Tree radial growth can have significantly differ-ent responses to climate change depending on the environ-ment.To elucidate the effects of climate on radial growth and stable carbon isotope(δ^(13)C)fractionation of Q...Tree radial growth can have significantly differ-ent responses to climate change depending on the environ-ment.To elucidate the effects of climate on radial growth and stable carbon isotope(δ^(13)C)fractionation of Qing-hai spruce(Picea crassifolia),a widely distributed native conifer in northwestern China in different environments,we developed chronologies for tree-ring widths and δ^(13)C in trees on the southern and northern slopes of the Qilian Mountains,and analysed the relationship between these tree-ring variables and major climatic factors.Tree-ring widths were strongly influenced by climatic factors early in the growing season,and the radial growth in trees on the northern slopes was more sensitive to climate than in trees on the southern.Tree-ring δ^(13)C was more sensitive to climate than radial growth.δ^(13)C fractionation was mainly influenced by summer temperature and precipitation early in the growing season.Stomatal conductance more strongly limited stable carbon isotope fractionation in tree rings than photosynthetic rate did.The response between tree rings and climate in mountains gradually weakened as climate warmed.Changes in radial growth and stable carbon isotope fractionation of P.crassifolia in response to climate in the Qilian Mountains may be further complicated by continued climate change.展开更多
Climate change significantly impacts forest ecosystems in arid and semi-arid regions.However,spatiotemporal patterns of climate-sensitive changes in individual tree growth under increased climate warming and precipita...Climate change significantly impacts forest ecosystems in arid and semi-arid regions.However,spatiotemporal patterns of climate-sensitive changes in individual tree growth under increased climate warming and precipitation in north-west China is unclear.The dendrochronological method was used to study climate response sensitivity of radial growth of Picea schrenkiana from 158 trees at six sites during 1990-2020.The results show that climate warming and increased precipitation significantly promoted the growth of trees.The response to temperature first increased,then decreased.However,the response to increased precipitation and the self-calibrating Palmer Drought Severity Index(scPDSI)increased significantly.In most areas of the Tianshan Mountains,the proportion of trees under increased precipitation and scPDSI positive response was relatively high.Over time,small-diameter trees were strongly affected by drought stress.It is predicted that under continuous warming and increased precipitation,trees in most areas of the Tianshan Mountains,especially those with small diameters,will be more affected by precipitation.展开更多
Research on the spatial patterns of tree populations is critical for understanding the structure and dynamic processes of forests.However,little is known about how the underlying drivers shape these patterns and speci...Research on the spatial patterns of tree populations is critical for understanding the structure and dynamic processes of forests.However,little is known about how the underlying drivers shape these patterns and species interactions in forest systems.In this study,spatial point pattern analysis investigated the combined eff ects of intraspecifi c interactions and environmental heterogeneity on the spatial structure and internal maintenance mechanisms of Picea crassifolia in the Qilian Mountain National Nature Reserve,China.Data were obtained from a 10.2-ha dynamic monitoring plot(DMP)and sixteen 0.04-ha elevation gradient plots(EGPs).Under complete spatial randomness,both mature trees and saplings in the DMP demonstratedlarge-scale aggregation with negative correlations.In EGPs,saplings were clustered in small mesoscales,mature trees were randomly distributed,and the interactions of saplingstrees at all elevations were not correlated.By eliminating the interference of environmental heterogeneity through the inhomogeneous Poisson process,saplings in the DMP and EGPs were clustered in small scales and trees randomly distributed.Intraspecifi c associations were negatively correlated,in the DMP and at low elevations,and no correlations in high elevations of EGPs.In the vertical scale,saplings showed a small-scale aggregation pattern with increase in elevation,and the aggregation degree fi rst decreased and then increased.The interactions of saplings-trees and saplings–saplings showed inhibitions at small scales,with the degree of inhibition gradually decreasing.Spatial patterns and associations of adults–adults did not change signifi-cantly.The results revealed that intraspecifi c interactions and environmental heterogeneity regulated the spatial patterns of P.crassifolia at small and large scales,respectively.Environmental heterogeneity might be the most decisive factor aff ecting the spatial patterns of saplings,while trees were more aff ected by intraspecifi c interactions.Moreover,competition between trees in this area could be more common than facilitation for the growth and development of individuals.展开更多
