The Effect of Growth Retardants CCC and B-9 on Certain Factors Related to Cold Acclimation of Plants

Cabbage plants treated with growth retardants CCC (2-chloroethyl/trimethylammoninm chloride) and B-9 (N,N-dimethyiaminosuccinamic acid) were grown in light in temperature-controlled chambers. It was shown that progressively reduced temperature gave rise to slackened growth, accumulation of dry weight, reduced saturation of tissue with water, increased osmotic potential of cell sap, and increased content of reducing sugars. Considerable increase in the water-soluble protein content was also found. It seems that during the hardening process water-soluble compounds are primarily synthesized. Furthermore, a part of the water-insoluble compounds is converted into soluble compounds. The retardants investigated gave rise to enhanced leaf succulence, increased osmotic potential of cell sap, and, primarily, increased content of watersoluble protein and nonprotein compounds, but only in the hardened plants. Frost damage caused by a temperature of -10 C also was much less in the hardened plants, especially in the hardened plants treated with growth retardants. It seems that a temperature of +5 C may be designated as the hardening temperature for cabbage. With cabbage, CCC appears to be a more effective substance than B-9