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

Abstract

Gametophytes of Jamesoniella colorata (Jungermanniaceae) and Isotachis lyallii (Isotachidaceae) 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.

Desiccation tolerance in red and green gametophytes of Jamesoniella colorata in relation to photoprotection

“…The red morph held proportionately more carotenoids than did the green morph (Table 2), which could relate to a better oxygen radical scavenging capacity. In addition, they contain red pigments in the cell wall of their leaves with possible light-screening characteristics (Hooijmaijers and Gould 2007). Red pigments, therefore, could reduce excess light quanta that strike the chloroplasts during stressful periods, such as during drying and rehydration, and consequently reduce photooxidative damage.…”

“…3). Even though the red form has a greater NPQ capacity at high irradiances than the greens (Hooijmaijers and Gould 2007), the low irradiance used in the present study might have prevented exploitation of enhanced xanthophyll cycle activity, which is known to be a light dependent process (Demmig-Adams and Adams III 1992, Horton et al 1996). Gametophytes of J. colorata did not have a particularly fast recovery from severe water deficits, and only the red gametophytes recovered completely from mild water deficits within 12 h after rehydration (Figs.…”

“…Red pigments in bryophytes, therefore, are hardly well placed to participate in metabolic processes and thus not likely to be involved in cell osmotic regulation. However, red cell wall pigments in the leaves of J. colorata have been implicated to assist photoprotection through light-screening (Hooijmaijers and Gould 2007), and consequently could reduce the susceptibility for photooxidative damage during dehydration-rehydration cycles.…”

Morfología y distribución de Dolotortula mniifolia y Trachyphyllum dusenii (Bryophyta) en Panamá.

“…Los especímenes colectados en el Cerro Chucantí se encontraron en un sitio más seco y expuesto que los colectados en El Valle de Antón. En hepáticas foliosas se ha demostrado que pigmentos asociados a las paredes celulares pueden ayudar a mitigar daños celulares producto de altas intensidades lumínicas y aumentar la tolerancia a la desecación (Hooijmaijers & Gould, 2007;Hooijmaijers, 2008).…”

Cloning gene fragment containing sequences of B gene activates anthocyanin biosynthesis in local sticky corn cultivars (Zea mays subsp. ceratina (Kuelshov) Zhuk)

“…Anthocyanin được tìm thấy trong không bào của tế bào biểu bì, mô mạch dẫn với màu đỏ, đỏ tía, tím và xanh đậm (David et al, 2006;Gould et al, 2006;Hooijmaijers et al, 2007). Anthocyanin được coi là một dấu hiện stress và là một phần trong cơ chế hạn chế tác động của stress hạn gây ra.…”