Spirostanic analogues of brassinosteroids enhance the rice (Oryza sativa L.) seedling growth under NaCl stress

Abstract

Spirostanic analogues of brassinosteroids are synthesized, compounds in Cuba and some of their formulations have demonstrated to enhance the growth when plants grow under saline stress. Recently, a new analogue (Biobras-25) which should have a good biological activity has been synthesized. For this reason, the objective of this paper was to evaluate rice seedling growth under NaCl stress by fourteen days, when the seeds were treated with Biobras-25 or Biobras-16. Two experiments were performed, in the first one, rice seeds of cv. INCA-17 were soaked in BB-25 or BB-16 solutions (0; 0,005; 0,05 y 0,5 mg L-1) and after germination, they were placed in pots which contained Hoagland nutritive solution with the addition or not of NaCl 0,1 mol L-1 and remained during fourteen days in a growth room. At the end of the experiment, root and shoot length and dry mass were evaluated to 25 plants by treatment. Later, a second experiment was performed with the best concentrations of both formulations and, also, the growth indicators described above,  leaf proline, a, b and total chlorophylls and total carotenes were determined. Results showed that both analogues exhibited a distinct behavior. Biobras-25 not only enhanced significantly seedling growth under NaCl stress but also increased significantly pigment concentration and decreased the proline content in leaves.