|Budget Amount *help
¥2,100,000 (Direct Cost : ¥2,100,000)
Fiscal Year 1995 : ¥400,000 (Direct Cost : ¥400,000)
Fiscal Year 1994 : ¥500,000 (Direct Cost : ¥500,000)
Fiscal Year 1993 : ¥1,200,000 (Direct Cost : ¥1,200,000)
To investigate the function of roots in higher plants, isolation and characterization of four rice (Oryza sativa L.) short-root mutants, RM1, RM8, RM10 and LM10, that had been selected as growth-inhibiting mutants from M2 popuplations of Ohchikara and IR8 were conducted.
Root length of RM1 seedlings was 30% of the wild type Ohchikara, while a significant defference was not observed between the mutant and the wild type in plant height. Short root of RM1 was caused by short cortex cell of the roots. Root length of RM8 and RM10 seedlings was 70% and 30% of the wild type Ohchikara, respectively. However, cortex cell length of the mutants was the same as the wild type. It was inferred that short root was caused by shorter cell and/or decrease of cell number. Root length of LM10 seedlings also was 30% of the wild type IR8, while plant height of LM10 was not significantly different from the wild type. Root growth of LM10 was accelated by light exposure, although it was well known that the growth of plant shoot and roots was inhibited by light exposure compared to dark. LM10 was different from RM1, RM8 and RM10 in root growth with light exposure. A short root was analyzed by using crossing progenies between the mutants and their wild type. The segregating ratio of three mutants, RM1, RM8 and RM10, and the wild type in root length of the F2 indicated that the short root of RM1, RM8 and RM10 was controlled by a single recessive gene. The segregation analysis between the three mutants also indicated that the short root of them was controlled respectively defferent genes. The analysis was carried out using the F2, F3 and B1F1 between LM10 and its wild type. These results indicated that LM10 was controlled by a recessive gene. Moreover, the allelism test using the four mutants indicated that the short root genes of LM10, RM1, RM8 and RM10 were located at different locus.