Desenvolvimento e composição mineral do picão-preto sob diferentes níveis de pH
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Data
1994-01-01
Autores
Obara, Sergio Y.
Bezutte, Alexandre J. [UNESP]
Alves, Pedro L. C. A. [UNESP]
Título da Revista
ISSN da Revista
Título de Volume
Editor
Sociedade Brasileira da Ciência das Plantas Daninhas
Resumo
Visando estudar a tolerância do picão-preto (Bidens pilosa) a diferentes níveis de pH do substrato, conduziu-se um ensaio em condições de câmara de crescimento e utilizando-se a técnica de hidroponia, no qual três plântulas foram transplantadas para recipientes contendo solução nutritiva de Hoagland & Arnon, com pH ajustado para 3,5, 4,0, 5,0, 6,0, 7,0 e 8,0. O delineamento experimental utilizado foi o inteiramente casualizado com três repetições. Ao final do período experimental, 42 dias após o transplante, observou-se que as plantas que se desenvolveram nos pHs 3,5 e 8,0 apresentaram-se menores, com menor comprimento e volume do sistema radicular, menor número de folhas vivas e, consequentemente, menor peso de matéria seca das folhas, caule e raízes. Os teores de N e S nas raízes diminuiram com o aumento do pH do substrato, enquanto os de Ca e Mg aumentaram e os de K e P diminuiram no pH 5,0 a 6,0. No caule, apenas o teor de Mg foi afetado pelo pH, mostrando resposta positiva. Na folha obteve-se os maiores teores de P, S, Ca e Mg quando a planta se desenvolveu em pH 6,0. Não se constatou diferença significativa entre os efeitos dos pHs 5,0, 6,0 e 7,0 nos parâmetros avaliados, sendo que foi no pH 6,0 que se estimou, através de análise de regressão, melhor desenvolvimento do picão-preto. Concluiu-se que o picãopreto apresenta melhor desenvolvimento em pHs próximo ao neutro, com certa tolerância a pHs extremos (3,5 e 8,0).
An assay was conducted under growth chamber condition to study the hairy beggar-ticks (Bidens pilosa) tolerance to different pH levels of the substrate. Three seedlings were transplanted into recipients containing Hoaglands & Anion's nourfishing solution with pH ajusted to 3.5, 4.0, 5.0, 6.0, 7.0 and 8.0 . The experimental design used was the completely randomized with three replications. At the end of the experimental period (42 days after transplantation) the development of the plants at pHs 3.5 and 8.0 appeared to be smaller in the following aspects: radicular system in length and volume, number of living leaves, and dry matter of the leaves, stem and roots. The N and S contents in the roots diminished as the substrate pH increased, while the Ca and Mg contents increased and K and P diminished at pH 5.0 to 6.0. Mg was the only element to be affected in the stem, showing a positive response. The highest contents of P, S, Ca and Mg were obtained on the leaves when the plant developed at pH 6,0. No significant difference was observed among the pHs 5.0, 6.0 and 7.0 on the evaluated parameters; however, at pH 6.0 a better development of the begga r-tick was evaluated through a regression analysis. It was concluded that the beggar-tick shows its better development at pHs close to neutral, although it presents certain tolerance to extreme pHs (3.5 and 8.0).
An assay was conducted under growth chamber condition to study the hairy beggar-ticks (Bidens pilosa) tolerance to different pH levels of the substrate. Three seedlings were transplanted into recipients containing Hoaglands & Anion's nourfishing solution with pH ajusted to 3.5, 4.0, 5.0, 6.0, 7.0 and 8.0 . The experimental design used was the completely randomized with three replications. At the end of the experimental period (42 days after transplantation) the development of the plants at pHs 3.5 and 8.0 appeared to be smaller in the following aspects: radicular system in length and volume, number of living leaves, and dry matter of the leaves, stem and roots. The N and S contents in the roots diminished as the substrate pH increased, while the Ca and Mg contents increased and K and P diminished at pH 5.0 to 6.0. Mg was the only element to be affected in the stem, showing a positive response. The highest contents of P, S, Ca and Mg were obtained on the leaves when the plant developed at pH 6,0. No significant difference was observed among the pHs 5.0, 6.0 and 7.0 on the evaluated parameters; however, at pH 6.0 a better development of the begga r-tick was evaluated through a regression analysis. It was concluded that the beggar-tick shows its better development at pHs close to neutral, although it presents certain tolerance to extreme pHs (3.5 and 8.0).
Descrição
Palavras-chave
Mineral nutrition, weed biology, Plant growth, Weed, Bidens pilosa, Nutrição mineral, Biologia, Crescimento, Planta daninha, Bidens pilosa
Como citar
Planta Daninha. Sociedade Brasileira da Ciência das Plantas Daninhas , v. 12, n. 1, p. 52-56, 1994.