Effect of photochemically produced oxidants on growth of Avena coleoptile sections

Abstract
Sections were pre-incubated in solutions through which photachemical-ly produced oxidant mixtures, ozone or peroxyacetyl nitrate (PAN) were metered. The sections were subsequently transferred to oxidant-free fresh growth solutions with or without indoleacetic acid. Treatment with a UV irradiated mixture of trans-2-butene and NO2 recording as 1.4 ppm oxidant results in about 50% inhibition of elongation. PAN at 1.5 ppm also inhibits growth to about the same degree. Approximately 170 ppm ozone produced comparable magnitudes of inhibition. In all cases basal respiration is inhibited little or not at all. Depending on concentration, PAN and the UV mixtures produce non-lethal inhibition of growth. With the passage of time this inhibition tends to disappear.