Improved In Vitro Propagation of Paulownia elongata, P. fortunei and its Interspecific Hybrid P. elongata x P. fortunei

摘要

Our paper presents an effective micropropagation protocol for Paulownia sp. (P. elongata, P. fortuneiand a P. elongata x P. fortunei hybrid). For in vitro culture initiation, axillary buds as well as seeds wereused. For the multiplication stage, modified Murashige & Skoog (MS) was tested, supplemented with0.5 mg/l BAP (6-benzilaminopurine) and mT (meta-topoline) at the concentrations of 0.5, 0.7 and 1mg/l. The media supplemented with BAP ensured intense proliferation of axillary buds but they alsocaused negative physiological effects (abundant callus growth at the plantletsa€? base). In the P. elongata xP. fortunei hybrid as well as in P. elongata 1 mg/l mT ensured the highest proliferation and multiplicationrates, but the plantlets that resulted from the media supplemented with 0.5 and 0.7 mg/l mT were morevigorous and well developed. In P. fortunei 1 mg/l mT ensured average proliferation rates of 9.28 andaverage multiplication rates of 12.92. Wheat starch proved to be a cheap and very effective alternativegelling agent. Ex vitro rooting and acclimatization was very successful by using Jiffy7 pellets and floatingperlite, the latter being a technique elaborated at the Fruit Research Station Cluj, with acclimatizationpercentages of more than 80 % in the 3-5 cm long shoots and more than 60 % in the 2-2.5 cm longshoots. The protocol developed allowed eliminating the in vitro rooting stage in the commonly usedprocesses in the industry.