Freezing stress and membrane injury of Norway spruce (Picea abies) tissues |
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Authors: | Pawel Pukacki Stanislawa Pukacka |
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Affiliation: | Polish Academy of Sciences, Inst. of Dendrology, PL-62–035 Kórnik, Poland. |
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Abstract: | Effects of sub-zero temperatures (−5 to −35°C) on the tissues of needles, buds and shoots of Norway spruce [ Picea abies (L.) Karst.] were studied. The freezing caused increased efflux of cellular electrolytes. Freezing injury of the primordial shoots and 1-year-old shoots was the result of the spontaneous freezing of a deep supercooled cellular water. The crystallization injures the cellular membranes leading to the loss of semipermeability and to the drastic efflux of K+. In the needles there was no deep supercooling of water and two patterns of changes in the membranes, depending upon the range of the applied temperatures, could be distinguished. At 0 to – 25°C, which do not kill the cells, we observed a disturbance in the membrane semipermeability as monitored by electrolytes efflux within a few hours after thawing of the needles. At lower temperatures (−35°C) we observed irreversible loss of the membrane semipermeability, and death of the tissue. Those changes occurred 10 h after thawing and were probably caused by the released lytic enzymes and some toxic compounds, which acted on the cellular membranes. |
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Keywords: | Freezing injury ion leakage membrane semipermeability supercooling |
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