Abstract
In order to confirm the result of the first experiment concerning the cold resistance of artificial polyploid, similar one was carried out using 2x and 4x plants of Eruca sativa Mill.. The superior winter hardiness was also displayed by the 4x plants with higher osmotic pressure than in the diploids. Here again no remarkable differences were noted between 4x and 2x in the content of water, total nitrogen, and total sugers in the plant tissue, except in that of soluble sugar. It has been suggested strongly that the difference in winter hardiness might be due to the difference in osmotic pressure ; and that the difference in osmotic pressure might be due to the difference in soluble sugar content, quite the same as in the case of the first experiment with Brassica chinensis L.
