Abstract
Natural seasonal variation and the effects of cold treatment and nitrogen fertilization on protein
expression with special emphasis on dehydrin proteins, were studied using different aged Scots pine
(Pinus sylvestris L.). Several different dehydrins were found and their expression
depended on the tissue type, tree age or specific treatment. Their concentrations fluctuated seasonally and
in response to nitrogen fertilization, but no effects of low temperature on the dehydrins of seedlings were
observed. A 60-kDa dehydrin was associated with cold acclimation in the bud and bark tissues of mature trees
and in the needles of seedlings. In the needles of mature trees, this dehydrin was associated with
springtime desiccation, which was detected as a significant decrease in the osmotic potential of
needles.
The quantity and quality of soluble proteins altered seasonally in Scots pine tissues, but low
temperature treatment alone did not have any effect on the proteins. Soluble protein concentration increased
during autumn and decreased in spring in buds and bark, but not in the needles of mature trees. In needles
of seedlings, however, protein concentrations altered seasonally. Several proteins, of varying molecular
weights, were more abundant in winter in all the tissues studied and some increased in concentration in the
nitrogen-fertilized seedlings. The role of these proteins as a storage reserve in Scots pine is
discussed.
The osmotic potential of needles showed seasonal fluctuation, being high in the summer and low during
the winter. Low temperature treatment decreased the osmotic and water potential of needles and increased the
concentrations of soluble sugars in seedlings. Based on carbohydrate analyses, the metabolism of seedlings
acclimated to low temperature in less than ten days. Nitrogen fertilization increased the content of total
nitrogen and the soluble protein concentrations in the needles of seedlings and the growth both in the
mature trees and seedlings. Although the frost resistance showed no response to nitrogen-fertilization, the
soluble proteins and dehydrins were affected in a manner that suggested an earlier growth resumption of
spring in the fertilized trees.
| Identifer | oai:union.ndltd.org:oulo.fi/oai:oulu.fi:isbn951-42-5911-4 |
| Date | 12 February 2001 |
| Creators | Kontunen-Soppela, S. (Sari) |
| Publisher | University of Oulu |
| Source Sets | University of Oulu |
| Language | English |
| Detected Language | English |
| Type | info:eu-repo/semantics/doctoralThesis, info:eu-repo/semantics/publishedVersion |
| Format | application/pdf |
| Rights | info:eu-repo/semantics/openAccess, © University of Oulu, 2001 |
| Relation | info:eu-repo/semantics/altIdentifier/pissn/0355-3191, info:eu-repo/semantics/altIdentifier/eissn/1796-220X |
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