The Effect of Silver Ion, 1-Naphthalene Acetic Acid and 6-Benzylaminopurine on Micropropagation of "Fastigiate" Tree Shape Variety Populus alba cl. LBM

In this work the effects of silver ion, 1-Naphthalene acetic acid (NAA) and 6-Benzylaminopurine (BAP) and their interactions on micropropagation of Populus alba cl. LBM, male genotype with fastigiate tree shape were studied. Three concentrations of silver nitrate [(Ag NO3), (0, 1.0 and 2.0 mu M)], two concentrations of NAA (0 and 0.1 mu M) and three concentrations of BAP (0, 0.5 and 2 mu M) were added to solidified Aspen culture (AC) media containing 2.0 mu M of kinetin and 10 g L-1 sucrose. Three traits were examined: percentage rooting, percentage microshoots with new shoots and the ratio of shoot length increment within the first and fourth week and length after the first week. The results showed a significant effect of NAA concentration on all the examined traits. The main effects of all examined factors and the interaction between different concentrations of three growth regulators had a significant effect on rooting and multiplication percentage. The inclusion of NAA in the medium at a concentration of 0.1 mu M stimulated multiplication and suppressed shoot growth and rooting, while BAP had the opposite effect. Silver ions stimulated both shoot multiplication and rooting, thus suggesting that it masked the effects of endogenous inhibitors such as ethylene