[Volatile metabolites and external CO2 exchange of wheat cenoses under optimal conditions and thermal stress].

The effects of elevated temperature (35 and 45 degrees C) on photosynthesis, respiration, and both the qualitative and quantitative compositions of volatile emissions (VE) of wheat (Triticum aestuvum L. cultivar 232) cenoses at light intensities of 70, 150, or 240 W/m2 of photosynthetically available radiation (PAR) were studied. At a PAR of 240 W/m2, the thermal stabilities of photosynthesis and respiration increased at 35 degrees C and decreased at 45 degrees C. Elevated temperatures nonuniformly changed the rates and direction of VE syntheses. In this process, the highest increase in VE evolution was observed at 70 W/m2; the lowest, at 240 W/m2 and 35 degrees C. In addition, the concentrations and composition of VE during the repair period differed from the initial values.