Rajesh Tandon
Department of Botany, University of Delhi, Delhi-110007
Rajesh Tandonis presently working as Professor at the Department of Botany, University of Delhi. He obtained his Ph.D. in 1998 from the University of Delhi. He has been teaching and conducting research at the Institute for over 18 years, and so far has supervised 15 Ph.D. scholars for the doctoral degree and five for the M.Phil. His research group has been actively involved in generating crucial database on the reproductive biology of many plant species for their further application in germplasm conservation and sustainable utilization. His work has demonstrated that many of these species are self-incompatible, and exhibit obligate reliance on pollinators, be it birds, bats, honeybees, flies and even squirrels and snails. His findings on the reproductive biology of threatened tree species, the Indian Podostemaceae, cryopreservation of pollen, pollination ecology, plant-pollinator-robber interaction, are among the frequently cited authentic works worldwide. He has published over 55 manuscripts in reputed International and National journals, and contributed chapters to several books. He has participated, delivered invited lectures in several National and International conferences, and served as resource person for workshops on plant reproductive biology. He is a co-author of a practical manual entitled Reproductive Ecology of Flowering Plants: A Manual (Springer, 2014) and the lead editor of a recent book - Reproductive Ecology of Flowering Plants: Patterns and Processes (Springer, 2020). He was awarded Dr Y. S. Murthy Young Scientist Medal (2008), and VishwambharPuri Medal (2020) by the Indian Botanical Society. (Detailed Information: http://www.du.ac.in/du/uploads/Faculty%20Profiles/Botany/Botany_Rajesh_Tandon.pdf)
Symposium Lecture
REPRODUCTIVE BIOLOGY OF HIMALAYAN SEABUCKTHORN
Himalayan Seabuckthorn (Hippophae rhamnoides) is an intriguing high altitude wild plant species of immense agronomic importance. The plant is prized for highly nutritious berry-like fruits that are used for making a variety of nutraceutical and medicinal products. At present, fruits are exclusively sourced from the wild, and commercial plantations of this predominantly dioecious species are yet to be established. Our over a decade-long ongoingstudies in Leh-Ladakh region and adjoining valleys have generated hitherto unknown information on several reproductive attributes which would be useful in organising the orchards of this species. Besides, some recent findings on the sexuality of plants suggest that the species can serve as a promising model system to investigate evolutionary dynamics of dioecy. Our studies have shown that Seabuckthornis a genetically diverse species. The species is subdioecious, as the populations are comprised of male, female and polygamomonoecious plants.Such populations of mixed sexuality are considered to represent an evolutionary intermediate state between cosexuality and dioecy.Assessment of inter-morph crosses, resource allocation pattern to the essential organs and the gender ratio indicates that subdioecyhas most likely emerged via monoecious pathway in the species.Flowers are non-showy, non-rewarding, reduced, and attuned for pollinationexclusively by wind. The pollen tube pathway incorporates elements of both completely externalized as well as internalized compitum. Controlled pollinationsestablished that the species is a facultative apomict; the embryo may either develop by sexual or adventitious pathways. The entire seed is surrounded by fleshy perianth and fruit, a pseudo-drupe, represents the diaspore unit; dispersal usually occurs by water streams. We have identified a couple of reliable gender-specific by employing AFLP and RDA markers, which would be helpful in early recognition of males while establishing the orchards.In silico analysis of one of the gender-specific loci showed accumulation of satellite sequences and transposons, indicating their degenerate nature. Also, there is high level of similarity between male and female genomes, which possibly suggests a recent evolutionary divergence of genders in the species.