Leaves are important‘source’organs that synthesize organic matter,providing carbon sources for plant growth.Here,we used Populus talassica×Populus euphratica,the dominant species in ecological and timber forest...Leaves are important‘source’organs that synthesize organic matter,providing carbon sources for plant growth.Here,we used Populus talassica×Populus euphratica,the dominant species in ecological and timber forests,to simulate carbon limitation through artificial 25%,50%,and 75%defoliation treatments and explore the effects on root,stem,and leaf morphology,biomass accumulation,and carbon allocation strategies.At the 60th d after treat-ment,under 25%defoliation treatment,the plant height,specific leaf weight,root surface area and volume,and concentrations of non-structural carbohydrates in stem and root were significantly increased by 9.13%,20.00%,16.60%,31.95%,5.12%,and 9.34%,respectively,relative to the control.There was no significant change in the growth indicators under 50%defoliation treatment,but the concentrations of non-structural carbohydrates in the leaf and stem significantly decreased,showing mostly a negative correlation between them.The opposite was observed in the root.Under 75%defoliation treatment,the plant height,ground diameter,leaf number,single leaf area,root,stem,and total biomass were significantly reduced by 14.15%,10.24%,14.86%,11.31%,11.56%,21.87%,and 16.82%,respectively,relative to the control.The concentrations of non-structural carbohydrates in various organs were significantly reduced,particularly in the consumption of the starch concentrations in the stem and root.These results indicated that carbon allocation strategies can be adjusted to increase the con-centration of non-structural carbohydrates in root and meet plant growth needs under 25%and 50%defoliation.However,75%defoliation significantly limited the distribution of non-structural carbohydrates to roots and stems,reduced carbon storage,and thus inhibited plant growth.Defoliation-induced carbon limitation altered the carbon allocation pattern of P.talassica×P.euphratica,and the relationship between carbon reserves in roots and tree growth recovery after defoliation was greater.This study provides a theoretical basis for the comprehen-sive management of P.talassica×P.euphratica plantations,as well as a reference for the study of plantation car-bon allocation strategies in the desert and semi-desert regions of Xinjiang under carbon-limitation conditions.展开更多
High-throughputsingle-cellRNAsequencing(sc RNA-seq) has advantages over traditional RNA-seq to explore spatiotemporal information on gene dynamic expressions in heterogenous tissues. We performed Drop-seq, a method fo...High-throughputsingle-cellRNAsequencing(sc RNA-seq) has advantages over traditional RNA-seq to explore spatiotemporal information on gene dynamic expressions in heterogenous tissues. We performed Drop-seq, a method for the dropwise sequestration of single cells for sequencing, on protoplasts from the differentiating xylem of Populus alba × Populus glandulosa. The sc RNA-seq profiled9,798 cells, which were grouped into 12 clusters.Through characterization of differentially expressed genes in each cluster and RNA in situ hybridizations,we identified vessel cells, fiber cells, ray parenchyma cells and xylem precursor cells. Diffusion pseudotime analyses revealed the differentiating trajectory of vessels, fiber cells and ray parenchyma cells and indicated a different differentiation process between vessels and fiber cells, and a similar differentiation process between fiber cells and ray parenchyma cells. We identified marker genes for each cell type(cluster) and key candidate regulators during developmental stages of xylem cell differentiation. Our study generates a high-resolution expression atlas of wood formation at the single cell level and provides valuable information on wood formation.展开更多
High potential productivity together with short rotation periods have made hybrid aspen an interesting option for wood production on former arable land in Nordic countries.In this study,some of the oldest active exper...High potential productivity together with short rotation periods have made hybrid aspen an interesting option for wood production on former arable land in Nordic countries.In this study,some of the oldest active experimental plots with hybrid aspen in Sweden were remeasured at 23–30 years of age.A main aim was to assess age and productivity at the time of maximum mean annual volume increment.In addition,the infl uence of commercial thinning on stand development and diff erences in genetic gain among clones were investigated.Data from fi ve experiments in southern Sweden were used,including three genetic trials,one demonstration stand with a clone mixture and one stand regenerated from root suckers.The three genetic trials were treated as single plot experiments,subject to a standard thinning program.In the remaining experiments,diff erent thinning strategies were tested in a balanced block design.Volume growth had culminated or was close to maximum at age 25–30 years.Mean annual stem volume increment at culmination was 20–22 m 3 ha^−1 a^−1.Dominant height reached 30–35 m at 28–30 years of age.Mean diameter at breast height was 27–29 cm after 29–30 years in the genetic trials.Clonal ranking based on diameter at age 7–9 years was positively correlated with the ranking at the fi nal measurement in the genetic trials,20 years later.This indicates that clones can be selected for superior growth based on results from young trials.More intense thinning programs increased the mean diameter compared to light thinning.The study indicates that one or two early and relatively heavy thinnings can promote the development of crop trees,without jeopardizing total volume production during a rotation of 25–30 years.展开更多
基金funded by the Talents ans its Youth Project of Xinjiang Production and Construction Corps(38000020924,380000358).
