Effects of cadmium chloride on oxygen consumption and gill morphology of Indian flying barb, Esomus danricus.

Effects of three sub lethal concentrations of cadmium chloride (0.636, 0.063 and 0.006 mg l-1) on oxygen consumption and gill morphology in Indian flying barb, Esomus danricus (Hamilton-Buchanan), a teleost fish, were studied. When compared to control, 0.636 mg l-1 of cadmium chloride after 7, 14, 21 and 28 day exposure showed a significant decline in rates of oxygen consumption at 32.98, 28.40, 23.88 and 21.69 ml hr-1 100g-1 of tissue, respectively; while, 0.063 mg l-1 of cadmium chloride for the same exposure durations showed a significant decline in rates of oxygen consumption at 34.28, 29.30, 28.05 and 26.47 ml hr-1 100g-1 of tissue, respectively. However, significant decline in the rate of oxygen consumption at 0.006 mg l-1 of cadmium chloride could be observed from 21st day of exposure. Gill tissue showed various histopathological changes including epithelial lifting, hyperplasia, mucous secretion, marked leucocyte infiltration in the epithelium after 28 days of cadmium chloride exposure.

Ethical and Policy Concerns pertaining to Rice Landraces in Asia.

Abstract: Domestication of rice (Oryza sativa L.) from the wild species O. rufipogon and O. nivara by Neolithic Asian farmers more than 10,000 years ago represents one of the most important events in human history, as this crop is the major staple food of over one-third of the world’s population, meeting around 20 % of the global calorie intake. The Asian rice, O. sativa, which is grown worldwide, has three major “variety groups” or subspecies: indica varieties of the Indian subcontinent; tropical japonica or javanica varieties very common in southeast Asia and southern China; and temperate japonica varieties predominantly cultivated in northeastern Asia. Furthermore, cultivation and farmer selection over a long period of time have given rise to over 120,000 varieties or farmer’s landraces of rice. These include glutinous and non-glutinous landraces, aromatic landraces; those taking different times to mature; with different levels of tolerance to abiotic stresses like cold, drought, submergence and salinity; and even differing in their resistance to pests and diseases. However, a few hundred “high-yielding” “improved” varieties have largely replaced these traditional landraces, with the latter finding their place of preservation in the rice germplasm banks. While it is true that various genes of the traditional landraces have been incorporated into many modern varieties, questions arise as to the ethical propriety of banishing ‘live’ and ‘flourishing’ life forms that are also integrally linked to the culture of many communities, to a ‘synthetic, and overtly utilitarian existence. The present paper aims to discuss these issues in the light of ethical principles as well as policies pertaining to traditional knowledge and practices.

Euglenoid blooms in the floodplain wetlands of Barak Valley, Assam, North eastern India.

Red blooms of Euglena sp. in the floodplain wetland ecosystems of Barak Valley, Assam, India, were found to be induced by high concentrations of NH3-N, NO3, Fe, Mg and to some extent, PO4, Cu and Zn in their water. The trace elements were rapidly accumulated by the bloom organisms to high levels, whereby their concentrations in the water declined, leading to a collapse of the bloom, which tended to reappear as decomposition again led to the release of the nutrients. The bloom also harboured fairly high density of certain other algae and zooplankton, thereby acting as a sub-system within the wetland ecosystem. The bloom is non-toxic and is exploited as a fish food by the fish-farmers who artificially induce a bloom for augmenting the growth of surface-feeding species of fishes.