Interactive Effects of Salinity and Ozone on Growth and Yield of Garden Beet

Abstract

AbstractThe interactive effects of root media salinity and ambient ozone on injury, growth, and yield of garden beets (Beta vulgaris L.) were determined under controlled environmental conditions. Plants were grown in nonsaline and saline nutrient solution cultures having osmotic potentials of −0.4, −4.4, and −8.4 bars, respectively, and were exposed 5 weeks to 0.20 ppm ozone for 0 to 3 hours/day.Growth of the nonsaline beet plants were not significantly affected by 0.20 ppm ozone until exposure times exceeded 1 hour/day, although foliar injury in the form of a reddish‐purple stipple had developed on mature leaves. Longer ozone exposures produced severe leaf necrosis and reduced the growth of tops and storage and fibrous roots as much as 50, 40, and 67%, respectively. In contrast, foliar ozone injury on plants grown in saline media developed more slowly and the growth of both tops and roots were relatively unaffected by ozone exposures of up to 3 hours/day. Some reduction in yield of storage roots did occur at −4.4 bars osmotic potential when plants were exposed to ozone for 3 hours/day. However, the beneficial effect of salinity in reducing ozone damage was offset by the suppressive effect of salinity on the yield of the storage root. Dry weights of the storage root were reduced nearly 25% at −4.4 bars osmotic potential.