The effect of salinity stress alone and with foliar
application with 100 ppm riboflavin (vit. B2) on seedling growth,
organic solutes accumulation, ion uptake and the activity of antioxidant
enzymes in Hibiscussabdariffa L. was investigated. Analysis
of data (ANOVA) revealed that, growth of Hibiscus sabdariffa L.
seedlings was reduced with increasing NaCl concentration, while water
content and dry matter were not changed significantly at the low levels
of salinity. Soluble carbohydrate, protein and proline were found to be
increased significantly. The content of Na+ was significantly
increased, while K+ as well as K+/Na+
and Ca++/Na+ ratios were decreased as salinity levels
increased. Calcium and total cationswere slightly affected.
Foliar application with vit. B2 induced stimulatory effects
on almost measured parameters. On the other hand, Na+ content
decreased significantly. Further, salinity induced marked increases in
lipid peroxidation and the activity of antioxidant enzymes (CAT, POD,
APX and GR), while membrane stability index was significantly decreased.
Spraying of salinized seedlings with vit. B2 induced a marked
increase in MSI and antioxidant enzymes, whereas the content of lipid
peroxidation was decreased in comparing with salinized seedlings. Results
suggest that, vit. B2 may have a potential role as an effective
antioxidant by regulating osmotic and ionic balance and enhancing the
resistance of H. sabdariffa L. seedlings to salinity stress.
M.M. Azooz , 2009. Foliar Application with Riboflavin (Vitamin B2) Enhancing
the Resistance of Hibiscussabdariffa L. (Deep Red Sepals
Variety) to Salinity Stress. Journal of Biological Sciences, 9: 109-118.