Root physiology of japonica and indica rices (Oryza sativa L.) . I. Growth features of excised root and embryo cultures
Lai, K.L.; Hou, C.R.
Journal of the Agricultural Association of China 124: 1-9
Root diameters and growth rates of excised roots of three indica rices (including short, medium and long-grained types) grown on R1, R2 and nitrogen-modified media were greater than those of three japonica varieties. Roots of the japonica varieties, but not those of the indica rice, grew slightly better when urea or casein provided the nitrogen source. When excised embryos of the japonica variety Taichung 65 and the indica variety Taichung Native 1 were cultured on R2 medium, the roots of both varieties grew equally well. The root growth of Taichung 65 was faster than in the experiment with excised roots. It is suggested that the root growth of japonica rice may depend on shoot and/or embryo factors. Increase in diam. and length of excised root tips on synthetic media was greater in indica than in japonica cv. If N was supplied as urea or casein growth of roots of japonica cv. was slightly increased but that of indica cv. was not affected. In cultured excised embryos, roots of both indica and japonica cv. grew well. The results indicated that roots of japonica rice cv. may depend on factors from the shoot.