Do anthocyanins protect leaves of New Zealand native species from UV-B?

Abstract

Anthocyanin pigments must reside in the uppermost tissues of a leaf if they are to be effective as UV-B filters. However, in our survey of leaves and phylloclades from 25 native New Zealand plants, only four species held anthocyanins in the upper epidermis and/or hypodermis. For 18 species, anthocyanins were located in vacuoles of the palisade and/or spongy mesophyll, the same tissues that are potentially susceptible to UV-B-induced photoinhibition. Leaf pigmentation patterns varied among species and were correlated to the histological distributions of anthocyanins. Most species held cyanidin-derived pigments. UV-B filtration cannot be regarded as a unified theory for anthocyanin function in leaves.