Does interspecific competition alter effects of early season ozone exposure on plants from wet grasslands? Results of a three-year experiment in open-top chambers.

Chronic effects of ozone on wet grassland species early in the growing season might be altered by interspecific competition. Individual plants of Holcus lanatus, Lychnis flos-cuculi, Molinia caerulea and Plantago lanceolata were grown in monocultures and in mixed cultures with Agrostis capillaris. Mesocosms were exposed to charcoal-filtered air plus 25 nl l(-1) ozone (CF+25), non-filtered air (NF), non-filtered air plus 25 nl l(-1) ozone (NF+25) and non-filtered air plus 50 nl l(-1) ozone (NF+50) early in the growing seasons of 2000 through 2002.

Responses of bean (Phaseolus vulgaris L. cv. Pros) to chronic ozone exposure at two levels of atmospheric ammonia.

Plants of bean (Phaseolus vulgaris cv. Pros) were exposed to a range of O3 concentrations up to 70 nl litre(-1) for 9 h day(-1) in the presence (45 nl litre(-1)) and absence (21 nl litre(-1)) of enhanced NH3 in 12 open-top chambers. Treatment effects on visible injury, growth and yield were assessed after 49 (intermediate harvest) and 62 days of exposure (final harvest).

Monitoring the effects of atmospheric ethylene near polyethylene manufacturing plants with two sensitive plant species.

Data of a multi-year (1977-1983) biomonitoring programme with marigold and petunia around polyethylene manufacturing plants was analysed to assess plant responses to atmospheric ethylene and to determine the area at risk for the phytotoxic effects of this pollutant. In both species, flower formation and growth were severely reduced close to the emission sources and plant performance improved with increasing distance. Plants exposed near the border of the research area had more flowers than the unexposed control while their growth was normal.

Assessing effects of ambient ozone on injury and yield of bean with ethylenediurea (EDU): three years of plant monitoring at four sites in The Netherlands.

EDU (ethylenediurea) and non-EDU-treated bean plants (Phaseolus vulgaris L. cv. Lit) were exposed to ambient air at four rural sites in The Netherlands during the growing seasons of 1994 through 1996 to investigate the responses to ambient ozone.

Growth responses to ozone in plant species from wetlands.

Ten wet grassland species were fumigated with four concentrations of ozone (charcoal-filtered air, non-filtered air and non-filtered air plus 25 or 50 nl l(-1) ozone) in open-top chambers during one growing season to investigate the long-term effect of this air pollutant on various growth variables. Only Eupatorium cannabinum showed ozone-related foliar injury, while five species reacted with significantly ozone-enhanced senescence. Premature senescence was paralleled by a significant ozone-induced reduction of green leaf area in Achillea ptarmica, E.