Frost tolerance and hardening capacity during the germination and early developmental stages of four white spruce (Picea glauca) provenances

Abstract

Frost tolerance during the germination stages of four white spruce (Picea glauca (Moench) Voss) provenances (between 45°37′ and 50°17′N) was studied at four different developmental stages (imbibed seed, radicle, cotyledon, and young seedling), and their hardening capacity was determined for the latter three stages. Hardening capacity was examined by submitting radicle-stage germinants to two temperature-photoperiod treatments (20:15°C -16-h photoperiod or 5:5°C -8 h) for 14 days and by submitting cotyledon and young seedling stage germinants to four treatments (20:15°C -16 h; 20:15°C -8 h; 5:5°C -16 h; 5:5°C -8 h). Frost tolerance was determined immediately after these treatments. Latitude of origin showed no clear pattern with respect to either frost tolerance or hardening capacity at any of the developmental stages. Imbibed seeds had the greatest degree of frost tolerance. With the exception of the most northern provenance, radicle-stage germinants did not respond to a 5:5°C day:night temperature and 8-h photoperiod hardening treatment. A low-temperature treatment of 5:5°C increased the frost tolerance of cotyledon and young seedling stage germinants, while their response to a shortened photoperiod (8 h) was quite variable. However, an 8-h photoperiod did enhance the effect of the low-temperature treatment at the young-seedling stage. Thus, the timing of germination in the field appears to be an important factor in the ability of germinants to tolerate freezing stress.

Constitutive expression of the pea ABA‐responsive 17 (ABR17) cDNA confers multiple stress tolerance in Arabidopsis thaliana

“…Therefore, it is extremely important to identify other genes/gene products capable of enhancing multiple stress tolerance so as to augment existing tools to engineer stress tolerance. In the extreme cold conditions of the Canadian prairies, as well as in other parts of the world, successful growth of many crops is based on their ability to germinate and survive better in cold temperatures (Coursolle et al ., 1998). As a result of the risk of early spring or autumn frosts, the identification of novel stress‐tolerant genes and the generation of transgenic plants with enhanced germination and early maturity may have very useful application for farmers.…”

“…Therefore, it is extremely important to identify other genes/gene products capable of enhancing multiple stress tolerance so as to augment existing tools to engineer stress tolerance. In the extreme cold conditions of the Canadian prairies, as well as in other parts of the world, successful growth of many crops is based on their ability to germinate and survive better in cold temperatures (Coursolle et al, 1998). The phytohormone ABA plays a very crucial role in response to environmental stresses such as desiccation, salinity and cold, and is also involved in regulating events such as dormancy and maturation during late seed development (McCarty, 1995;Leung and Giraudat, 1998).…”

CLIMATE AND PICEA MARIANA SEED MATURATION RELATIONSHIPS: A MULTI‐SCALE PERSPECTIVE

“…As for the neoinsular sites of the Robert-Bourassa Reservoir, the mean germination percentages for all of the seeds produced in 1998 and 1999 are comparable to those of the Umiujaq site, situated at 38 of latitude farther north. The mechanism underlying this pattern is probably associated with the thermal sum accumulation during the initial phase of reproductive development (Coursolle et al 1998, Owens et al 2001. The thermostatic properties of water, including its high specific heat and strong thermal conductivity (Eichenlaub 1979), are the cause of the delay or deficit in thermal sum accumulation near large water bodies (Gregory and Smith 1967, Eichenlaub 1979, Antonioletti et al 1982.…”

Yukon Taiga – Past, Present and Future

“…Air temperature hypotheses have long been a favoured avenue to explain climatic tolerance (Weiser, 1970;Coursolle et al, 1998;Arft et al, 1999;Körner, 2007;Brandt 2009). However, low winter temperature per se is an improbable factor, because a variety of tree species of good size occur at sites such as Snag, Yukon, and Oymyakon, Siberia, locations of record temperature minima in the northern hemisphere.…”