ALLELOPATHIC ACTIVITY OF Amburana cearensis SEED EXTRACTS ON MELON EMERGENCE

Andreya Kalyana De Oliveira,Maria De Fatima Barbosa Coelho,Francisco Esio Porto Diógenes

doi:10.1590/1983-21252020v33n130rc

Andreya Kalyana De Oliveira, Maria De Fatima Barbosa Coelho + Show 1 more

Open Access

https://doi.org/10.1590/1983-21252020v33n130rc

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Abstract

ABSTRACT Amburana cearensis is a species rich in coumarin, a phenolic compound that is a natural inhibitor of the germination process. In Caatinga, this species occurs in areas where melons are cultivated, and even after deforestation, they may be present in the soil seed bank. The aim of this study was to investigate the allelopathic activity of A. cearensis aqueous seed extract fractions on the emergence of melons and to carry out photochemical analyses of the extracts. Four experiments were carried out based on the fractionation of the seed extract: E1 - hexane fraction, E2 - dichloromethane fraction, E3 - ethyl acetate fraction, and E4 - aqueous fraction. The statistical design was completely randomized, with four replicates, each having 20 seeds. The treatments were composed of different extract concentrations (1, 0.5, 0.25, 0.125, and 0%) and phytochemical prospecting of the extracts obtained during fractionation was performed. The extracts obtained from the hexane fraction affected the emergence and initial development of melon seedlings. The dichloromethane, ethyl acetate, and aqueous extracts had negative effects on the formation of dry matter, shoots, and roots, with the highest concentrations prompting the most negative effects. Coumarin was present in all extracts, but its concentration was highest in the hexane fraction, which was consequently characterized as highly phytotoxic during the bioassays.

Highlights

A. cearensis is rich in coumarin, a phenolic compound that inhibits the germination process
The osmotic potential and pH of the different concentrations of hexane, dichloromethane, ethyl acetate, and the aqueous fractions of A. cearensis crude seed extracts, were within the normal ranges; these factors were unlikely to be responsible for the possible changes in melon germination (Table 1)
The evaluation of pH and osmotic potential of of leaves and branches of C. martii and C. reticulata the plant extracts is fundamental, as extreme values had high potential to inhibit seed germination. of both can act on the seeds/seedlings and mask the Malheiros et al (2014) found that ethanolic extracts allelopathic effect (TAIZ et al 2017)

Summary

Introduction

The presence of coumarin in the integument is responsible for controlling the oxygen intake inside the seed, as it is able to fix the O2 absorbed by the seeds, preventing its accumulation into the seeds (FELIX, 2007). Compounds such as coumarin are called allelochemicals and are involved in a process called allelopathy, which is a biochemical interaction between certain plants and microorganisms. These direct or indirect interactions are harmful or beneficial, and chemicals are released into the medium (RICE, 1984)

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