| Study on hardy Eucalyptus is a new research starting point in China. Eucalyptus dunnii seed source and family selection have been made some progress, but its seeds have been relied on imports. Because Eucalyptus dunnii flowering and fruitification (origin) are so poor that there are no homegrown seeds for afforestation. Seed import from Australia is too expensive to be promoted in the production of the species. In this paper, a new technological research will be be introduced that the Eucalyptus seeds from Australia have been used to nurture its container seedlings and been used as explants to induce organ and callus. A survey how Eucalyptus dunnii planting was damaged on the northern six counties (cities) in Fujian is conducted. And different materials from the survivors of the cold hardiness have been used as explants so as to consider which factor is the most important to establish a stable and effect system of Eucalyptus dunnii rapid propagation. By this way, it can provide not only a technical support to produce a high degree of quality and cold hardiness of Eucalyptus dunnii but also a technology platform for genetic engineering and molecular breeding. Its main findings are as follows.It is compared using flat pad filter as germination bed indoor with using yellow subsoil 98% + SSP 2% outdoor and with using yellow subsoil 50% + burned soil 48% + SSP 2% outdoor for Eucalyptus dunnii seeds. The result shows that when using flat pad filter as germination bed indoor, the germination rate is the same as that in laboratory. The germination is only a few days after Seeds are sown. Germination time is the just the same. And if the seedlings are transplanted into container bags in time, it is conducive to the growth of seedlings. Compared using yellow subsoil 98% + SSP 2% as germination bed, the average germination rate with using flat pad filter as germination bed indoor increases by 37.58%.And compared in the subsoil 50% + burned soil 48% + SSP 2%, 24.88 % increases. The average transplant survival rate is 63.3%, when the shoots used are cultured in the flat filter pad. And the average transplant survival rate is only 32.7%, when the shoots used are cultured in the yellow subsoil 98% + SSP 2%. While the average transplant survival rate is only 37.7%, when the shoots used are cultured in the yellow subsoil 50% + burned soil 50% + SSP 2%. After the seedlings cultured indoor on the flat filter pad have been cultivated for 3 months in autumn and winter, they can be accounted for more than 70% at height up to 10 cm, and can be relatively early reforested uphill. It will be able to reduce labor costs from 18% to 47% when transplanting the nurturing container seedlings cultured indoor on the flat filter pad indoor. In the nurserying, after determination of the seed quality, we can accurately calculate and arrange the seed amount. One way to induct callus is using Eucalyptus dunnii seeds directly as explants. The other way is sowing seeds in the medium, then using the shoots, cotyledons, and roots as explants to induct, after the seeds sprout.The results show that: MS is a suitable basic medium for Eucalyptus dunnii seed germination and growth. MS + KT1.0 mg / L +2,4-D2 .0 mg / L + cysteine 30 mg / L is the ideal medium to induce seeds to dedifferentiate directly into callus. MS+ Ad 2.0mg / L + IAA0.2mg / L is respectively an ideal medium for its shoots to shoot. B5+ 6- BA2.0mg/L + NAA0.2mg / L is the best medium for its seedling roots to dedifferentiate. MS + 6-BA 2.0 mg/L +2,4-D0.2 mg/L is the best medium to induce its seedling's hypocotyls into buds. B5+Ad2.0 mg/L +IAA0.2mg/L is a better medium to induce its seedling's hypocotyls into a callus which can differentiate and form a normal shoots.An investigation was taken to extremely serious damaged Eucalyptus dunnii throughout the northern Fujian after the disaster was taken in 2005 which happens about one time in 20 years. The statistics shows that the damage degree order follows: Pucheng County> Shaowu City> Jianyang City> Shunchang County> Jianou City> Yanping District. Eucalyptus dunnii damaged extent is related to their age. Afforestation in 2004> afforestation in 2003 > afforestation in 2002. And the damage severity is related to the cultivating techniques. If the first fertilizer application was done to Eucalyptus dunnii on May this year, then the second one before August, Eucalyptus dunnii will promote higher growth, improve the shoot lignified level, and not easy to be damaged.If