Allelopathic effects of leachates of Lumnitzera littorea fruits on germination, seedling growth and antioxidant enzymes of native mangrove species Sonneratia caseolaris

We evaluated the allelopathic effects of Lumnitzera littorea fruits leachates (0.1 g/ml, 0.2g/ml, 0.4 g/ml) on the seed germination, seedling growth and antioxidant enzymes of Sonneratia caseolaris. The fruit extract leachates of L. littorea at 0.4 g/ml concentration reduced the seed germination index, seedlings hypocotyl and root length of S. caseolaris. These fruits leachates increased the activities of superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX) in S. caseolaris seedlings. Peroxidase (POD) in S. caseolaris was improved at the lower leachate concentrations than control but was inhibited at highest concentration (0.4 g/mL) of L. littorea fruit leachates. The MDA contents increased with the increasing leachate concentrations, while, the proline content decreased at the lower concentrations but increased at higher concentrations. The GC-MS analysis of L. littorea fruits leachate extracted in ethyl ether revealed that allelopathic Methyl hexadecanoate and tetratriacontane were found in the highest concentration. Our findings indicated that allelochemicals in the L. littorea fruits may inhibit the seed germination and growth of S. caseolaris.