Abstract
The purpose of this study was to make clear the relation of cold resistance to the amount of negative colloid in the mature leaves by colloid titration method. In the stronger varieties in cold resistance, negative colloid content was greater than that in weaker ones, so it was pointed out that the absolute amount of negative colloid would be of great importance in cold resistance. The fact that the older plants were more resistant to cold than the younger ones was well proved by the difference of their amount of negative colloid by this method. Qualitative investigation was made on the ingredient in this trial colloid, but the principal ingredient in negative colloid could not be made clear yet.
