This study investigated the feasibility of hyperspectral imaging techniques to estimate the vigor of heatdamaged Quercus variabilis seeds.Four thermal damage grades were classified according to heat treatment duration...This study investigated the feasibility of hyperspectral imaging techniques to estimate the vigor of heatdamaged Quercus variabilis seeds.Four thermal damage grades were classified according to heat treatment duration(0,2,5,and 10 h).After obtaining hyperspectral images with a 370–1042 nm hyperspectral imager that included visible and near infrared light,germination was tested to confirm estimates.The Savitzky–Golay(SG)second derivative was used to preprocess the spectrum to reduce any noise impact.The successive projections algorithm(SPA),principal component analysis,and local linear embedding algorithm were used to extract the characteristic spectral bands related to seed vigor.Finally,a model for seed vigor classifi-cation of Q.variabili s based on partial least squares support vector machine(LS-SVM)with different spectral data sets was developed.The results show that the spectrum after SG second derivative preprocessing was better for developing the model,and SPA performed the best among the three feature band selection methods.The combination SG second derivative-LS-SVM provided the best classification model for Q.variabilis seed vigor,with the prediction set reaching 98.81%.This study provides an important basis for rapid and nondestructive assessment of the vigor of heat-damaged seeds using hyperspectral imaging techniques.展开更多
The slope aspect is one of the most critical topographic factors in mountainous areas.Little is known,however,about the eff ect of the aspect on the ectomycorrhizal(ECM)fungal community.Additionally,we know very littl...The slope aspect is one of the most critical topographic factors in mountainous areas.Little is known,however,about the eff ect of the aspect on the ectomycorrhizal(ECM)fungal community.Additionally,we know very little about the composition of ECM fungal communities associated with Quercus variabilis,which is widely distributed in East Asia.In this study,we compared the richness,community composition,and exploration types of ECM fungi associated with Q.variabilis between predominantly south-and north-facing slopes in the Taihang Mountain,North China for the fi rst time.DNA was extracted from the root tips of Q.variabilis,and Illumina MiSeq sequencing was used to identify ECM fungi.In total,168 operational taxonomic units belonging to 28 genera were detected,and the ECM community was found to be dominated by Russula,Inocybe,Tomentella,Scleroderma,and Cortinarius.Compared with the north-facing slopes,the ECM communities on the south-facing slopes had higher diversity.The community composition and exploration types were directly aff ected by the slope aspect.Also,the aspect-induced edaphic variables,such as total phosphorus,total nitrogen,total potassium,pH,and soil water content,were important sources of variation in ECM fungal richness and distributions of exploration types.Diff erent genera tended to be distributed in various slope aspects.Cenococcum,Genea,and Clavulina were signifi cantly enriched in north-facing slopes,while Geopora,Helvelosebacina,Scleroderma,Gyroporus,Astraeus,Boletus,Tricholoma,Hebeloma,Cortinarius and unclassifi ed Thelephoraceae were more abundant in south-facing slopes.Hydrophobic ECM fungi were obviously enriched in the south-facing slope,but there was no statistical diff erence between hydrophilic among the south-and north-facing slopes.Our study deepened our knowledge of the aspect-driven variation in ECM fungal communities associated with Q.variabilis.展开更多
The objective of this study was to investigate the effects of root cutting stress on the dynamic changes of endogenous hormone content and growth characteristics of Quercus variabilis roots,and to explore the physiolo...The objective of this study was to investigate the effects of root cutting stress on the dynamic changes of endogenous hormone content and growth characteristics of Quercus variabilis roots,and to explore the physiological role of endogenous hormones in regulating root-crown interactions in the short term.The morphological characteristics and endogenous hormone contents of normal roots(no root cutting,CK)and cut roots(cut by 1/3 of the length of the main root,RP)were determined by liquid chromatography,which was combined with mass spectrometry at different levels of different developmental stages.The results showed that the root growth indexes and root endogenous hormones in the RP group were superior to those in the CK group.Through comprehensive analysis of endogenous hormones,it was found that the crosstalk of IAA,JA,ABA and SA could activate the root growth defense.After the root cutting treatment,the root growth of Quercus variabilis seedlings could compensate for the inhibition of taproot growth by promoting lateral root growth.The growth and development of compensatory lateral roots contribute to the increase the total root length of plants,thus promoting the absorption of water and nutrients.It is speculated that plant hormones may be the key factors affecting their development,but this is not only related to the content of a single hormone,but more importantly,it is the interaction between various hormones.展开更多
