Qualidade fisiológica de sementes de milho na presença de bioestimulantes / Physiological quality of corn seeds in the presence of biostimulants

RESUMO

Os reguladores de crescimento podem influenciar na qualidade fisiológica das sementes assim como na atividade de enzimas envolvidas na germinação. Podem ainda apresentar em suas formulações micronutrientes que atuam principalmente como catalisadores de enzimas. Nesta pesquisa sementes de milho híbrido da cultivar GNZ 2004, e da linhagem Le 57 foram tratadas com os seguintes bioestimulantes e dosagens 1.Stimulate® 12,5mL/kg de sementes, 2.Cellerate® 10,0mL/kg, 3.mistura de Cellerate®+ Stimulate® (10,0mL/kg + 12,5 mL/kg), 4.Booster® 100 mL/20kg e 5.testemunha. Logo após o tratamento, as sementes foram submetidas aos testes de germinação, envelhecimento acelerado, teste de frio e emergência de plântulas. Foram avaliadas ainda a massa de matéria seca de plântulas, parte aérea e raiz e as atividades das enzimas á-amilase, catalase, esterase e peroxidase. Nas sementes tratadas com os bioestimulantes não houve melhoria na qualidade de sementes e sob condições de estresses a utilização dos bioestimulantes Stimulate®+Cellerate® e Cellerate® reduziu a qualidade fisiológica de sementes de milho. Menor atividade da enzima peroxidase foi observada em sementes tratadas com Stimulate®, Cellerate® e Stimulate®+Cellerate® . Maior atividade da enzima esterase foi observada em sementes tratadas com Stimulate®+ Cellerate® indicando fitotoxidez dos mesmos.

ABSTRACT

Growth regulators can influence the physiological quality of seeds as well as the activity of enzymes involved in germination. They may, further, present in their formulation micronutrients which act mainly as enzyme catalysts. In this research work, hybrid corn seeds of the cultivar GNZ 2004 and line Le 57 were treated with the following biostimulants and dosages 1.Stimulate® 12.5mL/kg of seed, 2.Cellerate® 10,0mL/kg, 3.mixtue of Cellerate®+ Stimulate® (10.0mL/kg + 12.5 mL/kg), 4.Booster® 100 mL/20kg and 5.control. Soon after the treatment, the seeds were submitted to the tests of germination, accelerated ageing and cold and seedling emergence tests. In addition, mass of dry matter of seedlings, shoot and roots and the activities of the enzymes á-amylase, catalase, esterase and peroxidase were evaluated. In the biostimulanttreated seeds, there were no improvements in the quality of seeds and under stressful conditions, the use of the biostimulants Stimulate®+Cellerate® and Cellerate® reduced the physiological quality of corn seeds. Increased activity of the peroxidase enzyme was found in seeds treated with Stimulate®, Cellerate® and Stimulate®+Cellerate® . Increased activity of the enzyme esterase was observed in seeds treated with Stimulate®+ Cellerate® pointing out phytotoxicity of them.