In this study,pot experiments were conducted on the seedlings of Pinus sylvestris var.mongolica to study the influence of Trichoderma(Trichoderma harzianum E15)and Ectomycorrhizal fungi(Suillus luteus N94)on the growt...In this study,pot experiments were conducted on the seedlings of Pinus sylvestris var.mongolica to study the influence of Trichoderma(Trichoderma harzianum E15)and Ectomycorrhizal fungi(Suillus luteus N94)on the growth of these seedlings.In particular,the effects of these fungi on the fungal community structure in the rhizosphere soil of the seedlings were investigated.Inoculation with Trichoderma harzianum E15 and Suillus luteus N94 significantly(P<0.05)promoted the growth of the Pinus sylvestris seedlings.The non-metric multidimensional scaling(NMDS)results indicated a significant difference(P<0.05)between the fungal community structures in the rhizosphere soil of the annual and biennial seedlings.In the rhizosphere soil of annual seedlings,the main fungi were Ascomycota,Basidiomycota,Zygomycota.Ascomycota,Basidiomycota,Mortierellomycota,and p-unclassified-k-Fungi were the main fungi in the rhizosphere soil of biennial seedlings.The dominant genus in the rhizosphere soil and a key factor promoting the growth of the annual and the biennial seedlings was Trichoderma,Suillus,respectively.Both of them were negatively correlated with the relative abundance of microbial flora in the symbiotic environment.Trichoderma had a significant promoting effect on the conversion of total phosphorus,total nitrogen,ammonium nitrogen,nitrate nitrogen,and the organic matter in the rhizosphere soil of the seedlings,while Suillus significantly promoted the conversion of organic matter and total phosphorus.展开更多
In order to examine the causes of degradation of Pinus sylvestris var.mongolica plantations on sandy land,the foliar concentrations of N,P,K and C were analyzed and compared between the field grown P.sylvestris var.mo...In order to examine the causes of degradation of Pinus sylvestris var.mongolica plantations on sandy land,the foliar concentrations of N,P,K and C were analyzed and compared between the field grown P.sylvestris var.mongolica trees from two provenances(natural forests and plantations).The results indicated that natural tree needles had lower N,P and C concentrations,and higher K concentrations than those of plantation tree needles.For plantation tree needles,ratios of N:P,P.K and N:K increased with tree age before 45 years old;but they were not clear for the natural tree needles.Compared with the conclusions reported on Pinus spp.,we found that the foliar N and P concentrations were in the optimal range for both natural and plantation tree needles.This result suggested that N or P might not be the absolute limit factors in plant nutrient for P sylvestris var.mongolica on sandy land.However,foliar K concentrations in both natural and plantation tree needles were much lower than those reported on Pinus spp.(〉4.80 g kg-1).The N:P ratio of natural needles was in the adequate ranges,but N:P ratio of plantation needles was out of the adequate ranges.These results indicated that there was a better balanced nutrition status in the natural forest than in the plantations.If only considering the foliar nutrient concentrations of P sylvestris var.mongolica from different provenances,it might be concluded that the degradation phenomenon of P.sylvestris var.mongolica plantations was not induced by nutrition deficiency of absolute nutrients of N and P,but might be induced by other mineral nutrients or by the effectiveness of N and P nutrients.The unbalanced nutrition status and relatively quick decomposition of needles in the plantations might also contribute to the degradation.展开更多
Water potential (φ w .) and net photosynthetic rate (Pn) of Larix olgensis and Pinns.sylvestris var. mongolica deercased with the deerease of soil water content φw and Pn of L.olgensis changed hardly during the fi...Water potential (φ w .) and net photosynthetic rate (Pn) of Larix olgensis and Pinns.sylvestris var. mongolica deercased with the deerease of soil water content φw and Pn of L.olgensis changed hardly during the first 9 davs after stopping watering, then deereased sharply at the 10th dav Pn of P sylvestris var mongolica deereased slightly during the lirst 8 days, then deereased sharply at the 9th day Their respiration rate, chlorophyll content and their a/b ratio changed hardly. The tollowing 3 conclusions were obtained and discussed exhaustively . (Ⅰ) φ w can be used to direct watering as a sensitive index of judging whether L. olgensis and P.sylvestris var. mongolica lacking water (2 )The deereasc of Pn of L. olgensis and P. sylvestris var. mongolica when drought had nothing to do with chlorophyll. (3) P. sylvestris var. mongolica had morphological drought resistance . while L,olgensis had physiological drought resistance, and their drought resistance was discnssed comparatively first time.展开更多
A study was conducted to determine the influences of initial planting densities, thinning intensities, exposures and slope sites on physical property （wood density） and mechanical properties such as modulus of elast...A study was conducted to determine the influences of initial planting densities, thinning intensities, exposures and slope sites on physical property （wood density） and mechanical properties such as modulus of elasticity （MOE）, bending strength, impact strength, compression strength along grain and hardness） of Pinus sylvestris var. mongolica plantation in Mao＇ershan Forest Farm, Northeast China. Results show that the different initial planting densities （1.5 m×1.0 m, 1.5 m×2.0 m and 1.5 m×2.5 m） had significant effects on wood density and MOE, and the highest mean wood density and indexes of mechanical properties occurred in the stand with an initial planting density of 1.5 m×1.0 m. The indexes of mechanical properties such as hardness of end, bending strength, MOE and compression strength along grain of wood increased after mild thinning, but decreased after violent thinning. The exposures （sunny slope and shady slope） had a significant effect on MOE, and the highest mean MOE occurred on sunny slope. The slope sites （upper site and lower site） had a significant effect on wood density and main mechanical properties, except hardness. The highest mean wood density and mechanical properties occurred at lower site.展开更多
The spatial distribution pattern of needle bright disease was mathematically studied. The results showed that it is tally with negative binomial distribution. The infected area and damaged amount can be forecasted wit...The spatial distribution pattern of needle bright disease was mathematically studied. The results showed that it is tally with negative binomial distribution. The infected area and damaged amount can be forecasted with this spatial distribution pattern. Through the study on probability distribution of spatial points for single tree, the method and equations for calculation of the disease index of whole forest belt were determined.展开更多
Mongolian pine is an important afforestation species widely used for ecological management in northeast China. The environment in this region is very unstable and the flora are regularly subjected to drought stress.Th...Mongolian pine is an important afforestation species widely used for ecological management in northeast China. The environment in this region is very unstable and the flora are regularly subjected to drought stress.This paper reports on the influence of inoculation with the Suillus luteus on seedlings under different water conditions.Both inoculated and non-inoculated ectomycorrhizal fungi(ECMF)-S. luteus seedlings were maintained under wellwatered or water-stress conditions for 3 months. The S.luteus colonization rate under water stress was higher than that in well-watered conditions. Under water stress, inoculated seedlings had greater growth than non-inoculated seedlings. In addition, under water stress, S. luteus-inoculated seedlings had greater superoxide dismutase and peroxidase activity, higher soluble protein content, lower proline content, and lower malondialdehyde content than non-inoculated seedlings. S. luteus colonization increased the rhizosphere soil-enzyme activity and the rhizosphere soil nutrition content under both well-watered and water-stress conditions. Given the positive impact on seedling growth and physiology, S. luteus shows potential for use in the arid and semi-arid regions of northeast China for afforestation.展开更多
Three treatment measures for raising seedlings by sowing, Le. covering seeds with two layers of forest soil, culturing seedlings under full sunshine and timely sowing in late autumn, were adopted in this study. The re...Three treatment measures for raising seedlings by sowing, Le. covering seeds with two layers of forest soil, culturing seedlings under full sunshine and timely sowing in late autumn, were adopted in this study. The results indicated that the three treatments were of good prevention effects on sheath blight or seedling blight, sunscald and rat damage in Pinus sylvestris var. mongolica, could avoid the pollution of agrochemicals to soil and environment as well as decrease cost for raising seedlings, and thus could promote the development of bio-agrochemicals or bio-fungicides with high efficiency and no pollution for resisting the pathogens of sheath blight.展开更多
Background The forest floor humus layer is an important carbon pool and serves as a key interface that influences forest soil carbon and nutrient cycling,especially in temperate and boreal forests.Over the past decade...Background The forest floor humus layer is an important carbon pool and serves as a key interface that influences forest soil carbon and nutrient cycling,especially in temperate and boreal forests.Over the past decades,China has implemented numerous forestry ecological programs,leading to an increasing quantity of forest floor litter and the formation of humus layers,which has altered the interface between aboveground litter and surface soil.Our previous study revealed that these alterations affect the litter decomposition rate;however,it is still unclear how the litter decomposition process changes,how nutrients are released or imported and the extent to which these changes depend on the humus layer.Results In this study,we used a 535-day in situ litterbag experiment to monitor the litter decomposition process and nutrient variations under forest floor humus layer removal in a Pinus sylvestris var.mongolica plantation in Northeast China.The results revealed that the litter decomposed quickly when a forest floor humus layer was present,with the decomposition rate constant(k value)increasing from 0.122 to 0.328.Accordingly,during decomposition,the litter C,N and P concentrations increased,whereas their contents varied only slightly(with the exception of the litter P content,which decreased significantly)compared with those in the treatment where the humus layer was removed.However,both the litter C and N contents decreased,whereas the litter P content increased significantly compared with the initial litter content.Moreover,the litter C:N,C:P and N:P ratios decreased significantly during decomposition.In addition,the microbial community diversity of the litter showed no significant change,whereas the relative abundances of several major fungal and bacterial taxa at the phylum and genus levels varied significantly.Furthermore,redundancy analysis revealed effective relationships among the k values,chemical traits and microbial communities,and the least squares method suggested that the C,P and C:P ratios of the litter were significantly correlated with the litter decomposition rate.Conclusions These results enhance our understanding of the role of the humus layer in forest soil-plant carbon and nutrient cycling and should be considered in carbon cycle models in the future.展开更多
The experiment was conducted at the Ganqika Sandy Land Ecological Station in Ke抏rqinzuoyihouqi County, Inner Mongolia, in a growing season from April 28 to October 28, 2001. Peat and weathered coal were added to the ...The experiment was conducted at the Ganqika Sandy Land Ecological Station in Ke抏rqinzuoyihouqi County, Inner Mongolia, in a growing season from April 28 to October 28, 2001. Peat and weathered coal were added to the aeolian sandy soil in different ratios. Two-year-old Pinus sylvestris var. mongolica seedlings and plastic pots were used in the experiment. The experimental results indicated that: 1) the peat and weathered coal could significantly improve the physical and chemical prop-erties of aeolian sandy soil, and thus promoted the growth of seedlings; 2) the effect of peat on seedling growth, including height, base diameter, root length and biomass, presented an order of 8%>10%>5%>2%>0 in terms of peat contents, and the effect of weathered coal on seedling growth presented an order of 5%>8%>10%>2%>0 in terms of weathered coal contents for height and basal diameter, 5%>8%>2% >10%>0 for root length, and 5%>2%>8% >10%>0 for biomass; 3) the effects of peat were generally greater than that of weathered coal. Meanwhile, 8% peat was the best treatment to promote the growth of P. sylvestris var. mongolica seedlings.展开更多
Water transport at the root/soil interface of 1 year old Pinus sylvestris Linn. var. sylvestriformis (Takenouchi) Cheng et C. D. Chu seedlings under CO 2 doubling was studied by measuring soil electric conductanc...Water transport at the root/soil interface of 1 year old Pinus sylvestris Linn. var. sylvestriformis (Takenouchi) Cheng et C. D. Chu seedlings under CO 2 doubling was studied by measuring soil electric conductance to survey soil water profiles and comparing it with root distribution surveyed by soil coring and root harvesting in Changbai Mountain in 1999. The results were: (1) The profiles of soil water content were adjusted by root activity. The water content of the soil layer with abundant roots was higher. (2) When CO 2 concentration was doubled, water transport was more active at the root/soil interface and the roots were distributed into deeper layer. It was shown in this work that the method of measuring electric conductance is an inexpensive, non_destructive and relatively sensitive way for underground water transport process.展开更多
The gas_well system permanently installed in the soil was adopted for studying the dynamic relationship between CO 2 profiles and seedling root growth of Pinus sylvestris var. sylvestriformis (Takenouchi) Che...The gas_well system permanently installed in the soil was adopted for studying the dynamic relationship between CO 2 profiles and seedling root growth of Pinus sylvestris var. sylvestriformis (Takenouchi) Cheng et C. D. Chu. The study was conducted in the Open Research Station of Changbai Mountain Forest Ecological System, The Chinese Academy of Sciences from 1999 to 2001. Four treatments were arranged in the rectangular open_top chambers (OTCs): ambient CO 2+no_seedling, 700 μmol/mol CO 2+no_seedling, ambient CO 2 +seedlings, 700 μmol/mol CO 2+seedlings. By collecting and analyzing soil gas synchronously, it was found that the dynamics of CO 2 profiles were related to the biological activity of seedlings. There were more roots distributed in the top soil and the boundary layer across soil and sand, which made more contributions to the CO 2 profiles due to respiration root. Compared with the ambient CO 2, elevated CO 2 led to the peak of CO 2 concentration distribution shifted from soil surface layer to the boundary layer as seasonally growing of seedling roots. It is suggested the gas_well system is an inexpensive, non_destructive and relatively sensitive method for study of soil CO 2 concentration profiles.展开更多
Inter Simple Sequence Repeat （ISSR） was used to detect genetic variation among nine provenances, including 135 individuals. A total of 108 loci were amplified using 10 random primers. The differentiation of the perc...Inter Simple Sequence Repeat （ISSR） was used to detect genetic variation among nine provenances, including 135 individuals. A total of 108 loci were amplified using 10 random primers. The differentiation of the percentage of polymorphic bands （PPB） among different provenances was evident, ranging from 27% to 54%. of which Honghuaerji provenance had the highest PPB and Kalunshan provenance had the lowest PPB. Shannon＇s Information index （1） at species level was 0.1581 and Nei＇s gene diversity （h） was 0.2393. Coefficient of gene differentiation （Gsr） calculated by Popgene was 0.3965, these results indicated that majority of genetic variation （60.35%） was found within provenances. According to dendrogram among pinus sylvestriv provenances, nine provenances were divided into two provenance areas. namely Daxing＇an and Xiaoxing＇an Mountains provenance area and Hulunbeier provenance area.展开更多
文摘In this study,pot experiments were conducted on the seedlings of Pinus sylvestris var.mongolica to study the influence of Trichoderma(Trichoderma harzianum E15)and Ectomycorrhizal fungi(Suillus luteus N94)on the growth of these seedlings.In particular,the effects of these fungi on the fungal community structure in the rhizosphere soil of the seedlings were investigated.Inoculation with Trichoderma harzianum E15 and Suillus luteus N94 significantly(P<0.05)promoted the growth of the Pinus sylvestris seedlings.The non-metric multidimensional scaling(NMDS)results indicated a significant difference(P<0.05)between the fungal community structures in the rhizosphere soil of the annual and biennial seedlings.In the rhizosphere soil of annual seedlings,the main fungi were Ascomycota,Basidiomycota,Zygomycota.Ascomycota,Basidiomycota,Mortierellomycota,and p-unclassified-k-Fungi were the main fungi in the rhizosphere soil of biennial seedlings.The dominant genus in the rhizosphere soil and a key factor promoting the growth of the annual and the biennial seedlings was Trichoderma,Suillus,respectively.Both of them were negatively correlated with the relative abundance of microbial flora in the symbiotic environment.Trichoderma had a significant promoting effect on the conversion of total phosphorus,total nitrogen,ammonium nitrogen,nitrate nitrogen,and the organic matter in the rhizosphere soil of the seedlings,while Suillus significantly promoted the conversion of organic matter and total phosphorus.
基金supported by Innovation Research Project of Chinese Academy of Sciences(KZCX3-SW-418)the 100 Young Researcher Project of Chinese Academy of Sciences.
文摘In order to examine the causes of degradation of Pinus sylvestris var.mongolica plantations on sandy land,the foliar concentrations of N,P,K and C were analyzed and compared between the field grown P.sylvestris var.mongolica trees from two provenances(natural forests and plantations).The results indicated that natural tree needles had lower N,P and C concentrations,and higher K concentrations than those of plantation tree needles.For plantation tree needles,ratios of N:P,P.K and N:K increased with tree age before 45 years old;but they were not clear for the natural tree needles.Compared with the conclusions reported on Pinus spp.,we found that the foliar N and P concentrations were in the optimal range for both natural and plantation tree needles.This result suggested that N or P might not be the absolute limit factors in plant nutrient for P sylvestris var.mongolica on sandy land.However,foliar K concentrations in both natural and plantation tree needles were much lower than those reported on Pinus spp.(〉4.80 g kg-1).The N:P ratio of natural needles was in the adequate ranges,but N:P ratio of plantation needles was out of the adequate ranges.These results indicated that there was a better balanced nutrition status in the natural forest than in the plantations.If only considering the foliar nutrient concentrations of P sylvestris var.mongolica from different provenances,it might be concluded that the degradation phenomenon of P.sylvestris var.mongolica plantations was not induced by nutrition deficiency of absolute nutrients of N and P,but might be induced by other mineral nutrients or by the effectiveness of N and P nutrients.The unbalanced nutrition status and relatively quick decomposition of needles in the plantations might also contribute to the degradation.
文摘Water potential (φ w .) and net photosynthetic rate (Pn) of Larix olgensis and Pinns.sylvestris var. mongolica deercased with the deerease of soil water content φw and Pn of L.olgensis changed hardly during the first 9 davs after stopping watering, then deereased sharply at the 10th dav Pn of P sylvestris var mongolica deereased slightly during the lirst 8 days, then deereased sharply at the 9th day Their respiration rate, chlorophyll content and their a/b ratio changed hardly. The tollowing 3 conclusions were obtained and discussed exhaustively . (Ⅰ) φ w can be used to direct watering as a sensitive index of judging whether L. olgensis and P.sylvestris var. mongolica lacking water (2 )The deereasc of Pn of L. olgensis and P. sylvestris var. mongolica when drought had nothing to do with chlorophyll. (3) P. sylvestris var. mongolica had morphological drought resistance . while L,olgensis had physiological drought resistance, and their drought resistance was discnssed comparatively first time.
基金This study was supported by National Natural Science Foundation of China (30471355) and the Key Technologies R&D Program of Heilongjiang Province (G99B5-3)
文摘A study was conducted to determine the influences of initial planting densities, thinning intensities, exposures and slope sites on physical property （wood density） and mechanical properties such as modulus of elasticity （MOE）, bending strength, impact strength, compression strength along grain and hardness） of Pinus sylvestris var. mongolica plantation in Mao＇ershan Forest Farm, Northeast China. Results show that the different initial planting densities （1.5 m×1.0 m, 1.5 m×2.0 m and 1.5 m×2.5 m） had significant effects on wood density and MOE, and the highest mean wood density and indexes of mechanical properties occurred in the stand with an initial planting density of 1.5 m×1.0 m. The indexes of mechanical properties such as hardness of end, bending strength, MOE and compression strength along grain of wood increased after mild thinning, but decreased after violent thinning. The exposures （sunny slope and shady slope） had a significant effect on MOE, and the highest mean MOE occurred on sunny slope. The slope sites （upper site and lower site） had a significant effect on wood density and main mechanical properties, except hardness. The highest mean wood density and mechanical properties occurred at lower site.
文摘The spatial distribution pattern of needle bright disease was mathematically studied. The results showed that it is tally with negative binomial distribution. The infected area and damaged amount can be forecasted with this spatial distribution pattern. Through the study on probability distribution of spatial points for single tree, the method and equations for calculation of the disease index of whole forest belt were determined.
基金supported by the National Natural Science Foundation of China(31670649,31200484,31170597)
文摘Mongolian pine is an important afforestation species widely used for ecological management in northeast China. The environment in this region is very unstable and the flora are regularly subjected to drought stress.This paper reports on the influence of inoculation with the Suillus luteus on seedlings under different water conditions.Both inoculated and non-inoculated ectomycorrhizal fungi(ECMF)-S. luteus seedlings were maintained under wellwatered or water-stress conditions for 3 months. The S.luteus colonization rate under water stress was higher than that in well-watered conditions. Under water stress, inoculated seedlings had greater growth than non-inoculated seedlings. In addition, under water stress, S. luteus-inoculated seedlings had greater superoxide dismutase and peroxidase activity, higher soluble protein content, lower proline content, and lower malondialdehyde content than non-inoculated seedlings. S. luteus colonization increased the rhizosphere soil-enzyme activity and the rhizosphere soil nutrition content under both well-watered and water-stress conditions. Given the positive impact on seedling growth and physiology, S. luteus shows potential for use in the arid and semi-arid regions of northeast China for afforestation.
基金Supported by Basic Scientific Research Business Expense Project for Public-interest Scientific Institute of the Xinjiang Uyghur Autonomous Region"Collection of Introduced Tree Species of Populus fro Afforestation in Aroboretum of Xinjiang Academy of Forestry"~~
文摘Three treatment measures for raising seedlings by sowing, Le. covering seeds with two layers of forest soil, culturing seedlings under full sunshine and timely sowing in late autumn, were adopted in this study. The results indicated that the three treatments were of good prevention effects on sheath blight or seedling blight, sunscald and rat damage in Pinus sylvestris var. mongolica, could avoid the pollution of agrochemicals to soil and environment as well as decrease cost for raising seedlings, and thus could promote the development of bio-agrochemicals or bio-fungicides with high efficiency and no pollution for resisting the pathogens of sheath blight.
基金supported by the National Key Research and Development Program of China(2024YFD150140302)the Natural Science Foundation of China(Nos.32271843,41888101 and 41871027)the project of forestry science and technology innovation platform(No.LLC20245)
文摘Background The forest floor humus layer is an important carbon pool and serves as a key interface that influences forest soil carbon and nutrient cycling,especially in temperate and boreal forests.Over the past decades,China has implemented numerous forestry ecological programs,leading to an increasing quantity of forest floor litter and the formation of humus layers,which has altered the interface between aboveground litter and surface soil.Our previous study revealed that these alterations affect the litter decomposition rate;however,it is still unclear how the litter decomposition process changes,how nutrients are released or imported and the extent to which these changes depend on the humus layer.Results In this study,we used a 535-day in situ litterbag experiment to monitor the litter decomposition process and nutrient variations under forest floor humus layer removal in a Pinus sylvestris var.mongolica plantation in Northeast China.The results revealed that the litter decomposed quickly when a forest floor humus layer was present,with the decomposition rate constant(k value)increasing from 0.122 to 0.328.Accordingly,during decomposition,the litter C,N and P concentrations increased,whereas their contents varied only slightly(with the exception of the litter P content,which decreased significantly)compared with those in the treatment where the humus layer was removed.However,both the litter C and N contents decreased,whereas the litter P content increased significantly compared with the initial litter content.Moreover,the litter C:N,C:P and N:P ratios decreased significantly during decomposition.In addition,the microbial community diversity of the litter showed no significant change,whereas the relative abundances of several major fungal and bacterial taxa at the phylum and genus levels varied significantly.Furthermore,redundancy analysis revealed effective relationships among the k values,chemical traits and microbial communities,and the least squares method suggested that the C,P and C:P ratios of the litter were significantly correlated with the litter decomposition rate.Conclusions These results enhance our understanding of the role of the humus layer in forest soil-plant carbon and nutrient cycling and should be considered in carbon cycle models in the future.
基金This research was supported by Key Knowledge Innova-tion Project (SCXZD0102) of Institute of Applied Ecology Chinese Academy of Sciences and sponsored by the Science and Technology Department of Inner Mongolia Autonomic Region,P. R. China (2001010)
文摘The experiment was conducted at the Ganqika Sandy Land Ecological Station in Ke抏rqinzuoyihouqi County, Inner Mongolia, in a growing season from April 28 to October 28, 2001. Peat and weathered coal were added to the aeolian sandy soil in different ratios. Two-year-old Pinus sylvestris var. mongolica seedlings and plastic pots were used in the experiment. The experimental results indicated that: 1) the peat and weathered coal could significantly improve the physical and chemical prop-erties of aeolian sandy soil, and thus promoted the growth of seedlings; 2) the effect of peat on seedling growth, including height, base diameter, root length and biomass, presented an order of 8%>10%>5%>2%>0 in terms of peat contents, and the effect of weathered coal on seedling growth presented an order of 5%>8%>10%>2%>0 in terms of weathered coal contents for height and basal diameter, 5%>8%>2% >10%>0 for root length, and 5%>2%>8% >10%>0 for biomass; 3) the effects of peat were generally greater than that of weathered coal. Meanwhile, 8% peat was the best treatment to promote the growth of P. sylvestris var. mongolica seedlings.
文摘Water transport at the root/soil interface of 1 year old Pinus sylvestris Linn. var. sylvestriformis (Takenouchi) Cheng et C. D. Chu seedlings under CO 2 doubling was studied by measuring soil electric conductance to survey soil water profiles and comparing it with root distribution surveyed by soil coring and root harvesting in Changbai Mountain in 1999. The results were: (1) The profiles of soil water content were adjusted by root activity. The water content of the soil layer with abundant roots was higher. (2) When CO 2 concentration was doubled, water transport was more active at the root/soil interface and the roots were distributed into deeper layer. It was shown in this work that the method of measuring electric conductance is an inexpensive, non_destructive and relatively sensitive way for underground water transport process.
文摘The gas_well system permanently installed in the soil was adopted for studying the dynamic relationship between CO 2 profiles and seedling root growth of Pinus sylvestris var. sylvestriformis (Takenouchi) Cheng et C. D. Chu. The study was conducted in the Open Research Station of Changbai Mountain Forest Ecological System, The Chinese Academy of Sciences from 1999 to 2001. Four treatments were arranged in the rectangular open_top chambers (OTCs): ambient CO 2+no_seedling, 700 μmol/mol CO 2+no_seedling, ambient CO 2 +seedlings, 700 μmol/mol CO 2+seedlings. By collecting and analyzing soil gas synchronously, it was found that the dynamics of CO 2 profiles were related to the biological activity of seedlings. There were more roots distributed in the top soil and the boundary layer across soil and sand, which made more contributions to the CO 2 profiles due to respiration root. Compared with the ambient CO 2, elevated CO 2 led to the peak of CO 2 concentration distribution shifted from soil surface layer to the boundary layer as seasonally growing of seedling roots. It is suggested the gas_well system is an inexpensive, non_destructive and relatively sensitive method for study of soil CO 2 concentration profiles.
基金This study was supported by National Scientific and Technological Brainstorm Project.
文摘Inter Simple Sequence Repeat （ISSR） was used to detect genetic variation among nine provenances, including 135 individuals. A total of 108 loci were amplified using 10 random primers. The differentiation of the percentage of polymorphic bands （PPB） among different provenances was evident, ranging from 27% to 54%. of which Honghuaerji provenance had the highest PPB and Kalunshan provenance had the lowest PPB. Shannon＇s Information index （1） at species level was 0.1581 and Nei＇s gene diversity （h） was 0.2393. Coefficient of gene differentiation （Gsr） calculated by Popgene was 0.3965, these results indicated that majority of genetic variation （60.35%） was found within provenances. According to dendrogram among pinus sylvestriv provenances, nine provenances were divided into two provenance areas. namely Daxing＇an and Xiaoxing＇an Mountains provenance area and Hulunbeier provenance area.
