CO₂ enrichment and development of freezing tolerance in Norway spruce

Abstract

Plant growth and adaptation to cold and freezing temperatures in a CO2‐enriched atmosphere have received little attention despite their predicted effects on plant distribution and productivity. In this study we looked at the interaction between elevated CO2 and development of freezing tolerance in Norway spruce (Picea abies (L.) Karst.). First‐year seedlings were grown under controlled conditions in an atmosphere enriched in CO2 (70 Pa) for one simulated growth season. We measured shoot growth, registered the timing of growth cessation and bud set, measured needle net photosynthetic rate, and determined needle carbohydrate concentration (fructose+pinitol, glucose, sucrose, inositol, raffinose and starch). Freezing tolerance (LT50) was determined after exposing whole seedlings to temperatures ranging from −6.5 to −36.0°C and scoring for visual needle browning. Elevated CO2 did not affect height growth or the timing of growth cessation and bud set. The only statistically significant effects of CO2 treatment were on seedling dry weight, percent dry matter and starch content. During the three weeks after growth cessation and bud set, freezing tolerance increased from −10 to −35°C, and there was a marked increase in all soluble sugars except inositol. However, neither freezing tolerance nor the concentration of soluble sugars was significantly influenced by elevated CO2.

Photosynthetic responses of Larrea tridentata to seasonal temperature extremes under elevated CO2

“…At the same time, the maximum yield of PSII, an indicator of photosynthetic performance in response to temperature stress (Larcher, 1995; Loik et al ., 2000), was lowest during spring. These results are consistent with those for Norway spruce, for which soluble carbohydrate content and freezing tolerance were not affected by elevated CO 2 (Dalen et al ., 2001). For several grassland species from different functional groups, Obrist et al .…”

CO2 enrichment predisposes foliage of a eucalypt to freezing injury and reduces spring growth

“…1997), Picea mariana (Margolis & Vezina 1990), Bromus erectus, Cirsium acaule, Sangisorba minor, Salvia pratensis and Trifolium medium ( Obrist, Arnone & Korner 2001). Finally there are also several reports of elevated CO 2 having no effect on freeze tolerance in evergreen species (Wiemken, Kossatz & Ineichen 1996; Dalen, Johnsen & Ogner 2001; Naumburg, Loik & Smith 2004). Obviously there are species‐specific changes in freeze tolerance at elevated CO 2 which may be related to the signalling mechanisms that lead to acclimation and de‐acclimation of plants to freezing temperatures.…”

Effect of phenology on susceptibility of Norway spruce (Picea abies) to fungal pathogens

“…All samples were frozen on liquid nitrogen and stored at −40°C until analysis. Each plant was analysed separately as described in Dalen et al. (2001).…”