Sinergism among auxins, gibberellins and cytokinins in tomato cv. Micro-Tom

Resumo

Plant development results from the combination of many signals, and from interactions and crosstalks among them. The aim of this study was to evaluate the effect of isolated and combined applications of gibberellic acid (GA) (gibberellin), indolbutyric acid (IBA) (auxin) and KN (cytokinin) on vegetative (dry matter mass of the shoot and root, and the ratio of these two organs) and reproductive development (fresh and dry matter mass of fruits and fruit size) of tomato test plants (Solanum lycopersicum L. cv. Micro-Tom), to better elucidate the interactions among these hormonal classes. The following treatments were accomplished through foliar application: GA (5 mg L^-1); IBA (5 mg L^-1); KN (9 mg L^-1); GA + IBA (5 mg L^-1 + 5 mg L^-1); GA + KN (5 mg L^-1 + 9 mg L^-1); IBA + KN (5 mg L^-1 + 9 mg L^-1); GA + IBA + KN (5 mg L^-1 + 5 mg L^-1 + 9 mg L^-1) and Stimulate® (ten times diluted). Plants from the control were sprayed with water. Stimulate®, liquid formulation containing KN (90 mg L^-1), GA (50 mg L^-1) and IBA (50 mg L^-1). Some combined applications of GA, IBA and KN or Stimulate® promoted significant increases in the dry matter accumulation of roots and fresh and dry matter mass of fruit compared to the control. Besides the perspective to extend such results for commercial tomato production, the relevance of known hormonal interactions for the results obtained is discussed.