Spectroscopic analiysis of chlorophyll bleaching in heat-pretreated thylakoid membranes isolated from cucumber cotyledons

Title:

Spectroscopic analiysis of chlorophyll bleaching in heat-pretreated thylakoid membranes isolated from cucumber cotyledons

Creator:

Waloszek, A., Tulej, M., and Wbeckowski, S.

Identifier:

https://cdk.lib.cas.cz/client/handle/uuid:37340374-6e95-43da-8d45-9e2f03536a84
uuid:37340374-6e95-43da-8d45-9e2f03536a84
urnnbn:urn:nbn:cz:aba007-000fap

Type:

model:internalpart and TEXT

Format:

print

Description:

Effects of heat pre-treatment (60 oC for 15 min) on the chlorophyll (Chl) bleaching and excitation energy transfer in thylakoids, isolated from the cucumber cotyledons, were studied by anaiysis of the overlapping absorption and the low temperature fluorescence spectra. The Chl forms C678 and C672 appeared to be the most heat-susceptible components, whereas C684 was found to be very heat-stable. Subsequent exposure of the thylakoid suspension to a high photon flux density (ca. 3 500 pmol m‘2 s'i) caused further bleaching of all the tested forms: ca. 8-20 or 2-5 % of chlorophyll was degraded duríng the initial (0-4 min) or later (4-10 min) period of irradiation, respectively. The heat pre-treatment of thylakoids led to the decrease of the 472 and 486 nm bands in Chl fluorescence excitation spectrum and the 730 nm band in the Chl fluorescence emission spectrum. The F730/F685 ratio decreased by ca. 4-, 3- or 2-fold when excited with the wavelengths of 437, 742 or 486 nm, respectively. These ratios increased by 60-90 % after 10 min irradiation with high photon flnx density.

Language:

Multiple languages

Rights:

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

Coverage:

109-118 and 127-136

Source:

Photosynthetica | 1992 Volume:27 | Number:1-2

Harvested from:

CDK

Metadata only:

false