Ação de bioestimulantes na mitigação do estresse por deficiência hídrica em soja
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Data
2020-02-28
Autores
Rosa, Vanessa do Rosário
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Universidade Estadual Paulista (Unesp)
Resumo
A soja possui grande importância no mercado mundial, e para atender a sua crescente demanda é preciso aumentar a produtividade, que tem se tornado um desafio em condições de ausência de chuva. Para contornar os efeitos negativos do déficit hídrico, tem-se adotado práticas agrícolas com a aplicação de bioestimulantes como os compostos por ácidos fúlvicos e extrato da alga marinha Ascophyllum nodosum (L.), que atuam na melhoria do desenvolvimento das plantas em condições estressantes. Neste estudo, objetivou-se compreender como ácidos fúlvicos e extrato da alga marinha Ascophyllum nodosum (L.) atuam em conjunto nos mecanismos fisiológicos e bioquímicos das plantas e possibilitando a mitigação dos efeitos negativos gerados pelo estresse, e ainda determinar qual formulação e dose do bioestimulante tem melhor efeito sobre o desenvolvimento de plantas de soja submetidas ao déficit hídrico. O experimento foi conduzido em casa de vegetação, em vasos contendo 10 kg de solo sob delineamento experimental de blocos casualizados em fatorial duplo com dois fatores adicionais, com cinco repetições e 11 tratamentos constituídos por três formulações do bioestimulante e três doses (0,25; 0,50 e 1,0 kg ha-1), controle com déficit hídrico e controle sem déficit hídrico. As plantas foram submetidas a 50% da capacidade de campo por três dias, em seguida foram reidratadas e receberam a aplicação do bioestimulante, com exceção dos controles. Foram avaliados parâmetros de crescimento, fisiológicos, bioquímicos e os componentes de produtividade. Todos os tratamentos que receberam a aplicação do bioestimulante produziram mais que o controle com déficit hídrico. Nas plantas com aplicação de bioestimulante foram observadas maiores taxas fotossintéticas, mecanismos protetores mais eficientes, maiores atividades de enzimas antioxidativas, percepção do reestabelecimento hídrico mais eficiente e rápida retomada das atividades metabólicas após a suspensão do déficit hídrico. O bioestimulante aumentou a tolerância da soja em condições estressantes e reduziu perdas de produtividade.
Soy has great importance in the world market, and to meet its growing demand it is necessary to increase productivity, which has become a challenge in conditions of absence of rain. To circumvent the negative effects of the water deficit, agricultural practices have been adopted with the application of biostimulants such as those composed of fulvic acids and extract from the seaweed Ascophyllum nodosum (L.), which act in improving the development of plants in stressful conditions. In this study, the objective was to understand how fulvic acids and extract of the seaweed Ascophyllum nodosum (L.) act together in the physiological and biochemical mechanisms of plants and enabling the mitigation of the negative effects generated by stress, and also determine which formulation and dose of biostimulant has a better effect on the development of soybean plants submitted to water deficit. The experiment was carried out in a greenhouse, in pots containing 10 kg of soil under a randomized double-block design with two additional factors, with five replications and 11 treatments consisting of three biostimulant formulations and three doses (0.25; 0.50 and 1.0 kg ha-1), control with water deficit and control without water deficit. The plants were submitted to 50% of the field capacity for three days, then they were rehydrated and received the application of the biostimulant, with the exception of the controls. Growth, physiological, biochemical parameters and productivity components were evaluated. All treatments that received the application of the biostimulant produced more than the control with water deficit. In plants with the application of biostimulant, higher photosynthetic rates, more efficient protective mechanisms, greater activities of antioxidative enzymes, perception of more efficient water restoration and faster resumption of metabolic activities were observed after the suspension of water deficit. The biostimulant increased the tolerance of soy under stressful conditions and reduced losses of productivity.
Soy has great importance in the world market, and to meet its growing demand it is necessary to increase productivity, which has become a challenge in conditions of absence of rain. To circumvent the negative effects of the water deficit, agricultural practices have been adopted with the application of biostimulants such as those composed of fulvic acids and extract from the seaweed Ascophyllum nodosum (L.), which act in improving the development of plants in stressful conditions. In this study, the objective was to understand how fulvic acids and extract of the seaweed Ascophyllum nodosum (L.) act together in the physiological and biochemical mechanisms of plants and enabling the mitigation of the negative effects generated by stress, and also determine which formulation and dose of biostimulant has a better effect on the development of soybean plants submitted to water deficit. The experiment was carried out in a greenhouse, in pots containing 10 kg of soil under a randomized double-block design with two additional factors, with five replications and 11 treatments consisting of three biostimulant formulations and three doses (0.25; 0.50 and 1.0 kg ha-1), control with water deficit and control without water deficit. The plants were submitted to 50% of the field capacity for three days, then they were rehydrated and received the application of the biostimulant, with the exception of the controls. Growth, physiological, biochemical parameters and productivity components were evaluated. All treatments that received the application of the biostimulant produced more than the control with water deficit. In plants with the application of biostimulant, higher photosynthetic rates, more efficient protective mechanisms, greater activities of antioxidative enzymes, perception of more efficient water restoration and faster resumption of metabolic activities were observed after the suspension of water deficit. The biostimulant increased the tolerance of soy under stressful conditions and reduced losses of productivity.
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Palavras-chave
Glycine max (L.) Merrill, Estresse abiótico, Bioproteção, Efeito antiestresse, Trocas gasosas, Atividade antioxidante, Abiotic stress, Bioprotection, Anti-stress effect, Gas exchange, Antioxidant activity