コルヒチンに依る Secale, Haynaldia 及び Aegilops の染色體倍加

1. By colchicine treatment, chromosome numbers have been doubled in 6 diploid species-Secale cereale, Haynaldia villosa, Aegilops bicornis, Ae. comosa, Ae. squarrosa and Ae. uniaristata-and in one sterile species hybrid, Ae. caudata×umbellulata.2. The germinating seeds, whose coleoptile grown about 2mm long, were removed by a pincette, were immersed in 0.02-0.1% aqueous solution of colchicine for about 24 hours. The dropping method with 0.2% solution was employed to the operated seeds of Ae. squarrosa. For the control Sears' method was used. The results are summarized in Tables 1 and 2.3. Difference in size between 2x- and 4x-spikes is quite distinct (Figs. 1-2). 4x-plants have gigas habit. Epidermal cell elements of the 4x-leaves become about 11/2 times the length of those of normal plants (Fig. 3). The autotetraploids have more aborted pollen grains than the normals. Good pollen grains of 4x-individuals are larger than those of the diploids (Fig. 4). The sterile hybrid (Ae. Caudata× umbellulata) has exclusively aborted pollen grains, but the amphidiploid has good pollen grains.4. In most PMCs of S. cereale and H. villosa the chromosome configuration is found to be 1IV+1III+10II+1I and 2IV+10II (Fig. 6). At the first metaphase of PMC 2-5 polyvalents are formed in the autotetraploids of Ae. bicornis, Ae. squarrosa and Ae. uniaristata (Fig. 7; b, d & e). In the amphidiploid 0-2 polyvalents and 0-5 univalents are observed (Fig. 7; f).5. The fertility of the normals, the autotetraploids and the amphidiploid is shown in Table 3.