IN VITRO GERMINATION AND EVALUATION OF THE TOXICITY OF DISINFECTING AGENTS IN SEEDLINGS OF BRAÚNA

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Elisa Regina da Silva
Ingridh Medeiros Simões
Julcinara Oliveira Baptista
Kelly Nery Bighi
Milene Miranda Praça Fontes
Edilson Romais Schmildt
José Carlos Lopes
Marcos Vinícius Winckler Caldeira
Rodrigo Sobreira Alexandre

Abstract

The development of tissue cultured-based protocols applied to braúna, an endangeres
species, would be though highly desirable. However, contamination-free explants are
determinant for the success of this technique, which might be vulnerable to the toxicity of
disinfectants. Here, we aimed at establishing an efficient protocol for in vitro production of
axenic seedlings of braúna and to evaluate the toxicity of disinfectant agents in the
Lactuca sativa model species. Experiments I and II: Seeds were treated with sodium hypochlorite
(NaOCl) and fungicide captan, with and without residue, by different immersion times,
respectively. The following were analyzed: contamination; germination and normal and
abnormal seedlings. Experiment III: Lettuce seeds placed in Petri dishes were exposed
to 2.5 mL captan at 0.5; 1; 2; 4 and 8%; 0.01% glyphosate and distilled water. The
germination, length of seedlings, cell cycle, nuclear and chromosomal alterations of the
cells of the root meristem were assesed. The isolated use of NaOCl was not efficient
in the disinfestation of braúna seeds. However, the immersion of the seeds in captan,
for 10 minutes with its residue, led to higher germination and vigor indexes; however,
resulted in the formation of abnormal seedlings. This compound exhibited toxicity in the
lettuce model seeds because affected the germination and the whole development of the
seedlings, showing clastogenic and aneugenic action in the meristematic cell cycle.

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