Acorn production in oak(Quercus spp.)shows considerable inter-annual variation,known as masting,which provides a natural defence against seed predators but a highly-variable supply of acorns for uses such as in commer...Acorn production in oak(Quercus spp.)shows considerable inter-annual variation,known as masting,which provides a natural defence against seed predators but a highly-variable supply of acorns for uses such as in commercial tree planting each year.Anthropogenic emissions of greenhouse gases have been very widely reported to influence plant growth and seed or fruit size and quantity via the‘fertilisation effect’that leads to enhanced photosynthesis.To examine if acorn production in mature woodland communities will be affected by further increase in CO_(2),the contents of litter traps from a Free Air Carbon Enrichment(FACE)experiment in deciduous woodland in central England were analysed for numbers of flowers and acorns of pedunculate oak(Quercus robur L.)at different stages of development and their predation levels under ambient and elevated CO_(2) concentrations.Inter-annual variation in acorn numbers was considerable and cyclical between 2015 and 2021,with the greatest numbers of mature acorns in 2015,2017 and 2020 but almost none in 2018.The numbers of flowers,enlarged cups,immature acorns,empty acorn cups,and galls in the litter traps also varied amongst years;comparatively high numbers of enlarged cups were recorded in 2018,suggesting Q.robur at this site is a fruit maturation masting species(i.e.,the extent of abortion of pollinated flowers during acorn development affects mature acorn numbers greatly).Raising the atmospheric CO_(2) concentration by 150μL L^(−1),from early 2017,increased the numbers of immature acorns,and all acorn evidence(empty cups+immature acorns+mature acorns)detected in the litter traps compared to ambient controls by 2021,but did not consistently affect the numbers of flowers,enlarged cups,empty cups,or mature acorns.The number of flowers in the elevated CO_(2) plots’litter traps was greater in 2018 than 2017,one year after CO_(2) enrichment began,whereas numbers declined in ambient plots.Enrichment with CO_(2) also increased the number of oak knopper galls(Andricus quercuscalicis Burgsdorf).We conclude that elevated CO_(2) increased the occurrence of acorns developing from flowers,but the putative benefit to mature acorn numbers may have been hidden by excessive pre-and/or post-dispersal predation.There was no evidence that elevated CO_(2) altered masting behaviour.展开更多
The most important process before leaf senescence is nutrient resorption,which reduces nutrient loss and maximizes plant fitness during the subsequent growth period.However,plants must retain certain levels of nitroge...The most important process before leaf senescence is nutrient resorption,which reduces nutrient loss and maximizes plant fitness during the subsequent growth period.However,plants must retain certain levels of nitrogen(N)in their leaves to maintain carbon assimilation during hardening.The objective of this study was to investigate the tradeoffs in N investment between leaf N resorption and N for photosynthesis in seedlings with increased soil fertility during the hardening period.A field experiment was conducted to determine if and how soil fertility treatments(17,34,or 68 mg N seedling−1)affected N resorption and allocation to the photosynthetic apparatus in Quercus mongolica leaves during the hardening period.Seedlings were sampled at T1(after terminal bud formation),T2(between terminal bud formation and end of the growing period),and T3(at the end of the growing period).Results showed that photosynthetic N content continued to rise in T2,while N resorption started from non-photosynthetic N.Leaf N allocation to the photosynthetic apparatus increased as soil fertility increased,delaying N resorption.Additionally,soil fertility significantly affected N partitioning among different photosynthetic components,maintaining or increasing photosynthetic traits during senescence.This study demonstrates a tradeoff in N investment between resorption and photosynthesis to maintain photosynthetic assimilation capacity during the hardening period,and that soil fertility impacts this balance.Q.mongolica leaves primarily resorbed N from the non-photosynthetic apparatus and invested it in the photosynthetic apparatus,whereas different photosynthetic N component allocations effectively improved this pattern.展开更多
The spatial distribution and population dynamics of Quercus liaotungensis Koidz., Fraxinus rhynchophylla Hance and Acer mono Maxim. were studied in three warm temperate deciduous forests in Dongling Mountain, Beijing....The spatial distribution and population dynamics of Quercus liaotungensis Koidz., Fraxinus rhynchophylla Hance and Acer mono Maxim. were studied in three warm temperate deciduous forests in Dongling Mountain, Beijing. Clumped distributions appeared in most seedlings (≤0.4 m), short saplings (0.4-1 m) and tall saplings (1-2 m). Random distributions appeared in adults of Q. liaotungensis in Plot 1, F. rhynchophylla in Plot 3. The LSD method was used to discern the differences of different aged population. The class distribution of Q. liaotungensis was nearly a reverse-J shape for Plot 1 and Plot 3, suggesting that the population regenerates continuously. The age-structures of F. rhynchophylla and A. mono in Plot 1 and the test results indicated that they would increase continuously. In Plot 2, the class distribution and the test results showed that all populations would not regenerate continuously.展开更多
