Diurnal course of photochemical activity of winter-adapted Scots pine at subzero temperatures

Title:

Diurnal course of photochemical activity of winter-adapted Scots pine at subzero temperatures

Creator:

Šiffel, P. and Šantrůček, J.

Identifier:

https://cdk.lib.cas.cz/client/handle/uuid:1f652970-b4f1-425e-bb75-ae24af94818f
uuid:1f652970-b4f1-425e-bb75-ae24af94818f
issn:0300-3604
doi:10.1007/s11099-005-0063-5

Subject:

chlorophyll fluorescence, cold adaptaation, diurnal changes, photosystem 2, Pinus sylvestris L., and quantum yield

Type:

model:article and TEXT

Format:

bez média and svazek

Description:

The photochemical activity of native Central Siberian Scots pine trees (Pinus sylvestris L) was estimated from the middle of February to the middle of March 2001. We measured chlorophyll (Chl) fluorescence in attached intact needles from trees located approx. 30 km west of the Yenisey river (60°44'N, 89°09'E) near the village of Zotino. In this period, the air temperature varied between -39 °C and +7 °C. At temperatures below -10 °C, P. sylvestris needles did not exhibit any variable Chl fluorescence during the daylight period. During the night, however, the effective quantum yield of photosystem 2 (PS2) photochemistry, Φ2 [Φ2 = (Fm' - Ft)/Fm'), increased from values near zero to values between 0.05 and 0.20 depending on the needle temperature and sample investigated. The increase started soon after dusk and lasted for 3-6 h depending on the temperature. A faster increase of Φ2 was found for temperatures around -16 °C, and lower rates occurred at lower temperatures. Irrespective of the temperature, Φ2 decreased rapidly to near zero values at dawn, when the photosynthetic photon flux density increased to about 1-5 µmol m-2 s-1, and remained near zero throughout the day. At temperatures higher than -10 °C, the diurnal decrease and the nocturnal increase of Φ2 were less distinct or disappeared completely. Hence the winter-adapted Scots pine maintains some photochemical activity of PS2 even at extremely cold temperatures. The capacity of photochemical reactions below -10 °C is, however, very limited and PS2 photochemistry is saturated by an extremely low irradiance (less than 5 µmol m-2 s-1). and P. Šiffel, J. Šantrůček.

Language:

Multiple languages

Rights:

http://creativecommons.org/licenses/by-nc-sa/4.0/
policy:public

Coverage:

395-402

Source:

Photosynthetica | 2005 Volume:43 | Number:3

Harvested from:

CDK

Metadata only:

false