Influence of heavy metals in root chemistry of Cyperus vaginatus R.Br:A study through optical spectroscopy

Phyto-sequestration of heavy metals originating from urban runoff entering into wetland systems is one of the ways to mitigate the pollution. Due to the chemical environment of runoff wetlands, the plants and especially their roots are often stressed. While growing on contaminated environment, wetland plants undergo a number of physio-chemical changes in their roots, stems and leaves in the form of ecological adaptations. In this study, the three category samples of the macrophyte Cyperus vaginatus R.Br. growing in a wetland, near to the wetland (100 m) were collected to determine heavy metals and organic matter status in roots. This study revealed hyperaccumulation of metals in plants growing in the wetland compared to nearby and far from the wetland. Statistical analysis showed metals accumulating pattern to be distinct for each sampling category based on location. The UV spectra of C. vaginatus root produced a distinct shoulder peak at 324 nm whereas the plants growing far from the wetland showed a spectroscopic shoulder at 267 nm. The plant root growing near to wetland showed both shoulders at 324 nm and 267 nm but with reduced peak height. Statistical analysis of UV spectra also followed location specificity pattern. UV spectral result was further validated by FTIR analysis where plants growing in wetland and near to wetland possessed spectra similar to UV spectral results. This observation leads us to conclude that C. vaginatus R.Br. exhibited changes in root chemical composition to tolerate metal toxicity and perform phytoaccumulation

Stress responses and specific metal exclusion on mine soils based on germination and growth studies by Australian golden wattle

We reported the Australian golden wattle as a copper stabilizer in abandoned copper mine soils earlier. Here we investigate to confirm this plant’s suitability to grow on metal contaminated mine soils based on stress indication. The seeds of Acacia pycnantha collected from mining area were germinated after heat and no heat treatment on two types of irrigation. The daily irrigated and heat treated seeds gave up to 85% germination on sandy soil. The A. pycnantha was grown under greenhouse condition in six different soils collected from abandoned copper mine at Kapunda in South Australia. Among the six soil samples, soil-1 with the highest copper concentration produced 2.05 mmol g−1 tissue of proline. Proline expression was prominent in more saline soils (1, 5 and 6) having electrical conductivity (EC) 1184, 1364 and 1256 μS, respectively. Chlorophyll a, b and carotenoid levels in plants showed a gradually decreasing trend in all the soils as experiment progressed. The plants grown on soil sample-1, containing 4083 ± 103 mg kg−1 of copper resulted in 18 ± 2 mg kg−1 accumulation in its leaf. The calcium accumulation was significant up to 11648 ± 1209 mg kg−1 in leaf. Although pore water samples showed higher Cu concentration in soils, an increased mobility of arsenic and lead was observed in all the soil samples. Our experiment points out the need for proper monitoring of revegetation processes to avoid revegetation and reclamation failure

Application of green remediation on soil salinity treatment: A review on halophytoremediation

The salinity of soil and water resources is one of the economically expensive challenges to achieve sustainable development across the world. Salinity, which is a major environmental issue for both arid and semi-arid regions, is highly stressful for vegetation and adds to other stresses including water scarcity, nutrient deficiencies and soil alkalinity. Remediation is a strategy to clean up pollutants from the plant root zone in order to reduce vegetation stress and enhance productivity. This strategy involves biological management of soil and water which often leads to increased soil infiltration and leaching of excess salts out of the root zone. Several methods of soil and water remediation have been proposed that can be classified into the two main groups of engineering-based remediation and green remediation. Green remediation is the use of vegetation to remove or contain environmental contaminants such as heavy metals, trace elements, organic compounds and radioactive compounds in soil or water. There has recently been increased interest in green remediation using halophytes, particularly in developing countries. This paper reviews the different methods of phytoremediation and their application in green remediation. It also describes how halophytes are an emerging means of desalination and how they can be used for phytoremediation of heavy metals