The members of Clusiaceae, are distributed mostly in tropics of Asia and America. In Indian subcontinent (comprising of Bangladesh, Bhutan, Myanmar, Nepal, Pakistan, Sri Lanka and India), it is well represented (65% of the total taxa). The present paper deals with distribution, phytoendemism, possible fossil ancestry, potential survival threat on existing taxa, etc. of Clusiaceae in Indian subcontinent.
The members of the family Theaceae are distributed in tropical and subtropical regions, in America and Asia, a few in Africa. In Indian subcontinent (comprising of Bangladesh, Bhutan, Myanmar, Nepal, Pakistan, Sri Lanka and India), it is well-represented (50% of the total taxa). The present paper deals with distribution, phytoendemism, possible fossil ancestry, potential survival threat on existing taxa etc. of Theaceae in Indian subcontinent.
Authors:R. Kundu, K. Bhattacharyya, A. Majumder and S. Pal
Arsenic, the toxic metalloid, widely available in the natural ecosystem, poses serious problem through contaminated groundwater and drinking water. The emerging areas of arsenic hazards in agricultural systems through use of contaminated irrigation water and entry of toxin in crops has been largely overlooked. Arsenic accumulation by plants and its translocation to edible parts were observed to vary within crops and also across the cultivars. Wheat is an alternative choice of summer rice, due to low water requirement. With this background, the current experiment was conducted with four popular wheat cultivars to study the arsenic accumulation and varietal tolerance under different soils and groundwater. The arsenic content was determined by using atomic absorption spectrophotometer (AAS). Result revealed that, wheat cultivars differed in their grain arsenic concentration (0.23–1.22 mg kg−1), which differed across the sites and year of experiment. The arsenic translocation in wheat grains usually least, and accumulation by different tissues followed the order root > stem > leaf > grain across the cultivars. The cultivar UP-262 was found to accumulate least arsenic in grains and cultivar Kalyansona the highest under same growing condition, due to phyto-extraction or phyto-morphological potential of the varieties.
Authors:S. Dutta, A. Kundu, M. R. Chakraborty, S. Ojha, J. Chakrabarti and N. C. Chatterjee
Siderophores are low molecular weight
(<1000 D) iron chelating compounds produced by microorganisms. Production of
siderophore is a device of antagonism as by virtue of the capacity of
siderophore production, a microorganism competes for Fe (III) with the others.
Production of siderophores by 9 different soil fungi and wood-decay fungi was
studied following CAS - assay and CAS - agar plate assay. Optimization for the production of
siderophores was done by varying the levels of pH and Fe (III) concentrations
in the low nutrient medium. All the test fungi could produce siderophores,
though the degree of production recorded to be very low both in Botryodiplodia
theobromae and in Fusarium spp. On the other hand, all the species of
Trichoderma showed their excellency in siderophore production. The optimum pH
for production of siderophores remained at neutral pH level though the range
varied from pH 6.0-8.0. The optimum range of the
concentration of Fe (III) required for siderophore production was recorded to
be 1.5-21.0 µM. However, the stress condition of
iron might be a decisive factor for siderophore production.