Elevated CO2 ameliorates O3-induced stress and enhances growth, metabolomic, and yield attributes of two wheat (Triticum aestivum L.) cultivars under fully open-air field conditions
摘要
Two wheat cultivars (PBW-154, WH-1105), grown in the free-air CO2 and O3 enrichment (FAOCE) facility, were exposed to alone or combined elevated CO2 (ECO2) and/or elevated O3 (EO3). EO3 exposure (+ 20 ppb above ambient) caused a reduction in growth and yield in both wheat cultivars. ECO2 exposure (550 ppm) enhanced plant growth, photosynthetic rate (A), and yield. Total phenol, flavonoid, gallic, ferulic, caffeic acid, and kaempferol content showed significant induction in leaves of O3-exposed cultivars at the flowering phase. Significant increases in glucose, sucrose, d-galactose, and malic acid, whereas significant reductions in gamma-aminobutyric acid, alanine, leucine, isoleucine, threonine, and tryptophan content were found in leaves of cultivars exposed to ECO2. Lower concentrations of sugars and amino acids were recorded in ECO2, and combined elevated CO2 + O3-exposed cultivars than in EO3-exposed cultivars due to the alleviating effect of ECO2 on O3-stressed cultivars. WH-1105 (modern cultivar) was found to be more O3 sensitive than the older (PBW-154) cultivar in terms of biomass and yield. This study depicted that EO3 caused alterations in the growth, physiological, biochemical, metabolic, and yield traits of wheat, but ECO2 ameliorated these O3-caused changes and increased yield performance. PBW-154 performed better under combined ECO2 and EO3 treatment than the WH-1105 cultivar. The positive effects of ECO2 are likely to be more pronounced in cultivars that are highly responsive to CO2. Therefore, future breeding efforts should prioritize developing O3-tolerant wheat cultivars having improved CO2 responsiveness to address the challenges posed by rising atmospheric CO2 and O3 levels.