Abstract

Salicylic acid (SA) has been reported to improve in vitro regeneration as well as induce abiotic stress tolerance in plants. The effects of varying SA concentrations (0, 0.5, and 1 mM) on in vitro shoot apices of two Hibiscus species, Hibiscus moscheutos (cv ‘Luna Red’) and Hibiscus acetosella, grown under various salt (NaCl) concentrations (0, 175, and 200 mM) were assessed for shoot growth and multiplication, root formation, root elongation, plant survival rate, and proline accumulation. Application of exogenous SA, at 0.5 mM had a beneficial effect on all these parameters in both species under saline and non-saline conditions.  Results obtained showed that H. moscheutos was more salt tolerant than H. acetosella and that SA could be used to improve in vitro regeneration and salt tolerance in these two species. Furthermore, the in vitro regeneration and screening system developed here could be incorporated in a breeding program for a rapid initial screening, further evaluation, and eventual development of salt tolerant Hibiscusplants.

Key words: Hibiscus, in vitro, salt tolerance, salicylic acid.