Morpho-anatomical changes in leaves that present brown spots on Gaylussacia brasiliensis

Abstract

Pathogens trigger biochemical changes in the host plant, triggering defense responses. Responses to the actions of pathogens may include the biosynthesis of salicylic acid, induction of ethylene biosynthesis, increased cell wall lignification, to produce various antimicrobial compounds and a way to rapid cell death, called the hypersensitive response. The objective was to perform a comparative analysis between morphological and anatomical Gaylussacia brasiliensis leaves with and without brown spots. The leaves were cut free hand in cross sections, longitudinal and paradermic. Sections were diaphanized solution of sodium hypochlorite to 20%, left for five minutes in acetic acid to 5% and stained for 10 seconds in a mixture of astra blue and safranin (3:1). In leaves with patches of sclerenchyma, fibers were formed by deposition of lignin in the region of spongy parenchyma, and there was no other kind of modification of the structures in relation to the pattern observed in the leaves that had not stain. These spots would result in a possible response to pathogens, promoting lignification of spongy parenchyma cells surrounding the invading agent and the formation of sclerenchyma in the region.