Survival of Cornus sericea L. stem cortical cells following immersion in liquid helium

Abstract

Cold‐acclimated stems of red‐osier dogwood (Cornus sericea L.) were sampled in midwinter and early spring and subjected to the following low temperature treatments: (a)0 →−40 → 0°C; (b) 0 →−40 →− 196 → 0°C; (c) 0 →−40 →−196 →−269 →−196 → 0°C; (d) 0 →−40 →−269 →−196 → 0°C; (e) 0 →−196 → 0°C; (f) 0 →−269 →−196 →0°C. The cortical parenchyma cells of the outer stem layers survived exposure to −269°C when pre‐frozen to −40°C and either transferred directly to −269°C or to −196°C and then to −269°C (treatments c and d). Acclimated stems transferred to a greenhouse (22°C) 2 weeks prior to the low temperature treatments deacclimated and were not able to survive freezing to −10°C. Cortical cells of stem samples taken in March, near the time when dogwood naturally deacclimates, survived −196°C (treatment b), but not −269°C (treatment cord). Thus, the freezing tolerance of dogwood varies seasonally from near −10°C to below −269°C.

Freezing Stress Response in Woody Tissues Observed Using Low-Temperature Scanning Electron Microscopy and Freeze Substitution Techniques

“…The LN2 submersion treatment was done to completely kill the specimens to consistently yield a "0 = all cells dead" rating. It was previously reported ( 13,23) that red osier dogwood survived LN2 temperatures if tissues were first cooled slowly to -40°C before placing in LN2. In these experiments, tissues were plunged directly into LN2, and this treatment was lethal (Table I).…”

Phylogenetic Analyses inCornusSubstantiate Ancestry of Xylem Supercooling Freezing Behavior and Reveal Lineage of Desiccation Related Proteins

“…As a consequence of dehydration, cellular contents may become highly viscous and nondestructively vitrify. Vitrification may partially explain how C. sericea is capable of surviving the temperature of liquid helium (Guy et al, 1986;Pearce, 2001). From an evolutionary point of view, the acquisition of a nonsupercooling behavior would be advantageous for geographical expansion into harsh low temperature environments.…”

“…In nonsupercooling tissues, ice formation is initiated within extracellular spaces and generates a dehydrative vapor pressure gradient between extracellular ice and intracellular water. Nonsupercooling cells readily desiccate in response to extracellular ice formation (George et al, 1982; and are capable of surviving low temperature extremes (Guy et al, 1986) due to an inherent capacity to tolerate desiccation Fujikawa et al, 1997). In supercooling tissues, ice may also initiate in extracellular spaces; however, cells are thought to resist intracellular desiccation (Burke et al, 1976;George et al, 1982;Wisniewski and Ashworth, 1985;Fujikawa et al, 1994) and maintain intracellular water in a nonequilibrium condition.…”

“…The freezing behavior in seven Cornus species has been previously determined and found to consist of both nonsupercooling and supercooling species (George et al, 1974;George et al, 1982;Ishikawa and Sakai, 1982;Ristic and Ashworth, 1993). One of the examined nonsupercooling species, C. sericea, is among the most freeze tolerant plants known and is capable of withstanding gradual cooling to the temperature of liquid helium (2269°C; Guy et al, 1986). In addition, our recent study in C. sericea xylem documented the marked winter accumulation (Sarnighausen et al, 2002) of a 24-kD dehydrin-like protein that directly correlates to increased freeze tolerance (Karlson et al, 2003).…”

Response of Xylem Ray Parenchyma Cells of Red Osier Dogwood (Cornus sericea L.) to Freezing Stress (Microscopic Evidence of Protoplasm Contraction)

“…The HTE is linked to freezing of water in xylem vessels and extracellular spaces, and this freezing event is not injurious (Quamme et al, 1972;Burke et al, 1976). Some tissues exhibiting extracellular freezing are cold hardy and can survive temperatures below -4OoC, in some cases as low as -196OC (Sakai, 1960;Guy et al, 1986).…”