title: Carbohydrate concentrations and freezing stress resistance of silver birch buds grown under elevated temperature and ozone.
abstract: The effects of slightly elevated temperature (+0.8 °C), ozone (O3) concentration (1.3 × ambient O3 concentration) and their combination on over-wintering buds of Betula pendula Roth were studied after two growing seasons of exposure in the field. Carbohydrate concentrations, freezing stress resistance (FSR), bud dry weight to fresh weight ratio, and transcript levels of cytochrome oxidase (COX), alternative oxidase (AOX) and dehydrin (LTI36) genes were studied in two clones (clones 12 and 25) in December. Elevated temperature increased the bud dry weight to fresh weight ratio and the ratio of raffinose family oligosaccharides to sucrose and the transcript levels of the dehydrin (LTI36) gene (in clone 12 only), but did not alter the FSR of the buds. Genotype-specific alterations in carbohydrate metabolism were found in the buds grown under elevated O3. The treatments did not significantly affect the transcript level of the COX or AOX genes. No clear pattern of an interactive effect between elevated temperature and O3 concentration was found. According to these data, the increase in autumnal temperatures and slightly increasing O3 concentrations do not increase the risk for freeze-induced damage in winter in silver birch buds, although some alterations in bud physiology occur.
authors: Finnish Forest Research Institute, FIN-77600 Suonenjoki, Finland. Johanna.riikonen@metla.fi
authors: Johanna
authors: J
authors: Riikonen
authors: Sari
authors: S
authors: Kontunen-Soppela
authors: Elina
authors: E
authors: Vapaavuori
authors: Arja
authors: A
authors: Tervahauta
authors: Marjo
authors: M
authors: Tuomainen
authors: Elina
authors: E
authors: Oksanen
mesh_terms: D000064:Acclimatization; D029662:Betula / Q000201:enzymology / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D018533:Biomass; D050260:Carbohydrate Metabolism; D002241:Carbohydrates / Q000032:analysis; D003576:Electron Transport Complex IV / Q000235:genetics; D005615:Freezing; D018506:Gene Expression Regulation, Plant; D005838:Genotype; D024101:Mitochondrial Proteins / Q000235:genetics; D010088:Oxidoreductases / Q000235:genetics; D010126:Ozone; D010788:Photosynthesis; D018515:Plant Leaves; D010940:Plant Proteins / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics; D018749:RNA, Plant / Q000235:genetics; D012621:Seasons; D013696:Temperature; D013997:Time Factors; D014197:Trees; D000099188:Alternative Oxidase
chemical_list: D002241:Carbohydrates; D003576:Electron Transport Complex IV; D024101:Mitochondrial Proteins; D010088:Oxidoreductases; D010126:Ozone; D010940:Plant Proteins; D012333:RNA, Messenger; D018749:RNA, Plant; D000099188:Alternative Oxidase; C070556:dehydrin proteins, plant