The leaves and stems of Quercus variabilis Blume afforded a new cycloartane nortriterpenoid, 3α-acetyloxy-4α, 14α-dimethyl- 9β, 19-eycloergost-24-oic acid （1）, along with five known compounds （2-6）. The struct...The leaves and stems of Quercus variabilis Blume afforded a new cycloartane nortriterpenoid, 3α-acetyloxy-4α, 14α-dimethyl- 9β, 19-eycloergost-24-oic acid （1）, along with five known compounds （2-6）. The structure of 1 was elucidated by 1D and 2D NMR and mass spectroscopy. 2009 Qi Shi Sun. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.展开更多
[Objectives]The paper was to classify natural types of Quercus variabilis and to study its regularity of variation.[Methods]Through the analysis of correlation coefficient matrix of tree age,DBH,tree height,breast hei...[Objectives]The paper was to classify natural types of Quercus variabilis and to study its regularity of variation.[Methods]Through the analysis of correlation coefficient matrix of tree age,DBH,tree height,breast height and bark thickness,petiole length,leaf width and leaf length,the breast height and bark thickness and petiole length were chosen as the main indices for classifying natural types of Q.variabilis.[Results]There were 4 natural types of Q.variabilis in Shaanxi Province,including long-petiole-thick-bark type,short-petiole-thick-bark type,long-petiole-thin-bark type and short-petiole-thin-bark type.The short-petiole-thick-bark type accounted for the largest proportion in Q.variabilis population(34.44%).On the northern slope of Bashan Mountains and the Huanglong Mountains,the short-petiole-thick-bark type was the dominant type,while on the northern slope of Qinling Mountains the long-petiole-thick-bark type accounted for a larger proportion.[Conclusions]This study will provide a basic foundation for making full use of excellent types of Q.variabilis natural resources.展开更多
Elevation changes may affect intraspecific relationships or interspecific relationships among species.However,previous studies on Quercus variabilis have rarely investigated how its population interactions vary with e...Elevation changes may affect intraspecific relationships or interspecific relationships among species.However,previous studies on Quercus variabilis have rarely investigated how its population interactions vary with elevation and how the factors affect them.Here,we examined the species relationships in Q.variabilis natural secondary forests across the three different elevation ranges(lower,medium,and higher elevation areas)using the niche and the Hegyi competition method.As the elevation increased,Q.variabilis strengthened its dominant position,and the overall association between populations shifted from positive to negative,as evidenced by a significant decrease in the positive-to-negative correlation ratio from 0.45(85/191)to 0.41(80/196)and then to 0.32(29/91),indicating that the interspecific relationship gradually transitioned from facilitation to competition.The ratios of the intraspecific competition index to interspecific competition index were 3.09,8.92 and 6.82,respectively,indicating that Q.variabilis forests had greater intraspecific competition compared to interspecific competition,especially in the medium elevation area.The intraspecific and interspecific competition in the lower and medium elevation areas showed a decreasing trend with the increase of diameter class,while the competition among individuals in the higher elevation area became more stable.The SEM showed that soil properties were indirectly negatively correlated with the species competition through a significant negative effect on forest density,while community characteristics only had a significant negative effect on intraspecific competition.Our results demonstrated that elevation factors decreased the intraspecific and interspecific relationships within Q.variabilis forests,providing new insights into the effective conservation of Q.variabilis natural forests.展开更多
