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Khan, S; Soja, G.
(2003): Yield responses of wheat to ozone exposure as modified by drought-induced differences in ozone uptake
WATER AIR SOIL POLL. 2003; 147(1-4): 299-315. FullText FullText_BOKU

Over a period of two years greenhouse experiments were carried out to quantify the interaction ozone exposure x water stress in winter wheat (Triticum aestivum L. cv. Perlo). Assessment of effects carried out on various yield parameters showed that abundant water supply made the plants most sensitive to ozone exposure. In well-watered plants (75% of soil water capacity, s.w.c.), the AOT40 ozone exposure doses of 26.8 and 24.9 mumol mol(-1) hr(-1) (ppm.h) caused grain yield reductions by 35 and 39%. No reductions of yields were observed at severe water stress (35% of s.w.c.) condition. The decrease in ozone responsiveness under drought can be explained by a distinct reduction in ozone uptake (18 vs. 2 mmol m(-2) in well-watered vs. severely stressed plants at the same ozone exposure). The calculations of ozone uptake were based on repeated measurements of leaf conductance. Generally curvi-linear regression functions explained the dependence of relative yield on ozone and on water stress better than multiple simple linear regression functions. The consideration of ozone uptake instead of ozone exposure improved the performances of the models further. For explaining grain yield, 96.8% of the variances could be explained by a model resulting from curvi-linear regression fitting. A suggestion for calculating correction factors to modify critical levels in the case of limited water supply is presented.
Authors BOKU Wien:
Soja Gerhard

Find related publications in this database (Keywords)
air pollutant
critical level
pollutant uptake
stomatal conductance
water stress
winter wheat

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