Plant antiherbivore defenses in Fabaceae species of the Chaco.

A L B Sartori,T E Lima,M L M Rodrigues

doi:10.1590/1519-6984.12815

Abstract

The establishment and maintenance of plant species in the Chaco, one of the widest continuous areas of forests in the South American with sharp climatic variations, are possibly related to biological features favoring plants with particular defenses. This study assesses the physical and chemical defenses mechanisms against herbivores of vegetative and reproductive organs. Its analyses of 12 species of Fabaceae (Leguminosae) collected in remnants of Brazilian Chaco shows that 75% present structural defense characters and 50% have chemical defense - defense proteins in their seeds, like protease inhibitors and lectins. Physical defenses occur mainly on branches (78% of the species), leaves (67%), and reproductive organs (56%). The most common physical characters are trichomes and thorns, whose color represents a cryptic character since it does not contrast with the other plant structures. Defense proteins occur in different concentrations and molecular weight classes in the seeds of most species. Protease inhibitors are reported for the first time in seeds of: Albizia niopoides, Anadenanthera colubrina, Mimosa glutinosa, Prosopis rubriflora, and Poincianella pluviosa. The occurrence of physical and chemical defenses in members of Fabaceae indicate no associations between defense characters in these plant species of the Chaco.

Highlights

When present in plants, physical and chemical defenses affect the development and survival of their attackers – herbivores (Hanley et al, 2007)
Physical defenses act as barriers to herbivory through rigid protuberances and structures as thorns and/or spines, trichomes, leaf rigidity, formation of minerals - raphides and druses - in vegetal tissues, and seeds protected by hard testae (Dickison, 2000; Valverde et al, 2001)
Chemical defenses against herbivores are characterized by the synthesis of primary metabolites, as defense proteins, and secondary metabolites, as terpenoids and nitrogen-containing and phenolic compounds, resulting from the production of compounds that are essential to plants (Chen, 2008)

Summary

Introduction

Physical and chemical defenses affect the development and survival of their attackers – herbivores (Hanley et al, 2007). Physical defenses act as barriers to herbivory through rigid protuberances and structures as thorns and/or spines, trichomes, leaf rigidity, formation of minerals - raphides and druses - in vegetal tissues, and seeds protected by hard testae (Dickison, 2000; Valverde et al, 2001). Among plant defense proteins are protease inhibitors (PIs) and lectins, which are found in vegetal tissues, mainly in reserve organs, and usually act against insects, bacteria and fungi (Peumans and Van Damme, 1995; Dunaevsky et al, 2005). Lectins and PIs affect the digestive process of insects by reducing the breakdown of the ingested proteins into amino acids (Murdock and Shade, 2002; Macedo et al, 2004; Vandenborre et al, 2011)

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Results

Conclusion