Nutrição mineral do mamoeiro (Carica papaya L.): II - deficiência de boro em condições de campo e casa de vegetação

Abstract

Com o objetivo de caracterizar a deficiência de boro no mamoeiro (Carica papaya L.) em condições de casa de vegetação e correlacionar com o problema que ocorre em condições de campo, conhecido como careca do mamoeiro ou queda do chapéu, foram instalados dois ensaios. O primeiro foi conduzido em condições de campo no município de Botucatu, SP., em um solo pertencente ao grande grupo Terra Roxa Estruturada e de clima Cf.b.. O segundo ensaio foi conduzido em condições de casa de vegetação e soluções nutritivas. Os autores descrevem os sintomas de deficiência de boro em mamoeiro e correlacionam o problema conhecido como careca do mamoeiro, com a deficiência de boro.

The purpose of the present research was to characterize boron deficiency on papaya trees growing on nutrient solution, of which boron was excluded, as well as, to correlate it a field occuring problem called Careca. Plants growing on nutrient solution were cultivated under greenhouse conditions. The field experiment was set out in Botucatu, São Paulo, Brazil, with a climate classified as Cf.b. and Paleudalf soil type. Boron deficiency was characterized by the emergence of small leaves with narrow deformed and hard leaf blades, necrosed margins and prominent veins. As an advanced boron deficiency symptom, plant stunting occurred. Boron concentration in the leaves and stems of plants growing on nutrient solution, of which boron was excluded, was 20 ppm and 17 ppm respectively. They were smaller when compared with the check plants, with boron concentration of 136 ppm and 35 ppm on leaves and stems respectively. Is is concluded that field occurring problem called careca is correlated with boron deficiency.