Phloem mobility of Boron in two eucalypt clones

Edson Marcio Mattiello,Jorge Eduardo Souza Sarkis,Ivo Ribeiro Da Silva,Hugo Alberto Ruiz,Júlio César Lima Neves,Murilo Marques Pucci

doi:10.1590/s0100-06832009000600018

Edson Marcio Mattiello, Jorge Eduardo Souza Sarkis + Show 4 more

Open Access

https://doi.org/10.1590/s0100-06832009000600018

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Abstract

Boron deficiency causes large productivity losses in eucalypt stands in extensive areas of the Brazilian Cerrado region, thus understanding B mobility is a key step in selecting genetic materials that will better withstand B limitation. Thus, in this study B mobility was evaluated in two eucalypt clones (68 and 129), under B sufficiency or B deficiency, after foliar application of the 10B isotope tracer to a single mature leaf. Samples of young tissue, mature leaves and roots were collected 0, 1, 5, 12 and 17 days after 10B application. The 10B:11B isotope ratio was determined by HR-ICP-MS. Samples of leaves and xylem sap were collected for the determination of soluble sugars and polyalcohols by ion chromatography. Boron was translocated within eucalypt. Translocation of foliar-applied 10B to the young tissues, mature leaves and roots was higher in clone 129 than in 68. Seventeen days after 10B application to a single mature leaf, between 14 and 18 % of B in the young tissue was originated from foliar B application. In plants with adequate B supply the element was not translocated out of the labeled leaf.

Highlights

Boron is the micronutrient that is most frequently deficient (Gupta, 1993b)
In Brazil, soils are Bdeficient in several regions, especially in the Cerrado region, where eucalypt cultivation has expanded in recent decades
A single mature leaf of plants grown without B and another grown with B were immersed in H3BO3 solution enriched with 99 atom % 10B (Aldrich), at a concentration of 1.64 g L-1 10B during one minute

Summary

Introduction

Boron is the micronutrient that is most frequently deficient (Gupta, 1993b). In Brazil, soils are Bdeficient in several regions, especially in the Cerrado region, where eucalypt cultivation has expanded in recent decades. Boron deficiency is one of the most limiting factors for eucalypt growth, causing malfunctioning mainly of younger plant tissues (Sgarbi et al, 1999). A characteristic symptom of B deficiency is the death of the apical meristem, known as dieback, resulting in lateral oversprouting. Bdeficient plants usually present losses in wood yield and the wood quality is reduced.

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