Bioenergy sorghum maintains photosynthetic capacity in elevated ozone concentrations. (21st January 2021)

• Record Type: Journal Article
• Authors: Li, Shuai; Moller, Christopher A.; Mitchell, Noah G.; Lee, DoKyoung; Ainsworth, Elizabeth A.
• Is Part Of: Plant, cell and environment. Volume 44:Number 3(2021)
• Page Start: 729
• Page End: 746
• Publication Date: 2021-01-21
• Subjects: biomass -- BWB model -- chlorophyll fluorescence -- MED model -- photosynthesis -- stomatal conductance; Plant physiology -- Periodicals; Plant cells and tissues -- Periodicals; Plant communities -- Periodicals; 581.105
• DOI: 10.1111/pce.13962
• Languages: English
• ISSNs: 0140-7791

Abstract

Abstract: Elevated tropospheric ozone concentration (O3 ) significantly reduces photosynthesis and productivity in several C4 crops including maize, switchgrass and sugarcane. However, it is unknown how O3 affects plant growth, development and productivity in sorghum ( Sorghum bicolor L.), an emerging C4 bioenergy crop. Here, we investigated the effects of elevated O3 on photosynthesis, biomass and nutrient composition of a number of sorghum genotypes over two seasons in the field using free‐air concentration enrichment (FACE), and in growth chambers. We also tested if elevated O3 altered the relationship between stomatal conductance and environmental conditions using two common stomatal conductance models. Sorghum genotypes showed significant variability in plant functional traits, including photosynthetic capacity, leaf N content and specific leaf area, but responded similarly to O3 . At the FACE experiment, elevated O3 did not alter net CO2 assimilation ( A ), stomatal conductance ( g s ), stomatal sensitivity to the environment, chlorophyll fluorescence and plant biomass, but led to reductions in the maximum carboxylation capacity of phosphoenolpyruvate and increased stomatal limitation to A in both years. These findings suggest that bioenergy sorghum is tolerant to O3 and could be used to enhance biomass productivity in O3 polluted regions. Abstract : Sorghum ( Sorghum bicolor L.), a widely adapted and highly productive C4 grass, has potential as a bioenergy feedstock. In this study, we found that sorghum genotypes exhibit significant variability in plant functional traits, but a similar response to O3 . Elevated O3 did not alter net CO2 assimilation ( A ), stomatal conductance ( g s ) and chlorophyll fluorescence in multiple genotypes of sorghum in both field and chamber experiments. We suggest that sorghum could be used to enhance biomass production for bioenergy in O3 polluted regions.