Temporary immersion systems to improve alder micropropagation

A protocol has been developed for the propagation of Alnus glutinosa axillary shoots in liquid medium. The explants were cultured in Woody Plant Medium supplemented with 0.1 mg l− 1 benzyladenine and 0.5 mg l− 1 indole acetic acid. The effect of the bioreactor type (RITA® and Plantform™), frequency of the immersions, regulator concentrations, and volume of medium per explant was investigated. All the treatments with the temporal immersion systems (TIS) increased the proliferation rates. The best results were obtained on using the Plantform™ vessels and, unlike the shoots cultured in RITA® vessels, the culture in Plantform™ had very low hyperhydricity percentages. Shoots originating from the culture in semi-solid medium and in Plantform™ rooted in semi-solid medium with 0.1 mg/l indole butyric acid for 7 days. No significant differences were observed in the rooting or acclimatization percentages, with survival percentages greater than 85% being achieved. This is the first work on the use of TIS systems in alder propagation, with the results of this study providing new perspectives for its mass propagation. A new protocol is described in order to reduce the propagation costs of alder.