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The aim of this study was to evaluate the effect of isolated and combined applications of gibberellic acid (gibberellin), indolbutyric acid (auxin) and kinetin (cytokinin) on vegetative and reproductive development of tomato test plants (Solanum lycopersicum cv. Micro-Tom), to better elucidate the interactions among these hormonal classes. The following treatments were accomplished through foliar application: GA3 (5 mg L-1); IBA (5 mg L-1); KIN (9 mg L-1); GA3 + IBA (5 mg L-1 + 5 mg L-1); GA3 + KIN (5 mg L-1 + 9 mg L-1); IBA + KIN (5 mg L-1 + 9 mg L-1); GA3 + IBA + KIN (5 mg L-1 + 5 mg L-1 + 9 mg L-1) and Stimulate® (100 mL L-1). Plants from the control were sprayed with water. Stimulate®, is a commercial liquid formulation containing KIN (90 mg L-1), GA3 (50 mg L-1) and IBA (50 mg L-1). We analyzed the shoot dry matter (g), root dry matter (g); fruit fresh matter (g); fruit dry matter (g) and fruit size (cm). The experimental design was completely randomized with nine treatments and fifteen replications. The treatment means were compared by Tukey's test. Some combined applications of GA3, IBA and KIN or Stimulate® promoted significant increases in the dry matter accumulation of roots and fresh and dry matter 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.

Sweet sorghum has gained attention in tropical and subtropical regions because of its potential as a bioenergy crop. The present research was carried out to evaluate the physiological, biochemical and nutritional characteristics of sweet sorghum submitted to six plant growth regulators (thiamethoxam, biostimulant mixture, gibberellic acid, chlormequat chloride, ethephon, and trinexapac-ethyl). The compounds were applied via foliar spraying in order to increase the productive potential of plants and reduce the carbohydrates sink strength by inflorescences. The experiment was conducted in pots and the following variables were evaluated: plant height, inflorescence dry matter, soluble solids content, shoot dry matter, crude protein, ashes, neutral detergent fiber and in vitro digestibility. It were observed the action of trinexapac-ethyl and ethephon to reduce the inflorescence dry matter, chlormequat chloride to increase the shoot dry matter, and trinexapac-ethyl to improve ashes content and reduce the neutral detergent fiber contents. These results indicate that chlormequat chloride and trinexapacethyl are effective in restricting the plant growth and increasing sorghum nutritional quality.Keywords: Sorghum bicolor, plant growth, plant nutritional quality, bioenergy Reguladores vegetais em sorgo sacarino: análises fisiológicas e de qualidade nutricional ResumoO sorgo sacarino tem ganhado atenção em regiões tropicais e subtropicais devido ao seu potencial uso como cultivo bioenergético. Nosso estudo avaliou as características fisiológicas, bioquímicas e nutricionais do sorgo sacarino submetido a seis reguladores vegetais (thiamethoxam, mistura bioestimulante, ácido giberélico, cloreto de clormequat, etefon e etil-trinexapac). Os compostos foram aplicados via pulverização foliar, no intuito de avaliar o potencial aumento na produção das plantas, bem como reduzir a força do dreno de carboidratos promovida pelas inflorescências. O experimento foi conduzido em vasos, onde avaliaram-se as seguintes variáveis: altura de planta, massa seca das inflorescências, conteúdo de sólidos solúveis, massa seca da parte aérea, proteína bruta, cinzas, fibra em detergente neutro e digestibilidade in vitro. Entre os reguladores de crescimento testados, foi observada a ação do etil-trinexapac e do etefon na redução da matéria seca da inflorescência, do cloreto de clormequat no ganho de matéria seca da parte aérea e do etil-trinexapac para incrementar o teor de cinzas e reduzir a fibra em detergente neutro. Estes resultados indicam que o cloreto de clormequat e o etil-trinexapac são eficazes na restrição do crescimento e melhoria da qualidade nutricional do sorgo.Palavras chave: Sorghum bicolor, crescimento vegetal, qualidade nutricional, bioenergia