Effects of Elevated CO2 on the Photosynthesis, Chlorophyll Fluorescence and Yield of Two Wheat Cultivars (Triticum aestivum L.) under Persistent Drought Stress

The interactive effects of elevated [CO2] and drought on leaf photosynthesis, physiology yield in wheat (Triticum aestivum L.) are not well understood. This study evaluated the persistent stress (35–45% field water capacity) CO2 (ambient concentration + 200 ?mol mol–1) chlorophyll fluorescence, physiological indices, biomass, grain weight (in g m?2) two cultivars (large-spike cultivar Z175 multiple-spike Triumph) at open-top chamber (OTC) experimental facility North China. We found that enhanced positive Fv/Fm WUE but did ameliorate adverse PN cultivars. Moreover, as a large-spike cultivar, showed photosynthesis performance sink capacity (spike number kernel per spike) compared with Triumph filling stage under [CO2], which helped counteract drought. In contrast, although had more tillers spikes current concentration, most them were thin limited capacity. leaves main shoot spike significantly increase [CO2]. Hence, mitigated drought-induced inhibition plants stress.