Paclobutrazol Applied on Cotyledonal Leaves and Quality of Cucumber, Squash, Melon and Watermelon Seedlings

Abstract

The research was done to determine the effects of paclobutrazol (PBZ) through the dose of 150 mg·L -1 , on the quality of seedlings determined by the content of chlorophyll, height, leaf area, dry matter of roots and of the aerial part of cucumber, squash, melon and watermelon. Sowing of all species carried out on October 21, 2013 in polystyrene trays with 200 cavities filled with peat moss. Treatments were the doses of 150 mg of PBZ·L -1 water and the control (distilled water). The solution with PBZ and the distilled water were applied only once with manual atomizer on cotyledonal leaves by mean of 25 shots made approximately with the same force, having put physical barriers between experimental units. In the four species (cucumber, squash, melon and watermelon) the PBZ increased the chlorophyll content in 26.0%, 14.9%, 19.4% and 26.5%, respectively, compared to the control; height decreased in 24.0%, 34.7%, 16.3% and 23.4%; leaf area decreased in 40.1, 0.5, 30.4 and 16.2%; the dry matter of roots increased in 20.0%, 62.5%, 85.7% and 19.7%; whereas in cucumber the dry matter of the aerial part increased 12.3%, in squash decreased 5.3%, and in melon and watermelon increased in the respective 22.9 and 3.3%, so that the 150 mg dose of PBZ can be used to produce seedlings with higher quality for transplant.