抄録
Electrical conductivity (EC) and mineral element contents in the water effusate of leaf blades treated at different temperatures were estimated to know a relationship between EC and low temperature resistance of varieties. 1. EC increased far more in the leaf treated at low temperature (5°/5°C) in the dark than that at normal temperature (25°/20°C) in the light, the degree of increase being larger after 96 hr than 48 hr treatment (Fig. 1). Each mineral element content increased more under low temperature than under normal temperature, the degree of increase being K>Ca>Mg>Na in that order (Table 1, Fig. 2). The content of each element and EC showed significantly high positive correlation coefficients (Fig. 3). 2. The ultrastructure of chloroplasts in IR 24 treated for 96 hr at low temperature changed markedly; the grana stacks being broken down into numerous diffused vesicles. The chloroplasts of Sasanishiki changed little (Fig. 4). 3. Under normal temperature, there was no varietal difference in EC, but under low temperature a great varietal difference of EC was shown. In general, the degree of EC increase by low temperature was indica type>japonica×indica>japonica type in that order (Fig. 5). 4. It was suggested that EC values of the water effusate of leaf blades treated at low temperature may be an index of low temperature resistance of rice varieties.