The seed shadow of oak ( Quercus liaotungensis Koidz.) was investigated in a broad_leaved deciduous forest in Dongling Mountain in 1997. The seed rain patterns under oak tree crown for three out of four oak trees fit...The seed shadow of oak ( Quercus liaotungensis Koidz.) was investigated in a broad_leaved deciduous forest in Dongling Mountain in 1997. The seed rain patterns under oak tree crown for three out of four oak trees fit quadratic distribution, with high coefficients of determination. For each of the four trees selected in this study the seed rain size estimated from the viable acorns collected from the traps deployed under the crown was low, ranging from 26 to 259. For each of the four oak trees, the average density of the seed rain under oak tree crown ranged from 0.76 to 7.26 seeds/m 2. The average seed rain density estimated from the acorns in the traps deployed randomly in the field was 1.57 seeds/m 2. After all viable acorns fell, the acorn ground density estimated from the acorns in the quadrats was 0.13 seeds/m 2, but no viable acorns were found on the ground under the tree crown of the four oak trees, although the area under the crown was over 5 folds than the area of the combined quadrats. These results indicated that a large number of acorns was removed or predated by vertebrates once the acorns fell on the ground and acorns predation was more intensive in the sites directly under the parent trees than the sites away from the parent trees; this supports the distance_dependent hypothesis. Of the total acorns of all four oak trees, the viable acorns only accounted for 18.1%, and 17.8% for acorns infected by insect larvae, 12.1% for immature acorns, 3.6% for decayed acorns, and the acorns predated by rodent directly in the crown was the highest, accounting for 48.4%. The proportion of acorns predated by animals including vertebrates and invertebrates amounts up to 78.3%, indicating that acorn predation by animals is a limiting factor affecting acorn survival before seed dispersal. The sustained time of viable acorn fall ranged from September 8 to October 3 for the four oak trees, with the peak between 16th and 26th September. The number of acorns was not significantly different among the four directions around the trunk base.展开更多
Leaf litter decomposition of liaotong oak (Quercus liaotungensis Koize) under temperate, subtropical and tropical forests was examined using a litter bag technique. Decomposition rates and release dynamics of nutrient...Leaf litter decomposition of liaotong oak (Quercus liaotungensis Koize) under temperate, subtropical and tropical forests was examined using a litter bag technique. Decomposition rates and release dynamics of nutrients Ca, Cu, Fe, K, Mg, Mn and P were observed separately at all three sites for I to 2 a periods. The leaf litter mass loss of liaotong oak was simulated with Olson's exponential model. Significant differences of leaf litter mass loss were found in forests of all three climate zones. Litter decomposition was accelerated with the increase of both annual mean precipitation and temperature. Our results agreed with other studies demonstrating that litter decomposition processes were greatly affected not only by soil organisms (including soil fauna and microorganisms), but also by chemical factors. These chemical factors were important for controlling the release of nutrients, especially elements of Fe and Mn. We also found that Fe and Mn content increased in semi-decayed leaf litter as litter mass decreased. This result was presumably due to chelating process which accumulated soil Fe and Mn ions into the decomposing litter. In conclusion, our study allowed us to determine the classification of the characteristics of different nutrient release patterns.展开更多
[Objective] The aim was to compare the content changes between the non-structural carbohydrates（NSC）and the total nitrogen in various growing seasons,and to explore the response relationship between altitude and the...[Objective] The aim was to compare the content changes between the non-structural carbohydrates（NSC）and the total nitrogen in various growing seasons,and to explore the response relationship between altitude and the contents.[Method] Taking Quercus aquifolioides scrub which widely distributed in Zheduoshan in the west of Sichuan as the experimental objects,the changes between NSC and the toal nitrogen in various growing seasons at different altitude were studied.[Result] The results showed that the content of NSC in Quercus aquifolioides underground increased with the lift of elevation in the dormancy,but decreased in the early germination,growing period and growth stage.The content of NSC in the ground tissue changed non-linearly with increasing elevation.In addition,the total nitrogen of Quercus aquifolioides organizations was decreasing with increasing elevation in the dormant period,which did not change significantly in the other periods.This result implied that the content of NSC in Quercus aquifolioides underground was more sensitive to temperature.[Conclusion] The experiment laid basis for the exploration of the physical and ecological mechanism of underground plants adaptability to highland environment,their response to global climate changes and adjustment to high altitude ecological system.展开更多
