High aluminum concentration and initial establishment of Handroanthus impetiginosus: clues about an Al non-resistant species in Brazilian Cerrado

Ane Marcela Das Chagas Mendonça,João Paulo Rodrigues Alves Delfino Barbosa,Jean Marcel Sousa Lira,Ana Luiza De Oliveira Vilela,Daniel Amorim Vieira,Nayara Cristina De Melo

doi:10.1007/s11676-019-01033-5

Abstract

Cerrado soils are acidic and nutrient-poor, with high content of solubilized Al3+. Plants growing in these conditions may display adaptations to cope with high aluminum concentrations especially during early developmental stages. We investigated leaf nutritional status, and photosynthetic and growth characteristics during the initial establishment of Handroanthus impetiginosus (Mart. Ex Dc.) Mattos, a secondary tree species distributed in the Brazilian Cerrado. Our goal was to understand leaf-level traits related to different aluminum concentrations. H. impetiginosus plants were cultivated in four different aluminum sulfate concentrations: 0, 1, 2, and 4 mM Al, for 40 days. We performed analyses of growth, leaf gas exchange, chloroplast pigment content, and leaf mineral nutrients. We observed a linear increase of Al leaf content as a function of Al concentration in the nutrient solution. Plants grown in 1 mM Al showed a remarkable increase of K leaf content, net photosynthesis, stomatal conductance, and transpiration, while in 4 mM Al there were reductions of N, P, and K contents, gas exchange characteristics, and height. H. impetiginosus did not have mechanisms of avoidance, compartmentalization, or resistance to high Al concentrations. Indeed, this species showed a hormetic response, with low Al concentrations stimulating and high Al concentrations inhibiting plant responses.

Highlights

Ex Dc.) Mattos., popularly known as ipê roxo, is a secondary tree species distributed in Cerradão and Cerrado strictu sensu landscapes (Scolforo 2008; Salomão and Camilo 2016)
The low concentration of 1 mM Al showed a stimulatory effect on net photosynthesis, stomatal conductance, and transpiration, with an increase of more than 50% in relation to the concentration of 0 mM Al (Fig. 2a–c)
A higher value of 2.18% for K leaf content was observed for the treatment 1 mM Al (Fig. 2d), possibly indicating that this nutrient plays a role in photosynthesis of plants under high Al conditions (Wang et al 2015), by maintaining stomatal opening (Ridolfi and Garrec 2000)

Summary

Introduction

Ex Dc.) Mattos., popularly known as ipê roxo, is a secondary tree species distributed in Cerradão and Cerrado strictu sensu landscapes (Scolforo 2008; Salomão and Camilo 2016). It stands out for the aesthetic appeal of its flowers and it is one of the symbols of the Brazilian Cerrado (Lorenzi 2008). Under low pH conditions, aluminum (Al) is solubilized to Al3+ and its high content may turn toxic for plants (Fageria 2001; Siqueira Neto et al 2009; Brunner and Sperisen 2013; Bojórquez-Quintal et al 2017). Aluminum can have either beneficial or toxic effects, depending on a diverse range of factors, including plant species,

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