Enhanced photosystem 2 thermostability during leaf growth of Elm (Ulmus pumila) seedlings

Title:

Enhanced photosystem 2 thermostability during leaf growth of Elm (Ulmus pumila) seedlings

Creator:

Jiang, C.-D., Jiang, G.-M., Wang, X., Li, L.-H., Biswas, D. K., and Li, Y.-G.

Identifier:

https://cdk.lib.cas.cz/client/handle/uuid:09c9a053-b67c-4575-abb4-8e3109d7efdb
uuid:09c9a053-b67c-4575-abb4-8e3109d7efdb
issn:0300-3604
doi:10.1007/s11099-006-0044-3

Subject:

chlorophyll a fluorescence, JIP-test, leaf growth, and thermostability of photosystem 2

Type:

model:article and TEXT

Format:

bez média and svazek

Description:

We examined photosynthetic activities and thermostability of photosystem 2 (PS2) in leaves of elm (Ulmus pumila) seedlings from initiation to full expansion. During leaf development, net photosynthetic rate (PN) increased gradually and reached the maximum when leaves were fully developed. In parallel with the increase of PN, chlorophyll (Chl) content was significantly elevated. Chl a fluorescence measurements showed that the maximum quantum yield of PS2 (ϕPS2), the efficiency a trapped exciton, moved an electron into the electron transport chain further than QA- (Ψo), and the quantum yield of electron transport beyond QA (ϕEo) increased gradually. These results were independently confirmed by our low irradiance experiments. When subjected to progressive heat stress, the young leaves exhibited considerably lower ϕPS2 and higher minimal fluorescence (F0) than the mature leaves, revealing the highly sensitive nature of PS2 under heat in the newly initiating leaves. Further analysis showed that PS2 structure in the newly initiating leaves was strongly altered under heat, as evidenced by the increased fluorescence signals at the position of the K step. We therefore demonstrated an inhibition in the oxygen-evolving complex (OEC) in the young leaves. This resulted in decrease in amount of the functional PS2 reaction centres and relative increase in the PS2 reaction centres with inhibited electron transport at the acceptor side under heat. We suggest that the enhanced thermostability of PS2 during leaf development is associated with improved OEC stability. and C.-D. Jiang ... [et al.].

Language:

Multiple languages

Rights:

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

Coverage:

411-418

Source:

Photosynthetica | 2006 Volume:44 | Number:3

Harvested from:

CDK

Metadata only:

false