Arsenic tolerances in rice (Oryza sativa) have a predominant role in transcriptional regulation of a set of genes including sulphur assimilation pathway and antioxidant system

World wide arsenic (As) contamination of rice has raised much concern as it is the staple crop for millions. Four most commonly cultivated rice cultivars, Triguna, IR-36, PNR-519 and IET-4786, of the West Bengal region were taken for a hydroponic study to examine the effect of arsenate (As^V) and arsenite (As^III) on growth response, expression of genes and antioxidants vis-à-vis As accumulation. The rice genotypes responded differentially under As^V and As^III stress in terms of gene expression and antioxidant defences. Some of the transporters were up-regulated in all rice cultivars at lower doses of As species, except IET-4786. Phytochelatin synthase, GST and γ-ECS showed considerable variation in their expression pattern in all genotypes, however in IET-4786 they were generally down-regulated in higher As^III stress. Similarly, most of antioxidants such as superoxide dismutase (SOD), ascorbate peroxidase (APX), guaiacol peroxidase (GPX), catalase (CAT), monodehydroascorbate reductase (MDHAR) and dehydroascorbate reductase (DHAR) increased significantly in Triguna, IR-36 and PNR-519 and decreased in IET-4786. Our study suggests that Triguna, IR-36 and PNR-519 are tolerant rice cultivars accumulating higher arsenic; however IET-4786 is susceptible to As-stress and accumulates less arsenic than other cultivars.     

Leaf surface structure alterations due to particulate pollution in some common plants

The plant foliar surface is the most important receptor of atmospheric pollutants. It undergoes several structural and functional changes when particulate-laden air strikes it. In the present investigation, ten annual plant species viz., Abelmoschus esculentus, Celosia cristata, Coleus blumei, Cyamopsis tetragonolobus, Gomphrena globosa, Impatiens balsamina, Ocimum sanctum, Phaseolus vulgaris, Solanum melongena, and Zinnia elegans were studied for their growth parameters and leaf morphological features. They were subjected to dust experimentally for 60 days. The micro-morphological traits like wax, cuticle, epidermis, stomata, and trichomes were observed under light and scanning electron microscopes. Remarkable differences in the growth parameters and micro-morphological features were recorded in the dust-treated plants when compared to the respective controls. The reduction in growth parameters, the size of epidermal cells, and stomata were reduced and cuticle damage was also observed. The relative proportion of fine particles, which play a major role in hampering the overall growth of a plant, was higher in comparison to ultra-fine and coarse particles.     

Growth and biochemical parameters of Cicer arietinum L. grown on amended fly ash

Growth and metal accumulation were investigated in two Cicer arietinum L. varieties (var. CSG-8962 and var. C-235) when grown in various combinations of fly ash (FA) amended with garden soil (GS), press mud (PM) or saw dust (SD). In addition, the levels of photosynthetic pigments, nitrate reductase (NR) activity, cysteine, non-protein thiols (NP-SH), and ascorbic acid were studied. FA amended with GS or PM led to a 5–10 times increase in biomass compared to FA control and was most pronounced in the less metal tolerant variety CSG-8962. Amendment of FA with either GS or PM only moderately increased the contents of some essential metals whereas the non-essential Cd and Cr remained similar or decreased slightly compared to FA control. FA combined with either GS or PM increased the amount of photosynthetic pigments and was largely absent when SD was added to FA. Improved nitrogen availability led to increased nitrate reductase (NR) activity with all amendments but less so with SD. Metal stress indicating parameters were generally reduced (cysteine and non-protein thiols) or unchanged (ascorbic acid). In conclusion, of the tested ameliorants both GS and PM greatly improved growth of C. arietinum making FA a suitable component of plant growth substrates.     

Monitoring of toxic elements present in sludge of industrial waste using CF-LIBS

Industrial waste is one of the main causes of environmental pollution. Laser-induced breakdown spectroscopy (LIBS) was applied to detect the toxic metals in the sludge of industrial waste water. Sludge on filter paper was obtained after filtering the collected waste water samples from different sections of a water treatment plant situated in an industrial area of Kanpur City. The LIBS spectra of the sludge samples were recorded in the spectral range of 200 to 500 nm by focusing the laser light on sludge. Calibration-free laser-induced breakdown spectroscopy (CF-LIBS) technique was used for the quantitative measurement of toxic elements such as Cr and Pb present in the sample. We also used the traditional calibration curve approach to quantify these elements. The results obtained from CF-LIBS are in good agreement with the results from the calibration curve approach. Thus, our results demonstrate that CF-LIBS is an appropriate technique for quantitative analysis where reference/standard samples are not available to make the calibration curve. The results of the present experiment are alarming to the people living nearby areas of industrial activities, as the concentrations of toxic elements are quite high compared to the admissible limits of these substances.     

Comparative assessment of Azolla pinnata and Vallisneria spiralis in Hg removal from G.B. Pant Sagar of Singrauli Industrial region, India

The aim of the present work was to monitor the Hg pollution in water and sediments of G.B. Pant Sagar located in Singrauli Industrial Region, India and to suggest the efficient aquatic plants for its phytoremediation. The study assessed the comparative potential of a free floating water fern Azolla pinnata and submerged aquatic macrophyte Vallisneria spiralis to purify waters polluted by Hg. Six days laboratory experiments have been conducted to mark the percentage removal of Hg at initial concentration of 0.1, 0.5, 1.0 and 3.0 mg L(-1). The percentage removal of Hg was higher for A. pinnata (80-94%) than V. spiralis (70-84%). Likewise, the Hg accumulated in dry mass was much higher for A. pinnata and a high correlation (R(2) = 0.91 for A. pinnata and 0.99 for V. spiralis) was obtained between applied Hg doses and accumulated amounts in biomass. A concentration dependent decrease in chlorophyll a, protein, RNA, DNA and nutrients (NO(3-) and PO(4)(3-)) uptake was detected in A. pinnata and V. spiralis due to Hg toxicity. The decrease was more prominent in Azolla than Vallisneria. The results recommended the use of A. pinnata and V. spiralis to ameliorate the industrial effluents (thermal power, chlor-alkali and coal mine effluent) contaminated with Hg.     

Designing a community-based insurance scheme to reduce human–wildlife conflict

Environment, Development and Sustainability - Globally, human–wildlife conflict (HWC) is a burning issue, which the conservationists have attempted to address through various conservation...