Efeito isolado da alta temperatura na reversão sexual de mamona (Ricinus communis. L)
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Data
2019-03-25
Autores
Androcioli, Leonardo Godoy [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
O óleo da mamona (Ricinus communis) possuí inúmeras aplicações na área industrial e na produção de biodiesel, demonstrando assim sua importância econômica. O Brasil é o quarto maior produtor mundial de óleo de mamona com grande potencial para ser protagonista na produção de mamona, sendo a utilização de híbridos uma alternativa para tal fim, contudo existe dificuldade da obtenção devido às variações climáticas. Assim, o presente trabalho teve por objetivo a construção de uma câmara de crescimento, para simular diversas condições climáticas para auxiliar na seleção de plantas, além de utilizar essa câmara de crescimento para avaliar o efeito isolado da alta temperatura na reversão sexual da mamona. Para criação da câmara de crescimento foram utilizadas lâmpadas, ar condicionado, aquecedores e sensores; além de um Arduino Mega 2560 R3, que controla todo o sistema. Durante esse experimento, foram feitas avaliações quanto à intensidade luminosa requerida para o total desenvolvimento das plantas de mamona. Nessa mesma câmara de crescimento, foi realizado o experimento do efeito isolado da alta temperatura com relação à taxa de flores masculinas e femininas no híbrido FCA 2007-1 e na reversão sexual sobre as fêmeas MRZ 14. O delineamento experimental utilizado para avaliar a taxa de flores entre masculina e feminina do híbrido FCA 2007-1 foi de blocos ao acaso, em parcelas subdivididas com três repetições. As parcelas foram constituídas pelo número de dias após a emergência em que foi iniciado o estresse de alta temperatura (14, 21, 28 e 35 dias), e as subparcelas, pelo primeiro e segundo cacho. Já o delineamento experimental utilizado para avaliar o número flores masculinas nas plantas estritamente femininas MRZ 14, também foi blocos ao acaso, em parcelas subdivididas com três repetições. As parcelas foram constituídas pelos dias após a emergência, que foi iniciado o estresse de alta temperatura (14, 21, 28 e 35 dias), e as subparcelas, pelos cachos até completar os 6 meses de estresse. Com os resultados obtidos pode-se assegurar que a intensidade luminosa de 35.000 lux ou 493,5 µmol m-2 s-1 é suficiente para o desenvolvimento completo das plantas iguais ao encontrado no campo. Isso demonstra que é possível a utilização da câmara de crescimento construída para simulação de ambientes controlados. Já quanto aos resultados da taxa de florescimento no híbrido FCA 2007-1, fica evidente que a taxa de flores masculinas e femininas não é modificada pelo estresse isolado por altas temperaturas. O mesmo ocorre nas fêmeas MRZ 14, não causando reversão sexual independente do período avaliado. Esse resultado pode estar relacionado ao aumento na quantidade dos hormônios relacionados à indução de flores femininas, mantendo a feminilidade nas fêmeas MRZ 14 e nos híbridos FCA 2007-1, uma vez que há o aumento na quantidade dos hormônios como auxina, citocinina, giberelinas e etileno quando plantas são submetidas ao estresse por altas temperaturas.
