EFFECT OF BA AND CPPU ON PROTEASE AND α-AMYLASE ACTIVITY OF IN VITRO CULTURED EXPLANTS OF ROSA HYBRIDA L.

Summary. The present study was focused on the effect of N 6 -benzyladenine (BA) and N 1 -(2-chloro-4-pyridyl)-N 2 -phenylurea (CPPU) on protease and α-amylase activity regarding the in vitro break and growth of lateral buds of rose (Rosa hybrida L.), cvs. Madelon and Motrea. Cv. Madelon shows strong apical growth and suppressed branching, whereas cv. Motrea is an easy branching variety. The explants were subcultured every five weeks on standard medium and then transferred onto media containing growth regulators. The impact of cytokinins BA and CPPU on protease and α-amylase activity was traced within a period of one month. On day 1st of culture cv. Motrea showed lower protease activity than that in the control in response both to CPPU and BA while in cv. Madelon an opposite effect of enhanced protease activity was found. After 4 days a decrease of protease activity occurred for cv. Madelon in media with either BA or CPPU. On the same day an acceleration of enzyme activity was observed in cv. Motrea when cultured with BA. In comparison to hormone free media much lower protease activity was detected in one-month-old plants of cv. Madelon when treated with cytokinins and a decline was established in cv. Motrea in respect to the tendency within the first 7 days. We suggest that keeping the activity of proteases at lower level cytokinins are able to support the growth and development of lateral shoots. The α-amylase activity was enhanced on day 1st most probably due to mechanical stress at explant isolation. A stronger increase of αamylase activity was observed upon treatment with CPPU and this coincided