Deciphering Genetic Diversity in Spathodea campanulata Beauv. from South India Based On Randomly Amplified Polymorphic DNA Markers

The African tulip (Spathodea campanulata) is a monophyletic species native to tropical forests of sub-Saharan Africa belonging to family Bignoniaceae. Although its endemism in sub-Saharan Africa, it is listed as potential alien invasive species in Pacific, Indian and Caribbean, but also Singapore, Papua New Guinea and Australia. The expansion of its range from ornamental to invasive is being observed in South India. In this study, RAPD based DNA markers have been used to determine genetic diversity of the monophyletic species. About 14 populations were studied from 6 states of South India using 41 random decamer primers. The total number of 517 bands were scored which are generated by 41 primers producing 12.6 bands on an average per primer, of these 517 bands produced 379 were polymorphic showing 73% polymorphism revealing higher level of genetic polymorphism in the study population. The similarity coefficient ranged from 0.312 to 0.837 and the dendrogram constructed by the UPGMA based on Jaccard\u27s similarity matrix farmed two clusters. In the present study, results showed the high degree of genetic diversity within the populations of S. campanulata supporting high degree of adaptation and its range expansion from ornamental to possible invasive species in South India

Effect of biologically treated petroleum sludge on seed germination and seedling growth of Vigna unguiculata (L.) Walp. (Fabaceae)

The present investigation was carried out to study the response of different concentrations of treated petroleum sludge on seed germination, root and shoot length and tolerance of Vigna unguiculata (L.) Walp. The biologically treated petroleum sludge with bacterial consortium showed 54.8% reduction in total petroleum hydrocarbons. Treated sludge was utilized with agricultural soil in known concentration for the assessment of growth of V. unguiculata. A remarkable absence of seed germination was observed at higher sludge concentration. The different concentrations of treated petroleum sludge showed severe decline on the length, weight and vigour index of the tested seedlings with increasing sludge concentrations. The results showed that the difference in rate of seed germination was significant among various concentrations. Under environmental stress condition, germination is the most critical phase of life cycle in crop plants. In this present study, the high oil content found to alter the osmotic relation between seed and water and thus reduce the amount of water absorbed. It was concluded that the concentration of nutrients and oil present in the treated sludge were toxic to the plant