Relative Humidity and Nutrient Concentration Affect Nutrient Uptake and Growth of Begonia × hiemalis

Abstract

Young plants of Begonia × hiemalis Fotsch `Schwabenland Red' were grown for 10 weeks at 60% ± 5% or 90% ± 5% relative humidity (RH) in growth rooms. Plants were watered with three nutrient solution concentrations (1, 2, and 4 mS·cm -1 ). Transpiration of the plants was 56% lower at the high RH level, while the concentration of the nutrient solution had less effect (10% to 20%). Plant dry weight, height, width, and leaf size were significantly higher at the higher RH. Dry weight, height, width, and leaf size of the plants were higher in the 2 mS·cm -1 than in the 1 mS·cm -1 solution when grown at high RH, but not at a lower RH. A further increase of the nutrient solution concentration either had no effect or was detrimental. The higher RH decreased the concentration of N, P, and K in leaves and stems of plants, but an increase in the concentration of the nutrient solution increased the concentration of N, P, K, and Ca in both leaves and stems. At termination of the experiment, the number of flowers and flower buds and percent of flowering plants was higher at 90% RH than at 60% RH. These values also were higher at the higher nutrient solution concentrations. Time of anthesis was not affected.