By measuring the contents of soil organic carbon(SOC),total nitrogen(TN),and total phosphorus(P)in rhizosphere and non-rhizosphere soils of Quercus variabilis forests with different ages(22,35,and 45 a)and origins(nat...By measuring the contents of soil organic carbon(SOC),total nitrogen(TN),and total phosphorus(P)in rhizosphere and non-rhizosphere soils of Quercus variabilis forests with different ages(22,35,and 45 a)and origins(natural forests and planted forests)in the Funiu Mountain area,the stoichiometric characteristics of carbon,nitrogen,and phosphorus in Q.variabilis forest soils were evaluated.The research results indicated that:(i)there were significant differences(P<0.05)in the SOC content between the rhizosphere and non-rhizosphere soils of Q.variabilis planted forests at different stand ages.Moreover,as the stand age increased,the SOC content in both the rhizosphere and non-rhizosphere soils of the planted forests initially decreased and then increased.The TN and TP contents in the rhizosphere and non-rhizosphere soils of Q.variabilis planted forests did not show significant differences across different stand ages,and they exhibited different trends as the stand age increased.(ii)The SOC and nitrogen to phosphorus ratio(N:P)exhibited significant rhizosphere effects,whereas the rhizosphere effects of the TN,TP,carbon to nitrogen ratio(C:N),and carbon to phosphorus ratio(C:P)were not prominent.In terms of the influence of stand age,the SOC,TN,TP,C:P,and N:P were significantly affected.However,the effect of the C:N at the stand age level was not significant.The interactive effects of soil carbon,nitrogen,phosphorus,and their stoichiometric ratios were all significant.It is recommended to appropriately supplement soil nitrogen and phosphorus to ensure the sustainable development of Q.variabilis forest stand.展开更多
A study was conducted to evaluate the cultivable filamentous fungal diversity in organic layers (L, F, and H layers) and A1 layer of two main forest types, Pinus massoniana and Liguidambar formasana mixed forest and Q...A study was conducted to evaluate the cultivable filamentous fungal diversity in organic layers (L, F, and H layers) and A1 layer of two main forest types, Pinus massoniana and Liguidambar formasana mixed forest and Quercus variabilis forest, in Zijin Mountain(325?N, 11848?E), Nanjing, China. A total of 67 taxa comprising 56 Deuteromycetes, 3 Zygomycetes, 5 Asco-mycetes and 3 unidentified fungi were recognized from samples from the forest floor of the two forest types. The most abundant group was Deuteromycetes. The dominant genera in both forests were Alternaria sp., Aspergillus sp., Cladosporium sp., Mucor sp., Penicillium sp., Rhizopus sp., Gliocladium sp. and Trichoderma spp. The fungal diversity was higher in the mixed forest than that in Q. variabilis forest. For both forest types, the maximum fungal diversity was found in layer F and there existed significantly different in fungal diversity between layer F and layer L. In the mixed forest, richness of fungi isolated from needle litter (P. massoniana) was lower than that from leaf litter (L. formasana). The richness of fungi from needle litter increased with the in-crease of forest floor depth, but for leaf litter, the fungal diversity decreased with the depth of forest floor. The co-species of fungi from the two forest types, as well as from two kinds of litters in mixed forest, increased with the depth of the forest floor. The succession of fungi along with the process of decomposition was discussed here. The results also showed that litter quality was a critical factor affecting fungal diversity.展开更多
基金funded by the National Natural Science Foundation of China(Grant No.31770769)the National Key Research and Development Program of China(No.2017YFC0504403)the Fundamental Research Funds for the Central Universities(No.2015ZCQ-GX-03).
文摘This study investigated the feasibility of hyperspectral imaging techniques to estimate the vigor of heatdamaged Quercus variabilis seeds.Four thermal damage grades were classified according to heat treatment duration(0,2,5,and 10 h).After obtaining hyperspectral images with a 370–1042 nm hyperspectral imager that included visible and near infrared light,germination was tested to confirm estimates.The Savitzky–Golay(SG)second derivative was used to preprocess the spectrum to reduce any noise impact.The successive projections algorithm(SPA),principal component analysis,and local linear embedding algorithm were used to extract the characteristic spectral bands related to seed vigor.Finally,a model for seed vigor classifi-cation of Q.variabili s based on partial least squares support vector machine(LS-SVM)with different spectral data sets was developed.The results show that the spectrum after SG second derivative preprocessing was better for developing the model,and SPA performed the best among the three feature band selection methods.The combination SG second derivative-LS-SVM provided the best classification model for Q.variabilis seed vigor,with the prediction set reaching 98.81%.This study provides an important basis for rapid and nondestructive assessment of the vigor of heat-damaged seeds using hyperspectral imaging techniques.
基金the National Key Technology Research and Development Program of the Ministry of Science and Technology of China(2015BAD07B02).
