Abstract
Three vars. of alfalfa were grown in the greenhouse and artificially hardened at 2[degree]C in the light. Before and after hardening, the ice-formation in the roots was detd. calorimetrically after freezing at 2 temps. Duplicate samples were thawed and refrozen at the same temp. before determining ice-formation. Injury, by measure-merit of exosmosis, and total soluble extractable electrolytes were detd. More water is frozen during the 2d freeze (after thawing) than during the initial freeze. More water is left unfrozen in hardened plants than in unhardened ones, and the concn. of minerals is lower in the unfrozen water in hardened than in unhardened plants.