An intergeneric artificial hybridization was conducted between Cunninghamia R. Br. and Cryptomeria D.Don The results are as follows:1. A considerable number of hybrid seeds shed from 76 pollinated cones were ...An intergeneric artificial hybridization was conducted between Cunninghamia R. Br. and Cryptomeria D.Don The results are as follows:1. A considerable number of hybrid seeds shed from 76 pollinated cones were empty and a total of 628 looks plump. Soft X ray radiographs showed that, still and all, a majority of the “plump" seeds were embryoless (597, 95.6%) whereas some were partially developed (17,2.7%) and only a few were really full (14, 2.2%). 2. Germination test showed that all of the radiographed hybrid seeds with fully developed embryos were germinable whereas those with partially developed embryos were ungerminable. 3. Physiologically, the growth rate of hypocotyl, the date for shedding of seed coat and spreading of cotyledons, the elongation of epicotyl, and the branching of shoot of the 11 month old seedlings showed a tendency to fall behind those of the female parent; morphologically, the 11 month old hybrid seedlings with linear leaves appeared rather short, slender and weak, whereas the seedlings of the female parents with linear_lanceolate leaves appeared rather tall, stout and strong. 4. It is considered that the hybrid may be true and the crossability reveals a close phylogenetic affinity of Cunninghamia with Cryptomeria.展开更多
We investigated the effect of forest thinning on soil nitrogen mineralization, nitrification and transformation in a Cryptomeria japoni-ca plantation at high elevation to provide basic data for forest manage-ment. We ...We investigated the effect of forest thinning on soil nitrogen mineralization, nitrification and transformation in a Cryptomeria japoni-ca plantation at high elevation to provide basic data for forest manage-ment. We chose four study plots for control, light, medium and heavy thinning treatment, and three sub-plots for buried bag studies at similar elevations in each treatment plot to measure the net N mineralization and nitrification rates in situ. The contents of soil inorganic N （ammonium and nitrate） were similar between treatments, but all varied with season, reaching maxima in September 2003 and 2004. The seasonal maximum net Nmin rates after four treatments were 0.182, 0.246, 0.303 and 0.560 mg？kg-1？d-1 in 2003, and 0.242,0.258,0.411 and 0.671 mg？kg-1？d-1in 2004, respectively. These estimates are approximate with the lower annual rates of N mineralization for this region. Forest thinning can enhance net N mineralization and microbial biomass carbon. The percentage of annual rates of Nmin for different levels of forest thinning compared with the control plot were 13.4%, 59.8%and 154.2%in 2003, and 0.1%, 58.8%and 157.7%in 2004 for light, medium, and heavy thinning, respectively. These differences were related to soil moisture, temperature, precipita-tion, and soil and vegetation types. Well-planned multi-site comparisons, both located within Taiwan and the East-Asia region, could greatly im-prove our knowledge of regional patterns in nitrogen cycling.展开更多
Cryptomeria fortunei(Chinese cedar)is a highly adaptable woody species and one of the main forest plantation trees in subtropical high-altitude areas in China.However,there are few studies on its chloroplast(cp)genome...Cryptomeria fortunei(Chinese cedar)is a highly adaptable woody species and one of the main forest plantation trees in subtropical high-altitude areas in China.However,there are few studies on its chloroplast(cp)genome.In this study,the complete cp genome of C.fortunei was sequenced and evaluated via comparative analyses with those of related species(formerly the Taxodiaceae)in Cupressaceae.The C.fortunei cp genome was 131,580 bp in length,and the GC content of the whole genome was 35.38%.It lost one relevant large inverted repeat and contained 114 unique genes,including 82 protein-coding genes,28 tRNAs and 4 rRNAs.The relative synonymous codon usage(RSCU)of codons ending with A/U was more than twice that of codons ending with G/C.Thirty long repeat structures(LRSs)and 213 simple sequence repeat(SSR)loci were detected in the C.fortunei cp genome.Comparative analyses of 10 cp genomes revealed that substantial rearrangements occurred in the gene organization.Additionally,6 cp hotspot regions(trnS-GGA,ycf1,trnP-GGG,trnC-GCA,psbZ and accD)were identified,and 4 genes(petL,psbM,rpl22 and psaM)had likely underwent positive selection.Phylogenetic analysis showed that Cupressaceae,Taxaceae and Cephalotaxaceae clustered to form a clade and that C.fortunei was most closely related to C.japonica(Japanese cedar),C.japonica cv.Wogon Hort and Taxodium distichum(baldcypress).These results provide references for future studies of population genetics,phylogenetic status and molecular markers among Cupressaceae species and for the cultivation of improved varieties.展开更多
The cell wall in wood is mainly composed of three components: cellulose, hemicellulose and lignin. According to electron microscopy observations of the innermost surface of cell walls in the tracheids of Cryptomeria j...The cell wall in wood is mainly composed of three components: cellulose, hemicellulose and lignin. According to electron microscopy observations of the innermost surface of cell walls in the tracheids of Cryptomeria japonica , cellulose microfibrils are deposited during the day and a matrix containing hemicellulose is deposited at night. This indicates that the deposition of cell wall components exhibits diurnal periodicity. To gain new insights into the diurnal periodicity of lignin deposition not revealed by microscopic observations, we examined diurnal fluctuations in the expression of genes involved in monolignol biosynthesis in C. japonica saplings grown in the field and in growth chambers under a 12 h light/dark cycle. In the field experiment, two gene expression peaks were observed daily, at dusk and dawn. In the growth chamber experiment, two daily peaks were observed 0 h and 6 - 9 h after the light switched on.展开更多
The inheritance of mitochondrial (mt) DNA and chloroplast (cp) DNA was investigated in intergeneric hybrids from crossing between Cunninghamia lanceolata (Lamb.) Hook. and Cryptomeria fortunei Hooibrenk. The c...The inheritance of mitochondrial (mt) DNA and chloroplast (cp) DNA was investigated in intergeneric hybrids from crossing between Cunninghamia lanceolata (Lamb.) Hook. and Cryptomeria fortunei Hooibrenk. The chloroplast trnL trnF region and one intra genic segment of the mitochondrial gene, Cox Ⅲ, were amplified from those of the parents and hybrids by PCR using gene specific primers. Cp and mtDNA polymorphisms of the amplified regions were detected between the parents after restriction digestions. Restriction fragment length polymorphism (RFLP) analysis revealed that all the F 1 individuals possessed Cox Ⅲ restriction fragment patterns (characteristic of the paternal parent Cryptomeria fortunei ) and the trnL trnF region (identical to the maternal parent Cunninghamia lanceolata ) showing that a different mode of inheritance for organelle DNA has occurred in the hybrids. Furthermore, the maternal inheritance of chloroplast DNA is reported here for the first time in coniferophyta.展开更多
文摘An intergeneric artificial hybridization was conducted between Cunninghamia R. Br. and Cryptomeria D.Don The results are as follows:1. A considerable number of hybrid seeds shed from 76 pollinated cones were empty and a total of 628 looks plump. Soft X ray radiographs showed that, still and all, a majority of the “plump" seeds were embryoless (597, 95.6%) whereas some were partially developed (17,2.7%) and only a few were really full (14, 2.2%). 2. Germination test showed that all of the radiographed hybrid seeds with fully developed embryos were germinable whereas those with partially developed embryos were ungerminable. 3. Physiologically, the growth rate of hypocotyl, the date for shedding of seed coat and spreading of cotyledons, the elongation of epicotyl, and the branching of shoot of the 11 month old seedlings showed a tendency to fall behind those of the female parent; morphologically, the 11 month old hybrid seedlings with linear leaves appeared rather short, slender and weak, whereas the seedlings of the female parents with linear_lanceolate leaves appeared rather tall, stout and strong. 4. It is considered that the hybrid may be true and the crossability reveals a close phylogenetic affinity of Cunninghamia with Cryptomeria.
