Seed cryopreservation and longevity of two Salix hybrids (original) (raw)

Characterization and Cryopreservation of Malus sieversii Seeds

Kazakhstan is one of the centers of origin and evolution of apple (Malus). The main forest species is Malus sieversii (Ledeb.) M. Roem., representatives of which have important traits such as disease and insect resistance, cold hardiness, and fruit quality. The area of these unique wild forests is continually decreasing as a result of human activities. An expedition was held in September 2008 to collect and safeguard the genetic resources of Malus sieversii in Kazakhstan. Over 4400 seeds from the fruit of 34 Malus sieversii accessions were collected in the Zailyiski Alatau Mountains near Almaty (Bel-Bulak and Issyk Gorges). The trees where fruit was collected showed high variability in habit and fruit size, shape and flavor. Fruit color varied from yellow white to red. Seeds were variable in both color and length. We tested seed cryopreservation for long-term storage of wild Malus biodiversity. Seeds were air dried to a mean moisture content of 8.23%. Seeds were directly immersed in liquid nitrogen (LN) for 30 min and rewarmed at room temperature to test the effect of LN exposure. Viability following LN as evaluated by 2,3,5-triphenyltetrazolium chloride (TZ) ranged from 72.4% to 90.0% and did not differ significantly from the controls or from the germination tests. Germination tests indicated slightly but not significantly higher viability for LN exposed seeds, but germination vigor for LN exposed seeds was significantly higher than controls over the 6 week germination period. These results indicate that cryopreservation in LN is an option for long-term conservation of this important germplasm.

Impact of protective agents and drying methods on desiccation tolerance of Salix nigra L. seeds

Plant physiology and biochemistry : PPB / Société française de physiologie végétale, 2014

Willow seeds are classified as orthodox, but they show some recalcitrant characteristics, as they lose viability in a few weeks at room temperature. The aim of this work was to improve the desiccation tolerance of willow seeds (Salix nigra L.), as a model of sensitive materials to dehydration, through imbibition in solutions and later vacuum (VD) or freeze-drying (FD). Imbibition was conducted with 45% w/v trehalose or polyethylene glycol 400 -PEG- or water prior to dehydration treatments. Water- and especially trehalose-imbibed seeds subjected to VD showed better germination capability with respect to the freeze-dried ones. Water crystallization was mainly responsible for the great loss of capability germination observed in water- or trehalose-imbibed seeds subjected to FD. PEG behavior was better when seeds were FD instead of VD. DSC thermograms of seeds allowed to identify two thermal transitions corresponding to lipids melting and to proteins denaturation. This last transition r...