水稻无侧根突变体的根向重力性异常

用化学诱变剂 (NaN3 )处理粳稻品种大力 (O ryzasativaL .cv .Oochikara) ,得到具有 2 ,4 D抗性、无侧根和根向重力性异常的突变体RM 10 9。对原品种为父本和突变体为母本的杂交后代F1、F2 根向重力性的遗传分离进行了研究。结果表明 :突变体的根向重力性异常 ,其性状是单显性基因控制且不受光照和黑暗培养的影响。通过对根冠组织切片观察发现 :突变体根冠中含淀粉体的细胞数量比大力少 ,根冠细胞中淀粉体的直径为原品种的 5 0 %且集中排列于细胞内的一角 ,其排列沉积方向与重力方向相同。推测 :突变体的根向重力性异常与淀粉体直径变小有关

The Abnormal Root Gravitropism in a No-lateral-root Mutant of Rice

The seeds of rice (Oryza sativa L. cv. Oochikara) were treated with chemical mutagen (NaN 3), mutant RM109 was obtained. It is resistant to 2,4-D, has no lateral root and is abnormal in geotropic growth (Fig.1a,b). Character of the genetic analysis of gravitropism in F 1 and F 2 (wild type as male parent and mutant as female parent) seedling seminal root, the diameter and numbers of amyloplasts in wild type and mutant root cap cells, with light and dark condition, and also the angle of seminal root geotropic growth in mutant and wild type were studied. The results showed that abnormal gravitropism of seminal root in mutant, which was dominated by single dominant gene (Table 1), and could not be affected by light or dark under culture (Table 2). The observations of tissues slices of root caps showed: the number of columella cells containing amyloplasts in mutant was found to be less than that in wild type, the diameter of amyloplasts in root cap cells was 50% of wild type (Table 3). The amyloplasts crowded in one corner of the cells and the direction of sedimentantion was the same as that of gravity (Fig.1c, d, e, f). So we conclused that this was relationship between the abnormal gravitropism of mutant root and the decreasing diameter of amyloplasts in mutant root cap cells of mutant.