Prohexadiona cálcica no desenvolvimento de mudas e plantas de tomateiro
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2020-10-22
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Universidade Estadual Paulista (Unesp)
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O objetivo deste trabalho foi avaliar os efeitos de diferentes concentrações de prohexadiona cálcica – (ProCa) no controle do crescimento de mudas de tomateiro, e seus possíveis efeitos nas plantas, após o transplante e na produção e qualidade de frutos. O trabalho foi dividido em dois capítulos. O capítulo I teve o objetivo de investigar as respostas das mudas de tomateiro tratadas com diferentes concentrações de ProCa. O delineamento experimental foi inteiramente casualizado, composto por cinco tratamentos: 0, 50, 100, 200 e 400 mg de ProCa L-¹, com quatro repetições de 30 mudas cada. Os tratamentos foram aplicados com pulverizador manual de CO2, quando as mudas completaram 20 dias após a semeadura. Dez dias após a aplicação dos tratamentos foram avaliados: comprimento do caule, número de folhas, comprimento e largura de folhas, índice SPAD, trocas gasosas, fluorescência da clorofila a e análises bioquímicas, relacionadas ao estresse oxidatívo. Pelos resultados obtidos neste capítulo foi possível concluir que as concentrações de ProCa inibiram o crescimento das mudas, não comprometendo seu aparato fotossintético. As mudas tratadas com ProCa apresentaram maiores taxas de peroxidação lipídica e de atividade das enzimas superóxido dismutase, catalase e peroxidase. Entretanto, a ativação do sistema antioxidante contribuiu para que as mudas se desenvolvessem satisfatoriamente. No capítulo II, o experimento foi dividido em duas etapas. Na primeira, o delineamento experimental foi o inteiramente casualizado, composto por cinco tratamentos: 0, 50, 100, 200 e 400 mg de ProCa L-¹, com quatro repetições de 30 mudas cada. Os tratamentos foram aplicados com pulverizador manual de CO2 quando as mudas completaram 20 dias após a semeadura. Dez dias após a aplicação dos tratamentos, foram avaliados: altura da parte aérea, diâmetro do caule, massa fresca e seca da parte aérea e de raiz. Para a etapa II, as concentrações de 200 e 400 mg de ProCa foram selecionadas por proporcionarem maior redução no crescimento das mudas e, juntamente com uma testemunha, foram transplantadas para o campo. O arranjo experimental foi em blocos casualizados, com total de 120 plantas avaliadas, onde se avaliou em períodos diferentes: a altura das plantas, o número de folhas, o diâmetro do coleto e os dias até a antese. Também foram realizadas avaliações de fluorescência da clorofila a, trocas gasosas, análises bioquímicas de estresse oxidatívo, de produção e de qualidade de frutos. Para a etapa I foi possível observar que as concentrações de ProCa reduziram o crescimento das mudas de tomateiro, não afetando apenas o comprimento de raiz. Na etapa II, as concentrações de ProCa não influenciaram as variáveis de crescimento e os dias até a antese das plantas. Também não houve efeito significativo nos parâmetros fisiológicos de fluorescência da clorofila a e de trocas gasosas. Entretanto, após o transplante, as plantas em campo passaram por estresse. Todavia, a produção e os aspectos de qualidade investigados não foram afetados pelo regulador vegetal. Pelos resultados deste trabalho, é possível concluir que o ProCa é um eficiente regulador vegetal no controle do crescimento das mudas, com baixa pecistencia nas plantas, não comprometendo a fenologia das plantas após o transplante, a produção e a qualidade dos frutos, podendo ser uma alternativa viável para viveiristas e produtores.
