Abstract
Five species of Umbilicaria were used in experiments to determine the effect of moderately below zero temperature pretreatments. Both air-dry and fully-imbibed plants were exposed to-25° C for nine months. The experiments were conducted using samples collected in midsummer and mid-winter. The gas exchange activity of the plants was measured following the low temperature stress, and was compared to the response of unstressed plants. A four-light-level by three-temperature-assay of net CO2 exchange was used throughout. The results showed that exposure of dry plants to-25° C has few effects, but that exposure when imbibed produces a range in response from serious damage to apparent stimulation. For all species the results are consistent with what would be expected knowing the extent and duration of the snow cover is the natural habitat.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
