Efeitos salinos no crescimento e desenvolvimento do arroz; alterações fisiológicas

The effects of NaCI on vegetative growth of rice ( Oryza sativa L.) cultivar IAC 25 plants, were studied in greenhouse at the Centro de Ciencias Agrarias of the Universidade Federal do Ceara, Fortaleza, CE, Brazil Rice plants were grown in osmotic potentials of 0.0, - 0.4, - 0.8, and - 1.2 MPa of NaCl. The total dry matter yield, shoot dry matter yield, root shoot ratio, root length and volume, number of tillers per plant and transpiration/plant/day were studied. Plant growth was significantly affected and significant reductions were observed in shoots by increasing salt concentration. Root length and volume were significantly reduced with increasing NaCl concentration in nutrient solution. Although being a genetic characteristic, the number of tillers/plant was significantly reduced with the increase of NaCl concentration. The increase in salinity reduced the volume of water tanspirated, especially in the treatments with osmotic potential of - 0.4 MPa. Salinization of the growth medium resulted in early senescence of rice plants.