Abstract: Osmotic adjustment is an important and effective defence mechanism of salinity resistance in crop plants. The compatibles osmolytes in leaf and root of IR20, POKKALI, IR29 and NERICAI rice varieties were examined under NaCl and Na2SO4 solutions at 0 (control), 5, 10 and 15 ds/m. Leaf proline and lipid peroxidase as well as root protein contents increased with increasing salinity in all the cultivars with the highest values recorded at 15 ds/m except in NERICA1 where there was a significant reduction in leaf proline and lipid peroxidase under Na2SO4 treatment, and IR29 with a significant decrease compared to the control and other treatments under both salts. The highest increase in the parameters obtained at 15 ds/m was generally more under NaCl than Na2SO4 relative to their respective control treatments in all the cultivars. The highest percentage increase in leaf proline was best in IR20 and IR29 under NaCl and Na2SO4 respectively while lipid peroxidase was best in IR20 under both salts. Salinity increased root protein content significantly in plants treated with saline solution except in IR29. The percentage increase was also higher under NaCl than Na2SO4 in IR20 and NERICA1 while the reverse was the case in POKKALI. Root total phenol was significantly reduced by salinity in the plants except in IR20 under NaCl as well as in IR20 and POKKALI under Na2SO4 treatment. The reduction was highest at 15 ds/m, which was more under NaCl than Na2SO4. Root reducing and non-reducing sugars declined under salt treatment. The decrease in reducing sugar was more in POKKALI and IR29 under NaCl as well as in IR20 and NERICA1 under Na2SO4. The non-reducing sugar decrease was however more under Na2SO4 in the plants except IR20. IR20 and NERICA1 showed the highest reduction under NaCl and Na2SO4 respectively. The rice cultivars showed aconsiderable changes in compatible osmolytes in response to salinity stress with variations depending on the cultivar and salt type.
Keywords: adaptation, compatible osmolyte, proline, rice cultivars, salinity.
Title: Osmotic Adjustment: A Defence Mechanism in Four High-Yielding Oryza Sativa L. Genotypes to Salt Stress
Author: Foluso Ologundudu, Otitoloju Kekere
International Journal of Interdisciplinary Research and Innovations
ISSN 2348-1218 (print), ISSN 2348-1226 (online)
Research Publish Journals
