Silício na mitigação de estresse nutricional de fósforo e de déficit hídrico em mudas de eucalipto propagadas por sementes e por ministesquia
Carregando...
Arquivos
Data
2023-03-01
Autores
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Estadual Paulista (Unesp)
Resumo
A suficiência em fósforo (P) é essencial para a produção de mudas de eucalipto com reflexos no crescimento inicial no campo, mas em deficiência ou excesso, o P pode causar danos biológicos nas plantas. Uma estratégia para atenuar o estresse nutricional de P em mudas de eucalipto é o fornecimento do silício (Si). Esse estudo objetivou avaliar o efeito da nutrição com P associada à aplicação ou não de Si na formação de mudas de duas espécies de eucalipto e no desenvolvimento posterior em vasos sob duas condições hídricas. Quatro experimentos foram conduzidos. Os dois primeiros experimentos consistiram na formação de mudas em tubetes de 50 ml, sendo um com mudas propagadas por miniestaquia de Eucalyptus grandis X E. urophylla, e outro com mudas seminais de Corymbia citriodora. Esses experimentos foram conduzidos em delineamento de blocos ao acaso, em esquema fatorial 3 x 2 (3 concentrações de P: 0,1; 1,0 e 10 mmol L-1 de P, correspondentes a 10%, 100% e 1000% de P com base na solução de Hoagland e Arnon, com ou sem a aplicação de 2 mmol L-1 Si) com 5 repetições de 6 mudas. Os outros dois experimentos foram conduzidos com mudas de C. citriodora e de E. grandis X E. urophylla provenientes dos tratamentos de 10 e 100% das concentrações de P dos experimentos anteriores, na presença e ausência de Si, submetidas a dois níveis de disponibilidade hídrica no solo (30 e 60% da capacidade de retenção de água no solo – CRA). Esses experimentos foram conduzidos em vasos preenchidos com 8,5 Kg de solo. O delineamento experimental foi em blocos ao acaso, com seis repetições, em esquema fatorial 2 x 2 x 2 (mudas formadas com 10 e 100% da concentração de P x com ou sem adição de 2 mmol.L-1 Si x 30% ou 60% da CRA). Para os dois primeiros experimentos de formação de mudas observou-se que: o aumento da concentração de P promoveu maior matéria seca da parte aérea, enquanto o fornecimento de Si aumentou a produção da matéria seca de raiz para C. citriodora; para o híbrido as plantas com fornecimento de Si aumentou a matéria seca das raízes e apresentou maior relação raiz-parte aérea; o fornecimento de Si promoveu aumento no acúmulo do elemento em todos os tratamentos, para a parte aérea o aumento da concentração de P aumentou o acúmulo de Si para C. citriodora; o Si é um elemento benéfico que ajuda a mitigar os efeitos da deficiência de P durante a formação de mudas de eucalipto. Nos experimentos desenvolvidos em vasos observou-se que: as plantas de C. citriodora e de E. grandis X E. urophylla foram prejudicadas pela deficiência hídrica, independentemente da dose de P e, ou Si na formação das mudas; o efeito positivo da adubação com P é dependente da boa disponibilidade hídrica, tendo favorecido o crescimento apenas quando não houve deficiência hídrica; a aplicação de Si, em geral, não afetou o desenvolvimento das plantas, mas em C. citriodora a aplicação de Si sob adequada disponibilidade hídrica favoreceu o acúmulo de matéria seca nas raízes.
