Abstract
Kinetin-induced tuber formation was investigated with regard to the role of temperature, sucrose concentration, time of kinetin application, and inhibitors of protein and nucleic acid biosynthesis. Low temperatures (15°C and 20°C) failed to promote tuber formation in the absence of kinetin, and at 15°C K-induced tuber formation was partially prevented. Similarly, sucrose concentration per se did not promote tuber formation, however, K-induced tuber formation required a 6% or greater concentration of sucrose in the medium. Stolons preincubated in K prior to incubation on a basal medium without K failed to form tubers but tubers were formed if they were incubated on a basal medium with K. In order to induce tuber formation, K is only required in the basal medium for 3–4 days. Thereafter tuber formation can progress unimpaired on a basal medium only. The inhibitors of protein and nucleic acid synthesis (ACTD, PFA, 2-TU, CHL, 5-FUDR) delayed tuber formation but failed to inhibit the process. The results are discussed in relation to the possible existence of a tuber forming hormone related to cytokinins and the possible effect of temperature on its action. The possibility that tuber formation may be independent of protein and nucleic acid synthesis is also discussed.