Submitted to: African Journal of Biotechnology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/9/2009
Publication Date: 4/20/2009
Citation: Sakhanokho, H.F., Kelley, R.Y. 2009. Influence of Salicylic Acid on In Vitro Micropropagation and Salt Tolerance in Two Hibiscus Species, H. acetosella and H. moscheutos (cv ‘Luna Red’). African Journal of Biotechnology 8: 1474-1481. Interpretive Summary: Salicylic acid (SA) is a hormone-like substance which plays an important role in the regulation of plant growth and development. For example, SA is involved in defense mechanisms under both biotic and abiotic stresses, including salinity, which is a major abiotic stress that negatively affects plant growth worldwide. SA has also been reported to improve in vitro micropropagation in some plant species. The objective of this study was to determine whether adding various salicylic acid concentrations to tissue culture media would improve in vitro micropropagation and induce salt tolerance in meristem shoots of two Hibiscus species, Hibiscus moscheutus (cv ‘Luna Red’) and Hibiscus acetosella. The treatments consisted of three salicylic acid concentrations (0, 0.5, and 1 mM) and three salt concentrations (0, 175, and 200 mM). Adding salicylic acid, particularly at the 0.5 mM level, to the tissue culture media improved shoot growth under both saline and non saline environments in both Hibiscus species. Also, this concentration (0.5 mM SA) was more effective in inducing salt tolerance in the two species tested. The results obtained showed that H. moscheutus was more salt tolerant than H. acetosella. They also suggest that the system developed in this study could be used to quickly screen for salt tolerance in Hibiscus or other plant species.
Technical Abstract: Salicylic acid (SA) is a hormone-like substance that plays an important role in the regulation of plant growth and development. It 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, H. moscheutos (cv ‘Luna Red’) and H. acetosella, grown under various salt concentrations (0, 175, and 200 mM) were assessed with respect to shoot growth and multiplication, percentage of root formation, root elongation, survival rate, and proline accumulation. Application of exogenous SA, in particular 0.5 mM SA, 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 SA could be used to improve in vitro regeneration and induce salt tolerance in plants. They also showed that the system developed in this study could be incorporated in a breeding program aimed at a rapid screening and development of salt tolerant Hibiscus cultivars.