Response and Bioaccumulation Potential of Boerhavia diffusa L. Towards Different Heavy Metals

Effect of different concentrations of heavy metals such as Cadmium, Chromium, Mercury and Leadwas studied by cultivating rooted propagules of Boerhavia diffusafor a period of twenty days in Hoagland nutrient medium artificially contaminated with known concentration of those heavy metal ions. Concentrations of the metals selected to impart visible symptoms of growth retardation and to permit survival for prolonged period are 30µM cadmium chloride (CdCl2), 400 µM potassium dichromate (K2Cr2O7), 10 µM mercuric chloride (HgCl2), and 600 µM lead acetate (CH3-COO)2Pb. More or less uniform growth performance was shown by the plants irrespective of the differences of concentration of the heavy metals. However, parameters such as root - and stem length, stomatal - and tolerance index varied among the treatments. Significant differences were observed in the heavy metal accumulation potential among metals and between plant parts such as root, stem and leaf and the pattern was dependent on growth period

Heavy metal accumulation potential and medicinal property of Bacopa monnieri - a paradox

Bioaccumulation of Mercury and Cadmium in Bacopa monnieri (L.) Pennell, cultivated in Hoagland medium artificially contaminated with micro quantities of HgCl2 and CdCl2 is investigated. Bioaccumulation potential of B. monnieri is more towards Cd than Hg. Absorption and translocation of Hg and Cd are proportional to the availability of the metal in the growth media and period of growth. Effect of acidic pH showed enhanced accumulation while basic pH resulted in significant reduction in the accumulation of Hg and exorbitant reduction of Cd. As a result of combined treatment of HgCl2 and CdCl2, accumulation was very low in both acidic and basic pH. In addition to pH, antagonistic effect of Ca2+ present in lime water which was added to raise the pH of the growth medium also controls the accumulation and absorption of Hg and Cd ions. Bioaccumulation of Hg and Cd in B. monnieri reveals the phytoremediation potential while the bioaccumulation is hazards to health since the plant is highly medicinal and one important ingredient of many Ayurvedic preparations

BIO-ACCUMULATION AND RELEASE OF MERCURY IN VIGNA MUNGO (L.) HEPPER SEEDLINGS

Effect of mercury on the seedling of Vigna mungo seedlings was studied by culturing the seedlings in Hoagland medium artificially contaminated with 5 and 10mM Mercuric Chloride. Histochemical localization of the mercury in shoot and root tissues was done by staining with dithizone and quantitative analyses of mercury content accumulated in root, stem and leaf tissues were done using mercury analyser. Localization of mercury was observed as coloured masses in the cells of root and stem. Stem tissues of seedlings showed anatomical modification in the epidermal cells as trichomes. Patterns of bioaccumulation of mercury was root> stem> leaves revealing feeble translocation to the shoot system. A comparison of residual mercury content retained in the growth medium after sample harvesting and quantity accumulated in the plant body reveals that some quantity of mercury is lost presumably through the trichomes developed on the stem and/ or through stomata of the leaves

Distribution of Bio-accumulated Cd and Cr in two Vigna species and the Associated Histological Variations

In nutrient culture experiments, bioaccumulation and anatomical effects of cadmium (CdCl2 - 20μM) and chromium (K2Cr2O7 - 600 μM) on the structure of root and stem was studied by histochemical and analytical methods in Vigna radiata and Vigna unguiculata. Each metal exerted specific influences on the anatomy of various tissues in root and stem. Histochemical localisation of cadmium and chromium was observed in the stained sections of root and stem. Atomic Absorption Spectrophotometric study revealed maximum accumulation of cadmium and chromium in the root tissue as compared to shoot with significant variation among the species. Abundant occurrences of densely stained deposits of chromium were seen in the root stelar region of V. unguiculata and to a lesser extend in V. radiata. Cadmium accumulation in V. radiata was comparatively more than that of V. unguiculata. The findings also revealed that the accumulation pattern of cadmium and chromium varies between species and hence is species specific

Accumulation Pattern of Heavy Metals in Chromolaena odorata (L.) King & Robins. Grown in Nutrient Solution and Soil

Accumulation pattern of Al, Cd, Fe, Hg, Cr, Cu, Pb, Ni and Zn in Chromolaena odorata plants grown in Hoagland nutrient solution and soil contaminated with known quantities of the above said metals was investigated. Significant variations in the quantity of accumulation as well as distribution among plant parts like root, stem and leaf were shown between the metals. Accumulation of Pb was maximum in the root followed by Fe and Al. Maximum quantity of each metal was accumulated in the root as compared to stem and leaf. Drastic differences in the accumulation pattern of metals between the nutrient solution and soil culture was observed. Comparatively small quantity of metal was accumulated in the plants of soil despite several fold quantity of each metal was given. The results are discussed in terms of BCF, TF, metal specificity as well as detoxification mechanisms

Influence of Desiccation and Associated Metabolic Changes During Seed Germination in Corypha umbraculifera Linn.

Corypha umbraculifera L. is a monocarpic palm, which usually flowers after 30-60 years of growth. In C. umbraculifera seeds are the only propagating unit, but the germination rate is very low and seeds are highly recalcitrant. In this context, it was imperative to investigate the desiccation sensitivity, physiological and biochemical changes accompanying the desiccation and germination in C. umbraculifera seeds. Therefore, to make a detailed study, freshly collected C. umbraculifera seeds were desiccated at room temperature for a period of 35 d and physiological and biochemical changes during desiccation and germination were monitored at an interval of 7 d. It was observed that there was a sharp decline in the moisture content of the seed as desiccation proceeded. As the desiccation period progressed, the germination percentage decreased which was below 50% after 35 d. The dry weight percentage of the embryo and endosperm increased with the desiccation period and the increase in dry weight of embryo was significant in comparison with the endosperm. Total protein content of embryo was more compared to that of the endosperm. Peroxidase activity in the embryo was increased up to 28 d of desiccation and decreased further. The endosperm registered a gradual reduction of peroxidase activity during desiccation. In contrast, SOD activity in the embryo was comparatively higher in the fresh seeds and further declined during desiccation, while that of the endosperm remained almost unaltered. The results give a strong indication that desiccation in C. umbraculifera is accompanied by abundant activity of peroxidase in embryo, thereby viability is retained up to 35 days. Whereas, feeble activity of SOD is not seen to be linked with seed viability of C. umbraculifera