| The Mausoleum of the Yellow Emperor is the spirit of the Chinese civilization, its ancient Platycladus orientalis community is the historical heritage of thousands of years. It is not only “the history testimony” of ancient Chinese civilization, the "green" cultural relics, but also the precious germplasm resources that nature endowed human, which is not recycled and replicated. In recent years, however, due to the influence of multiple factors such as the climate change, plant diseases and insect pests, natural disasters, and man-made destruction, the ancient Platycladus orientalis community is showing the weak trend and some ancient trees had died. The lost of the precious germplasm will be a great pity, so the task of protection and continuation of the excellent precious germplasm resources is imminent. The Platycladus orientalis community is the rare germplasm resources, presently, the protection work for them is mainly focused on the prevention and control of plant diseases and insect pests, the root regeneration and so on, the relevant study on its germplasm resources preservation system has not been saw yet. The author used the pollen and seeds of the ancient Platycladus orientalis in the Mausoleum of the Yellow Emperor as the main material, to make the related study of pollen viability, low-temperature preservation and cryopreservation for pollen, and the ultra-drying storage test for seeds.In the storage study of ancient Platycladus orientalis pollen, vitro culture method and TTC staining were used to explore the pollen viability, the different viability of different ages of Platycladus orientalis was also compared, the effect of different storage methods on pollen germination was studied, at the same time, in the cryopreservation method, the effect of pollen water content, input and thawing method was also explored. The results showed that:(1) In the study of pollen viability, the pollen germination rate reached the highest after cultured 4 days on the culture medium with 9% sucrose and 0.01% boric acid. The TTC staining method was not suitable for the determination of pollen vitality.(2) The pollen viability of different tree age is that: 30 a > 200 a > 3000 a.(3) In the study of storage method, in 90 days, the pollen storaged at 20℃ lost its viability quickly in 20 days, enviroment of-20℃ can protect the pollen viability but showed a downward trend overall, cryopreservation had the highest pollen germination rate and kept the best. Accordingly, cryopreservation is the best way to achieve the long-term preservation of the ancient Platycladus orientalis pollen.(4) In the cryopreservation method, pollen without drying(11.5%), directly put into the liquid nitrogen without precooling, thawing under the condition of 37℃ water achieved the best storage effect, the interaction effect between pollen water content, input and thawing method was significant.In the ultra-drying storage study of ancient Platycladus orientalis seed, the ultra-dried process of ancient Platycladus orientalis seed was achieved by using silica gel. After the artificial accelerated aging(50℃, 30d), the anti-aging ability of different moisture content seed was tested by measuring the vigor indexes such as germination index, relative electrical conductivity, dehydrogenase activity and so on.The results showed that:(1) The drying speed of ancient Platycladus orientalis seed was slow, seeds moisture content were dried from 5.8% to 2.5% in 14 days.(2) The dynamic indicators showed that ultra-dried storage method is feasible to be applied to the preservation work of ancient Platycladus orientalis seed.(3) The seed with 3.6% moisture content, its germination potential, germination rate and dehydrogenase activity remained at a relatively high level, its relative electric conductivity was low, it had the best anti-aging ability. Above all, 3.6% was the best moisture content of the ancient Platycladus orientalis seed for its ultra-dry preservation. |
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