文摘The slope aspect is one of the most critical topographic factors in mountainous areas.Little is known,however,about the eff ect of the aspect on the ectomycorrhizal(ECM)fungal community.Additionally,we know very little about the composition of ECM fungal communities associated with Quercus variabilis,which is widely distributed in East Asia.In this study,we compared the richness,community composition,and exploration types of ECM fungi associated with Q.variabilis between predominantly south-and north-facing slopes in the Taihang Mountain,North China for the fi rst time.DNA was extracted from the root tips of Q.variabilis,and Illumina MiSeq sequencing was used to identify ECM fungi.In total,168 operational taxonomic units belonging to 28 genera were detected,and the ECM community was found to be dominated by Russula,Inocybe,Tomentella,Scleroderma,and Cortinarius.Compared with the north-facing slopes,the ECM communities on the south-facing slopes had higher diversity.The community composition and exploration types were directly aff ected by the slope aspect.Also,the aspect-induced edaphic variables,such as total phosphorus,total nitrogen,total potassium,pH,and soil water content,were important sources of variation in ECM fungal richness and distributions of exploration types.Diff erent genera tended to be distributed in various slope aspects.Cenococcum,Genea,and Clavulina were signifi cantly enriched in north-facing slopes,while Geopora,Helvelosebacina,Scleroderma,Gyroporus,Astraeus,Boletus,Tricholoma,Hebeloma,Cortinarius and unclassifi ed Thelephoraceae were more abundant in south-facing slopes.Hydrophobic ECM fungi were obviously enriched in the south-facing slope,but there was no statistical diff erence between hydrophilic among the south-and north-facing slopes.Our study deepened our knowledge of the aspect-driven variation in ECM fungal communities associated with Q.variabilis.
基金funded by National Natural Science Foundation of China,Grant Number 31700549China Postdoctoral Science Foundation Project,Grant Number 2017M612401.
文摘The objective of this study was to investigate the effects of root cutting stress on the dynamic changes of endogenous hormone content and growth characteristics of Quercus variabilis roots,and to explore the physiological role of endogenous hormones in regulating root-crown interactions in the short term.The morphological characteristics and endogenous hormone contents of normal roots(no root cutting,CK)and cut roots(cut by 1/3 of the length of the main root,RP)were determined by liquid chromatography,which was combined with mass spectrometry at different levels of different developmental stages.The results showed that the root growth indexes and root endogenous hormones in the RP group were superior to those in the CK group.Through comprehensive analysis of endogenous hormones,it was found that the crosstalk of IAA,JA,ABA and SA could activate the root growth defense.After the root cutting treatment,the root growth of Quercus variabilis seedlings could compensate for the inhibition of taproot growth by promoting lateral root growth.The growth and development of compensatory lateral roots contribute to the increase the total root length of plants,thus promoting the absorption of water and nutrients.It is speculated that plant hormones may be the key factors affecting their development,but this is not only related to the content of a single hormone,but more importantly,it is the interaction between various hormones.
文摘The leaves and stems of Quercus variabilis Blume afforded a new cycloartane nortriterpenoid, 3α-acetyloxy-4α, 14α-dimethyl- 9β, 19-eycloergost-24-oic acid （1）, along with five known compounds （2-6）. The structure of 1 was elucidated by 1D and 2D NMR and mass spectroscopy. 2009 Qi Shi Sun. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.
基金National Natural Science Foundation of China(30740059)Western Action Plan Project of Chinese Academy of Sciences(ZCX2-XB2-05)National Key Technology R&D Program(2006BAD09B03).
文摘[Objectives]The paper was to classify natural types of Quercus variabilis and to study its regularity of variation.[Methods]Through the analysis of correlation coefficient matrix of tree age,DBH,tree height,breast height and bark thickness,petiole length,leaf width and leaf length,the breast height and bark thickness and petiole length were chosen as the main indices for classifying natural types of Q.variabilis.[Results]There were 4 natural types of Q.variabilis in Shaanxi Province,including long-petiole-thick-bark type,short-petiole-thick-bark type,long-petiole-thin-bark type and short-petiole-thin-bark type.The short-petiole-thick-bark type accounted for the largest proportion in Q.variabilis population(34.44%).On the northern slope of Bashan Mountains and the Huanglong Mountains,the short-petiole-thick-bark type was the dominant type,while on the northern slope of Qinling Mountains the long-petiole-thick-bark type accounted for a larger proportion.[Conclusions]This study will provide a basic foundation for making full use of excellent types of Q.variabilis natural resources.
基金supported by the Science and Technology for Forestry Project of Henan Province(YLK202405)the Key Science and Technology Research Project of Henan Province(222102110418).
