Plastid terminal oxidase (PTOX) has the potential to act as a safety valve for excess excitation energy in the alpine plant species Ranunculus glacialis L. - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Plant, Cell and Environment Année : 2013

Plastid terminal oxidase (PTOX) has the potential to act as a safety valve for excess excitation energy in the alpine plant species Ranunculus glacialis L.

Résumé

Ranunculus glacialis leaves were tested for their plastid terminal oxidase (PTOX) content and electron flow to photorespiration and to alternative acceptors. In shade-leaves, the PTOX and NAD(P)H dehydrogenase (NDH) content were markedly lower than in sun-leaves. Carbon assimilation/light and C(i) response curves were not different in sun- and shade-leaves, but photosynthetic capacity was the highest in sun-leaves. Based on calculation of the apparent specificity factor of ribulose 1*5-bisphosphate carboxylase/oxygenase (Rubisco), the magnitude of alternative electron flow unrelated to carboxylation and oxygenation of Rubisco correlated to the PTOX content in sun-, shade- and growth chamber-leaves. Similarly, fluorescence induction kinetics indicated more complete and more rapid reoxidation of the plastoquinone (PQ) pool in sun- than in shade-leaves. Blocking electron flow to assimilation, photorespiration and the Mehler reaction with appropriate inhibitors showed that sun-leaves were able to maintain higher electron flow and PQ oxidation. The results suggest that PTOX can act as a safety valve in R. glacialis leaves under conditions where incident photon flux density (PFD) exceeds the growth PFD and under conditions where the plastoquinone pool is highly reduced. Such conditions can occur frequently in alpine climates due to rapid light and temperature changes.

Dates et versions

hal-00789674 , version 1 (18-02-2013)

Identifiants

Citer

Constance Laureau, Rosine de Paepe, Gwendal Latouche, Maria Moreno-Chacón, Giovanni Finazzi, et al.. Plastid terminal oxidase (PTOX) has the potential to act as a safety valve for excess excitation energy in the alpine plant species Ranunculus glacialis L.. Plant, Cell and Environment, 2013, 36 (7), pp.1296 - 1310. ⟨10.1111/pce.12059⟩. ⟨hal-00789674⟩
237 Consultations
0 Téléchargements

Altmetric

Partager

Gmail Mastodon Facebook X LinkedIn More