Global climate changes have significantly affected tree growth and forest structures and functions in some arid and semi-arid regions,which are becoming warmer and wetter.Due to natural factors such as climate and ter...Global climate changes have significantly affected tree growth and forest structures and functions in some arid and semi-arid regions,which are becoming warmer and wetter.Due to natural factors such as climate and terrain,some tree species may form different forest patches at the edges of their distribution areas.However,how forest patches of various sizes respond to climate change is unclear.In this study,we collected 203 tree cores from six different sizes of forest patches at the edge of the distribution area of Picea crassifolia Kom.in the northeast Tibetan Plateau.And we used the dendrochronology method to study the response of tree growth and resilience in different forest patches to climate change from 1961 to 2020.We simultaneously measured the contents of nonstructural carbohydrates(NSC),total nitrogen and total phosphorus of tree needles.Our results showed that the growth of trees in small-and medium-size forest patches(0.8–18.6 ha)has increased significantly.The early growing season(May–July)minimum temperature was the most important climate factor driving the growth of small-and medium-sized patch trees.The early growing season maximum temperature was the most important climate factor that inhibited the growth of trees in the largest patches(362.8 ha).The growth of individual trees in medium forest patches was better and the correlation with annual minimum temperature,maximum temperature,precipitation,actual evapotranspiration,and palmer drought severity index was stronger.The higher NSC content,stronger photosynthesis,and higher nitrogen utilization efficiency in leaves might be one of the reasons for the better growth of trees in moderate forest patches.In extreme drought years,as the forest patch area increased,the overall trend of tree growth resistance showed a unimodal pattern,with the highest at a forest patch area of 7.1 ha,while the overall trend of tree growth recovery was opposite.Therefore,we should strengthen the management of trees in large forest patches to cope with climate change.展开更多
Picea mongolica is an endemic and endangered species in China. Ecosystem made of Picea mongolica is a special sandy forest ecosystem in China. It is found at ecotone between forest and steppe, or agricultural district...Picea mongolica is an endemic and endangered species in China. Ecosystem made of Picea mongolica is a special sandy forest ecosystem in China. It is found at ecotone between forest and steppe, or agricultural district and pastoral area. Based on investigation, this paper discussed the formation and distribution of Picea mongolica and studied its nature according to ecotone theory. It is clarified that Picea mongolica belongs to Picea meyeri series. That is to say, it became a local race through long-term adaptation to the local climate, then formed allopatric semi-species, and finally turned into a taxonomical species. Picea mongolica forest is a super zonal climax community developing in ecotone between forest zone and steppe zone.展开更多
Dendroclimatic methods were used to investigate the fundamental relationships between the temperature variables and the growth of climatically relic Picea meyeri Rehd. et Wils. on sandy land of Inner Mongolian gra...Dendroclimatic methods were used to investigate the fundamental relationships between the temperature variables and the growth of climatically relic Picea meyeri Rehd. et Wils. on sandy land of Inner Mongolian grasslands in the Xilin River Basin. The annual mean temperature and accumulated temperature (above 5 ℃, 10 ℃) respectively showed no significant correlation with the spruce growth relative to summer mean temperature, which displayed strong coherence with tree growth ( P <0.01). The mean temperature in May showed significantly negative correlation with spruce growth ( P <0.05). Furthermore, it was revealed that the negative influence of May temperature was due to monthly mean maximum temperature ( T max ) ( P <0.01) other than monthly mean minimum temperature ( T min ) values ( P <0.1), which indicated that the use of T min and T max separately can allow much more insights on the temperate influence. In addition, extreme maximum temperature in May and June might impose the most detrimental influence on tree growth in semi_arid Inner Mongolian grassland. The analysis of the recorded meteorological data demonstrated that the increases in temperature were synchronous with slight decreases in precipitation in the growing season, which suggested that P. meyeri may reduce growth due to temperature_induced drought. On the other hand, the analysis for decadal periods explored that trees appeared to reduce the sensitivity to the warming, and consequently increased sensitivity to rainfall. This may serve as a baseline for more accurate predictions of the potential impacts of altered climate regimes on tree growth.展开更多
