Effect of various inhibitors of polyamine synthesis on the growth of Helianthus tuberosus.
- 1 December 1981
- journal article
- Vol. 59, 403-9
Abstract
The growth effect of various inhibitors of polyamine synthesis was studied on explants obtained from Helianthus tuberosus tubers during dormancy and dormancy break and cultured for 20 days on a sterile agarized medium. Explant growth was strongly inhibited by canavanine and canaline, natural non-protein amino acid analogues of arginine and ornithine, respectively, as well as by canavanine in combination with putrescine. Methylglyoxal-bis-guanylhydrazone, an inhibitor of S-adenosylmethionine decarboxylase, did not increase growth inhibition caused by canavanine. Methylglyoxal-bis-guanylhydrazone alone, as well as alpha-methylornithine, 1,3-diaminopropane and 1,3-diaminopropan-2-o1 - which are inhibitors of ornithine decarboxylase - showed no growth inhibition with respect to the control treated with 2,4-dichlorophenoxyacetic acid. 1,3-Diaminopropane caused a paradoxic enhancement of callus growth and a much greater polyamine accumulation than in the control with 2,4-dichlorophenoxyacetic acid alone. During the first cell cycle inactivated tuber slices, 40 microM methylglyoxal-bis-guanylhydrazone inhibited spermidine and spermine synthesis up to 6 h, and their accumulation up to 1 h; RNA synthesis and accumulation and DNA accumulation were reduced at 1 h, and later enhanced. During the same period, 1 mM canavanine inhibited putrescine synthesis in the S and M phases, and spermidine and spermine synthesis only at 24 h; accumulation of putrescine and spermidine was reduced only at 12 h. Canavanine also reduced RNA synthesis throughout the S and M phases, while RNA accumulation was reduced at 18 and 24 h. Two different hypotheses are put forward concerning the induction of new pathways of polyamine synthesis.This publication has 0 references indexed in Scilit: