Study On Somatic Embryo Culture And Development Of Artificial Seeds Of Taxus Cuspidate ’Nana’

Taxus cuspidate Sieb.et Zucc is the evergreen needle arbor tree in Taxus.L of Taxaceae.The plants in Taxus.L belong to diaecious, and the natural seeding rate is low. Therefore, thenatural seed reproduction of Taxus cuspidate Sieb.et Zucc is limited largely. This study takesthe seed and axillary bud of Taxus cuspidate ’Nana’, the variant of Taxus cuspidate Sieb.etZucc, as the propagulum, and establishes the culture system of somatic embryo andartificial seeds of Taxus cuspidate ’Nana’, for the purpose of solving the problem ofshort resources of Taxus cuspidate Sieb.et Zucc through the technology of rapidreproduction by somatic embryo and artificial seeds. The results were as follows:1. The germination rate of seeds of Taxus cuspidate ’Nana’ dipped in200mg/L gibberellin for24h was the highest, reached66%.2. The whole seed with a cut of2-3mm long was cultured on the media of mB5+0.5mg/L2,4-D+4mg/L NAA+0.2mg/L KT under darkness for27d, the induction rate of callusreached to66.7%; however, the induction rate of callus was only8.9%, when the embryo wasseparated from the seed and cultured on the same media.3. The formula of mB5+3mg/L ZT was proven to be suitable for somatic embryo induction.After20d of culture, it was found that white granular culture occurred on the surface of callus,and it was further confirmed that this culture was characteristic of embryonic tissue underlight microscope.4. Development of artificial seeds with sodium alginate and CaCl₂at different concentrations,and together with the effects of store temperature （4℃and24℃） on water loss wereconducted. The results showed that3.0%sodium alginate and2.5%CaCl₂was the bestcombination for artificial seed coat. The water loss of storage at4℃was less than that of24℃.5. Addition of1.5%soluble starch to artificial endosperm could improve the water retentionproperty of artificial endosperm. The water loss rate was only25.29%after15d of storageat24℃; in addition, among the elicitors employed,10^-6mg/L salicylic acid performed bestfor its uniform and transparent particles.6. We next develop the artificial seeds using the callus from young shooting of Taxus cuspidate ’Nana’ and axillary bud as propagule. The artificial seeds using axillary bud wereapt to germinate, and the highest germination rate reached38.1%after30d of culture. On thecontrary, the artificial seeds using callus exhibited less ability of germination.7. The artificial seeds of Taxus cuspidate ’Nana’ still maintained vigor by5.0%of germinationrate after5d of storage at low-temperature （4℃）, and the ability of germination of all seedswas lost after10d of storage at the same temperature.