Regulation of sugar metabolism in rice (Oryza sativa L.) seedlings under arsenate toxicity and its improvement by phosphate

The effect of arsenate with or without phosphate on the growth and sugar metabolism in rice seedlings cv. MTU 1010 was studied. Arsenate was found to be more toxic for root growth than shoot growth and water content of the seedlings gradually decreased with increasing concentrations. Arsenate exposure at 20 μM and 100 μM resulted in an increase in reducing sugar content and decrease in non-reducing sugar content. There was a small increase in starch content, the activity of starch phosphorylase was increased but α-amylase activity was found to be decreased. Arsenate toxicity also affected the activities of different carbohydrate metabolizing enzymes. The activities of sucrose degrading enzymes viz., acid invertase and sucrose synthase were increased whereas, the activity of sucrose synthesizing enzyme, viz. sucrose phosphate synthase declined. The combined application of arsenate with phosphate exhibited significant alterations of all the parameters tested under the purview of arsenate treatment alone which was congenial to better growth and efficient sugar metabolism in rice seedlings. Thus, the use of phosphorus enriched fertilizers may serve to ensure the production of healthy rice plants in arsenic contaminated soils.     

Problems and perspectives of palaeoanthropology in India

In recent years the importance and meaning of palaeoanthropology have gained a sharper focus. The scope of palaeoanthropological research in India is promising, and this is perhaps one of the few ideal places where the whole spectrum of the study of this discipline can be set forth, both in biological and cultural aspects. The present paper takes it to span the period from the beginning of the process of human evolution during the late Tertiary period to the surviving primitive communities. The relevant biological data in the form of fossil remains have been found only for the earliest stage, pre-Pleistocene. Afterwards, up to the end of the Pleistocene, there is no positive evidence of human skeletal remains, which are obtained only from post-Pleistocene onwards. In this subcontinent, the emphasis for a significant stretch of the human evolutionary process is thus almost exclusively on the cultural traits which, however, play a dominant role. An attempt has been made to suggest a tentative frame-work of bio-cultural evolution in India. In this context, reference has been made also to the relevance of studying the primitive communities of the recent period.     

Pollen Morphology of Indian Species of Saraca L. (Leguminosae)-A Threatened and Legendary Medicinal Tree

The genus Saraca L. (Leguminosae) is a universal panacea in herbal medicine. The present study investigates the comparative pollen morphology of four species of Saraca viz. S. asoca (Roxb.) de Wilde, S. declinata (Jack) Miq., S. indica L., and S. thaipingensis Cantley ex Prain growing in India to reveal differences of their pollen structures to aid taxonomic and evolutionary values. The detailed morphology and surface structure of pollen grains were studied and described using light microscopy and scanning electron microscopy. The pollen grains of Saraca showed isopolar, para-syncolporate, tricolporate, with radially symmetric, prolate and prolate-spheroidal structure. The surface of pollen of S. indica is rugulate with large lirae but in S. declinata, the surface is micro-rugulate to vermiculate with relatively thin lirae and that of S. thaipingensis is indistinct as the psilate surface with a frequent protuberance and fewer perforations were observed along with the gemmae like structure. Exine ornamentation helped to separate S. indica and S. asoca. Exine thickness varies from 3-4 μm. Presence of protuberance and exine thickness varies among individuals of the species spread over different locations. Present work also provides a unique palynological identity and interrelationship of these four species based on cluster analysis taking 23 pollen characters with the help of statistical method like the plotting of ternary graph. Ternary plots also helped to calculate the level of plasticity of each character in the intra- and inter-specific level.     

Influence of arsenate imposition on modulation of antioxidative defense network and its implication on thiol metabolism in some contrasting rice (Oryza sativa L.) cultivars

BioMetals - Globally, many people have been suffering from arsenic poisoning. Arsenate (AsV) exposure to twelve rice cultivars caused growth retardation, triggered production of As-chelatin...