Dergiler / Turkish Journal of Botany / 2015 / Cilt: 39 - Sayı: 3
Temperature sensitivity of photosystem II in isolated thylakoid membranes from fluridone-treated pea leaves
- Sayfa
- 420–428
- DOI
- —
Özet
High temperature-induced changes in the photosystem II (PSII) activity of thylakoid membranes isolated from pea (Pisum sativum L. 'Ran') plants treated with low (10-8 M) and high (10-7 M) concentrations of fluridone were investigated. Pulse amplitude modulated (PAM) chlorophyll fluorescence and photosynthetic oxygen evolution (measured by polarographic oxygen rate electrode) were used to estimate the effect of high temperature on the functional activity of PSII. Higher temperature treatments lead to stronger inhibition of the flash oxygen evolution than the primary photochemistry of PSII (Fv/Fm). The inhibitory effect of higher temperature on the PSII? centers is stronger than on the PSIIÃ centers. The heat-induced damage in the PSII$\alpha$ centers as well as in the donor side of all PSII centers (PSII$\alpha$ and PSIIÃ) is accentuated by fluridone.
Abstract
High temperature-induced changes in the photosystem II (PSII) activity of thylakoid membranes isolated from pea (Pisum sativum L. 'Ran') plants treated with low (10-8 M) and high (10-7 M) concentrations of fluridone were investigated. Pulse amplitude modulated (PAM) chlorophyll fluorescence and photosynthetic oxygen evolution (measured by polarographic oxygen rate electrode) were used to estimate the effect of high temperature on the functional activity of PSII. Higher temperature treatments lead to stronger inhibition of the flash oxygen evolution than the primary photochemistry of PSII (Fv/Fm). The inhibitory effect of higher temperature on the PSII? centers is stronger than on the PSIIÃ centers. The heat-induced damage in the PSII$\alpha$ centers as well as in the donor side of all PSII centers (PSII$\alpha$ and PSIIÃ) is accentuated by fluridone.