Effects of leaf epidermis peeling on the CO2 exchange rate and chlorophyll fluorescence quenching, and estimation of photorespiration rate from electron transport in mungbean (Vigna radiata (L.) Wilczek) leaves

Shinji Tokuda, Fumitake Kubota, Kenji Hirao, Kazuyuki Saitou

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)

Abstract

CO2 gas exchange rates (CER) in a peeled leaf (PL) and nonpeeled leaf (NL) of mungbean (Vigna radiata (L.) Wilczek) were measured in a saturating light intensity to identify their responses to CO2 concentrations ([CO2]) and leaf temperatures. The CER of PL was regarded as an indicator for the photosynthetic potential in mesophyll. When measured at 35 °C, CER was enhanced by peeling the epidermis, whereas it was less effective at 25 °C and almost not effective at 15 °C. In [CO2]-CER response curves, CER of PL had a highest plateau in 500 to 1,000μmolmol-1 [CO2] at 35 °C, whereas at both 25 and 15 °C CER showed a peak in 500μmolmol-1 [CO2]. When measured in the air of 20% O2 concentration ([O2]) in a light intensity of 300μmolm-2s-1 photosynthetically photon flux density (PPFD) at 25 °C, the CO2 quantum yield (ΦCO2) in PL was higher than that in NL, whereas the photosystem II (PSII) quantum yield (Φe) was a little lower in PL. The number (k) of electron equivalents required to fix 1 mol CO2 was greatly increased in NL due to the increased photorespiration. In 2% [O2] k of PL was 4.62, which was a little larger than a theoretical minimum (k=4). From the relationships between k, CER and adenosine 5′-triphosphate (ATP) required for photosynthesis, the rates of photorespiration were estimated in different environments.

Original languageEnglish
Pages (from-to)293-302
Number of pages10
JournalJournal of the Faculty of Agriculture, Kyushu University
Volume43
Issue number3-4
Publication statusPublished - Feb 1999

All Science Journal Classification (ASJC) codes

  • Agricultural and Biological Sciences (miscellaneous)

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