Effects of Soaking Cucumber and Tomato Seeds in Paclobutrazol Solutions on Fruit Weight, Fruit Size, and Paclobutrazol Level in Fruits

Abstract

Determination of plant growth regulator accumulation in fruits and vegetables for human consumption is an important safety issue even when it is applied to seeds. Paclobutrazol accumulated preferentially in the seedcoats when soaking cucumber (Cucumis sativus L., cv. Poinsett 76SR) seeds in 1000 or 4000 mg·L–1 paclobutrazol. Cucumber plants grown from seeds soaked in 1000 mg·L–1 paclobutrazol had lower average fruit weights than the control plants. Individual fruit length in cucumber was reduced by 40% when seeds were soaked in 1000 mg·L–1 paclobutrazol solutions for 180 minutes. Soaking tomato (Solanum lycopersicum L., cv. Sun 6108) seeds in 0 to 1000 mg·L–1 paclobutrazol did not reduce average fruit weight or diameter per treatment. Paclobutrazol residue was not detected in cucumber and tomato fruits harvested from plants grown from seeds soaked in 1000 mg·L–1 paclobutrazol for 180 minutes. Soaking seeds in paclobutrazol solutions represents a promising method of applying plant growth regulators to tomato and cucumber without accumulation of paclobutrazol residue in fruits.