Tracheid characteristics ofPicea koraiensis from natural stand in Liangshui area and plantation in Mao'ershan area were studied. The results of variance analysis showed that the tracheid length, diameter, and thic...Tracheid characteristics ofPicea koraiensis from natural stand in Liangshui area and plantation in Mao'ershan area were studied. The results of variance analysis showed that the tracheid length, diameter, and thickness of tracheid wall were significant differences between the growth rings. All those characteristics tend to increase from heart-center to bark. In natural stand, it has positive correlation between the characteristics. In plantation, the tracheid length has positive correlation with the trachied diameter, while both the trachied length and the trachied diameter has negative correlation with the thickness of trachied wall. The tracheid length and diameter have no significant difference in growth between natural stand and plantations. The thickness of tracheid wall from the plantation is a little thicker than that from the natural stand before 15 years.展开更多
Picea crassifolia and P.wilsonii,commonly used for afforestation in northern China,are increasingly likely to be subjected to high temperatures and soil drought stress as a result of global warming.However,little is k...Picea crassifolia and P.wilsonii,commonly used for afforestation in northern China,are increasingly likely to be subjected to high temperatures and soil drought stress as a result of global warming.However,little is known about the effects of these stresses on foliar photosynthesis in the two species.To investigate how photosynthetic characteristics and sensitivity respond to prolonged high temperatures and soil drought,foliar gas exchange and other closely related parameters were recorded from four-year-old seedlings of both species.Seedlings were grown under two temperature treatments(25/15 and 35/25 °C) and four soil water regimes [80,60,40 and 20% of maximum field capacity(FC)] for 4 months.Although all treatments significantly reduced photosynthetic rates(Pn) of both species,P.crassifolia exhibited greater photosynthetic acclimation than P.wilsonii.Differences in photosynthetic acclimation were mainly related to variations in stomatal conductance(Cond) and the maximum quantum yield of PSII(Fv/Fm) between treatments.Indeed,higher Cond and Fv/Fmin all treatments were shown for P.crassifolia than for P.wilsonii.Moreover,photosynthesis in P.crassifolia exhibited inherently lower temperature sensitivities(broader span for the temperature response curves; lower b) and higher thermostability(invariable b between treatments).Further,severe drought stress(20% FC) limited the survival of P.wilsonii.Our results indicate that P.wilsonii is more susceptible to high temperatures and soil drought stress.Planting P.crassifolia would be more expected to survive these conditions and hence be of greater benefit to forest stability if predicted increases in drought and temperature in northern China occur.展开更多
Based on two tree-ring maximum latewood density (MXD) chronologies of Picea schrenkiana from the Manas River Basin, Xinjiang, the response characteristics of MXD to climate variation was discussed. Correlation analy...Based on two tree-ring maximum latewood density (MXD) chronologies of Picea schrenkiana from the Manas River Basin, Xinjiang, the response characteristics of MXD to climate variation was discussed. Correlation analysis between MXD chronologies and instrumental records from Shihezi meteorological station showed that each chronology was significantly and positively correlated with the maximum monthly average temperature in July-August, and especially, the regional chronology (RC) was the most highly correlated variable (r=0.54, P〈0.001). Afterwards, the maximum average temperature in July-August was reconstructed using RC. Comparison among reconstructed temperature, observed values, and the drought index (Is) confirmed that precipitation would affect MXD when the absolute value of Is is greater than 1.5σ (|Is| 〉 2.5 during 1953-2008) or near to 1.5a over a 2-3 year period. The response characteristics are related to the semiarid climate of the study area. In dry years, lack of precipitation would limit the thickening of latewood cell walls and, as a result, impact MXD. Therefore, compared with relatively humid regions, the response of tree-ring MXD to air temperature similarly would be influenced by extreme moisture conditions in semiarid areas, and MXD, as a temperature proxy, should be used prudently on a limited scale.展开更多
[Objective] The experiment aimed to determine the optimum ISSR-PCR reaction system of Picea crassifolia kom. [Method] Picea crassifolia kom. was used as material to select and optimize influencing factors of ISSR-PCR ...[Objective] The experiment aimed to determine the optimum ISSR-PCR reaction system of Picea crassifolia kom. [Method] Picea crassifolia kom. was used as material to select and optimize influencing factors of ISSR-PCR such as Mg2+, dNTPs, Taq DNA polymerase, template DNA, primers, annealing temperature. [Result] The optimum ISSR-PCR reaction system in 20 μl reaction system was consisted of 1 μl 10×buffer, 1.5 mmol/L Mg2+, 0.2 mmol/L dNTPs, 1.0 U Taq DNA polymerase, 40 ng template DNA, 0.6 μmol/L primers. According to gradient test of annealing temperature in optimum ISSR-PCR reaction system of Picea crassifolia kom, it was found that the optimum annealing temperature of UBC 818 was 54.2 ℃ and the annealing temperature was different for different primers.[Conclusion]The construction of ISSR-PCR reaction system provided technical basis for classification of germplasm resources, construction of genetic map, gene mapping of Picea crassifolia kom. through using ISSR technology.展开更多