Castor oil (Ricinus communis) is present in many industrial applications and in the production of biodiesel, demonstrating its economic importance. Brazil is the fourth largest castor oil producer in the world with great potential to be a protagonist of castor bean, and the use of hybrids is an alternative for this purpose, however there is difficulty in obtaining it due to climatic variations. So, the aim of the present work was the construction of a growth chamber, in which it simulates various climatic conditions to aid in the selection of plants, besides using this growth chamber to evaluate the isolated effect of high temperature on the castor's sexual reversion. To create the growth chamber were used lamps, air conditioning, heaters and sensors; plus, an Arduino Mega 2560 R3, which controls the entire system. During this experiment, evaluations were made to know how much light intensity is required for the full development of castor bean plants. In this same growth chamber, the isolated high temperature effect experiment was performed in relation to male and female flowers rate in the FCA 2007-1 hybrid and in the sexual reversion on MRZ females 14. The experimental design used to evaluate the flower rate between male and female in the FCA 2007-1 hybrid was a randomized block design with split-plots with three replicates. The plots consisted of the days after the emergence of the plants, when the high temperature stress (14, 21, 28 and 35 days) was started, and the sub-plots, by the first and second bunch. The experimental design used to evaluate the number of male flowers in the strictly feminine plants MRZ 14 was also randomized blocks, in split-plots with three replicates. The plots were constituted by the days after the emergency, which was initiated the high temperature stress (14, 21, 28 and 35 days), and the sub-plots by the bunches until the 6 months of stress. With the results obtained we can assure that the luminous intensity of 35,000 lux or 493,5 μmol m-2 s-1 is sufficient for the complete development of the plants equal to the one found in the field. This demonstrates that it is possible to use the growth chamber built for simulation of controlled environments. Regarding the results of the flowering rate in the hybrid FCA 2007-1, it is evident that the rate of male and female flowers is not modified only by high temperatures stress. The same occurs in females MRZ 14, not causing sexual reversion independent of the period evaluated. This result may be possibly due to the increase in the amount of hormones related to the induction of female flowers, maintaining femininity in females MRZ 14 and in hybrids FCA 2007-1, since there is an increase in the amount of hormones such as auxin, cytokinin, gibberellins and ethylene when plants are subjected to high temperature stress.
Castor oil (Ricinus communis) is present in many industrial applications and in the production of biodiesel, demonstrating its economic importance. Brazil is the fourth largest castor oil producer in the world with great potential to be a protagonist of castor bean, and the use of hybrids is an alternative for this purpose, however there is difficulty in obtaining it due to climatic variations. So, the aim of the present work was the construction of a growth chamber, in which it simulates various climatic conditions to aid in the selection of plants, besides using this growth chamber to evaluate the isolated effect of high temperature on the castor's sexual reversion. To create the growth chamber were used lamps, air conditioning, heaters and sensors; plus, an Arduino Mega 2560 R3, which controls the entire system. During this experiment, evaluations were made to know how much light intensity is required for the full development of castor bean plants. In this same growth chamber, the isolated high temperature effect experiment was performed in relation to male and female flowers rate in the FCA 2007-1 hybrid and in the sexual reversion on MRZ females 14. The experimental design used to evaluate the flower rate between male and female in the FCA 2007-1 hybrid was a randomized block design with split-plots with three replicates. The plots consisted of the days after the emergence of the plants, when the high temperature stress (14, 21, 28 and 35 days) was started, and the sub-plots, by the first and second bunch. The experimental design used to evaluate the number of male flowers in the strictly feminine plants MRZ 14 was also randomized blocks, in split-plots with three replicates. The plots were constituted by the days after the emergency, which was initiated the high temperature stress (14, 21, 28 and 35 days), and the sub-plots by the bunches until the 6 months of stress. With the results obtained we can assure that the luminous intensity of 35,000 lux or 493,5 μmol m-2 s-1 is sufficient for the complete development of the plants equal to the one found in the field. This demonstrates that it is possible to use the growth chamber built for simulation of controlled environments. Regarding the results of the flowering rate in the hybrid FCA 2007-1, it is evident that the rate of male and female flowers is not modified only by high temperatures stress. The same occurs in females MRZ 14, not causing sexual reversion independent of the period evaluated. This result may be possibly due to the increase in the amount of hormones related to the induction of female flowers, maintaining femininity in females MRZ 14 and in hybrids FCA 2007-1, since there is an increase in the amount of hormones such as auxin, cytokinin, gibberellins and ethylene when plants are subjected to high temperature stress.
Descrição
Palavras-chave
Câmara de crescimento, Reversão sexual, Estresse por calor, Expressão sexual, Sistema reprodutivo, Growth chamber, Sexual reversion, Heat stress, Sexual expression, Reproductive system