Superação da dormência de sementes, morfologia de sementes e plântulas e crescimento de plântulas de Bauhinia scandens L.
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Data
2020-11-19
Autores
Jeromini, Tatiane Sanches [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
A espécie Bauhinia scandens L. possui potencial ornamental devido a suas flores exuberantes, e propriedades medicinais principalmente em suas folhas. Foram realizados três experimentos e com os objetivos foram: (I) determinar um método para a superação da dormência e crescimento inicial de plântulas de B. scandens, (II) caracterização morfológica de sementes, germinação e plântulas de B. scandens e (III) determinar o substrato e umedecimento mais favoráveis a emergência e crescimento de plântulas de B. scandens. No primeiro experimento, as sementes foram submetidas aos seguintes tratamentos: testemunha, escarificação mecânica, imersão em água a 26 °C, imersão em água quente, imersão em H2SO4 (95%) por 15, 30, 45 e 60 minutos. As sementes foram avaliadas quanto ao teor de água, germinação (plântulas normais, anormais, sementes dormentes e mortas), primeira contagem, tempo médio de germinação e frequência relativa. As plântulas foram avaliadas quanto à emergência em areia, primeira contagem, índice de velocidade de emergência, comprimento e massa de matéria seca. O delineamento foi inteiramente casualizado, com oito tratamentos. No segundo experimento foram avaliados o teor de água, o peso de mil sementes e a coloração das sementes, descrição e biometria da semente, estrutura (externa e interna), germinação e morfologia das plântulas. A morfologia interna das sementes foi avaliada por corte anatômico e método de raios X. Foi realizada análise descritiva e frequência de germinação. No terceiro experimento, as sementes de B. scandens foram dispostas em três substratos, sendo eles areia, vermiculita e substrato comercial, mantidos em quatro níveis de umedecimento 25, 50, 75 e 100% da capacidade de retenção de água do substrato. Foram avaliados a emergência, índice de velocidade e tempo médio de emergência, número de folhas, comprimento da parte aérea e de raiz, diâmetro do colo, massa fresca e seca de parte aérea e de raiz. O delineamento foi inteiramente casualizado, em esquema fatorial de 3x4. Concluiu-se com estes experimentos que as sementes de B. scandens possuem dormência tegumentar e devem ser imersas em H2SO4 por 45 minutos e opcionalmente realizar a escarificação mecânica antes da semeadura para superar a dormência de sementes e aumentar a velocidade de emergência de plântulas. O crescimento das plântulas não foi afetado pelo método de superação de dormência. Sementes de B. scandens tem coloração que varia do vermelho muito escuro acinzentado ao bruno avermelhado escuro e possuem formato oblongo achatado, base e ápice arredondados e margens inteiras ou pouco onduladas. Plântulas normais são formadas na maioria apenas a partir de sementes com estrutura interna bem formadas. O pecíolo avermelhado das folhas das plântulas é uma característica taxonômica para identificação de B. scandens. A semeadura de B. scandens deve ser realizada em vermiculita com capacidade de retenção de 100% para o estabelecimento da emergência das plântulas e o crescimento das plântulas deve ser conduzido em substrato comercial mantendo-se entre 50 e 75% da capacidade de retenção.