The spatial distribution of plant populations is an important feature of population structure and it de- termines the population's ecological preferences, biological characteristics and relationships with environment...The spatial distribution of plant populations is an important feature of population structure and it de- termines the population's ecological preferences, biological characteristics and relationships with environmental factors. The point pattern analysis method was adopted to study the distribution pattern of Picea schrenkiana indi- viduals of different size classes and the correlations between two size classes as well as the impact of topog- raphical attributes on the population distribution. With increasing diameter at breast height, the plant density of the P. schrenkiana population showed a declining trend. Old trees showed a random distribution at a small spatial scale (0-12 m), whereas saplings, small trees and big trees all had an aggregated distribution at all scales. With the increase of tree age, the scales at which maximal aggregation occurred gradually increased and the aggregation strength decreased. At a small scale (0-16 m), all size classes showed a negative correlation and the larger the difference between tree size, the more significant the negative correlation. The number of medium, big and old trees had a significantly positive correlation with elevations, whereas the number of saplings and small trees was not significantly correlated with elevations. The numbers of saplings, small and medium trees showed a significant positive correlation with slope gradient, whereas the number of big trees was not significantly correlated, and the number of old trees was negatively correlated with gradient. With the exception of old trees, saplings, small, me- dium and big trees showed negative correlations with convexity index. The study provides a theoretical basis for the conservation, rehabilitation and sustainable management of forest ecosystems in the Tianshan Mountains.展开更多
With Picea koraiensis as the research object which have similar growth vigor in a same habitat, the photosynthetic rate, transpiration rate, chlorophyll content, weight of dry-matter and leaf color change of Picea kor...With Picea koraiensis as the research object which have similar growth vigor in a same habitat, the photosynthetic rate, transpiration rate, chlorophyll content, weight of dry-matter and leaf color change of Picea koraiensis in different lighting conditions were determined. Environment without light sources was taken as the control group. The results showed that different light sources and different distances from light sources to plants had diversified impact on the photosynthetic physiology of Picea koraiensis. Among these different color lights, green light had the least influence on Picea koraiensis, yellow light and purple light had greater influence.展开更多
基金supported by Basic Research Operating Expenses of the Central level Non-profit Research Institutes (IDM2022003)National Natural Science Foundation of China (42375054)+2 种基金Regional collaborative innovation project of Xinjiang (2021E01022,2022E01045)Young Meteorological Talent Program of China Meteorological Administration,Tianshan Talent Program of Xinjiang (2022TSYCCX0003)Youth Innovation Team of China Meteorological Administration (CMA2023QN08).
文摘Tree radial growth can have significantly differ-ent responses to climate change depending on the environ-ment.To elucidate the effects of climate on radial growth and stable carbon isotope(δ^(13)C)fractionation of Qing-hai spruce(Picea crassifolia),a widely distributed native conifer in northwestern China in different environments,we developed chronologies for tree-ring widths and δ^(13)C in trees on the southern and northern slopes of the Qilian Mountains,and analysed the relationship between these tree-ring variables and major climatic factors.Tree-ring widths were strongly influenced by climatic factors early in the growing season,and the radial growth in trees on the northern slopes was more sensitive to climate than in trees on the southern.Tree-ring δ^(13)C was more sensitive to climate than radial growth.δ^(13)C fractionation was mainly influenced by summer temperature and precipitation early in the growing season.Stomatal conductance more strongly limited stable carbon isotope fractionation in tree rings than photosynthetic rate did.The response between tree rings and climate in mountains gradually weakened as climate warmed.Changes in radial growth and stable carbon isotope fractionation of P.crassifolia in response to climate in the Qilian Mountains may be further complicated by continued climate change.
