Influence of Potassium Concentrations in Fertilizer Solution on the Growth, Appearance of Physiological Disorder and Tissue Nutrient Contents of Eggplant {Solanum melogena L.)

摘要

Objective of this research was to investigate the effect of various potassium concentrations in fertiUzer solution on growth of and nutrient uptake by 'Chugyang' eggplant {Solanum melongena L.). Tissue analyses were conducted to determine the threshold levels of potassium in plants when disorders develop for potassium. The lower leaves of K deficient plants became spotted, yellowing in color, and finally necrosis occurred. The necrosis spread inward and upward. K toxic plants developed necrotic spotat the margin of old leaves and the surface of old leaves were twisted. The tissue K contents in the most recently fully expanded leaves and dry weight of full above ground plant tissue at 35 days after transplanting showed linear and quadratic responseto elevated K concentrations with the equation of y=1.127+0.3147x (R^=0.8916) and y=14.92+2.2743x-0.1402x2 (R^=0.8659). When 10% reduction in dry weight set to threshold levels, optimum tissue K contents are in the range from 2.1 to 5.1%. The yield through 150 days after transplanting and tissue K contents at 150 days after transplanting also showed quadratic and linear responses to elevated potassium concentrations in fertigation solution with the equation of y=153.24+345.5x-18.46x^ (R-=0.8620) and y=0.9921+0.3860x (R^=0.9611), respectively. When the 10% reduction in yield is set to threshold levels, the tissue K contents for maximum yield should be around 3.4% to 5.9% in most recently fully expanded leaves.