基金supported by Future Trees Trust,The Patsy Wood Trust,Scottish Forestry Trust,Aitchinson Tait Trust,and Action Oak for fundingsupport from the UK Natural Environment Research Council (NE/S015833/1 (QUINTUS))+1 种基金support from the JABBS Trust,Norbury Park Estate,The John Horseman Trust,Ecological Continuity Trust,and the University of BirminghamAccess to BIFoR Core Data was funded by Royal Society University Research Fellowship URFR1191326
文摘Acorn production in oak(Quercus spp.)shows considerable inter-annual variation,known as masting,which provides a natural defence against seed predators but a highly-variable supply of acorns for uses such as in commercial tree planting each year.Anthropogenic emissions of greenhouse gases have been very widely reported to influence plant growth and seed or fruit size and quantity via the‘fertilisation effect’that leads to enhanced photosynthesis.To examine if acorn production in mature woodland communities will be affected by further increase in CO_(2),the contents of litter traps from a Free Air Carbon Enrichment(FACE)experiment in deciduous woodland in central England were analysed for numbers of flowers and acorns of pedunculate oak(Quercus robur L.)at different stages of development and their predation levels under ambient and elevated CO_(2) concentrations.Inter-annual variation in acorn numbers was considerable and cyclical between 2015 and 2021,with the greatest numbers of mature acorns in 2015,2017 and 2020 but almost none in 2018.The numbers of flowers,enlarged cups,immature acorns,empty acorn cups,and galls in the litter traps also varied amongst years;comparatively high numbers of enlarged cups were recorded in 2018,suggesting Q.robur at this site is a fruit maturation masting species(i.e.,the extent of abortion of pollinated flowers during acorn development affects mature acorn numbers greatly).Raising the atmospheric CO_(2) concentration by 150μL L^(−1),from early 2017,increased the numbers of immature acorns,and all acorn evidence(empty cups+immature acorns+mature acorns)detected in the litter traps compared to ambient controls by 2021,but did not consistently affect the numbers of flowers,enlarged cups,empty cups,or mature acorns.The number of flowers in the elevated CO_(2) plots’litter traps was greater in 2018 than 2017,one year after CO_(2) enrichment began,whereas numbers declined in ambient plots.Enrichment with CO_(2) also increased the number of oak knopper galls(Andricus quercuscalicis Burgsdorf).We conclude that elevated CO_(2) increased the occurrence of acorns developing from flowers,but the putative benefit to mature acorn numbers may have been hidden by excessive pre-and/or post-dispersal predation.There was no evidence that elevated CO_(2) altered masting behaviour.
基金supported by the National Natural Science Foundation of China(No.32171764,No.32101503)the 5·5 Engineering Research&Innovation Team Project at the Beijing Forestry University(BLRC2023B08).
文摘The most important process before leaf senescence is nutrient resorption,which reduces nutrient loss and maximizes plant fitness during the subsequent growth period.However,plants must retain certain levels of nitrogen(N)in their leaves to maintain carbon assimilation during hardening.The objective of this study was to investigate the tradeoffs in N investment between leaf N resorption and N for photosynthesis in seedlings with increased soil fertility during the hardening period.A field experiment was conducted to determine if and how soil fertility treatments(17,34,or 68 mg N seedling−1)affected N resorption and allocation to the photosynthetic apparatus in Quercus mongolica leaves during the hardening period.Seedlings were sampled at T1(after terminal bud formation),T2(between terminal bud formation and end of the growing period),and T3(at the end of the growing period).Results showed that photosynthetic N content continued to rise in T2,while N resorption started from non-photosynthetic N.Leaf N allocation to the photosynthetic apparatus increased as soil fertility increased,delaying N resorption.Additionally,soil fertility significantly affected N partitioning among different photosynthetic components,maintaining or increasing photosynthetic traits during senescence.This study demonstrates a tradeoff in N investment between resorption and photosynthesis to maintain photosynthetic assimilation capacity during the hardening period,and that soil fertility impacts this balance.Q.mongolica leaves primarily resorbed N from the non-photosynthetic apparatus and invested it in the photosynthetic apparatus,whereas different photosynthetic N component allocations effectively improved this pattern.
