The objective of this study was to investigate the performance of the growth regulators: gibberellic acid, spermine and abscisic acid, on the germination and early growth of seedlings of the lettuce cv. Grand Rapids. The experiments were conducted in the greenhouse and laboratory and the seeds treated with solutions of gibberellic acid, spermine and abscisic acid at concentrations of 0.5mM, 0.05mM and 0.04mM respectively. Tests for germination, first count of germination, emergence, emergence speed index, shoot and root lengths, fresh and dry seedling weights, electrical conductivity and α-amylase activity were conducted. Although the spermine applied by itself induced increased α-amylase activity, it had little effect on inducing germination in lettuce and generally reduced seed viability and vigor. However, when combined with gibberellic or abscisic acids it induced shoot growth and overcame the inhibitory action of abscisic acid. Abscisic acid had a positive effect on membrane reorganization. It can be inferred from the results that the growth regulators did not affect lettuce seed viability and that the performance of seeds treated with spermine was worse.
growth regulators; physiological quality; vigor
