Effects of ambient air pollution in open‐top chambers on bean (Phaseolus vulgaris L.)

Abstract

S U M M A R YField-grown bean plants (Phaseolus vulgaris L, cv. Taylor's Horticultural) were exposed to ambient air pollution in open-top chambers (OTCs) at two sites (urban and rural) in Northern Italy. At each site three OTCs received charcoal/Purafit filtered air (F) and three ambient non-filtered air (NF). Net photosynthesis, stomatal conductance and transpiration of selected leaves were measured from July to September 1989. The results showed that net photosyntbesis of NF plants decreased progressive!)' during the season in comparison with the F ones. The difference was greatest at September (-40"^.^ at urban .site and -23 % at rural site). Tbe maximum impairment of photosynthesis occurred during the ripening of tbe pods. For about 2 wk in August stomatal conductance of NF plants was greater than tbat of F plants at both sites. Later in August and in September tbe situation was reversed and stomatal conductance of NF plants was significantly lower tbati that of F ones. By this time a significant negative correlation between net photosyntbesis and sub-stomatal carbon dioxide concentration was found in NF plants at both sites, indicating an increased importance of non-stomatal limitation of photosynthesis. The measured leaves did not show any visible symptom of damage at the time of tbe physiological measurements; however brown spots on the upper surface became e^'ident later on 20 "o of total leaves of NF plants. Ambient ozone is suspected to be the major air contaminant involved in causing the observed physiological effects.

Ozone Effects on Fruit Productivity and Photosynthetic Response of Two Tomato Cultivars in Relation to Stomatal Fluxes

“…This latter parameter was not affected by ozone treatment, thus indicating that once the fructification process has started it is regularly carried on and concluded. The reduction in the total number of ripe fruits is also consistent with other results obtained for watermelon (Gimeno et al, 1999), beans (Schenone et al, 1992;Gerosa et al, submitted) and cucumber (Khan and Khan, 1999) and there is evidence that crop yield responses to ozone exposure are growth-stage dependent (Younglove et al, 1994;Stewart et al, 1996;Drogoudi and Ashmore, 2000). In this case it can be hypothesized the existence of an adverse effect of ozone on flowering or a higher susceptibility of plants during the period between flowering and fruit set, as suggested by other authors (Younglove et al, 1994;Calvo et al, 2007).…”

Temporal and Spatial Ozone Distribution over Egypt

“…There is an interest in investigating the impact of air pollutants on agricultural crops, and this interest has focused on the long-term low-level effects of the main phytotoxic gases on crop production [27][28][29][30][31][32]. Periodic exposure to air pollutants may cause yield losses [27,[33][34][35][36][37][38][39].…”

Yield responses of plants exposed to ambient ozone in the river Po Valley (Italy)

“…Leaf visible injury results and ecophysiological aspects are described elsewhere [1,17,21,22,26]. This paper reports yield responses for different species exposed to ozone at the experimental sites (Redecesio di Segrate and Isola Serafini) during the summer seasons from 1988 to 1996.…”