This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via CrossRef Citing Articles via Web of Science (34) Citing Articles via Google Scholar Google Scholar Articles by McLeester, R. C. Articles by Hall, T. C. Search for Related Content PubMed PubMed Citation Articles by McLeester, R. C. Articles by Hall, T. C. Agricola Articles by McLeester, R. C. Articles by Hall, T. C.

Articles

Multiple Freezing Points as a Test for Viability of Plant Stems in the Determination of Frost Hardiness ¹

^a Department of Horticultural Science, University of Minnesota, St. Paul, Minnesota 55101

A technique is presented for a simple, rapid, and reliable means of determining the viability of plant tissue subjected to freezing temperatures. Freezing curves of excised stems of Cornus stolonifera Michx., and several other genera were studied. Tissue temperature was recorded during freezing of plant stem sections. The heat of crystallization deflected the resultant freezing curves at points where tissue froze. Living stem sections of all genera studied revealed 2 freezing points, while dead tissue exhibited only 1. The influence of variables such as moisture content, sample size, thermocouple placement, and cooling rate on freezing curves was analyzed. Stem samples wrapped in moisture-proof film with a thermocouple inserted into the pith were frozen to a predetermined test temperature, thawed, and subjected to a second freezing cycle. The presence or absence of 2 freezing points in the second freezing cycle was used as a criterion for establishing viability. The results were immediately available and identical to results from regrowth tests which took about 20 days.

³ Present Address: Horticulture Department, University of Wisconsin, Madison, Wisconsin 53706.

¹ Scientific Journal Series Paper No. 6627, Minnesota Agricultural Experiment Station. This research was supported in part by a grant from the Louis W. and Maud Hill Family Foundation.

This article has been cited by other articles:

				C. J. Weiser Cold Resistance and Injury in Woody Plants: Knowledge of hardy plant adaptations to freezing stress may help us to reduce winter damage Science, September 25, 1970; 169(3952): 1269 - 1278. [Abstract] [PDF]