文摘The spatial distribution and population dynamics of Quercus liaotungensis Koidz., Fraxinus rhynchophylla Hance and Acer mono Maxim. were studied in three warm temperate deciduous forests in Dongling Mountain, Beijing. Clumped distributions appeared in most seedlings (≤0.4 m), short saplings (0.4-1 m) and tall saplings (1-2 m). Random distributions appeared in adults of Q. liaotungensis in Plot 1, F. rhynchophylla in Plot 3. The LSD method was used to discern the differences of different aged population. The class distribution of Q. liaotungensis was nearly a reverse-J shape for Plot 1 and Plot 3, suggesting that the population regenerates continuously. The age-structures of F. rhynchophylla and A. mono in Plot 1 and the test results indicated that they would increase continuously. In Plot 2, the class distribution and the test results showed that all populations would not regenerate continuously.
文摘The seed shadow of oak ( Quercus liaotungensis Koidz.) was investigated in a broad_leaved deciduous forest in Dongling Mountain in 1997. The seed rain patterns under oak tree crown for three out of four oak trees fit quadratic distribution, with high coefficients of determination. For each of the four trees selected in this study the seed rain size estimated from the viable acorns collected from the traps deployed under the crown was low, ranging from 26 to 259. For each of the four oak trees, the average density of the seed rain under oak tree crown ranged from 0.76 to 7.26 seeds/m 2. The average seed rain density estimated from the acorns in the traps deployed randomly in the field was 1.57 seeds/m 2. After all viable acorns fell, the acorn ground density estimated from the acorns in the quadrats was 0.13 seeds/m 2, but no viable acorns were found on the ground under the tree crown of the four oak trees, although the area under the crown was over 5 folds than the area of the combined quadrats. These results indicated that a large number of acorns was removed or predated by vertebrates once the acorns fell on the ground and acorns predation was more intensive in the sites directly under the parent trees than the sites away from the parent trees; this supports the distance_dependent hypothesis. Of the total acorns of all four oak trees, the viable acorns only accounted for 18.1%, and 17.8% for acorns infected by insect larvae, 12.1% for immature acorns, 3.6% for decayed acorns, and the acorns predated by rodent directly in the crown was the highest, accounting for 48.4%. The proportion of acorns predated by animals including vertebrates and invertebrates amounts up to 78.3%, indicating that acorn predation by animals is a limiting factor affecting acorn survival before seed dispersal. The sustained time of viable acorn fall ranged from September 8 to October 3 for the four oak trees, with the peak between 16th and 26th September. The number of acorns was not significantly different among the four directions around the trunk base.
文摘Leaf litter decomposition of liaotong oak (Quercus liaotungensis Koize) under temperate, subtropical and tropical forests was examined using a litter bag technique. Decomposition rates and release dynamics of nutrients Ca, Cu, Fe, K, Mg, Mn and P were observed separately at all three sites for I to 2 a periods. The leaf litter mass loss of liaotong oak was simulated with Olson's exponential model. Significant differences of leaf litter mass loss were found in forests of all three climate zones. Litter decomposition was accelerated with the increase of both annual mean precipitation and temperature. Our results agreed with other studies demonstrating that litter decomposition processes were greatly affected not only by soil organisms (including soil fauna and microorganisms), but also by chemical factors. These chemical factors were important for controlling the release of nutrients, especially elements of Fe and Mn. We also found that Fe and Mn content increased in semi-decayed leaf litter as litter mass decreased. This result was presumably due to chelating process which accumulated soil Fe and Mn ions into the decomposing litter. In conclusion, our study allowed us to determine the classification of the characteristics of different nutrient release patterns.
基金Supported by National Natural Science Fund(30872017)China Science Academy Knowledge Innovation Engineering Project Important Direction Program(KZCX2-YW-331-3,KSCX2-YW-N-066)Central University Basic Science Research Operation Special Fund(XDJK2009C110)~~
文摘[Objective] The aim was to compare the content changes between the non-structural carbohydrates（NSC）and the total nitrogen in various growing seasons,and to explore the response relationship between altitude and the contents.[Method] Taking Quercus aquifolioides scrub which widely distributed in Zheduoshan in the west of Sichuan as the experimental objects,the changes between NSC and the toal nitrogen in various growing seasons at different altitude were studied.[Result] The results showed that the content of NSC in Quercus aquifolioides underground increased with the lift of elevation in the dormancy,but decreased in the early germination,growing period and growth stage.The content of NSC in the ground tissue changed non-linearly with increasing elevation.In addition,the total nitrogen of Quercus aquifolioides organizations was decreasing with increasing elevation in the dormant period,which did not change significantly in the other periods.This result implied that the content of NSC in Quercus aquifolioides underground was more sensitive to temperature.[Conclusion] The experiment laid basis for the exploration of the physical and ecological mechanism of underground plants adaptability to highland environment,their response to global climate changes and adjustment to high altitude ecological system.