基金supported by Strategic Priority Research Program of the Chinese Academy of Sciences(XDA05070303)
文摘We investigated the effect of forest thinning on soil nitrogen mineralization, nitrification and transformation in a Cryptomeria japoni-ca plantation at high elevation to provide basic data for forest manage-ment. We chose four study plots for control, light, medium and heavy thinning treatment, and three sub-plots for buried bag studies at similar elevations in each treatment plot to measure the net N mineralization and nitrification rates in situ. The contents of soil inorganic N （ammonium and nitrate） were similar between treatments, but all varied with season, reaching maxima in September 2003 and 2004. The seasonal maximum net Nmin rates after four treatments were 0.182, 0.246, 0.303 and 0.560 mg？kg-1？d-1 in 2003, and 0.242,0.258,0.411 and 0.671 mg？kg-1？d-1in 2004, respectively. These estimates are approximate with the lower annual rates of N mineralization for this region. Forest thinning can enhance net N mineralization and microbial biomass carbon. The percentage of annual rates of Nmin for different levels of forest thinning compared with the control plot were 13.4%, 59.8%and 154.2%in 2003, and 0.1%, 58.8%and 157.7%in 2004 for light, medium, and heavy thinning, respectively. These differences were related to soil moisture, temperature, precipita-tion, and soil and vegetation types. Well-planned multi-site comparisons, both located within Taiwan and the East-Asia region, could greatly im-prove our knowledge of regional patterns in nitrogen cycling.
基金This research was funded by the National Forestry and Grassland Administration of China,National Forestry Public Welfare Industry Research Project(Grant No.201304104)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD).
文摘Cryptomeria fortunei(Chinese cedar)is a highly adaptable woody species and one of the main forest plantation trees in subtropical high-altitude areas in China.However,there are few studies on its chloroplast(cp)genome.In this study,the complete cp genome of C.fortunei was sequenced and evaluated via comparative analyses with those of related species(formerly the Taxodiaceae)in Cupressaceae.The C.fortunei cp genome was 131,580 bp in length,and the GC content of the whole genome was 35.38%.It lost one relevant large inverted repeat and contained 114 unique genes,including 82 protein-coding genes,28 tRNAs and 4 rRNAs.The relative synonymous codon usage(RSCU)of codons ending with A/U was more than twice that of codons ending with G/C.Thirty long repeat structures(LRSs)and 213 simple sequence repeat(SSR)loci were detected in the C.fortunei cp genome.Comparative analyses of 10 cp genomes revealed that substantial rearrangements occurred in the gene organization.Additionally,6 cp hotspot regions(trnS-GGA,ycf1,trnP-GGG,trnC-GCA,psbZ and accD)were identified,and 4 genes(petL,psbM,rpl22 and psaM)had likely underwent positive selection.Phylogenetic analysis showed that Cupressaceae,Taxaceae and Cephalotaxaceae clustered to form a clade and that C.fortunei was most closely related to C.japonica(Japanese cedar),C.japonica cv.Wogon Hort and Taxodium distichum(baldcypress).These results provide references for future studies of population genetics,phylogenetic status and molecular markers among Cupressaceae species and for the cultivation of improved varieties.
文摘The cell wall in wood is mainly composed of three components: cellulose, hemicellulose and lignin. According to electron microscopy observations of the innermost surface of cell walls in the tracheids of Cryptomeria japonica , cellulose microfibrils are deposited during the day and a matrix containing hemicellulose is deposited at night. This indicates that the deposition of cell wall components exhibits diurnal periodicity. To gain new insights into the diurnal periodicity of lignin deposition not revealed by microscopic observations, we examined diurnal fluctuations in the expression of genes involved in monolignol biosynthesis in C. japonica saplings grown in the field and in growth chambers under a 12 h light/dark cycle. In the field experiment, two gene expression peaks were observed daily, at dusk and dawn. In the growth chamber experiment, two daily peaks were observed 0 h and 6 - 9 h after the light switched on.
文摘The inheritance of mitochondrial (mt) DNA and chloroplast (cp) DNA was investigated in intergeneric hybrids from crossing between Cunninghamia lanceolata (Lamb.) Hook. and Cryptomeria fortunei Hooibrenk. The chloroplast trnL trnF region and one intra genic segment of the mitochondrial gene, Cox Ⅲ, were amplified from those of the parents and hybrids by PCR using gene specific primers. Cp and mtDNA polymorphisms of the amplified regions were detected between the parents after restriction digestions. Restriction fragment length polymorphism (RFLP) analysis revealed that all the F 1 individuals possessed Cox Ⅲ restriction fragment patterns (characteristic of the paternal parent Cryptomeria fortunei ) and the trnL trnF region (identical to the maternal parent Cunninghamia lanceolata ) showing that a different mode of inheritance for organelle DNA has occurred in the hybrids. Furthermore, the maternal inheritance of chloroplast DNA is reported here for the first time in coniferophyta.
