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Effects of Season and Low Temperature on Polypeptides from Thylakoids Isolated from Chloroplasts of Pinus silvestris
Author(s) -
ÖQUIST GUNNAR,
MARTIN BJÖRN,
MÅRTENSSON OLLE,
CHRISTERSSON LARS,
MALMBERG GUNILLA
Publication year - 1978
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.1978.tb08636.x
Subject(s) - p700 , chloroplast , darkness , thylakoid , chemistry , chlorophyll , chlorophyll a , polyacrylamide gel electrophoresis , frost (temperature) , chromatography , botany , biochemistry , photosystem i , biology , meteorology , organic chemistry , physics , gene , enzyme
Thylakoids isolated from pine chloroplasts were solubilized by sodium dodecyl sulphate and the polypeptides were separated by polyacrylamide gel electrophoresis. The chlorophyll‐protein complexes, P700‐CP a 1 and LH‐CP a/b , had apparent molecular weights of 92,000 and 25,000, respectively. When the chlorophyll of P700‐CP a 1 was extracted or photobleached, the apoprotein of P700‐CP a 1 appeared as a pronounced peak in the polypeptide scan profile. The molecular weight of the apoprotein was 70,000. During autumn and winter the complex P700‐CP a 1 was destroyed. This was primarily caused by bleaching of chlorophyll, as the 70,000 apoprotein increased in the scan profile when the complex P700‐CP a 1 decreased. The winter destruction of P700‐CP a 1 was less pronounced in old needles than in young. Freezing of frost‐hardened seedlings did not change the polypeptide scan profile, unless the temperature was lowered below the frost‐killing point followed by thawing and post‐treatment in light or darkness above 0°C. Again the main destruction occurred in the P700‐CP a 1 complex, but in this case no significant increase of the apoprotein was observed. These alterations in the polypeptide scan profile of frost‐killed needles were not caused by the low temperature treatment as such, but they occurred after thawing of the needles.