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ARS Home » Midwest Area » Urbana, Illinois » Global Change and Photosynthesis Research » Research » Publications at this Location » Publication #343464
Title: Elevated ozone reduces photosynthetic carbon gain by accelerating leaf senescence of inbred and hybrid maize in a genotype-specific manner

Author
item YENDREK, CRAIG - University Of Illinois
item ERICE, GORCA - University Of Illinois
item MONTES, CHRISTOPHER - University Of Illinois
item TOMAZ, TIAGO - University Of Illinois
item SORGINI, CRYSTAL - University Of Illinois
item BROWN, PATRICK - University Of Illinois
item MCINTYRE, LAUREN - University Of Illinois
item LEAKEY, ANDREW D B - University Of Illinois
item Ainsworth, Elizabeth - Lisa

Submitted to: Plant Cell and Environment
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/6/2017
Publication Date: 12/1/2017
Citation: Yendrek, C.R., Erice, G., Montes, C.M., Tomaz, T., Sorgini, C., Brown, P.J., McIntyre, L.M., Leakey, A.D.B., Ainsworth, E.A. 2017. Elevated ozone reduces photosynthetic carbon gain by accelerating leaf senescence of inbred and hybrid maize in a genotype-specific manner. Plant Cell and Environment. 40:3088-3100.

Interpretive Summary: Ground-level ozone negative impacts maize production in the U.S., but few studies have examined the impact of elevated ozone on maize physiology in the field. In this study we examined 10 diverse inbred and 8 diverse hybrid lines for ozone response. Maize was grown at ambient and elevated ozone concentrations in the field under fully open air conditions using Free Air gas Concentration Enrichment (FACE) technology. On average, growth at elevated ozone decreased photosynthesis in both inbreds and hybrids, but there was significant genetic variation in the degree of ozone-induced damage. Lower photosynthetic rates were associated with lower capacity for photosynthesis and not with variation in stomatal conductance. By testing a diverse panel of maize genotypes under field conditions in the world’s primary area of production, this study provides a foundation on which to investigate the genetic variation in maize oxidative stress tolerance, and begin to develop more stress tolerant germplasm.

Technical Abstract: Exposure to elevated tropospheric ozone concentration ([O3]) accelerates leaf senescence in many C3 crops. However, the effects of elevated [O3] on C4 crops including maize (Zea mays L.) are poorly understood in terms of physiological mechanism and genetic variation in sensitivity. Using Free Air gas Concentration Enrichment (FACE), we investigated the photosynthetic response of 18 diverse maize inbred and hybrid lines to season-long exposure to elevated [O3] (~100 nL L-1) in the field. Gas exchange was measured on the leaf subtending the ear throughout the grain filling period. On average over the lifetime of the leaf, elevated [O3] led to reductions in photosynthetic CO2 assimilation of both inbred (-22%) and hybrid (-33%) genotypes. There was significant variation among both inbred and hybrid lines in the sensitivity of photosynthesis to elevated [O3], with some lines showing no change in photosynthesis at elevated [O3]. Based on analysis of inbred line B73, the reduced CO2 assimilation at elevated [O3] was associated with accelerated senescence decreasing photosynthetic capacity, and not altered stomatal limitation. These findings across diverse maize genotypes could advance the development of more ozone tolerant maize, and provide experimental data for parameterization and validation of studies modeling how O3 impacts crop performance.