Effects of ascorbic acid on quantitative and qualitative characteristics of two Alternanthera repens genotypes (

In order to study the effects of ascorbic acid as an important antioxidant reducing salinity damage, an experiment was conducted on two Althernantera genotypes (“Entire leaf” and “Undulated leaf”) at research greenhouse of Shahid Chamran University in 2013. Concentrations of 0, 0.5 and 1 mM of Ascorbic acid were sprayed weekly on plants grown under 0, 30, 60, 90 mM NaCl. The experiment was carried out factorially based on a randomized complete block design with four replications. Plants were grown hydroponically using Hoagland’s solution.Salinity significantly affected all morphological (plant height, plant diameter and leaf area), physiological (electrolyte leakage, relative water content, fresh and dry weight) and biochemical (chlorophyll, proline and anthocyanin content) characteristics. StemLength in “Entire leaf” genotypereached from 100% to 28% and “Undulate leaf” genotype from reached 100% to 50%. Application of ascorbic acid decreased electrolyte leakage in plants treated with high NaCl concentrations. The lowest electrolyte leakage and the highest chlorophyll content were found in plants treated without NaCl (control) and 0.5 mM ascorbic acid. The highest leaf relative water content was found in control plants treated with 1 mM ascorbic acid. The highest proline content was found in plants treated with 90 mM NaCl and 1 mM ascorbic acid. The highest anthocyanin content was found in plants treated with 90 mM NaCl and 0 mM ascorbic acid. The results showed that Alternanthera is relatively resistant to salinity. “Entire leaf” cultivar was more resistant than “Undulate leaf” genotype. According to the results, ascorbic acid could increase salinity resistance.