Improving Adventitious Shoot Regeneration and Transient Agrobacterium-Mediated Transformation of Apricot (Prunus armeniaca L.) Hypocotyl Sections

The improvement of previously described protocols for the regeneration of shoots from ‘Canino’ mature seed hypocotyl slices has been accomplished. The effects of different factors such as the part of the hypocotyl used, vacuum-infiltration, 2,4-Dichlorophenoxyacetic acid pulse, vacuum-infiltration and sonication on regeneration and transient transformation were analyzed. When the three slices obtained from the hypocotyls were evaluated separately on regeneration medium, the highest percentages of regenerating explants were achieved in the part close to the epicotyl and in the central part. On the other hand, sonication of the explants for 30 s followed by vacuum-infiltration during Agrobacterium infection for 20 min allowed for an increase in the transformation events. The application of these modifications to the procedure increased the regeneration efficiencies, and transient transformation events and may reduce the frequency of failed experiments. An efficient regeneration/transformation protocol could facilitate its use as a biotechnological technique for apricot breeding.

Application of Vacuum Infiltration in Cryopreservation of Isolated Grape Buds

Preserving the gene pool of grapes, referred to the vegetatively propagated plants is a complicated task, which can be also solved by cryopreservation of the buds. To saturate such bulk and heterogeneous samples with cryoprotectants the novel methods are required. The effectiveness of vacuum infiltration and 60 min standard passive saturation (soaking) of isolated grape buds of the Russian Concord variety with a cryoprotective solution PVS 2 were compared in this research. To saturate by vacuum infiltration the buds were incubated in cryoprotective solution for 15 min at 40 kPa, afterwards, the pressure was gradually increased to atmospheric level. The efficiency of bud saturation was evaluated with low-temperature differential scanning calorimetry by changing the enthalpies and temperatures of phase transitions as well as the intensity of heat capacity jump at glass transition. The use of vacuum in the saturation of isolated grape buds were found to lead to a strong rise in cryoprotectant concentration in them and a significant decrease in the amount of free water crystallized during cooling compared to passive soaking in a PVS 2 vitrification solution.