基金funded by the National Natural Science Foundation of China(No.31971460 and 32271646)the National Key Research and Development Program of China(2021YFD2200401)。
文摘Climate change significantly impacts forest ecosystems in arid and semi-arid regions.However,spatiotemporal patterns of climate-sensitive changes in individual tree growth under increased climate warming and precipitation in north-west China is unclear.The dendrochronological method was used to study climate response sensitivity of radial growth of Picea schrenkiana from 158 trees at six sites during 1990-2020.The results show that climate warming and increased precipitation significantly promoted the growth of trees.The response to temperature first increased,then decreased.However,the response to increased precipitation and the self-calibrating Palmer Drought Severity Index(scPDSI)increased significantly.In most areas of the Tianshan Mountains,the proportion of trees under increased precipitation and scPDSI positive response was relatively high.Over time,small-diameter trees were strongly affected by drought stress.It is predicted that under continuous warming and increased precipitation,trees in most areas of the Tianshan Mountains,especially those with small diameters,will be more affected by precipitation.
基金supported by the National Natural Science Foundation of China(No.32060247)the Central Guidance on Local Science and Technology Development Fund of Gansu Province(No.22ZY2QG001).
文摘Research on the spatial patterns of tree populations is critical for understanding the structure and dynamic processes of forests.However,little is known about how the underlying drivers shape these patterns and species interactions in forest systems.In this study,spatial point pattern analysis investigated the combined eff ects of intraspecifi c interactions and environmental heterogeneity on the spatial structure and internal maintenance mechanisms of Picea crassifolia in the Qilian Mountain National Nature Reserve,China.Data were obtained from a 10.2-ha dynamic monitoring plot(DMP)and sixteen 0.04-ha elevation gradient plots(EGPs).Under complete spatial randomness,both mature trees and saplings in the DMP demonstratedlarge-scale aggregation with negative correlations.In EGPs,saplings were clustered in small mesoscales,mature trees were randomly distributed,and the interactions of saplingstrees at all elevations were not correlated.By eliminating the interference of environmental heterogeneity through the inhomogeneous Poisson process,saplings in the DMP and EGPs were clustered in small scales and trees randomly distributed.Intraspecifi c associations were negatively correlated,in the DMP and at low elevations,and no correlations in high elevations of EGPs.In the vertical scale,saplings showed a small-scale aggregation pattern with increase in elevation,and the aggregation degree fi rst decreased and then increased.The interactions of saplings-trees and saplings–saplings showed inhibitions at small scales,with the degree of inhibition gradually decreasing.Spatial patterns and associations of adults–adults did not change signifi-cantly.The results revealed that intraspecifi c interactions and environmental heterogeneity regulated the spatial patterns of P.crassifolia at small and large scales,respectively.Environmental heterogeneity might be the most decisive factor aff ecting the spatial patterns of saplings,while trees were more aff ected by intraspecifi c interactions.Moreover,competition between trees in this area could be more common than facilitation for the growth and development of individuals.
基金supported by the National Natural Science Foundation of China(Nos.31971460 and 32271646s).
文摘Global climate changes have significantly affected tree growth and forest structures and functions in some arid and semi-arid regions,which are becoming warmer and wetter.Due to natural factors such as climate and terrain,some tree species may form different forest patches at the edges of their distribution areas.However,how forest patches of various sizes respond to climate change is unclear.In this study,we collected 203 tree cores from six different sizes of forest patches at the edge of the distribution area of Picea crassifolia Kom.in the northeast Tibetan Plateau.And we used the dendrochronology method to study the response of tree growth and resilience in different forest patches to climate change from 1961 to 2020.We simultaneously measured the contents of nonstructural carbohydrates(NSC),total nitrogen and total phosphorus of tree needles.Our results showed that the growth of trees in small-and medium-size forest patches(0.8–18.6 ha)has increased significantly.The early growing season(May–July)minimum temperature was the most important climate factor driving the growth of small-and medium-sized patch trees.The early growing season maximum temperature was the most important climate factor that inhibited the growth of trees in the largest patches(362.8 ha).The growth of individual trees in medium forest patches was better and the correlation with annual minimum temperature,maximum temperature,precipitation,actual evapotranspiration,and palmer drought severity index was stronger.The higher NSC content,stronger photosynthesis,and higher nitrogen utilization efficiency in leaves might be one of the reasons for the better growth of trees in moderate forest patches.In extreme drought years,as the forest patch area increased,the overall trend of tree growth resistance showed a unimodal pattern,with the highest at a forest patch area of 7.1 ha,while the overall trend of tree growth recovery was opposite.Therefore,we should strengthen the management of trees in large forest patches to cope with climate change.
基金National Natural Science Foundation of China (39670133 39900019 30070129).
