Impacts of particulate matter pollution on plants: Implications for environmental biomonitoring

The present experiment was done to evaluate the impact of ambient air pollution on carrot (Dacus carotavar. Pusa Kesar) plants using open top chambers (OTCs) ventilated with ambient (NFCs) or charcoal filtered air (FCs) at a suburban site of Varanasi, India. Various morphological, physiological and biochemical characteristics of the plants were studied at different growth stages. Air monitoring data clearly showed high concentrations of SO2, NO2and O3in the ambient air of study site. SO2and NO2concentrations were higher during early growth stages of carrot, whereas O3concentration was highest during later growth stages. Filtration of air has caused significant reductions in all the three pollutant concentrations in FCs as compared to NFCs.Plants growing in FCs showed significantly higher photosynthetic rate, stomatal conductance, water use efficiency and variable fluorescence as compared to plants growing in NFCs. Protein content also showed a similar pattern, however, lipid peroxidation, ascorbic acid content and peroxidase activity were higher in plants growing in NFCs as compared to FCs. Shoot length, number of leaves per plant, leaf area and root and shoot weight increased significantly upon filtration of ambient air. Total nitrogen decreased significantly in root, but increased significantly in shoot of plants grown in NFCs. Total P, Mg, Ca and K contents decreased significantly in plants grown in NFCs as compared to FCs. The individual pollutant concentrations were below threshold for plant injury, but the combined effect of all the three seems to act synergistically in causing greater adverse impact on dry weight and physiology of carrot plants. The study clearly indicates that air pollutants are high enough in the ambient air to cause significant unfavorable impact on carrot plants. The work further supports the usefulness of OTCs for assessing air pollution damage under field conditions in developing countries.

Evaluation Of Ambient Air Pollution Impact On Carrot Plants At A Sub Urban Site Using Open Top Chambers

Summary 421

I. INTRODUCTION 421

II. EFFECTS OF OZONE ON REPRODUCTION 423

1. Pollen germination and pollen tube growth 424

2. Floral initiation and development 428

3. Effects on seed and fruit yield and yield components 433

4. Effects of ozone on seed and fruit quality, germination and seedling growth 437

III. INFLUENCE OF REPRODUCTIVE HABIT AND IMPLICATIONS FOR FIELD-GROWN PLANTS 438

IV. CONCLUSIONS AND FUTURE RESEARCH 441

Acknowledgements 442

References 442

Sexual reproductive development is a crucial stage in the life cycle of higher plants as any impairment of the processes involved might have significant implications for the productivity of crop plants and the survival of native species. There is considerable evidence that exposure to ozone, even at current ambient levels in many industrialized countries, reduces grain and fruit yields and adversely affects yield quality. It is also well established that sensitivity to ozone may differ not only between species, but also between cultivars and populations of individual species, and that the impact of exposure is highly dependent on ozone concentration and the duration and timing of exposure. However, few studies have attempted to distinguish between the direct effects of air pollutants on reproductive development, and indirect effects mediated by injury to the vegetative organs and associated changes in the supply of assimilates and other essential resources to support reproductive growth, or the levels of endogenous growth regulators. This review considers the impact of ozone on the reproductive biology of agricultural and native species, and examines its direct effects on specific reproductive processes. The extent to which compensatory responses redress the adverse effects of exposure is also explored, with particular reference to recent studies of Brassica napus (oilseed rape), Brassica campestris (Wisconsin Fast Plants), Plantago major (greater plantain) and Triticum aestivum (wheat).

Tansley Review No. 115: Impact of ozone on the reproductive development of plants.

The article is a comprehensive review of the occurrence of hormetic dose-response relationships induced by inorganic agents, including toxic agents, of significant environmental and public health interest (e.g., arsenic, cadmium, lead, mercury, selenium, and zinc). Hormetic responses occurred in a wide range of biological models (i.e., plants, invertebrate and vertebrate animals) for a large and diverse array of endpoints. Particular attention was given to providing an assessment of the quantitative features of the dose-response relationships and underlying mechanisms that could account for the biphasic nature of the hormetic response. These findings indicate that hormetic responses commonly occur in appropriately designed experiments and are highly generalizeable with respect to biological model responses. The hormetic dose response should be seen as a reliable feature of the dose response for inorganic agents and will have an important impact on the estimated effects of such agents on environmental and human receptors.

Inorganics and hormesis.

summary Sexual reproductive development is a crucial stage in the life cycle of higher plants as any impairment of the processes involved might have significant implications for the productivity of crop plants and the survival of native species There is considerable evidence that exposure to ozone, even at current ambient levels in many industrialized countries, reduces grain and fruit yields and adversely aects yield quality It is also well established that sensitivity to ozone may dier not only between species, but also between cultivars and populations of individual species, and that the impact of exposure is highly dependent on ozone concentration and the duration and timing of exposure However, few studies have attempted to distinguish between the direct eects of air pollutants on reproductive development, and indirect eects mediated by injury to the vegetative organs and associated changes in the supply of assimilates and other essential resources to support reproductive growth, or the levels of endogenous growth regulators This review considers the impact of ozone on the reproductive biology of agricultural and native species, and examines its direct eects on specific reproductive processes The extent to which compensatory responses redress the adverse eects of exposure is also explored, with particular reference to recent studies of Brassica napus (oilseed rape), Brassica campestris (Wisconsin Fast Plants), Plantago major (greater plantain) and Triticum aestivum (wheat)

S.R.K. Varshney

Papers

Effect of sulphur dioxide on pollen germination and pollen tube growth

Effects of SO2 on ascorbic acid in crop plants

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