Abstract
"Sectorial chimera kernel", possessing an endosperm divided sharply into giutinous and non-glutinous parts, as reported in the previous paper (Tsunoda, Fujimura and Wada, 1964 b) was cultivated and the behavior of germination and subsequent growth of the chimera kernel was closely observed, though the number of kernels to be tested was only one. Two pairs of coleoptile and radicule emerged from the germinated embryos of thc chimera kernel on the 5 th day after seeding. Subsequently, the primary and secondary foliar leaves developed successively from each plumule. From such behavior, "sectorial chnnera kernel" was recogul ed to be"twin", though the existence of two embryos had not been clearly determined by observation of the kernel before seeding (Fig. 1). The growth of these seedlings was inferior to that of normal seeds, and they withered on the 23 rd or 30 th day after seeding. This was mainly due to a decline in the absorption of water and nutrition caused by the very poor growth of the root system. From the fact that "sectonal chimera kernel" was also "twin" the hypothesis mentioned below is a likely explanation for its occurrence. On the supposition that the plant inducing the chimera kernel is heterozygous (Gl. gl) in gene constitution and self-pollinated, the follow-ing abnormal double- fertilization may be considered (Table 1). On fertilizing, two pollen-tubes enter the embryosac, one discharges the gametes partici-pating in the normal double-fertilization and the other discharges the gametes uniting with the synergid and antipodal cell. In addition to the abnormal phenomena mentioned above, if such gene combination occurs as shown in Table 1, consequently two starch tissues differing in chemical composition may differentiate and develop even in the same endosperm. According to the abovementioned hypothesis, two individuals developing from the twin would be gl.gl and Gl.gl in gene constitution respectively, but the withering of plants in the midst of cultivation made it impossible to verify this presumption.
