Novel Cytokinin Derivatives Do Not Show Negative Effects on Root Growth and Proliferation in Submicromolar Range

BACKGROUND: When applied to a nutrition solution or agar media, the non-substituted aromatic cytokinins caused thickening and shortening of the primary root, had an inhibitory effect on lateral root branching, and even showed some negative effects on development of the aerial part at as low as a 10 nanomolar concentration. Novel analogues of aromatic cytokinins ranking among topolins substituted on N9-atom of adenine by tetrahydropyranyl or 4-chlorobutyl group have been prepared and tested in standardized cytokinin bioassays [1]. Those showing comparable activities with N(6)-benzylaminopurine were further tested in planta. METHODOLOGY/PRINCIPAL FINDINGS: The main aim of the study was to explain molecular mechanism of function of novel cytokinin derivatives on plant development. Precise quantification of cytokinin content and profiling of genes involved in cytokinin metabolism and perception in treated plants revealed several aspects of different action of m-methoxytopolin base and its substituted derivative on plant development. In contrast to standard cytokinins, N9- tetrahydropyranyl derivative of m-topolin and its methoxy-counterpart showed the negative effects on root development only at three orders of magnitude higher concentrations. Moreover, the methoxy-derivative demonstrates a positive effect on lateral root branching and leaf emerging in a nanomolar range of concentrations, in comparison with untreated plants. CONCLUSIONS/SIGNIFICANCE: Tetrahydropyranyl substitution at N9-position of cytokinin purine ring significantly enhances acropetal transport of a given cytokinins. Together with the methoxy-substitution, impedes accumulation of non-active cytokinin glucoside forms in roots, allows gradual release of the active base, and has a significant effect on the distribution and amount of endogenous isoprenoid cytokinins in different plant tissues. The utilization of novel aromatic cytokinin derivatives can distinctively improve expected hormonal effects in plant propagation techniques in the future

David y Goliat. La primavera de las economias diversas

Entrando nei laboratori di queste economie che preferiamo chiamare \u201cdiverse\u201d, scopriamo pratiche, visioni e linguaggi, utopie concrete e immaginazione sociale di un mercato abitato e reso vivo da donne e uomini che riaprono, con moventi e movenze \u201csproporzionati\u201d, l\u2019interpretazione dominante imposta dal capitalismo. Un mercato variegato e complesso dove la pluralit\ue0 di voci, di corpi, di lingue e beni in movimento stanno al posto di un\u2019idea di mercato per voce sola, diventato oramai spazio desolato e inospitale dove alle persone che fanno economia \u2013 e societ\ue0 vera \u2013 in carne e ossa si preferisce il sistema economico con i suoi rituali e il suo triste refrain sul profitto

Nuovi soggetti dell'economico

I laboratori delle economie diverse mostrano l'attivazione di donne e uomini adulti che aprono un conflitto con le pratiche consumistiche. Attraverso una forte dimensione apprenditiva e di elaborazione di pensiero critico il consumo e la produzione diventano un'occasione per ripensare la cittadinanza