Comparison of the Growth of Rice Seminal Roots between Japonica and Japonica-Indica Hybrids by the Use of Root-Tip Culture Method

摘要

Using a culture method of excised root tip reported by KAWATA et al., the growth of seminal root tips of Japonica and Japonica-Indica hybrids were compared. Plant materials used were 20 cvs. of Japonica-Indica hybrids bred in Korea, 10 cvs. of Korean paddy rice and 10 cvs. of Japanese paddy rice. The 1 cm long root tips were excised from seminal roots and two root tips were grown in each flask containing 15 ml of the culture solution. They were grown at 27° or 3O°C in the dark for three weeks. The results obtained were as follows ; 1. Root length at 27°C varied from 10.9 to 18.0 cm in the Japonica and from 13.2 to 19.7 cm in the Japonica-Indica hybrids. At 30°C, it was from 9.1 to 19.0 cm in the former and from 16.7 to 27.3 cm in the latter (Table 1). 2. At 27° and 30°C, Japonica-Indica hybrids had more number of the primary branched roots than the Japonica (Table 2). Root dry weight was from 0.9 to 2.0 mg in the Japonica and from 3.2 to 5.7 mg in the Japonica-Indica hybrids at 27°C (Fig. 4), while it was from O.9 to 2.3 mg in the former and from 4.2 to 10.1 mg in the latter at 30°C (Fig. 5-b). 3. Excised root growth of the Japonica were better at 27°C than 30°C, while in the case of the Japonica-Indica hybrids this was reverse (Fig. 5-a, 5-b).