Under aseptic conditions, hypocotyls of mulberry were averagely cut into 3 segments which were then cultured on MS solid medium supplemented with 3.0 mg5L -1 6-BA, 0.3 mg5L -1 IAA, 1.0 mg5L -1 AgNO3 to select the best...
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Under aseptic conditions, hypocotyls of mulberry were averagely cut into 3 segments which were then cultured on MS solid medium supplemented with 3.0 mg5L -1 6-BA, 0.3 mg5L -1 IAA, 1.0 mg5L -1 AgNO3 to select the best region of hypocotyls for getting the more caesptose shoots. In this study, the tip part of hypocotyls（near the germ） developed quickly and induced adventitious buds easily. The caesptose shoots were dipped into 1,1.5, 2.5 g5L -1 colchicines solution for 2 or 3 days, or dropped with 1.5, 2, 2.5 g5L -1 colchicines solution 2 times a day for 5 days, and then transferred to fresh medium. Both the dipped-and dropped-treatments induced variant shoots. Examination of the chromosomes of the shoot tip cells of the regenerated plantlets revealed that they were either tetraploids or chineras. The rate of tetraploids produced from the dipped-and dropped-treatments was 14% and 20% respectively with the chromosomes number of 56（2n=4x=56） as compared to the diploid（2n=2x=28）.
rDNA internal transcribed spacer analysis(rDNA ITS)was used to study diversity of 12 representative mycorrhizal Rhizoctonia strains,which were isolated from Chinese orchids(Cymbidium)distributed in different sites and...
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rDNA internal transcribed spacer analysis(rDNA ITS)was used to study diversity of 12 representative mycorrhizal Rhizoctonia strains,which were isolated from Chinese orchids(Cymbidium)distributed in different sites and belonged to different ecologic *** Blast results indicated that all these strains belonged to Epulorhiza or Tulasnella,which was fully consistent with identification as Epulorhiza with morphological ***,based on rDNA ITS sequence cluster analysis,dendrogram of Cymbidium mycorrhizal strains showed that the distributed environments and orchids species were two crucial factors that affected the specificity-relation between Chinese orchids(Cymbidium)symbiotic mycorrhizae and hosts.
In this paper,the related properties(long-term dimensional stability,adhesion strength,painting film adhering capacity,painting film wearing and consuming value and wood surface hardness) of two plantation-grown hardw...
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In this paper,the related properties(long-term dimensional stability,adhesion strength,painting film adhering capacity,painting film wearing and consuming value and wood surface hardness) of two plantation-grown hardwoods(Betula alnoides and Castanopsis hystrix),compared with commonly used Quercus mongolia domestically,were investigated. The test on long-term dimensional stability is referred to the method established by New Zealand Forest Research Institute,test on adhesion strength is conducted according to the criteria ASTM D905-89,the test on painting film adhering capacity is referred to the criteria GB/T 1765-1999 and GB/T 1765-1999,and wood surface hardness is referred to JIS *** the meantime,adhesion strength and painting film adhering capacity are assigned to the corresponding grades according to different criterion based on a series of experimental results. The results show as follows: the adhesion strength,painting film adhering capacity of B. alnoides,C. hystrix and Q. mongolia belong to excellent grade with similar long-term dimensional stability. The total of radial and tangential swelling coefficient of the three species are 0.064%,0.068% and 0.066%,respectively. With regard to painting film wearing and consuming value of the three species,the quality grades are good,middle and good in order. The surface hardness on different wood surfaces of three species is 11.0,7.7 and 13.0 MPa on radial surface,14.2,10.6 and 12.5 MPa on tangential surface,33.0,26.6 and 38.1 MPa on end surface,respectively.
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