Phosphorus (P) sufficiency is essential for the production of eucalyptus seedlings, with effects on initial growth in the field, but in deficiency or excess, P can cause biological damage to plants. A strategy to attenuate the nutritional stress of P in eucalyptus seedlings is the supply of silicon (Si). This study aimed to evaluate the effect of nutrition with P associated with or without application of Si on the formation of seedlings of two eucalyptus species and in subsequent development in pots under two water conditions. Four experiments were attended. The first and second experiments consisted of the formation of seedlings in 50 ml tubes, one with seedlings propagated by minicuttings of Eucalyptus grandis X E. urophylla, and the other with seminal seedlings of Corymbia citriodora. These experiments were carried out in a randomized block design, in a 3 x 2 factorial scheme (3 concentrations of P: 0.1; 1.0 and 10 mmol L-1 of P, corresponding to 10%, 100% and 1000% of P based on Hoagland and Arnon's solution, with or without the application of 2 mmol L-1 Si) with 5 replications of 6 seedlings. The experiments 3 and 4 were carried out with seedlings of C. citriodora and E. grandis X E. urophylla from the treatments of 10 and 100% of the P concentrations of the previous experiments, in the presence and absence of Si, submitted to two levels of availability soil water retention (30 and 60% of the soil water retention capacity – WRC). These experiments were conducted in pots filled with 8.5 kg of soil. The experimental design was randomized blocks, with six replications, in a 2 x 2 x 2 factorial scheme (seedlings formed with 10 and 100% of the P x concentration with or without the addition of 2 mmol.L-1 Si x 30% or 60% of the WRC). For the two seedling formation experiments (experiment 1 and 2), it was observed that: the increase in P concentration promoted greater shoot dry matter, while the supply of Si increased root dry matter production for C. citriodora; for the hybrid, plants with Si supply showed higher root dry matter production and higher root-shoot ratio; the supply of Si promoted an increase in the accumulation of the element in all treatments, for the aerial part the increase in the concentration of P increased the accumulation of Si for C. citriodora; Si is a beneficial element that helps mitigate the effects of P deficiency during the formation of eucalyptus seedlings. In the experiments carried out in vases (experimente 3 and 4), it was observed that: the plants of C. citriodora and E. grandis X E. urophylla were harmed by water deficiency, regardless of the dose of P e, or Si in the formation of seedlings; the positive effect of fertilization with P is dependent on good water availability, favoring growth only when there was no water deficit; the application of Si, in general, did not affect the development of the plants, but in C. citriodora the application of Si under adequate water availability favored the accumulation of dry matter in the roots.
Phosphorus (P) sufficiency is essential for the production of eucalyptus seedlings, with effects on initial growth in the field, but in deficiency or excess, P can cause biological damage to plants. A strategy to attenuate the nutritional stress of P in eucalyptus seedlings is the supply of silicon (Si). This study aimed to evaluate the effect of nutrition with P associated with or without application of Si on the formation of seedlings of two eucalyptus species and in subsequent development in pots under two water conditions. Four experiments were attended. The first and second experiments consisted of the formation of seedlings in 50 ml tubes, one with seedlings propagated by minicuttings of Eucalyptus grandis X E. urophylla, and the other with seminal seedlings of Corymbia citriodora. These experiments were carried out in a randomized block design, in a 3 x 2 factorial scheme (3 concentrations of P: 0.1; 1.0 and 10 mmol L-1 of P, corresponding to 10%, 100% and 1000% of P based on Hoagland and Arnon's solution, with or without the application of 2 mmol L-1 Si) with 5 replications of 6 seedlings. The experiments 3 and 4 were carried out with seedlings of C. citriodora and E. grandis X E. urophylla from the treatments of 10 and 100% of the P concentrations of the previous experiments, in the presence and absence of Si, submitted to two levels of availability soil water retention (30 and 60% of the soil water retention capacity – WRC). These experiments were conducted in pots filled with 8.5 kg of soil. The experimental design was randomized blocks, with six replications, in a 2 x 2 x 2 factorial scheme (seedlings formed with 10 and 100% of the P x concentration with or without the addition of 2 mmol.L-1 Si x 30% or 60% of the WRC). For the two seedling formation experiments (experiment 1 and 2), it was observed that: the increase in P concentration promoted greater shoot dry matter, while the supply of Si increased root dry matter production for C. citriodora; for the hybrid, plants with Si supply showed higher root dry matter production and higher root-shoot ratio; the supply of Si promoted an increase in the accumulation of the element in all treatments, for the aerial part the increase in the concentration of P increased the accumulation of Si for C. citriodora; Si is a beneficial element that helps mitigate the effects of P deficiency during the formation of eucalyptus seedlings. In the experiments carried out in vases (experimente 3 and 4), it was observed that: the plants of C. citriodora and E. grandis X E. urophylla were harmed by water deficiency, regardless of the dose of P e, or Si in the formation of seedlings; the positive effect of fertilization with P is dependent on good water availability, favoring growth only when there was no water deficit; the application of Si, in general, did not affect the development of the plants, but in C. citriodora the application of Si under adequate water availability favored the accumulation of dry matter in the roots.
Descrição
Palavras-chave
Silvicultura, Eucalyptus, Corymbia citriodora, Estresse hídrico, Elemento benéfico