Effect of Brassinolide on Biochemical Constituents in Rice (Oryza sativa L.) under Salinity Stress

Brassinolide (BL) is a natural plant growth promoting substance that also exert anti-stress effects on plants. Five rice varieties viz., GR-7, GR-11, GR-12, Dandi and Gurjari were treated with 100 mM NaCl , 200 mM NaCl, 4 μM BL, 8 μM BL concentrations with water as control and supplemented solutions of BL with different salinity levels such as 100 mM NaCl+4 μM BL, 100 mM NaCl+8 μM BL, 200 mM NaCl+4 μM BL and 200 mM NaCl+8 μM BL. Salt solutions were supplemented with brassinolide to observe the ameliorating effect of the phytohormone in the rice seedlings under salinity stress. Biochemical constituents such as the seed reserves, stress proteins and mineral ions were affected by NaCl salt stress. Decrease in soluble protein and increase in soluble sugar, free amino acids and proline, Na⁺ ion content and decrease in K⁺ ion content in the rice seedlings with salinity were observed with increasing levels of salt stress. Brassinolide was found to ameliorate the adverse effects of salinity stress and thereby increase the yield of the crop.