文摘Picea mongolica is an endemic and endangered species in China. Ecosystem made of Picea mongolica is a special sandy forest ecosystem in China. It is found at ecotone between forest and steppe, or agricultural district and pastoral area. Based on investigation, this paper discussed the formation and distribution of Picea mongolica and studied its nature according to ecotone theory. It is clarified that Picea mongolica belongs to Picea meyeri series. That is to say, it became a local race through long-term adaptation to the local climate, then formed allopatric semi-species, and finally turned into a taxonomical species. Picea mongolica forest is a super zonal climax community developing in ecotone between forest zone and steppe zone.
文摘Dendroclimatic methods were used to investigate the fundamental relationships between the temperature variables and the growth of climatically relic Picea meyeri Rehd. et Wils. on sandy land of Inner Mongolian grasslands in the Xilin River Basin. The annual mean temperature and accumulated temperature (above 5 ℃, 10 ℃) respectively showed no significant correlation with the spruce growth relative to summer mean temperature, which displayed strong coherence with tree growth ( P <0.01). The mean temperature in May showed significantly negative correlation with spruce growth ( P <0.05). Furthermore, it was revealed that the negative influence of May temperature was due to monthly mean maximum temperature ( T max ) ( P <0.01) other than monthly mean minimum temperature ( T min ) values ( P <0.1), which indicated that the use of T min and T max separately can allow much more insights on the temperate influence. In addition, extreme maximum temperature in May and June might impose the most detrimental influence on tree growth in semi_arid Inner Mongolian grassland. The analysis of the recorded meteorological data demonstrated that the increases in temperature were synchronous with slight decreases in precipitation in the growing season, which suggested that P. meyeri may reduce growth due to temperature_induced drought. On the other hand, the analysis for decadal periods explored that trees appeared to reduce the sensitivity to the warming, and consequently increased sensitivity to rainfall. This may serve as a baseline for more accurate predictions of the potential impacts of altered climate regimes on tree growth.
基金part of State 9th Five-Year Plan project of "Early Mensuration of Picea koraiensis (nakai)".
文摘Tracheid characteristics ofPicea koraiensis from natural stand in Liangshui area and plantation in Mao'ershan area were studied. The results of variance analysis showed that the tracheid length, diameter, and thickness of tracheid wall were significant differences between the growth rings. All those characteristics tend to increase from heart-center to bark. In natural stand, it has positive correlation between the characteristics. In plantation, the tracheid length has positive correlation with the trachied diameter, while both the trachied length and the trachied diameter has negative correlation with the thickness of trachied wall. The tracheid length and diameter have no significant difference in growth between natural stand and plantations. The thickness of tracheid wall from the plantation is a little thicker than that from the natural stand before 15 years.
基金supported by the National Natural Science Foundation of China(Grant Nos.31370603,31170571 and31522013)the Fundamental Research Funds for the Central Universities(lzujbky-2016-ct10)
文摘Picea crassifolia and P.wilsonii,commonly used for afforestation in northern China,are increasingly likely to be subjected to high temperatures and soil drought stress as a result of global warming.However,little is known about the effects of these stresses on foliar photosynthesis in the two species.To investigate how photosynthetic characteristics and sensitivity respond to prolonged high temperatures and soil drought,foliar gas exchange and other closely related parameters were recorded from four-year-old seedlings of both species.Seedlings were grown under two temperature treatments(25/15 and 35/25 °C) and four soil water regimes [80,60,40 and 20% of maximum field capacity(FC)] for 4 months.Although all treatments significantly reduced photosynthetic rates(Pn) of both species,P.crassifolia exhibited greater photosynthetic acclimation than P.wilsonii.Differences in photosynthetic acclimation were mainly related to variations in stomatal conductance(Cond) and the maximum quantum yield of PSII(Fv/Fm) between treatments.Indeed,higher Cond and Fv/Fmin all treatments were shown for P.crassifolia than for P.wilsonii.Moreover,photosynthesis in P.crassifolia exhibited inherently lower temperature sensitivities(broader span for the temperature response curves; lower b) and higher thermostability(invariable b between treatments).Further,severe drought stress(20% FC) limited the survival of P.wilsonii.Our results indicate that P.wilsonii is more susceptible to high temperatures and soil drought stress.Planting P.crassifolia would be more expected to survive these conditions and hence be of greater benefit to forest stability if predicted increases in drought and temperature in northern China occur.
