Profiles of photosynthesis within red and green leaves of Quintinia serrata.

We have measured photosynthesis at the cellular, tissue, and whole leaf levels to understand the role of anthocyanin pigments on patterns of light utilization. Profiles of chlorophyll fluorescence through sections of red and green leaves of Quintinia serrata showed that anthocyanins in the mesophyll restricted absorption of green light to the uppermost palisade mesophyll. The distribution was further restricted when anthocyanins were also present in the upper epidermis. Mesophyll cells located beneath a cyanic light-filter assumed the characteristic photosynthetic features of shade-adapted cells. As a result, red leaves showed a 23% reduction in CO2 assimilation under light-saturating conditions, and a lower threshold irradiance for light-saturation, relative to those of green leaves. The photosynthetic characteristics of red leaves are comparable to those of shade-acclimated plants.