Leaf and Root Allelopathic Potential of the Vernonanthura brasiliana

H.A Nishimuta,G.F Pena,F.S Rossi,A.A.B Rossi,O.M Yamashita,L.D Giustina,P.H.A.D Santos

doi:10.1590/s0100-83582019370100142

Abstract

ABSTRACT: The Brazilian native weed assa-peixe (Vernonanthura brasiliana) is considered one of the main invasive plant species of pasture areas in the Amazon. It is thus necessary to know their biology and their behavior in the environment, and to enhance the development of management strategies, minimizing the use of herbicides. The objective of this study was to test the allelopathic effect on the germination and growth of the bioindicator species Lactuca sativa from leaf and root extracts obtained from fresh and dry V. brasiliana. The experiment consisted of six treatments with concentrations of 0, 12.5, 25, 50, 100, and 200 mg mL-1, using four replicates per treatment. The evaluated parameters were: germination percentage, first count, germination speed index, and shoot and root length. The aqueous extract of fresh V. brasiliana roots caused an allelopathic effect on all evaluated parameters, while the dry root extract only affected the germination speed index. Root growth inhibition and growth stimulation of lettuce seedlings were verified when submitted to dry and fresh root extracts. Extracts of V. brasiliana caused an allelopathic effect on the species Lactuca sativa L., where the aqueous extracts of dry leaves and fresh roots were the most influential.

Highlights

Vernonanthura brasiliana L., species known as assa-peixe, has become one of the most important weeds of livestock environments in the entire Amazon, and especially in the southern Amazon, which includes southern Pará and northern Mato Grosso
Picloram herbicides are persistent for long periods after their application, resulting in intensive discussions about their use (Franco et al, 2014)
There are no efficient alternative techniques for the management of weeds such as V. brasiliana, and the amount of information regarding these species in the livestock environment is little

Summary

Introduction

Vernonanthura brasiliana L., species known as assa-peixe, has become one of the most important weeds of livestock environments in the entire Amazon, and especially in the southern Amazon, which includes southern Pará and northern Mato Grosso. It has turned production more costly given the use of large volumes of herbicides from the auxin mimics chemical group for their effective control. There are no efficient alternative techniques for the management of weeds such as V. brasiliana, and the amount of information regarding these species in the livestock environment is little Knowledge of their behavior and effective aggressiveness would be relevant to develop management strategies that reduce the intensive use of herbicides, especially those with a prolonged effect on the environment

Objectives

Methods

Results