Elevated ozone reduces photosynthetic carbon gain by accelerating leaf senescence of inbred and hybrid maize in a genotype-specific manner

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