Impact of crude oil and waste water pollution on genetic diversity of Limoniastrum monopetalum (L.) Boiss. (Plumbaginaceae) populations

Résumé En

Limoniastrum monopetalum (L.) Boiss. populations growing in oil and waste water polluted sites were examined for the possible impact of pollution on their genetic diversity. Morphological features and RAPD analysis were assessed to evaluate the genetic diversity. Non-parametric (Kruskal-Wallis) test of morphological characters between groups (polluted and unpolluted) revealed that all characters were significantly different between groups except two characters. The morphological characters between polluted and unpolluted populations were significantly variable regardless of the pollution source. Plants growing in the polluted sites were physically larger than that of the unpolluted sites. Moreover, the number of flowers per spikelets of the polluted populations reached up to four, although the recorded number for this species is two flowers per spikelets. DNA markers (RAPD) analysis showed that out of fourteen random primers, four gave reproducible amplification. Banding patterns of 35 polymorphic bands out of 37 bands scored accounting for 94.59% polymorphism across the investigated populations. UPGMA clustering analysis based on morphological characters and RAPD markers separated the studied populations into two distinct clusters. The first cluster comprises all polluted populations while the second included unpolluted ones. The evaluation of genetic diversity parameters revealed that there is a slight difference between group populations, unpolluted and polluted in these parameters. The collected data supports the hypothesis that the new form of L. monopetalum with 4 flowers per spikelet, growing in the polluted sites, is possibly an ecotype adapted to pollution.