and 4^th groups were placed under the shade as control and K treated pots respectively. The results were analyzed on the basis of morphological assessment and physiological parameters. Plant height measured in the first week (wk) were taller under the shade (21.75cm) compared to plants in the sun (16.35cm), whereas at the end of two wks the plants in the sun increased in height (35.46cms) comparable to the shade plants (35.36cms). Chlorophyll concentration in the leaves of the plants in sun (wk2:32.53; wk 5: 38.6) was higher than in shade (wk 2:28.78; wk 5: 35.57) respectively. Application of K did not show any changes in the chlorophyll measurements. Stomatal conductance measured higher in plants in sun before K treatment [wk 1:14.55 mmol/(m²-s); wk 2: 10.5mmol/(m²-s)] compared to the plants in shade [wk 1: 9.28mmol/(m²-s); wk 2:7.91mmol/(m²-s)]. Stomatal conductance increased in the K treated plants [wk 5:11.67mmol/(m²-s)] in the sun compared to control [wk 5:18.55mmol/(m²-s)], however, no clear trend was observed in the shade measurements. We conclude that potassium treatment of soybean plants grown in the sun increased stomatal conductance transiently.