RESUMO
Salinity is a major abiotic stress that adversely affects several physiological and biochemical aspects of plants. Antioxidants can be used as a potential remediation mechanism to promote plant resilience. Therefore, the objective of the present study was to evaluate increasing doses of the antioxidant lycopene on the germination and initial growth of common bean seedlings under conditions of salt stress. Seeds were treated with the following lycopene concentrations: 0.018; 0.036; 0.072; 0.144; and 0.288 g L-1 and two controls (negative and positive) and evaluated under two growth conditions (without and with salt stress) for physiological quality and pigment content. Data were analyzed by completely randomized design, in 2 x 7 factorial (two growth conditions, with paper towel moistened with water or salt solution x seven treatments, including five lycopene doses and two controls), in four replicates of 50 seeds by concentration. With the results of the analysis of variance, growth conditions (without and with salt stress) were compared by the Tukey test (5%), and the effects of lycopene doses were analyzed by polynomial regression. Lycopene promoted tolerance of bean seeds to salt stress and had a positive influence on the attenuation of salt harmful effects to the initial growth of seedlings, mainly at the doses of 0.072 g L-1 and 0.144 g L-1.
Salinity is a major abiotic stress that adversely affects several physiological and biochemical aspects of plants. Antioxidants can be used as a potential remediation mechanism to promote plant resilience. Therefore, the objective of the present study was to evaluate increasing doses of the antioxidant lycopene on the germination and initial growth of common bean seedlings under conditions of salt stress. Seeds were treated with the following lycopene concentrations: 0.018; 0.036; 0.072; 0.144; and 0.288 g L-1 and two controls (negative and positive) and evaluated under two growth conditions (without and with salt stress) for physiological quality and pigment content. Data were analyzed by completely randomized design, in 2 x 7 factorial (two growth conditions, with paper towel moistened with water or salt solution x seven treatments, including five lycopene doses and two controls), in four replicates of 50 seeds by concentration. With the results of the analysis of variance, growth conditions (without and with salt stress) were compared by the Tukey test (5%), and the effects of lycopene doses were analyzed by polynomial regression. Lycopene promoted tolerance of bean seeds to salt stress and had a positive influence on the attenuation of salt harmful effects to the initial growth of seedlings, mainly at the doses of 0.072 g L-1 and 0.144 g L-1.
RESUMO
For adapting well to various soil and climatic conditions in Brazil and the tradition of high consumption, bean plays a key role in feeding the population. Despite the different environmental conditions, there are few specific cultivars for each planting season, particularly when aimed at the production of quality seeds. The objective of this study was to evaluate the physiological potential of bean seeds from five population densities, under the edafoclimatic conditions of Janaúba, northern Minas Gerais. The experiment was conducted on winter crop season, with planting in August 2011. The experimental design was a randomized block in 3 x 5 factorial, with four replicates. The treatments consisted of three cultivars of common bean with different growth types (Ouro Vermelho, Ouro Negro and BRSMG Madrepérola), and five densities (100, 200, 300, 400 and 500 thousand plants ha-1). Seeds were evaluated for water content, germination and vigor (tests of first count, seedling emergence, emergence speed and accelerated aging). From the results, it can be concluded that the bean seeds of the cultivar Ouro Negro present superior physiological potential in relation to the cultivars Ouro Vermelho and BRSMG Madrepérola. Increasing the sowing density up to 300 thousand plants ha-1 is suitable for the production of bean seeds on winter crop season, representing a good alternative for cultivation in the region.
Por se adaptar bem às mais variadas condições edafoclimáticas do Brasil e pela alta tradição de consumo, o feijoeiro desempenha papel fundamental na alimentação da população brasileira. Apesar das condições ambientais distintas, existem poucas cultivares específicas para cada época de plantio, principalmente quando visa à produção de sementes de qualidade. Objetivou-se com este trabalho avaliar o desempenho fisiológico de sementes de feijão-comum cultivado em cinco densidades populacionais, nas condições edafoclimáticas de Janaúba, Norte de Minas Gerais. O experimento foi conduzido na safra de inverno, com plantio em agosto de 2011. O delineamento experimental utilizado foi em blocos casualizados, em esquema fatorial 3 x 5, com quatro repetições. Os tratamentos consistiram em três cultivares de feijão-comum de diferentes tipos de crescimento (Ouro Vermelho, Ouro Negro e BRSMG Madrepérola), e cinco densidades populacionais (100, 200, 300, 400 e 500 mil plantas ha-1). As sementes foram avaliadas quanto ao teor de água, à germinação e ao vigor (testes de primeira contagem, emergência de plântulas, índice de velocidade de emergência e envelhecimento acelerado). Diante dos resultados, conclui-se que as sementes de feijão da cultivar Ouro Negro apresentam desempenho fisiológico superior em comparação com as cultivares Ouro Vermelho e BRSMG Madrepérola. O aumento da densidade de semeadura até 300 mil plantas ha-1 é adequado para a produção de sementes de feijão na safra de inverno, representando boa alternativa para o cultivo na região.