The Effect of Ultraviolet Radiation on Wheat Root Vesicles Enriched in Plasma Membrane

The irradiation of plant cells with UV radiation (254nm) causes various solutes to leak from the cells. Vesicles enriched in plasma membranes were prepared from wheat roots. These were used to determine whether UV radiation alters membrane function by direct action on the membranes and to distinguish between the chemical effects produced by high and low fluences of UV. The plasma membrane‐associated K + ‐stimulated ATPase was very sensitive to UV radiation (100% inhibition with 1.35kJ/m 2 ). ATPase activity measured in the absence of K + and K + ‐stimulated ATPase activity measured in the presence of diethylstilbestrol were much less sensitive. Lipid breakdown, as measured by malondialdehyde production, occurred only at UV fluences greater than 1.8 kJ/m 2 .