MORPHOLOGICAL AND PHYSIOLOGICAL CHANGES ON Schizolobium parahyba VAR. Amazonicum (HUBER EX DUCKE) BARNEBY PLANTS INTOXICATED BY GLYPHOSATE

Kaléo Dias Pereira,Jonilson Ribeiro Trindade,Rafael Gomes Viana,Rafael Amaral Cardoso

doi:10.1590/01047760201723022316

Kaléo Dias Pereira, Jonilson Ribeiro Trindade + Show 2 more

Open Access

https://doi.org/10.1590/01047760201723022316

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Abstract

ABSTRACT The objective of this study was to evaluate the morphological and physiological changes in paricá plants (Schizolobium parahyba var. amazonicum) intoxicated by glyphosate. The experiment was conducted in a protected environment using paricá plants during their planting stage, which were intoxicated with increasing doses of glyphosate: 0 (control); 43.2; 86.2; 129.6 and 172.8 g.ha-1. At 7 and 21 days after the application of the herbicide, the photosynthesis, transpiration, stomatal conductance and leaf temperature were measured. The visual intoxication degree and the growth of the shoot and the root of the plants were evaluated 21 days after the application. Paricá shows symptoms of visual intoxication characterized by chlorosis/winding, evolving to necrosis/abscission of the youngest leaflets. The growth of the stem and the roots of the intoxicated plants is preserved; however, an expressive leaf loss occurs, and paricá may have adaptation mechanisms to tolerate the action of the herbicide molecule. The photosynthesis decrease promoted by an indirect action of glyphosate represents the main reduction on the growth of plants. The decrease on the stomatal conductance, which was the most sensitive physiological variable to glyphosate, resulted in lower transpiration rates, which, consequently, caused increases on the leaf temperature.

Highlights

In 2012, the Brazilian government presented the final version of the Low Carbon Agricultural Plan – ABC Plan, which, among other goals, established the commitment of expanding the planted forest areas to 9 million hectares until 2020 (MAPA/MDA, 2011)
No records of the effect of glyphosate on paricá were found, the symptoms observed on this study are similar to the ones observed on eucalyptus by Tuffi Santos et al (2009), with the difference that the symptoms on paricá were more evident for the dose of 172.8 g.ha-1 of glyphosate
The visual intoxication observed 21 days after the application of glyphosate reached its maximum degree at a dose of 172.8 g.ha-1 of a.i. on acid equivalent, causing 43% of leaf damages (Figure 1A)

Summary

Introduction

In 2012, the Brazilian government presented the final version of the Low Carbon Agricultural Plan – ABC Plan, which, among other goals, established the commitment of expanding the planted forest areas to 9 million hectares until 2020 (MAPA/MDA, 2011). The growing interest for paricá is due to its quick growth It may reach a productivity of 38 m3.ha-1.year-1 (CARVALHO, 2007) even with no improvement degree; it is one of the few native species that may catch up with the productivity of eucalyptus. Another determining factor, according to Marques et al (2006), is the increase on the demand for wood to produce laminates and plywood, a context in which paricá is inserted (ROSA, 2006a)

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