Nickel accumulation and its effect on growth,physiological and biochemical parameters in millets and oats

With the boom in industrialization, there is an increase in the level of heavy metals in the soil which drastically affect the growth and development of plants. Nickel is an essential micronutrient for plant growth and development, but elevated level of Ni causes stunted growth, chlorosis, nutrient imbalance, and alterations in the defense mechanism of plants in terms of accumulation of osmolytes or change in enzyme activities like guiacol peroxidase (POD), catalase (CAT), and superoxide dismutase (SOD). Ni-induced toxic response was studied in seedlings of finger millet, pearl millet, and oats in terms of seedling growth, lipid peroxidation, total chlorophyll, proline content, and enzymatic activities. On the basis of germination and growth parameters of the seedling, finger millet was found to be the most tolerant. Nickel accumulation was markedly lower in the shoots as compared to the roots, which was the highest in finger millet and the lowest in shoots of oats. Plants treated with a high concentration of Ni showed significant reduction in chlorophyll and increase in proline content. Considerable difference in level of malondialdehyde (MDA) content and activity of antioxidative enzymes indicates generation of redox imbalance in plants due to Ni-induced stress. Elevated activities of POD and SOD were observed with high concentrations of Ni while CAT activity was found to be reduced. It was observed that finger millet has higher capability to maintain homeostasis by keeping the balance between accumulation and ROS scavenging system than pearl millet and oats. The data provide insight into the physiological and biochemical changes in plants adapted to survive in Ni-rich environment. This study will help in selecting the more suitable crop species to be grown on Ni-rich soils.

     

Optimization of regional hazardous waste management systems: an improved formulation

The planning and design of regional hazardous waste management system (RHWMS) involves selection of treatment and disposal facilities, allocation of hazardous wastes and waste residues from generator to the treatment and disposal sites and selection of the transportation routes. An improved formulation based upon multi-objective integer programming approach is presented to arrive at the optimal configuration of RHWMS components. This formulation addresses important practical issues like unique characteristics of the hazardous wastes reflecting on waste–waste and waste–technology compatibility. A utility function approach is presented to integrate both cost and risk related objectives. An illustrative case example is presented to demonstrate the usefulness of the improved formulation as a tool which can be used by environmental planning agencies in regional planning for hazardous waste management.     

Atmospheric dry deposition to leaf surfaces at a rural site of India

Dry deposition flux of major ions (Na+, K+, Ca2+, Mg2+, NH4+, F-, Cl-, NO3- and SO4(2-) to natural surfaces [guava (Psidium guyava) and peepal (Ficus religiosa) leaves] are determined at Rampur, a rural site of semi-arid region of India. Dry deposition flux is the highest for Ca2+ on guava leaves and for NH4+ on peepal leaves. Overall dry deposition flux is higher on guava leaves than of peepal leaves. The variation in deposition flux may be due to surface characteristics (surface roughness) and arrangement of leaves. Peepal leaves are arranged along the axis of the stem, whereas guava leaves are at right angles to the stem. The deposition flux of cations contributes 66% and 76% of dry deposition of all major ions on guava and peepal leaves, respectively as soil is major contributor towards dry deposition flux in tropical regions. ANOVA revealed no significant seasonal difference in deposition, although there is a trend for higher in winter. Deposition velocities of NH4+, NO3- and SO4(2-) are greater on guava leaves than peepal leaves, which can be attributed to the rougher surface of the guava leaf.     

Effects of coal-smoke pollutants from different sources on the growth, chlorophyll content, stem anatomy and cuticular traits of Euphorbia hirta L

Variations occurred in the growth, assimilate partitioning, chlorophyll content, stem anatomy and leaf cuticular traits of Euphorbia hirta L. on long-term exposure to coal-smoke pollutants prevailing at two sites, one situated close to a railway loco shed (site B) and another in the vicinity of a thermal power plant (site C). The Botanical Garden of Aligarh Muslim University, Aligarh, was considered as a control site (A). Site C possessed a greater load of coal-smoke pollutants than site B. The present study had shown that coal-smoke pollutants have led to a decrease in plant height, jeopardised the production of leaves and enhanced their fall, and caused a reduction in leaf area, leading to decreases of the total photosynthetic area of the plants, with increasing pollution load. The losses incurred in chlorophyll a were relatively more than chlorophyll b and, as a result, the total chlorophyll contents of leaves were decreased in polluted plants. The dry weights of stems, roots and leaves were decreased to different degrees, whereas the shoot/root dry weight ratio was found to increase in the polluted environment. The growth of stem cortex and pith were slightly affected on site B, but showed significant decreases on site C, due to a greater load of pollutants. Decreased area of xylem tissue was found to couple with an increasing number of vessels of reduced sizes. The stomatal density, pore size and index showed decreases, while the epidermal cells were larger and trichomes longer, on both surfaces of polluted leaves.     

Assessing drivers of post-harvest losses: tangible and intangible resources’ perspective

Environment, Development and Sustainability - Many stakeholders in agro-food industry are concerned about sustainability, especially in addressing post-harvest loss (PHL). However, resources...     

Matrix method for evaluation of existing solid waste management system in Himachal Pradesh,India

Journal of Material Cycles and Waste Management - Effective management of Municipal Solid Waste (MSW) is an essential function of the city municipal corporation. The present study reports on the...     

Bacterial tolerance strategies against lead toxicity and their relevance in bioremediation application

Among heavy metals, lead (Pb) is a non-essential metal having a higher toxicity and without any crucial known biological functions. Being widespread, non-biodegradable and persistent in every sphere of soil, air and water, Pb is responsible for severe health and environmental issues, which need appropriate remediation measures. However, microbes inhabiting Pb-contaminated area are found to have evolved distinctive mechanisms to successfully thrive in the Pb-contaminated environment without exhibiting any negative effects on their growth and metabolism. The defensive strategies used by bacteria to ameliorate the toxic effects of lead comprise biosorption, efflux, production of metal chelators like siderophores and metallothioneins and synthesis of exopolysaccharides, extracellular sequestration and intracellular bioaccumulation. Lead remediation technologies by employing microbes may appear as potential advantageous alternatives to the conventional physical and chemical means due to specificity, suitability for applying in situ condition and feasibility to upgrade by genetic engineering. Developing strategies by designing transgenic bacterial strain having specific metal binding properties and metal chelating proteins or higher metal adsorption ability and using bacterial activity such as incorporating plant growth-promoting rhizobacteria for improved Pb resistance, exopolysaccharide and siderophores and metallothionein-mediated immobilization may prove highly effective for formulating bioremediation vis-a-vis phytoremediation strategies.

     

Climate-proof planning for flood-prone areas: assessing the adaptive capacity of planning institutions in the Netherlands

It is generally acknowledged that adapting low-lying, flood-prone deltas to the projected impacts of climate change is of great importance. Deltas are densely populated and often subject to high risk. Climate-proof planning is, however, not only a new but also a highly complex task that poses problems for existing institutional and administrative structures, which are the product of times in which climate issues were of little importance. This paper assesses the capacity of the historically grown Dutch planning institutions to promote climate-proof planning for flood-prone areas. The Adaptive Capacity Wheel provides the methodological framework. The analysis focuses on two planning projects in the west of the Netherlands: the Zuidplas Polder project at the regional level and the Westergouwe project at the local level. It is shown that the planning institutions involved in these projects enable climate-proof planning, but to a limited extent. They face five institutional weaknesses that may cause risks on the long term. To climate-proof urban developments in flood-prone areas, it is necessary to break through the strong path–dependent development of planning institutions and to build in more flexibility in existing rules and procedures.