Photoprotective pigments in red and green gametophytes of two New Zealand liverworts

Abstract

Gametophytes of Jamesoniella colorata (Jungermanniaceae) and Isotachis lyallii (Isotachi‐daceae) produce red leaves in exposed habitats, but green leaves in shaded environments. To understand the functional significance of this colour polymorphism, the anatomy, pigment composition, optical properties, and kinetics of chlorophyll a fluorescence were compared for red and green gametophytes. Both colour morphs were structurally similar, but the red leaves held unidentified red pigment(s) firmly associated with the cell wall. Green morphs contained more chlorophylls and carotenoids, and had higher ratios of chlorophylls to carotenoids, than did the red morphs. Red leaves absorbed 10% more photosynthetically active radiation, with a maximum at 540 nm, than did the green leaves. Under high irradiance, the red leaves maintained higher apparent quantum efficiencies for photosynthesis, and had larger photochemical and non‐photochemical quenching values. The data indicate that red gametophytes have the greater potential to mitigate the damaging effects of high irradiance.