near future because both our understanding of plant physiology and our ability to manipulate plant cold hardiness have improved. Without question, resistance to low temperatures is a major factor determining the geographic distribution of plant species. Socalled chillmg-sensitive plants, such as the tropical banana and the semitropical avocado, can be severely injured or even killed by long-ter...

It has been much disputed whether seasonal variations in proteins or in sugars are better related to cold hardiness changes in certain over-wintering plants (for example, 1, 2, 3, 8, 12, 14). But proteins have been difficult to study, since they are not easily extracted from such plants as our native winter-hardy trees. This is because such proteins are often precipitated by vacuolar substances...

The majority of overwintering insects avoid lethal freezing by lowering the temperature at which ice spontaneously nucleates within their body fluids. We examined the effect of ice-nucleating-active bacteria on the cold-hardiness of the lady beetle, Hippodamia convergens, a freeze-intolerant species that overwinters by supercooling to ca. -16 degrees C. Topical application of the ice-nucleating...

Subterranean environments are characterized by the quasi absence of thermal variations (+/-1 degrees C within a year), and organisms living in these biotopes for several millions of years, such as hypogean crustaceans, can be expected to have adapted to this very stable habitat. As hypogean organisms experience minimal thermal variation in their native biotopes, they should not be able to devel...

In recent years, thousands of hectares of hybrid poplar plantations have been established in Canada for the purpose of carbon sequestration and wood production. However, boreal planting environments pose special challenges that may compromise the long-term survival and productivity of such plantations. In this study, we evaluated the effect of winter stress, that is, frequent freeze-thaw and ex...

Short day enhancement of cold acclimation in twigs of Cornus (red-osier dogwood), Weigela, and Pyracantha (firethorn) was studied using dark interruptions with red or with red-far red radiation. Hardiness was estimated by freezing stem tissues to preselected temperatures and evaluating injury electrolytically. Dark-period interruptions with red radiation suppressed cold acclimation in Cornus an...