Plant Protective Response to Enhanced UV-B Radiation under Field Conditions: Leaf Optical Properties and Photosynthesis

摘要

Plants of Vicia faba were grown in the field during early to midsummer while receiving two levels of supplemental UV-B radiation. Light-saturated photosynthesis and stomatal diffusive conductance of intact leaves did not show any indications of UV-radiation damage. Supplemental UV treatment did cause increased concentrations of UV-absorbing flavonoid pigments in leaf tissues and decreased epidermal transmittance of UV radiation. While epidermal transmittance was reduced 30% under the low-UV treatment, the high-UV treatment failed to elicit as large a change. However, total amounts of flavonoids in other leaf tissues did increase in response to the high-UV treatment up to 12% greater per unit leaf area than for control plants. This may have been a major factor protecting underlying photosynthetic tissues. (Copyright (c) 1985 Pergamon Press Ltd.)