文摘Leaves are important‘source’organs that synthesize organic matter,providing carbon sources for plant growth.Here,we used Populus talassica×Populus euphratica,the dominant species in ecological and timber forests,to simulate carbon limitation through artificial 25%,50%,and 75%defoliation treatments and explore the effects on root,stem,and leaf morphology,biomass accumulation,and carbon allocation strategies.At the 60th d after treat-ment,under 25%defoliation treatment,the plant height,specific leaf weight,root surface area and volume,and concentrations of non-structural carbohydrates in stem and root were significantly increased by 9.13%,20.00%,16.60%,31.95%,5.12%,and 9.34%,respectively,relative to the control.There was no significant change in the growth indicators under 50%defoliation treatment,but the concentrations of non-structural carbohydrates in the leaf and stem significantly decreased,showing mostly a negative correlation between them.The opposite was observed in the root.Under 75%defoliation treatment,the plant height,ground diameter,leaf number,single leaf area,root,stem,and total biomass were significantly reduced by 14.15%,10.24%,14.86%,11.31%,11.56%,21.87%,and 16.82%,respectively,relative to the control.The concentrations of non-structural carbohydrates in various organs were significantly reduced,particularly in the consumption of the starch concentrations in the stem and root.These results indicated that carbon allocation strategies can be adjusted to increase the con-centration of non-structural carbohydrates in root and meet plant growth needs under 25%and 50%defoliation.However,75%defoliation significantly limited the distribution of non-structural carbohydrates to roots and stems,reduced carbon storage,and thus inhibited plant growth.Defoliation-induced carbon limitation altered the carbon allocation pattern of P.talassica×P.euphratica,and the relationship between carbon reserves in roots and tree growth recovery after defoliation was greater.This study provides a theoretical basis for the comprehen-sive management of P.talassica×P.euphratica plantations,as well as a reference for the study of plantation car-bon allocation strategies in the desert and semi-desert regions of Xinjiang under carbon-limitation conditions.
基金This work was supported by grants from Fundamental Research Funds of Chinese Academy of Forestry(CAFYBB2018ZY001-5 and CAFYBB2017ZY001)the National Natural Science Foundation of China(31670667)。
文摘High-throughputsingle-cellRNAsequencing(sc RNA-seq) has advantages over traditional RNA-seq to explore spatiotemporal information on gene dynamic expressions in heterogenous tissues. We performed Drop-seq, a method for the dropwise sequestration of single cells for sequencing, on protoplasts from the differentiating xylem of Populus alba × Populus glandulosa. The sc RNA-seq profiled9,798 cells, which were grouped into 12 clusters.Through characterization of differentially expressed genes in each cluster and RNA in situ hybridizations,we identified vessel cells, fiber cells, ray parenchyma cells and xylem precursor cells. Diffusion pseudotime analyses revealed the differentiating trajectory of vessels, fiber cells and ray parenchyma cells and indicated a different differentiation process between vessels and fiber cells, and a similar differentiation process between fiber cells and ray parenchyma cells. We identified marker genes for each cell type(cluster) and key candidate regulators during developmental stages of xylem cell differentiation. Our study generates a high-resolution expression atlas of wood formation at the single cell level and provides valuable information on wood formation.
文摘High potential productivity together with short rotation periods have made hybrid aspen an interesting option for wood production on former arable land in Nordic countries.In this study,some of the oldest active experimental plots with hybrid aspen in Sweden were remeasured at 23–30 years of age.A main aim was to assess age and productivity at the time of maximum mean annual volume increment.In addition,the infl uence of commercial thinning on stand development and diff erences in genetic gain among clones were investigated.Data from fi ve experiments in southern Sweden were used,including three genetic trials,one demonstration stand with a clone mixture and one stand regenerated from root suckers.The three genetic trials were treated as single plot experiments,subject to a standard thinning program.In the remaining experiments,diff erent thinning strategies were tested in a balanced block design.Volume growth had culminated or was close to maximum at age 25–30 years.Mean annual stem volume increment at culmination was 20–22 m 3 ha^−1 a^−1.Dominant height reached 30–35 m at 28–30 years of age.Mean diameter at breast height was 27–29 cm after 29–30 years in the genetic trials.Clonal ranking based on diameter at age 7–9 years was positively correlated with the ranking at the fi nal measurement in the genetic trials,20 years later.This indicates that clones can be selected for superior growth based on results from young trials.More intense thinning programs increased the mean diameter compared to light thinning.The study indicates that one or two early and relatively heavy thinnings can promote the development of crop trees,without jeopardizing total volume production during a rotation of 25–30 years.
