Photosynthetic complex stoichiometry dynamics in higher plants: environmental acclimation and photosynthetic flux control

Abstract

The composition of the photosynthetic apparatus of higher plants is dynamically adjusted to long-term changes in environmental conditions such as growth light intensity and light quality, and to changing metabolic demands for ATP and NADPH imposed by stresses and leaf aging. By changing photosynthetic complex stoichiometry, a long-term imbalance between the photosynthetic production of ATP and NADPH and their metabolic consumption is avoided, and cytotoxic side reactions are minimized. Otherwise, an excess capacity of the light reactions, relative to the demands of primary metabolism, could result in a disturbance of cellular redox homeostasis and an increased production of reactive oxygen species, leading to the destruction of the photosynthetic apparatus and the initiation of cell death programs. In this review, changes of the abundances of the different constituents of the photosynthetic apparatus in response to environmental conditions and during leaf ontogenesis are summarized. The contributions of the different photosynthetic complexes to photosynthetic flux control and the regulation of electron transport are discussed.

Chlorophyll b degradation by chlorophyll b reductase under high-light conditions

“…The chlorophyll b level changes depending on the light intensity (Schöttler and Toth 2014 (Horie et al 2009). When the nyc1 and cbr plants are placed under dark conditions to induce chlorophyll degradation, chlorophyll a is degraded, whereas the chlorophyll b level remains stable.…”

Inducible Repression of Nuclear-Encoded Subunits of the Cytochrome b6f Complex in Tobacco Reveals an Extraordinarily Long Lifetime of the Complex

“…In addition to its low enzymatic turnover number, the cyt-bf is usually present in, or at maximum, stoichiometric amounts relative to both photosystems (Whitmarsh and Ort, 1984;Chow and Anderson, 1987;Evans, 1987Evans, , 1988Chow et al, 1988; De la Torre and Burkey, 1990; Anderson et al, 1997;Kirchhoff et al, 2002;Schöttler et al, 2004). Thus, plastoquinol reoxidation is the bottleneck of linear electron flux and should play a predominant role in photosynthetic flux control (Anderson, 1992;Schöttler and Tóth, 2014). It is noteworthy that in investigations published before 1997, cyt-bf contents may have been overestimated by 30%, because the difference extinction coefficient of cytochrome f has been substantially revised since then (Metzger et al, 1997), making a limiting function of the cyt-bf even more likely.…”

Fotossíntese de espécies de Anibae em resposta à exposição a ambientes contrastantes de luz

“…espécies para amenizar os fotodanos promovidos pelo excesso de irradiância. Alterações nas concentrações foliares de pigmentos cloroplastídicos também constituem estratégias para alcançar a melhor eficiência fotoquímica (Schöttler & Tóth 2014). Neste sentido, a redução na concentração de pigmentos (ICC) em pleno sol e o posterior aumento em sombra também pode ser entendido como estratégia de fotoaclimatação.…”