The species Bauhinia scandens L. has ornamental potential due to its exuberant flowers, and medicinal properties mainly on its leaves. Three experiments were carried out and the objectives were: (I) to determine a method for overcoming dormancy and initial growth of B. scandens seedlings, (II) morphological characterization of seeds, germination and seedlings of B. scandens and (III) the substrate and moistening more favorable to the emergence and growth of seedlings of B. scandens. In the first experiment, the seeds were subjected to the following treatments: control, mechanical scarification, immersion in water at 26 ° C, immersion in hot water, immersion in H2SO4 (95%) for 15, 30, 45 and 60 minutes. The seeds were evaluated for water content, germination (normal, abnormal seedlings, dormant and dead seeds), first count, average germination time and relative frequency. Seedlings were evaluated for sand emergence, first count, emergence speed index, dry matter length and mass. The design was completely randomized, with eight treatments. In the second experiment, the water content, the weight of a thousand seeds and the color of the seeds were evaluated, the description and biometry of the seed, structure (external and internal), germination and seedling morphology. The internal morphology of the seeds was evaluated by anatomical cut and X-ray method and realized descript analyses and germination frequency. In the third experiment, the seeds of B. scandens were placed on three substrates, sand, vermiculite, and commercial substrate, maintained at four levels of moistening 25, 50, 75 and 100% of the substrate's water retention capacity. The emergence, speed index and mean time of emergence, number of leaves, length of the aerial part and root, diameter of the neck, fresh and dry mass of aerial part and root were evaluated. The design was completely randomized, in a 3x4 factorial scheme. It was concluded with these experiments that the seeds of B. scandens have tegumentary dormancy and must be immersed in H2SO4 for 45 minutes and make optionally mechanical scarification before sowing to overcome seed dormancy and increase the speed of seedling emergence. Seedling growth was not affected by the dormancy overcoming method. B. scandens seeds have a color that varies from very dark gray red to dark reddish bruno and have a flat oblong shape, rounded base, and apex and entire or slightly wavy margins. Normal seedlings are formed mostly from seeds with well-formed internal structure. The reddish petiole of the seedling leaves is a taxonomic characteristic for the identification of B. scandens. The sowing of B. scandens should be carried out in vermiculite with a retention capacity of 100% for establishing the seedling emergence and the growth of the seedlings must be carried out on a commercial substrate, maintaining between 50 and 75% of the retention capacity.
The species Bauhinia scandens L. has ornamental potential due to its exuberant flowers, and medicinal properties mainly on its leaves. Three experiments were carried out and the objectives were: (I) to determine a method for overcoming dormancy and initial growth of B. scandens seedlings, (II) morphological characterization of seeds, germination and seedlings of B. scandens and (III) the substrate and moistening more favorable to the emergence and growth of seedlings of B. scandens. In the first experiment, the seeds were subjected to the following treatments: control, mechanical scarification, immersion in water at 26 ° C, immersion in hot water, immersion in H2SO4 (95%) for 15, 30, 45 and 60 minutes. The seeds were evaluated for water content, germination (normal, abnormal seedlings, dormant and dead seeds), first count, average germination time and relative frequency. Seedlings were evaluated for sand emergence, first count, emergence speed index, dry matter length and mass. The design was completely randomized, with eight treatments. In the second experiment, the water content, the weight of a thousand seeds and the color of the seeds were evaluated, the description and biometry of the seed, structure (external and internal), germination and seedling morphology. The internal morphology of the seeds was evaluated by anatomical cut and X-ray method and realized descript analyses and germination frequency. In the third experiment, the seeds of B. scandens were placed on three substrates, sand, vermiculite, and commercial substrate, maintained at four levels of moistening 25, 50, 75 and 100% of the substrate's water retention capacity. The emergence, speed index and mean time of emergence, number of leaves, length of the aerial part and root, diameter of the neck, fresh and dry mass of aerial part and root were evaluated. The design was completely randomized, in a 3x4 factorial scheme. It was concluded with these experiments that the seeds of B. scandens have tegumentary dormancy and must be immersed in H2SO4 for 45 minutes and make optionally mechanical scarification before sowing to overcome seed dormancy and increase the speed of seedling emergence. Seedling growth was not affected by the dormancy overcoming method. B. scandens seeds have a color that varies from very dark gray red to dark reddish bruno and have a flat oblong shape, rounded base, and apex and entire or slightly wavy margins. Normal seedlings are formed mostly from seeds with well-formed internal structure. The reddish petiole of the seedling leaves is a taxonomic characteristic for the identification of B. scandens. The sowing of B. scandens should be carried out in vermiculite with a retention capacity of 100% for establishing the seedling emergence and the growth of the seedlings must be carried out on a commercial substrate, maintaining between 50 and 75% of the retention capacity.
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Palavras-chave
Bauhinia trepadeira, Caracteres morfológicos, Crescimento, Escarificação, Planta medicinal, Planta ornamental