TEMPERATE FRUIT PLANT PROPAGATION THROUGH TEMPORARY IMMERSION

Abstract

So far many research activities have been reported on automation in micropropagation; many liquid media systems for tissue culture have been proposed in this regard. In this work the temporary immersion system (TIS) has been tested for in vitro propagation of strawberry, pear, apple, peach, cherry, plum, raspberry and papaya. Because the objectives of the experiments were to assay the media composition, to establish the immersion-period length and to define environmental parameters, a simple double bottle device, manually operated, was used. The temporary immersion of the explants was achieved filling the bottle containing the explants with the medium transferred through a silicon tube from the second bottle, in which an overpressure was created by a manual air pump. The effects on growth were compared to those of the stationary liquid and agarized cultures (control). The shoot multiplication rate was very high in strawberry, showing the typical juvenile unilobate morphology, raspberry and papaya. In pear the multiplication efficiency was strictly genotype dependent; TIS revealed to be highly efficient to prevent the apices necrosis. For the other species the TIS strongly affected the quality of the explants preventing the necrosis and the hyperhydricity. All the species maintained the juvenile habit during the TIS culture. Data on photosynthetic pigments and sugar contents seem to suggest a positive influence of TIS on the autotrophic activity.