Morphofunctional Diversity of Diaspores of Some Range Grasses of Punjab (India)

Grasslands occupy almost half of the terrestrial expanse of India ranging from coastal to alpine regions. Whyte (1958) defined ‘grassland as the land on which graminaceous species represent the dominance if not the exclusive vegetation’. Grasslands comprise the main source of fodder for the 500 million cattle population in the country besides providing habitat to several plant and animal species. But the grasslands are shrinking due to the pressure of intensive agriculture and urbanization not only in expanse but also in their biodiversity. In this context there is an urgent need to develop not only a policy towards a sustainable utilization of grassland resources but also to devise strategies to replenish and refurbish their productivity and biodiversity. Grasses have an unmatched ecological significance as well. They occur in nearly all the terrestrial ecosystems and habitats of the world and provide cover to nearly a fifth of the land surface. Taxonomic diversification and geographic diversification occurred during the Eocene in several phases beginning with the crown node of bambusoid grasses (53mya) and continuing with the pooid (47-38 mya), chloridoid (35-25mya) and panicoid (26mya) groups (Kellogg, 2001). With their origin in the southern land masses, grasses are believed to have spread to Eurasia via the Indian land mass

Reproductive biology of Withania ashwagandha sp. novo (Solanaceae)

Withania ashwagandha Kaul (Solanaceae) is an annual plant species of immense medicinal importance. It is a repository of a large number of pharmacologically active secondary metabolites known as withanolides. Evidence for the delimitation of the species from W. somnifera has been provided by our group using multidisciplinary approaches. Knowledge of reproductive biology of medicinal plants is crucial for improvement, effective conservation and management plans to evolve genetically superior varieties. The present paper reports our findings on the floral biology, pollination behavior and breeding system of W. ashwagandha in natural populations grown at our experimental field under near natural conditions. Flowering (peak) takes place during April–July and anthesis occurs between 08:00 and 11:00 h. The period of stigma receptivity coincides with anther dehiscence. Fruit set on pollination treatments ranged from 90.8% (passive autogamy), 72% (assisted autogamy), 30.30% (xenogamy), and 56.50% (geitonogamy) through 50.40% (open pollination). Xenogamy brings about very low fruit set, seed-set and seed germination percentages. It is inferred that W. ashwagandha is predominantly an autogamous and self-compatible species. Self-compatibility is mainly accomplished due to close proximity of stigma and anthers. This work is the first report on the reproductive biology of W. ashwagandha and will be useful for conservation and development of improved varieties of this multipurpose herb.The author acknowledge the University of Pretoria for providing Vice-Chancellors Post Doctoral Fellowship.http://www.elsevier.com/locate/indcrophb201

Intraspecific variation in the internal transcribed spacer (ITS) regions of rDNA in <i style="">Withania somnifera</i> (Linn.) Dunal

325-328Intraspecific variation in ITS regions of the rDNA among the five wild and five cultivated genotypes of Withania somnifera, were evaluated at nucleotide sequence level using restriction fragment length polymorphism (RFLP). The entire internal transcribed spacer (ITS1-5.8S-ITS2) region was first amplified by PCR and then cleaved with four different restriction enzymes (EcoRV, Hinf I, Afa I &amp; Hae III). Restriction endonuclease digests, types, and sequence length composition of ITS 1 and ITS 2 of nuclear ribosomal DNA provided discrete differences between the cultivated and wild genotypes. A 710 bp single amplified product was obtained in all the five wild genotypes whereas, two ITS bands named as ITS type A and B of 709 bp and 552 bp, respectively were obtained in the five cultivated genotypes. A single deletion at 672 position was noted in ITS type A of cultivated genotypes. There was no restriction site in 552 bp ITS band for all the four restriction enzymes used. The variation of ITS at amplification as well as digestion level is in conformity with morphological and phytochemical differences in W. somnifera genotypes