Absorção e redistribuição de boro em coqueiro-anão-verde

Abstract

Resumo -O objetivo deste trabalho foi verificar se ocorre redistribuição de boro em coqueiros (Cocos nucifera), quando a aplicação de ácido bórico é realizada na axila foliar ou no solo. Foram empregados os seguintes tratamentos com ácido bórico: 30 g aplicados sobre a axila da folha número 10; 60 g aplicados ao solo; e controle, sem aplicação. Foram realizadas duas aplicações de B, com um intervalo de cinco meses entre elas. A unidade experimental consistiu de duas plantas, com seis repetições, em delineamento inteiramente casualizado. Foram determinados os teores de boro nas folhas 2, 6, 10, 14 e 18, aos dois e quatro meses após a primeira aplicação de ácido bórico, e aos dois e cinco meses após a segunda aplicação. O boro se redistribuiu pela planta de coqueiro, independentemente da forma de aplicação. A elevação do teor de boro nas folhas persistiu por mais tempo, quando a aplicação de ácido bórico foi feita ao solo. As doses de ácido bórico aplicadas não causaram fitotoxidade, mesmo quando a aplicação foi repetida após um curto período.Termos para indexação: Cocos nucifera, filotaxia do coqueiro, micronutriente, nutrição mineral, translocação de boro. Boron absorption and redistribution in green dwarf coconut treeAbstract -The aim of this work was to verify if boron redistribution occurs among the coconut palm (Cocos nucifera) fronds, when boric acid is applied on frond axils or on soil. The treatments with boric acid were: 30 g applied on the axil of frond number 10; 60 g applied to the soil; and a control without boric acid application. The B applications were repeated after five-month interval. The experimental unit consisted of two plants, with six replicates, in a randomized complete block design. Boron contents were determined in fronds number 2, 6, 10, 14 and 18, two and four months after the first boric acid application, and two and five months after the second application. Boron was redistributed in coconut plants, regardless of the application form. Increases in boron concentration in fronds persisted longer when boric acid was applied to the soil. The applied doses of boric acid had no phytotoxity effect, even when the application was repeated after five months.

Applying boron to coconut palm plants: effects on the soil, on the plant nutritional status and on productivity boron to coconut palm trees

“…The application of boron directly into the soil is more efficient than foliar techniques due to the low mobility it shows in plant tissues. Boron applied to the soil has a more persistent effect than when it is deposited in leaf axillae (Pinho et al, 2008b;Broschat, 2011).…”

Diagnosis of Boron Deficiency in Green Dwarf Coconut Palm

“…There are several cultivated species with B deficiency, which, in turn, often occurs in sandy soil due to lixiviation. However, coconut palm grown in sandy soil with 710 g•kg −1 of sand and 31 g•kg −1 of organic matter in the layer of 0 -0.4 m, plants absorbed B, with no evidence of lixiviation after supplying the soil with 60 g of boric acid per plant [3]. In many parts of the world there are reports of boron deficiency in palms [4] [7].…”

“…Few academic studies describe the distribution of B in the leaves of coconut palm. In plants not fertilized with B, the tendency is to have similar contents in young and in old leaves; in those fertilized, however, the content of B increases, but it does not follow a consistent pattern of distribution between young and old leaves [3]- [16]. The correction of the deficiency in coconut palms is possible after application of B [12].…”

“…The correction of the deficiency in coconut palms is possible after application of B [12]. Doses of 30 g and 60 g of boric acid per plant, applied without dilution at the plant's axilla or in the soil, respectively, adequately nourish the plant and do not cause toxicity [3].…”

Adubação potássica aplicada na axila foliar e no solo em coqueiro anão verde

“…A aplicação do fertilizante potássico na axila foliar pode ser uma alternativa, a exemplo do que se faz com o boro em coqueiro (Pinho et al, 2008). Isso, porque, quando o fertilizante é aplicado diretamente na folha, pode ocorrer uma maior absorção de potássio pela planta.…”