Ozone-Induced Reduction in Quantity of Ribulose-1,5-bisphosphate Carboxylase in Alfalfa Foliage

The concentration of ribulose-1,5-bisphosphate carboxylase was measured in the foliage of ;Moapa 69,' ;Ladak,' and ;Vernal' cultivars of alfalfa (Medicago sativa L.) after plants were exposed to 0.25 or 0.30 microliters per liter ozone for 2 hours. The quantity of ribulose-1,5-bisphosphate carboxylase decreased 80%, 68%, and 36% in leaves which did not exhibit ozone symptoms and to undetectable levels, 99% and 79% in symptomatic foliage for each cultivar, respectively.