Absorção e translocação de boro em cafeeiro
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Data
2002-04
Autores
Leite, Vagner Maximino [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
Existe controvérsia sobre o modo de aplicação de B em cafeeiro, teor foliar e produtividade, que pode estar relacionada tanto com a absorção quanto com a translocação do nutriente em função do modo de aplicação e do cultivar utilizados. Com o intuito de avaliar a absorção, a translocação e alguns efeitos morfológicos e anatômicos do B sobre o cafeeiro, foram realizados 2 experimentos em campo e 2 em casa-de-vegetação, utilizando-se o isótopo estável 10B, medições e microscopia eletrônica de varredura. No primeiro experimento em campo, que teve a duração de 2 anos, o ácido bórico foi aplicado em diferentes doses, em pré e/ou pós-florada. Para as avaliações, os ramos foram coletados e divididos em 3 partes, sendo analisados quanto ao teor de B nas folhas, haste e estruturas reprodutivas, o número de nós, o número de folhas, o comprimento ramo e a matéria seca das folhas e dos frutos. Não houve diferenças significativas entre tratamentos para o conteúdo de B nas diferentes partes analisadas, e não foram observados alterações morfológicas ou efeito na produtividade do cafeeiro nos 2 anos. O pincelamento de ácido bórico enriquecido (H3 10BO3) nas folhas, constou do segundo experimento em campo, onde se observou a dependência das chuvas, para que ocorresse a translocação do B aplicado nas folhas para a haste, folhas do ponteiro e frutos. Do B contido nas folhas do ponteiro 30 dias após a aplicação e no fruto durante todo o período avaliado, 5% foi translocado do fertilizante pincelado. Os experimentos quanto ao modo de aplicação, foliar ou radicular, a translocação e as alterações anatômicas em suficiência ou deficiência de B foram realizados em casa-devegetação. As plantas cresceram em vasos com areia lavada recebendo solução nutritiva completa, menos B, o qual foi aplicado separadamente ou via... .
There is a controversy about B application way, foliar content and yields that can be related to the nutrient absorption and translocation as affected by application way and the cultivars. To evaluate B translocation and some morphological and anatomical effects on coffee plants, two experiments were conducted in field conditions and two in green house, using 10B, some morphological measurements and scanning electronic microscopy. In the first field experiment, conduced for 2 years, boric acid was applied in several concentrations pre and/or post-flowering. Branches were collected and split in 3 parts, and B content in leaves, stem and reproductive structures were analyzed, nodes number, leaves number, branch length and dry matter weight of leaves and fruits. No significant difference was found between treatments as regarding B content in the several plant parts, and there was no morphological changes or B effect on coffee yields in the 2 years. Brushing of the enriched boric acid on the leaves was the second field experiment, where it was observed a raindependency on leaf applied B translocation to stem, new leaves and fruits. Of the B found in the new leaves 30 days after application and in fruits during all the evaluations 5% was translocated from that applied to leaves. In green house the foliar and root absorption and translocation were studied, as well as the anatomical abnormalities. Plants were grown in pots with washed sand, receiving a complete nutrient solution less B, that was sprayed to leaves or supplied to the substrate. The morphological effects were similar to those in field experiments, and B content in the leaves showed positive correlation with coffee yields. Transpiratory stream was the main driving force 10B use in B translocation. The 10B was found in roots of plants receiving B foliar only. The leaves of plants grown... (Complete abstract, click electronic address below).
There is a controversy about B application way, foliar content and yields that can be related to the nutrient absorption and translocation as affected by application way and the cultivars. To evaluate B translocation and some morphological and anatomical effects on coffee plants, two experiments were conducted in field conditions and two in green house, using 10B, some morphological measurements and scanning electronic microscopy. In the first field experiment, conduced for 2 years, boric acid was applied in several concentrations pre and/or post-flowering. Branches were collected and split in 3 parts, and B content in leaves, stem and reproductive structures were analyzed, nodes number, leaves number, branch length and dry matter weight of leaves and fruits. No significant difference was found between treatments as regarding B content in the several plant parts, and there was no morphological changes or B effect on coffee yields in the 2 years. Brushing of the enriched boric acid on the leaves was the second field experiment, where it was observed a raindependency on leaf applied B translocation to stem, new leaves and fruits. Of the B found in the new leaves 30 days after application and in fruits during all the evaluations 5% was translocated from that applied to leaves. In green house the foliar and root absorption and translocation were studied, as well as the anatomical abnormalities. Plants were grown in pots with washed sand, receiving a complete nutrient solution less B, that was sprayed to leaves or supplied to the substrate. The morphological effects were similar to those in field experiments, and B content in the leaves showed positive correlation with coffee yields. Transpiratory stream was the main driving force 10B use in B translocation. The 10B was found in roots of plants receiving B foliar only. The leaves of plants grown... (Complete abstract, click electronic address below).
Descrição
Palavras-chave
Boro, Café - Nutrição, Translocação vegetal
Como citar
LEITE, Vagner Maximino. Absorção e translocação de boro em cafeeiro. 2002. xiii, 99 f. Tese (doutorado) - Universidade Estadual Paulista, Faculdade de Ciências Agronômicas, 2002.