抄録
The terminal bud of a tuber of "Konnyaku, "Amorphophallus Kanjac C. Koch, was previously cut with a knife to expose its growing point and 0.2-0.4 % colchicine solution was dropped on the cut surface of the tuber once a day for 2-3 days. Another method of treatment is soaking the terminal bud in the colchicine solution for 24 hours. 2.Out of 608 treated tubers from 3 varieties of Zairai, Bittya and Chinese only 3 were found to be tetraploid. Twenty six chromosomes were counted in the root tip cells of 2 x tubers and 52 chromosomes in those of 4 x tubers 3.Induced tetraploids are gigantic, as compared with diploids, in the size of stomatal cells, in the number of chloroplast in guard cells, and in other characters. 4. Tetraploid tubers produce thick and short stolevs which do not snap so easily as, those of dipoids.