文摘Elevation changes may affect intraspecific relationships or interspecific relationships among species.However,previous studies on Quercus variabilis have rarely investigated how its population interactions vary with elevation and how the factors affect them.Here,we examined the species relationships in Q.variabilis natural secondary forests across the three different elevation ranges(lower,medium,and higher elevation areas)using the niche and the Hegyi competition method.As the elevation increased,Q.variabilis strengthened its dominant position,and the overall association between populations shifted from positive to negative,as evidenced by a significant decrease in the positive-to-negative correlation ratio from 0.45(85/191)to 0.41(80/196)and then to 0.32(29/91),indicating that the interspecific relationship gradually transitioned from facilitation to competition.The ratios of the intraspecific competition index to interspecific competition index were 3.09,8.92 and 6.82,respectively,indicating that Q.variabilis forests had greater intraspecific competition compared to interspecific competition,especially in the medium elevation area.The intraspecific and interspecific competition in the lower and medium elevation areas showed a decreasing trend with the increase of diameter class,while the competition among individuals in the higher elevation area became more stable.The SEM showed that soil properties were indirectly negatively correlated with the species competition through a significant negative effect on forest density,while community characteristics only had a significant negative effect on intraspecific competition.Our results demonstrated that elevation factors decreased the intraspecific and interspecific relationships within Q.variabilis forests,providing new insights into the effective conservation of Q.variabilis natural forests.
基金Sponsored by the National Natural Science Foundation of China(32271848).
文摘By measuring the contents of soil organic carbon(SOC),total nitrogen(TN),and total phosphorus(P)in rhizosphere and non-rhizosphere soils of Quercus variabilis forests with different ages(22,35,and 45 a)and origins(natural forests and planted forests)in the Funiu Mountain area,the stoichiometric characteristics of carbon,nitrogen,and phosphorus in Q.variabilis forest soils were evaluated.The research results indicated that:(i)there were significant differences(P<0.05)in the SOC content between the rhizosphere and non-rhizosphere soils of Q.variabilis planted forests at different stand ages.Moreover,as the stand age increased,the SOC content in both the rhizosphere and non-rhizosphere soils of the planted forests initially decreased and then increased.The TN and TP contents in the rhizosphere and non-rhizosphere soils of Q.variabilis planted forests did not show significant differences across different stand ages,and they exhibited different trends as the stand age increased.(ii)The SOC and nitrogen to phosphorus ratio(N:P)exhibited significant rhizosphere effects,whereas the rhizosphere effects of the TN,TP,carbon to nitrogen ratio(C:N),and carbon to phosphorus ratio(C:P)were not prominent.In terms of the influence of stand age,the SOC,TN,TP,C:P,and N:P were significantly affected.However,the effect of the C:N at the stand age level was not significant.The interactive effects of soil carbon,nitrogen,phosphorus,and their stoichiometric ratios were all significant.It is recommended to appropriately supplement soil nitrogen and phosphorus to ensure the sustainable development of Q.variabilis forest stand.
基金This paper was supported by Chinese Program for High Technology Research and Development (2003AA209030) Scien-tific Research Foundation for doctoral supervising laboratory State Education Ministry (20030284044) and National Natural Sc
文摘A study was conducted to evaluate the cultivable filamentous fungal diversity in organic layers (L, F, and H layers) and A1 layer of two main forest types, Pinus massoniana and Liguidambar formasana mixed forest and Quercus variabilis forest, in Zijin Mountain(325?N, 11848?E), Nanjing, China. A total of 67 taxa comprising 56 Deuteromycetes, 3 Zygomycetes, 5 Asco-mycetes and 3 unidentified fungi were recognized from samples from the forest floor of the two forest types. The most abundant group was Deuteromycetes. The dominant genera in both forests were Alternaria sp., Aspergillus sp., Cladosporium sp., Mucor sp., Penicillium sp., Rhizopus sp., Gliocladium sp. and Trichoderma spp. The fungal diversity was higher in the mixed forest than that in Q. variabilis forest. For both forest types, the maximum fungal diversity was found in layer F and there existed significantly different in fungal diversity between layer F and layer L. In the mixed forest, richness of fungi isolated from needle litter (P. massoniana) was lower than that from leaf litter (L. formasana). The richness of fungi from needle litter increased with the in-crease of forest floor depth, but for leaf litter, the fungal diversity decreased with the depth of forest floor. The co-species of fungi from the two forest types, as well as from two kinds of litters in mixed forest, increased with the depth of the forest floor. The succession of fungi along with the process of decomposition was discussed here. The results also showed that litter quality was a critical factor affecting fungal diversity.
