Studies On Inbred Line In Vitro Conservation Of Zinnia Elegans And Super-low Temperature Storage Of Seeds

Zinnia elegans is a kind of annual flowers, with many garden forms of the species having been developed from wild plants growing in Mexico. Currently, the new species are usually preserved through its seeds. But the seed vitality often decreases as prolonged storage time, so it is required that sowing seeds annually to refresh the seed vitality. In order to resolve germplasm conservation, we attempted the tissue culture conservation and cryopreservation.In this study, we used inbred line S5、J9、J10 as the material of tissue culture and cryopreservation to test the optimum preservation system and the condition of cryopreservation, providing the theoretical and practical basis for the storage of inbred line in Zinnia elegans. The major results are as following:(1). Tissue culture conservation:Mature seeds were in-vitro cultured for propagation. The sterilizing process conducted as:firstly disinfected with 70% alcohol for 1min and 0.6% NaOCl for 20min, secondly removed the peel of achene, disinfected the second time with 0.6% NaOCl for 5min, then the germination rate grown in the MS medium was over 80.0%. The most appropriate sterile germination medium was the MS with 30g/L of sucrose content and under 14h/10h of light and dark culture conditions. Zinnia could proliferate 2.5 times on the MS medium without any plant hormones, which is also suitable for rooting. Though the effects of proliferation with B A is obviously,but the growth status of aseptic seedlings is not well.The effects of transplanting substrate is sensible. The survival rate was over 90%. The most appropriate medium for retarding growth was MS+6 mg/L PP333+15 g/L Sucrose, which could prolong over 3months of the subcultures interval.(2). The cryopreservation:an orthogonal design with inbred line S5 as the material was utilized to analyze the effects of the dominant parameters (water content, cryoprotectants, freezing and thawing methods) on preservation effects and established preliminarily cryopreservation. Firstly, reduced the water content of seed to the 5.54%, added 10% dimethyl sulfoxide as cryoprotectants in 0℃for 45min, then directly put them in-80℃for super-low-temperature refrigerator and defrosted in the water. The experiment proved the importance of freezing protectants. Under the best solution, the germination rate was significantly higher than that of CK seed and the germination index and vigor index showed no difference with CK. Similar results were got from J9 and J10. So this scheme was suitable for cryopreservation.