Multiple Consequences Induced by Epidermally-Located Anthocyanins in Young, Mature and Senescent Leaves of Prunus

Anthocyanic morphs are generally less efficient in terms of carbon gain, but, in turn, are
more photoprotected than anthocyanin-less ones. To date, mature leaves of different
morphs or leaves at different developmental stages within the same species have
generally been compared, whereas there is a lack of knowledge regarding different stages
of development of red vs. green leaves. Leaves (1-, 7-, and 13-week-old) of red- (RLP)
and green-leafed (GLP) Prunus in terms of photosynthetic rate, carbon metabolism and
photoprotective mechanisms were compared to test whether anthocyanin-equipped
leaves perform better than anthocyanin-less leaves and whether photoprotection
is the primary role of epidermally-located anthocyanins, using for the first time a
recently-developed parameter of chlorophyll fluorescence (qPd). GLP leaves had a higher
photosynthetic rate in 1- and 7-week-old leaves, but RLP leaves performed better at
an early stage of senescence and had a longer leaf lifespan. Anthocyanins contributed
to leaf photoprotection throughout the leaf development, but were tightly coordinated
with carotenoids. Besides photoprotecting, we propose that epidermal anthocyanins
may be principally synthetized to maintain an efficient carbon-sink strength in young and
senescent leaves, thus extending the RLP leaf lifespan.