Mitochondrial alternative oxidase pathway acts as an electron sink during photosynthetic induction in Rumex K-1 leaves

Chloroplast PSII photochemical efficiency is upregulated more rapidly than CO2 assimilation during photosynthesis induction, suggesting the existence of other electron sinks than that of CO2 assimilation. We hypothesized that the mitochondrial alternative oxidase (AOX) pathway could be such a sink. Inhibition of the AOX restricted light activation of the malate-oxaloacetate shuttle and caused an excessive reduction of PSI acceptor side and substantial accumulation of QA-, hindering the photosynthetic linear electron transport rate (ETR) and leading to an imbalance between light energy absorption and exploitation during photosynthetic induction. ETR limitation also restricted the formation of thylakoid pH gradient, evidenced by a decreased de-epoxidation of the xanthophyll cycle, thus preventing nonphotochemical quenching. Delayed CO2 assimilation due to thylakoid pH gradient restriction was partially reversed by exogenous ATP application. The AOX pathway acts as a photosynthetic electron sink, protecting the photosynthetic apparatus against photoinhibition and accelerating the induction of CO2 assimilation during photosynthetic induction in Rumex K-1 leaves..

Medienart:

E-Artikel

Erscheinungsjahr:

2021

Erschienen:

2021

Enthalten in:

Zur Gesamtaufnahme - volume:59

Enthalten in:

Photosynthetica - 59(2021), 4, Seite 615-624

Sprache:

Englisch

Beteiligte Personen:

D.D. CHENG [VerfasserIn]
L.T. ZHANG [VerfasserIn]

Links:

doi.org [kostenfrei]
doaj.org [kostenfrei]
ps.ueb.cas.cz [kostenfrei]
Journal toc [kostenfrei]
Journal toc [kostenfrei]

Themen:

Alternative oxidase
Botany
Photodamage
Photosynthetic induction
Photosystem ii photochemical efficiency
Rumex k-1

doi:

10.32615/ps.2021.047

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

DOAJ019452918