&lt;b&gt;Nutrient retranslocation in forest species in the Brazilian Amazon

Murilo Rezende Machado,Marcos Gervasio Pereira,João Ferraz,Paulo De Tarso Barbosa Sampaio,Rodrigo Camara

doi:10.4025/actasciagron.v38i1.26805

Abstract

Internal retranslocation is an important mechanism for nutrient conservation in plants, which depends on different factors. However, there are little data about this subject, especially on tropical forest species. This study aimed to evaluate the macronutrient retranslocation dynamic and the influence of ecological (P: pioneer x NP: non-pioneer) and phenological (ND: non-deciduous x D: semideciduous / deciduous) characteristics on the macronutrient content of leaves of five tree species on monospecific plantations in the Brazilian Amazon: Acacia mangium Willd., Parkia decussata Ducke, Dipteryx odorata (Aublet) Willd., Jacaranda copaia (Aubl.) D. Don and Swietenia macrophylla King. Photosynthetically active green leaves and senescent leaves (leaf litter) were collected. Retranslocation was estimated through an equation proposed by Attiwill, Guthrie and Leuning (1978). The pioneer species presented higher foliar contents of N; the non-pioneer species presented higher contents of K, Ca and S; and the results were inconclusive for P and Mg. The deciduous species presented higher foliar contents of K and of P, whereas the foliar contents of N, Ca, Mg and S were virtually identical between the phenological groups. The internal retranslocation of foliar nutrients in pioneer and non-deciduous species was higher than that of non-pioneer and deciduous species.

Highlights

Nutrients are monitored in forest plantations to identify and correct imbalances by means of plant tissue analysis
This study aimed to evaluate the influence of ecological and phenological groups on macronutrient foliar content and retranslocation in five tree species in monospecific plantations in the Brazilian Amazon: the exotic Acacia mangium Willd and the native species Parkia decussata Ducke, Dipteryx odorata (Aublet) Willd., Jacaranda copaia (Aubl.) D
There were small variations regarding the P and Mg contents in the green leaves (GL) among the forest species (0.90-1.00 and 1.382.05 g kg-1, respectively) (Table 1). This may be because there were no significant differences among the monospecific plantations in relation to the P and Mg availability in the soil (Table 3) as the foliar nutrient content may reflect the nutrient availability in the soil solutions (Aerts, 1996)

Summary

Introduction

Nutrients are monitored in forest plantations to identify and correct imbalances by means of plant tissue analysis. Agronomy plants (N, P, K and Mg) are internally redistributed from senescent leaves before their abscission to growing regions such as new leaves (Bambi, Lobo, Dalmolin, & Dias, 2011; Almeida et al, 2014). This internal retranslocation process is especially important because it conserves approximately 60 to 85% of the total content of the nutrients absorbed when the soil availability of the nutrient is low (Malavolta, 2006). Information on this process may contribute to a better understanding of the nutrient conservation strategy in plants and the adaptation of Maringá, v. 38, n. 1, p. 93-101, Jan.-Mar., 2016 certain species to low-fertility soils (Magalhães & Blum, 1999)

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