Bush bean (Phaseolus vulgaris L) leaf injury, photosynthesis and stomatal functions under elevated ozone levels
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Three bush bean cultivars (Lit, Groffy and Stella) were grown under four levels of ozone exposure (ambient air+50 ppb O3 ambient air+25 ppb O3, ambient air and charcoal filtered air) in open- top chambers. Number and leaf injury statistics showed significant reduction in the number of healthy leaves as the level of O3 increased. The area based leaf injury percentages of the cvs. Lit, Groffy and Stella were 69.8, 57.9 and 71.1% at the highest O3 level, 24.1, 19.6 and 30.3% at the 2nd highest O3 level, and 4.5, 0.7 and 5.6% at the ambient air, respectively. The plants grown in the filtered air revealed no injury symptoms. The stomatal conductances were found to decrease gradually in each cultivar as the O3 level increased. At the highest O3 level, Chlorophyll fluorescence measurements on the 2nd leaf from the top on 24th day of exposure resulted in significantly the highest Fv/Fm values, the lowest f0 and the highest Fm values whereas the 4th leaf showed the smallest Fm and correspondingly the smallest Fv/Fm values. This is an indication of photosystem II damage after accumulation of a high ozone dose in the 4th leaf. The photosynthetic rate of the 2nd leaf measured on 30th day of exposure was comparatively higher at the highest exposure but the data taken from the same leaf on 40th day of exposure showed significantly lower photosynthetic rate than the plants in ambient air. Both chlorophyll fluorescence and photosynthetic measurements indicated that ozone stressed leaves experience a stimulation of photosynthesis (possibly due to increased assimilate demand) prior to irreversible damage. Bush bean leaves need to accumulate a critical ozone dose(an AOT40 of presumably > 18 ppm-h) for reduction of the photosynthetic capacitys.
Key wordsbush bean ozone open-top chamber leaf injury chlorophyll fluorescence photosynthetic rate stomatal conductances
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- Bender, J., Weigel, H.J. and Jäger, H.J.: 1991, “Response of nitrogen metabolism in beans (Phaseolus vulgaris L.) after exposure to ozon and nitrogendiooxide, alone and in sequence”, New Phytol., 119, 261–267.Google Scholar
- Bolhàr-Nordenkampf, H.R., Long, S.P. and Lechner, E.G.: 1988, Bestimmung der photosynthesekapazität über Chlorophyllfluoreszenz als Maß für die Streßbelastung vom Bäumen, Phyton (Austria), 29 (1), 119–135.Google Scholar
- Freer-smith, P.H. and Dobson, M.C.: 1989, “ Ozone flux to Picea sitchensis (Bong) carr and Picea abies (L) during short episodes and the effect of these on transpiration and photosynthesis”, Environmental Pollution, 59, 161–17.Google Scholar
- Guidi, L., Panicucci, A., Lorenzini G. and Soldatini, G.F.: 1993, Ozone induced changes in chlrophyll fluorescence kinetics and CO2 assimilation in Vicia faba. J. of Plant Physiol. 141, 545–550.Google Scholar
- Hassan, I.A., Ashmore, M.R. and Bell, J.N.B.:1994, Effects of O3 on the stomatal behaviour of Egyptian varieties of radish (Raphanus sativus L. cv. Baladey) and turnip (Brassica rapa L. cv. Sultani). New Phytol., 128, 243–249.Google Scholar
- Lefohn, A.S., Knudsen, H.P, Logan, J.L., Simpson and Bhumralkar, C.: 1987, “ An evaluation of the kriging method to predict 7 — hr seasonal mean ozone concentrations for estimating crop losses”, J. Air Pollut. Control. Assoc., 37, 595–602.Google Scholar
- Lehnherr, B., Grandjean, A., Machler, F. and Fuhrer I.: 1987, “The effect of ozone in ambient air on ribulosebiphosphate, carboxylase / oxygenase activity decreases photosynthesis and grain yield in wheat”, J. Plant Physiol., 130, 189–200Google Scholar
- Monteith, J.L.: 1977, “Climate and the efficiency of crop production in Britain”, Phil. Trans. Roy. Soc. Sci. London Ser. B, 281, 277–294.Google Scholar
- Unsworth, M.H. and Black, V.J.: 1981, “Stomatal response to pollutants’, In Jarvis, P.E. and Mansfield, T.A. (eds.): Stomatal Physiology, pp. 187–203. Cambridge Univ. Press, Cambridge.Google Scholar
- Volze, A and Kley D.: 1988, Evaluation of the Montsouries of ozone measurements made in the ninteenth century, Nature, 332, 240–242.Google Scholar