Aspectos fisiológicos da toxidez de ácidos orgânicos em sementes de aveia

Abstract

Physiological aspects of toxicity of organic acids to oat seeds. For the cultivation of oats (Avena sativa L.) as an alternative which is economically viable in fl ooded soils, it is necessary to use cultivars that are tolerant to the main organic acids produced by the decomposition of the organic matter generated when cultivating
areas by direct seeding. The objective of this work was to determine the concentration rates and physiological stimuli necessary for use in the cultivar UPF 16 for tolerance to organic acids. We studied the effects of fi ve concentrations of the three main acids formed in the soil: acetic acid (0, 4, 8, 12 and 16mM), propionic acid (0, 4, 8, 12 and 16mM) and butyric acid (0, 2, 4, 8 and 12mM). The tests used for evaluation were: standard germination, length of the aerial part, length of the root, dried mass of the aerial part and dried mass of the root. According to the results it was verifi ed that the variable length of the root was the most responsive in all the acids and that the critical levels of toxicity of the acetic acid, propionic acid and butyric acid, that reduced 50%
of the length of the root, were 9.0, 6.5 and 3.0mM, respectively.