The objective of this work was to evaluate the effects of different concentrations of calcium prohexadione - (ProCa) on the growth control of tomato seedlings, and their possible effects on plants, after transplantation and on fruit production and quality. The work was divided into two chapters. Chapter I aimed to investigate the responses of tomato seedlings treated with different concentrations of ProCa. The experimental design was completely randomized, composed of five treatments: 0, 50, 100, 200 and 400 mg of ProCa L-¹, with four replications of 30 seedlings each. The treatments were applied with a manual CO2 sprayer, when the seedlings completed 20 days after sowing. Ten days after the treatments were applied: stem length, number of leaves, leaf length and width, SPAD index, gas exchange, chlorophyll a fluorescence and biochemical analyzes, related to oxidative stress. From the results obtained in this chapter it was possible to conclude that the concentrations of ProCa inhibited the growth of the seedlings, without compromising their photosynthetic apparatus. The seedlings treated with ProCa showed higher rates of lipid peroxidation and activity of the enzymes superoxide dismutase, catalase and peroxidase. However, the activation of the antioxidant system contributed for the seedlings to develop satisfactorily. In chapter II, the experiment was divided into two. In stage I, the experimental design was completely randomized, composed of five treatments: 0, 50, 100, 200 and 400 mg of ProCa L-¹, with four replications of 30 seedlings each. The treatments were applied with a manual CO2 sprayer when the seedlings completed 20 days after sowing. Ten days after the application of treatments, the following were evaluated: height of the aerial part, diameter of the stem, fresh and dry mass of the aerial part and root. For stage II, concentrations of 200 and 400 mg of ProCa were selected as they provide greater reduction in seedling growth and, together with a control, were transplanted to the field. The experimental arrangement was in randomized blocks, with a total of 120 plants evaluated, where it was evaluated in different periods: the height of the plants, the number of leaves, the diameter of the collection and the days until anthesis. Chlorophyll a fluorescence assessment, gas exchanges, biochemical analyzes of oxidative stress, production and fruit quality were also carried out. For stage I it was possible to observe that the concentrations of ProCa reduced the growth of tomato seedlings, not only affecting the root length. In stage II, the concentrations of ProCa did not influence the growth variables and the days until the anthesis of the plants. There was also no significant effect on the physiological parameters of chlorophyll a fluorescence and gas exchange. However, after transplantation, the plants in the field experienced stress. However, the production and quality aspects investigated were not affected by the plant growth regulator. From the results of this work, it is possible to conclude that ProCa is an efficient plant growth regulator in controlling the growth of seedlings, with low resistance to plants, without compromising the phenology of plants after transplantation, production and fruit quality, and can be a viable alternative for nurseries and producers.
The objective of this work was to evaluate the effects of different concentrations of calcium prohexadione - (ProCa) on the growth control of tomato seedlings, and their possible effects on plants, after transplantation and on fruit production and quality. The work was divided into two chapters. Chapter I aimed to investigate the responses of tomato seedlings treated with different concentrations of ProCa. The experimental design was completely randomized, composed of five treatments: 0, 50, 100, 200 and 400 mg of ProCa L-¹, with four replications of 30 seedlings each. The treatments were applied with a manual CO2 sprayer, when the seedlings completed 20 days after sowing. Ten days after the treatments were applied: stem length, number of leaves, leaf length and width, SPAD index, gas exchange, chlorophyll a fluorescence and biochemical analyzes, related to oxidative stress. From the results obtained in this chapter it was possible to conclude that the concentrations of ProCa inhibited the growth of the seedlings, without compromising their photosynthetic apparatus. The seedlings treated with ProCa showed higher rates of lipid peroxidation and activity of the enzymes superoxide dismutase, catalase and peroxidase. However, the activation of the antioxidant system contributed for the seedlings to develop satisfactorily. In chapter II, the experiment was divided into two. In stage I, the experimental design was completely randomized, composed of five treatments: 0, 50, 100, 200 and 400 mg of ProCa L-¹, with four replications of 30 seedlings each. The treatments were applied with a manual CO2 sprayer when the seedlings completed 20 days after sowing. Ten days after the application of treatments, the following were evaluated: height of the aerial part, diameter of the stem, fresh and dry mass of the aerial part and root. For stage II, concentrations of 200 and 400 mg of ProCa were selected as they provide greater reduction in seedling growth and, together with a control, were transplanted to the field. The experimental arrangement was in randomized blocks, with a total of 120 plants evaluated, where it was evaluated in different periods: the height of the plants, the number of leaves, the diameter of the collection and the days until anthesis. Chlorophyll a fluorescence assessment, gas exchanges, biochemical analyzes of oxidative stress, production and fruit quality were also carried out. For stage I it was possible to observe that the concentrations of ProCa reduced the growth of tomato seedlings, not only affecting the root length. In stage II, the concentrations of ProCa did not influence the growth variables and the days until the anthesis of the plants. There was also no significant effect on the physiological parameters of chlorophyll a fluorescence and gas exchange. However, after transplantation, the plants in the field experienced stress. However, the production and quality aspects investigated were not affected by the plant growth regulator. From the results of this work, it is possible to conclude that ProCa is an efficient plant growth regulator in controlling the growth of seedlings, with low resistance to plants, without compromising the phenology of plants after transplantation, production and fruit quality, and can be a viable alternative for nurseries and producers.
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Fenologia, Fisiologia vegetal, Reguladores vegetais, Solanum lycopersicum L., Phenology, Plant physiology, Plant growth regulator