ORGANIC ACIDS TOXICITY ON LOWLAND RICE CROP GENOTYPES

Abstract

The soils flooded for lowland rice crop promote anaerobiosis conditions and low molecular weight organic aliphatic acids are produced and affect the rice crop by toxicity. This study was carried out to evaluate the organic acids effects in nutrient solution on lowland rice crop genotypes root and shoot growth recommended in Rio Grande do Sul State. The study was developed under controlled conditions (growth chamber) in the Plant Nutrition Laboratory at UFPel/FAEM/DS. A factorial statistical design 4x3 with 4 replicates was used. The following organic acids treatments were tested: zero; acetic acid 5.0 mmol dm^-3; propionic acid 1.25 mmol dm^-3; and butyric acid 1.0 mmol dm^-3. Rice seedlings of genotypes EMBRAPA BRS-7 TAIM, IRGA 417 and EMBRAPA BRS PELOTA with 3 cm of root growth were put inside test tubes for 13 days with complete nutrient solution and organic acids. The effect of the organic acids was bigger in roots that those rice shoot; the PELOTA genotype was superior to that those genotypes in presence of organic acids, mainly butyric acid; the genotypes did not differed among them.