基金Supported by Natural Science Foundation of China(41275120,41271120,41301041)Strategic Science and Technology Planning Project of Institute of Geographic Sciences and Natural Resources Research of Chinese Academy of Sciences(2012ZD001)~~
文摘Based on two tree-ring maximum latewood density (MXD) chronologies of Picea schrenkiana from the Manas River Basin, Xinjiang, the response characteristics of MXD to climate variation was discussed. Correlation analysis between MXD chronologies and instrumental records from Shihezi meteorological station showed that each chronology was significantly and positively correlated with the maximum monthly average temperature in July-August, and especially, the regional chronology (RC) was the most highly correlated variable (r=0.54, P〈0.001). Afterwards, the maximum average temperature in July-August was reconstructed using RC. Comparison among reconstructed temperature, observed values, and the drought index (Is) confirmed that precipitation would affect MXD when the absolute value of Is is greater than 1.5σ (|Is| 〉 2.5 during 1953-2008) or near to 1.5a over a 2-3 year period. The response characteristics are related to the semiarid climate of the study area. In dry years, lack of precipitation would limit the thickening of latewood cell walls and, as a result, impact MXD. Therefore, compared with relatively humid regions, the response of tree-ring MXD to air temperature similarly would be influenced by extreme moisture conditions in semiarid areas, and MXD, as a temperature proxy, should be used prudently on a limited scale.
文摘[Objective] The experiment aimed to determine the optimum ISSR-PCR reaction system of Picea crassifolia kom. [Method] Picea crassifolia kom. was used as material to select and optimize influencing factors of ISSR-PCR such as Mg2+, dNTPs, Taq DNA polymerase, template DNA, primers, annealing temperature. [Result] The optimum ISSR-PCR reaction system in 20 μl reaction system was consisted of 1 μl 10×buffer, 1.5 mmol/L Mg2+, 0.2 mmol/L dNTPs, 1.0 U Taq DNA polymerase, 40 ng template DNA, 0.6 μmol/L primers. According to gradient test of annealing temperature in optimum ISSR-PCR reaction system of Picea crassifolia kom, it was found that the optimum annealing temperature of UBC 818 was 54.2 ℃ and the annealing temperature was different for different primers.[Conclusion]The construction of ISSR-PCR reaction system provided technical basis for classification of germplasm resources, construction of genetic map, gene mapping of Picea crassifolia kom. through using ISSR technology.
基金funded by the 12th Five-year Science and Technology Support Program(2011BAD38B0505)the Forestry Industry Research Special Funds for Public Welfare Projects (200804022C)the CFERN & GENE Award Funds on Ecological Papers
文摘The spatial distribution of plant populations is an important feature of population structure and it de- termines the population's ecological preferences, biological characteristics and relationships with environmental factors. The point pattern analysis method was adopted to study the distribution pattern of Picea schrenkiana indi- viduals of different size classes and the correlations between two size classes as well as the impact of topog- raphical attributes on the population distribution. With increasing diameter at breast height, the plant density of the P. schrenkiana population showed a declining trend. Old trees showed a random distribution at a small spatial scale (0-12 m), whereas saplings, small trees and big trees all had an aggregated distribution at all scales. With the increase of tree age, the scales at which maximal aggregation occurred gradually increased and the aggregation strength decreased. At a small scale (0-16 m), all size classes showed a negative correlation and the larger the difference between tree size, the more significant the negative correlation. The number of medium, big and old trees had a significantly positive correlation with elevations, whereas the number of saplings and small trees was not significantly correlated with elevations. The numbers of saplings, small and medium trees showed a significant positive correlation with slope gradient, whereas the number of big trees was not significantly correlated, and the number of old trees was negatively correlated with gradient. With the exception of old trees, saplings, small, me- dium and big trees showed negative correlations with convexity index. The study provides a theoretical basis for the conservation, rehabilitation and sustainable management of forest ecosystems in the Tianshan Mountains.
文摘With Picea koraiensis as the research object which have similar growth vigor in a same habitat, the photosynthetic rate, transpiration rate, chlorophyll content, weight of dry-matter and leaf color change of Picea koraiensis in different lighting conditions were determined. Environment without light sources was taken as the control group. The results showed that different light sources and different distances from light sources to plants had diversified impact on the photosynthetic physiology of Picea koraiensis. Among these different color lights, green light had the least influence on Picea koraiensis, yellow light and purple light had greater influence.