Evaluation of ElecTIS bioreactor for the micropropagation of Malus sylvestris (L.) Mill., an important autochthonous species of Albania

Malus sylvestris (L.) Mill., an economically-important fruit tree, is native to Albania and in many parts
of Europe. It is cultivated as an ornamental tree, while its fruits are collected for food and a source of antioxidant
substances. It is included in The IUCN Red List of Threatened Species. For these reasons, it is very important to
optimise a micropropagation protocol, in order to obtain great numbers of clonal plantlets for ex situ conservation
and production purposes. A liquid culture in a temporary immersion system (TIS) is a recently-proposed system
for large-scale in vitro plant propagation. In this study, lateral buds of M. sylvestris were inoculated in MS medium
with BAP (1 mg/L) and NAA (0.1 mg/L). In order to avoid oxidative stress, different antioxidants were previously
tested with the culture in a gelled medium, and the combination of ascorbic acid and citric acid (both at 100 mg/L)
was selected for the following culture in TIS. Stabilised explants were then cultivated in ElecTIS, an innovative TIS
bioreactor, and in a semisolid medium, after which the two culture systems were evaluated. Overall, the ElecTIS
showed to be more effective for all the tested parameters.