Efeito do condicionamento fisiológico em arroz sob condição de estresse por frio

Abstract

The rice (Oryza sativa L.) is considered one of the most important cereals of the globe, being cultivated and consumed on every continent. In Brazil, the culture corresponds to 20% of grain production, 60% of this production is concentrated in the state of Rio Grande do Sul, the largest producer of rice in the country. Countless times, however, the yields of culture in the state are hampered by damage caused by abiotic stresses and the stress caused by low temperatures one of the most damaging environmental factors to plant rice. The priming is a technique that can reduce the negative effects of environmental stresses on plant development. Therefore, this study aimed to evaluate the effect of priming in the phenotyping of rice genotypes, tolerance to cold. The work was developed in the Laboratory of Biotechnology, Federal University of Pampa, Campus - Itaqui. Rice genotypes (IRGA 424, IRGA 426, BRS Sinuelo, Guri and Diamond BRS), divided into two different seed lots, one underwent priming and drying and the other did not undergo any procedure - five were used. Both batches were exposed to low temperature (12 ° C ± 1 ° C) for 0, 24, 48 and 72 hours and were then immediately transferred to another chamber where germination at 25 ° C until they were 14 days of incubation. Variables coleoptile length, length of aerial part, root length, dry weight of shoot and root dry matter were evaluated. The results showed that a reduction of the average variable according to increasing time of exposure to low temperature, however, the seeds subjected to priming treatment medium showed better when compared to seeds that have not passed through conditioning. We conclude that priming increases CC, CPA, CR, and MSR MSPA all genotypes, except for CC and BRS Sinuelo CPA and genotype CC for Guri. The cold stress causes reduction in the variables analyzed. The genotypes that have better response to conditioning under stress condition by cold are the IRGA 424 and IRGA 426.