Photosynthetic downregulation in leaves of the Japanese white birch grown under elevated CO(2) concentration does not change their temperature-dependent susceptibility to photoinhibition.
Physiol Plant
; 147(2): 159-68, 2013 Feb.
Article
em En
| MEDLINE
| ID: mdl-22607385
ABSTRACT
To determine the effects of elevated CO(2) concentration ([CO(2)]) on the temperature-dependent photosynthetic properties, we measured gas exchange and chlorophyll fluorescence at various leaf temperatures (15, 20, 25, 30, 35 and 40°C) in 1-year-old seedlings of the Japanese white birch (Betula platyphylla var. japonica), grown in a phytotron under natural daylight at two [CO(2)] levels (ambient 400 µmol mol(-1) and elevated 800 µmol mol(-1)) and limited N availability (90 mg N plant(-1)). Plants grown under elevated [CO(2)] exhibited photosynthetic downregulation, indicated by a decrease in the carboxylation capacity of Rubisco. At temperatures above 30°C, the net photosynthetic rates of elevated-CO(2)-grown plants exceeded those grown under ambient [CO(2)] when compared at their growth [CO(2)]. Electron transport rates were significantly lower in elevated-CO(2)-grown plants than ambient-CO(2)-grown ones at temperatures below 25°C. However, no significant difference was observed in the fraction of excess light energy [(1 - q(P))× F(v)'/F(m)'] between CO(2) treatments across the temperature range. The quantum yield of regulated non-photochemical energy loss was significantly higher in elevated-CO(2)-grown plants than ambient, when compared at their respective growth [CO(2)] below 25°C. These results suggest that elevated-CO(2)-induced downregulation might not exacerbate the temperature-dependent susceptibility to photoinhibition, because reduced energy consumption by electron transport was compensated for by increased thermal energy dissipation at low temperatures.
Texto completo:
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Base de dados:
MEDLINE
Assunto principal:
Fotossíntese
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Temperatura
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Dióxido de Carbono
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Betula
Idioma:
En
Ano de publicação:
2013
Tipo de documento:
Article