fertilization was postponed to October, the shoots still grow in the winter and have the low lignified level of, then are vulnerable to be damaged. It is proposed that its cultivation in northern Fujian be limited to Jianyang City.Different materials of the survivors of Eucalyptus dunni by cold damage in 2005 were used as explants to induce. The results show that using the stem with bud and half-lignification (terminal bud following 3 ~ 6-bud), alcohol disinfection for 30 s and mercuric chloride for 10 min to disinfect can make the explants brown at the lowest rate, the germination at the highest rate, the pollution at the middle rate. When MS medium and sucrose consumption of 40 g / L are used, it takes the Eucalyptus dunnii stems with buds 5 days to sprout. And sprouting rate is 78%. Budding index is 2.6. Buds growing for 30 days are as high as 0.7 cm. The effective buds are 79%. And Buds are in a fair condition. The all composite indicators of its growth factors are the best. In selection and deployment of the type and concentration of cytokinin, it is found that when 0.5 mg / L KT and 1.0 mg / L 6 - BA are used, both of them are good. But if KT is used, several growth factors, such as sprouting rate, budding index, bud height and ratio of effective bud, are much better than those when 6– BA is used. By selecting and deploying the auxin types and concentrations, it is found that 0.05 mg / L NAA is the best auxin types and concentrations to induce Eucalyptus dunni buds. On the medium of MS + KT1.0 mg / L + NAA0.05 mg / L +4% sucrose, the buds grow normally. The callus grown at buds base is small. The buds have differentiation ability. And the sprouting rate of buds, the average height and the effective shoots rate are high. MS medium is the best medium for Eucalyptus dunni to subculture. Improved MS + KT0.8 mg / L + NAA1.0 mg / L + cysteine 20 mg / L is the best medium for buds to subculture and proliferation.It is as far as possible to use solar light or illumination of incandescent about 300 Lux as subculture conditions. It is beneficial for Eucalyptus dunni subcultures to grow high and root in future when temperature is adjusted from 26℃to 28℃. When modified MS + KT0.8 mg / L + NAA1.0 mg / L + cysteine 20 mg / L medium is used as a control, then added AC, VH and the organic composition as 1.5 times as that in MS, the test shows that whatever AC concentration is, a lot of callus on the leaves of subculture seedlings are produced, the seedlings are wilting and die at last, and no matter what VH concentration added in is, there is no significant effect on the subculture seedlings growth. But the largest effect on sturdy seedlings is organic ingredients. When organic ingredients are used as 1.5 times as that in MS, the subculture seedlings grow vigorously and have a high degree of half-lignification. It will play a very important role to next phase of rooting culture.Using cold resistance varieties of Eucalyptus dunni to do the rooting test, the results showed that ABT can effectively induce Eucalyptus dunni bud to root. The rooting number is increasing with concentration varied from 0.5 to 3.0 mg / L. The maximum rooting rate is 78%. When the concentration is more than 1.5 mg / L, the seedlings height is significantly limited. ABT can be used in conjunction with IBA can increase the rooting rate, and the maximum rooting rate is 96%. When ABT concentration used is more than 0.5 mg / L and IBA concentration used is more than 0.05 mg / L, the seedlings will be induced to produce callus, and be affected its high growth. The callus will be limited to produce in its rooting process and the growth of seedlings will be promoted, when GA 0.05mg / L is added in the medium. 1/2MS+ABT1.0～1.5mg/L+IBA0.05mg/L+GA0.05 is the best medium formula for Eucalyptus dunni seedlings to promote rooting. Using two-step rooting method, the callus formation can be inhibited. And root systems can directly grow from the base of seedlings and rooting rate will increase.Container seedlings in light matrix containers grow much better than that in soil ones. While in various raw material proportions, every growth factor of E. dunni is the best when it is planted in Matrix 6 which ratio of raw materials is bark 20% + hull 30% + sawdust 40%+ peat 28% + fertilizer2%. Its high growth is 23.9 cm,diameter is 0.25 cm, fresh weight on the part is 2.39g, dry weight is 0.65g and survival rate after being transplanted is 100%. |
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