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
凋落物是土壤呼吸的主要碳源,日益增加的大气氮沉降通过改变森林凋落物的输入与分解影响土壤呼吸。为揭示氮沉降及凋落物管理对森林土壤呼吸及其组分的影响,以贵州省国有扎佐林场15年生柳杉人工林为研究对象,设置4个氮添加处理:对照(CK,...凋落物是土壤呼吸的主要碳源,日益增加的大气氮沉降通过改变森林凋落物的输入与分解影响土壤呼吸。为揭示氮沉降及凋落物管理对森林土壤呼吸及其组分的影响,以贵州省国有扎佐林场15年生柳杉人工林为研究对象,设置4个氮添加处理:对照(CK,0 gN m^(-2)a^(-1))、低氮(LN,15 gN m^(-2)a^(-1))、中氮(MN,30 gN m^(-2)a^(-1))和高氮(HN,60 gN m^(-2)a^(-1)),并在每种氮添加处理下设置去除凋落物和保留凋落物两种处理,于2021年3月—2022年2月利用LI⁃8100测定土壤呼吸速率,并分析氮添加及凋落物处理对土壤呼吸速率影响,确定影响土壤呼吸速率变化的主要因子。结果表明:氮添加和去除凋落物处理没有改变土壤呼吸速率的时间变化,土壤呼吸速率月均最大值出现在7月,月均最小值出现在2月。氮添加对土壤呼吸速率无显著影响(P>0.05),除CK外,去除凋落物处理会显著降低土壤呼吸速率(P<0.05)。凋落物对土壤总呼吸速率的贡献率为8.6%—28.5%,且LN处理下凋落物对土壤呼吸速率的贡献率最大。土壤呼吸速率与5 m土壤温度呈显著指数相关(P<0.01),与5 cm土壤湿度呈显著负线性相关(P<0.01)。土壤温度解释了土壤呼吸速率变异的58.5%—79.5%,土壤湿度解释了土壤呼吸速率变异的26.4%—39.5%,以土壤温度和湿度构建的双变量模型拟合效果均好于单因子模型,土壤温湿度共同解释土壤呼吸速率变异的59.1%—85.8%。结论表明在大气氮沉降增加的背景下,温度是影响土壤呼吸的主要因素,凋落物管理是调控土壤呼吸的关键过程。展开更多
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.
文摘凋落物是土壤呼吸的主要碳源,日益增加的大气氮沉降通过改变森林凋落物的输入与分解影响土壤呼吸。为揭示氮沉降及凋落物管理对森林土壤呼吸及其组分的影响,以贵州省国有扎佐林场15年生柳杉人工林为研究对象,设置4个氮添加处理:对照(CK,0 gN m^(-2)a^(-1))、低氮(LN,15 gN m^(-2)a^(-1))、中氮(MN,30 gN m^(-2)a^(-1))和高氮(HN,60 gN m^(-2)a^(-1)),并在每种氮添加处理下设置去除凋落物和保留凋落物两种处理,于2021年3月—2022年2月利用LI⁃8100测定土壤呼吸速率,并分析氮添加及凋落物处理对土壤呼吸速率影响,确定影响土壤呼吸速率变化的主要因子。结果表明:氮添加和去除凋落物处理没有改变土壤呼吸速率的时间变化,土壤呼吸速率月均最大值出现在7月,月均最小值出现在2月。氮添加对土壤呼吸速率无显著影响(P>0.05),除CK外,去除凋落物处理会显著降低土壤呼吸速率(P<0.05)。凋落物对土壤总呼吸速率的贡献率为8.6%—28.5%,且LN处理下凋落物对土壤呼吸速率的贡献率最大。土壤呼吸速率与5 m土壤温度呈显著指数相关(P<0.01),与5 cm土壤湿度呈显著负线性相关(P<0.01)。土壤温度解释了土壤呼吸速率变异的58.5%—79.5%,土壤湿度解释了土壤呼吸速率变异的26.4%—39.5%,以土壤温度和湿度构建的双变量模型拟合效果均好于单因子模型,土壤温湿度共同解释土壤呼吸速率变异的59.1%—85.8%。结论表明在大气氮沉降增加的背景下,温度是影响土壤呼吸的主要因素,凋落物管理是调控土壤呼吸的关键过程。
