To study non-structural carbohydrate character-istics and nutrient utilization strategies of Pinus yunnanen-sis under continuous drought conditions,2-year-old seed-lings were planted in pots with appropriate water,lig...To study non-structural carbohydrate character-istics and nutrient utilization strategies of Pinus yunnanen-sis under continuous drought conditions,2-year-old seed-lings were planted in pots with appropriate water,light and moderate and severe drought treatments[(80±5),(65±5),(50±5),and(35±5)%of field water-holding capacity].Non-structural carbohydrates,carbon(C),nitrogen(N),and phosphorus(P)concentrations were measured in each plant component.The results show that:(1)With increasing drought,non-structural carbohydrates gradually increased in leaves,stems,and coarse roots,while gradually decreased in fine roots;(2)C concentrations of all were relatively stable under different stress levels.Phosphorous utilization of each component increased under light and moderate drought conditions,while N and P utilization efficiency of each plant component decreased under severe drought.Growth was mainly restricted by N,first decreasing and then increasing with increased drought;(3)There was a correlation between the levels of non-structural carbohydrates and C,N,and P in each component.Changes in N concentration affected the interconversion between soluble sugar and starch,which play a regulatory role in the fluctuation of the concentration of non-structural carbohydrates;and,(4)Plasticity analysis showed that P.yunnanensis seedlings responded to drought mainly by altering starch concentration,the ratio of soluble sugar to starch in leaves and stems,and further by alter-ing N and P utilization efficiencies.Overall,these results suggest that the physiological activities of all organs of P.yunnanensis seedlings are restricted under drought and that trade-offs exist between different physiological indicators and organs.Our findings are helpful in understanding non-structural carbohydrate and nutrient adaptation mechanisms under drought in P.yunnanensis seedlings.展开更多
Background:Drought can exert a profound influence on soil nutrient availability,and understanding whether and how tree species adapt to this change is a critical priority for predicting the consequence of climate chan...Background:Drought can exert a profound influence on soil nutrient availability,and understanding whether and how tree species adapt to this change is a critical priority for predicting the consequence of climate change on forest structure and function.The objective of this study was to examine the adaptability of Mongolian pine(Pinus sylvestris var.mongolica)to drought‑induced changes in soil nutrient availability from the perspective of root functions.Methods:We conducted a 7‑year precipitation manipulation experiment with three levels of throughfall reduction(0%,30%,and 50%)to simulate different drought intensities.We measured soil physicochemical properties and fineroot nutrient concentrations and biomass,and calculated the stoichiometric homeostatic regulation coefficient(1/H)of fine roots.Results:Drought reduced soil organic carbon(C),nitrogen(N),phosphorous(P)and inorganic N concentrations,as well as ratios of total N to total P,and available N to available P in the 0–20 cm soil layer.In contrast,drought had no significant effect on fine‑root N and P concentrations,and fine‑root biomass in the 0–40 cm soil layer.Fine roots displayed high homeostatic regulation coefficients of N(with 1/H values of 0.19 and 0)and P(with 1/H values of 0.33 and 0)concentrations in 0–20 and 20–40 cm soil layers,respectively.Conclusions:Our results indicate that drought leads to soil nutrient deficiency and the decoupling between N and P cycling,and provide evidence that Mongolian pine has high adaptability to drought‑induced decrease in soil nutrient availability by maintaining great fine‑root biomass to ensure sufficient nutrient uptake.展开更多
以南亚热带中心分布区的毛竹林为研究对象，比较不同生产力水平（Ⅰ：30000±1000 kg·hm -2 a -1；Ⅱ：34000±1000 kg·hm -2 a -1；Ⅲ：37000±1000 kg·hm -2 a -1；Ⅳ：42000±1000 kg·hm -2 a -...以南亚热带中心分布区的毛竹林为研究对象，比较不同生产力水平（Ⅰ：30000±1000 kg·hm -2 a -1；Ⅱ：34000±1000 kg·hm -2 a -1；Ⅲ：37000±1000 kg·hm -2 a -1；Ⅳ：42000±1000 kg·hm -2 a -1；Ⅴ：47000±1000 kg·hm -2 a -1）毛竹林植被和土壤的碳、氮、磷含量及计量特征，探讨生产力水平对毛竹林及土壤碳、氮、磷分布格局及化学计量特征的影响。结果表明：生产力水平对毛竹林植被碳和磷元素在不同器官间分配比例的影响较小，对氮素分配比例的影响较大；除竹叶碳元素分配比例在不同生产力水平间的差异达到显著水平外（P ＜0.01），各器官间碳、磷含量在不同生产力水平间差异均不显著；除竹秆外，毛竹不同器官氮分配比例在不同生产力水平间的差异均极显著（P＜0.01）；生产力水平对毛竹林植被 C∶N、C∶P、N∶P计量比值的影响较小，在不同生产力水平间的差异均未达到显著水平（P＜0.01），毛竹林主要养分元素的计量比具有内在的稳定性，符合“内稳性假说”；生产力水平对林地土壤碳、氮、磷、水解氮和有效磷含量有显著影响，土壤 C∶N、C∶P、N∶P 和 H-N∶A-P 在不同生产力间的差异均达到了极显著水平（P＜0.01）；当土壤N∶P＜14时，主要受到氮元素的限制，本研究中土壤N∶P为4.50～13.89，反映了研究区毛竹林主要受到氮元素的限制，受磷元素的限制较少，且 N∶P 比值随着生产力的提高呈降低的趋势，有可能成为未来毛竹林退化诊断的生态指示指标；毛竹林植被主要养分计量值与土壤主要养分计量值的相关性分析表明，二者间的相关性未达到显著水平。展开更多
【目的】探讨陆地生态系统生态化学计量学研究进展,以期推动对陆地生态系统物质循环及能量流动的进一步认识。【方法】利用Web of Science、CNKI等数据库,查阅相关文献,对陆地生态系统生态化学计量学研究进展进行综述。【结果】陆地植...【目的】探讨陆地生态系统生态化学计量学研究进展,以期推动对陆地生态系统物质循环及能量流动的进一步认识。【方法】利用Web of Science、CNKI等数据库,查阅相关文献,对陆地生态系统生态化学计量学研究进展进行综述。【结果】陆地植被生态化学计量学特征研究表明,C、N、P是生态化学计量学领域研究的主要对象,其中N和P是陆地植被生长2种最重要的限制元素;土壤中的碳氮磷比值是评价土壤质量重要指标,从全球尺度研究发现,土壤中的碳氮磷比值基本为恒值;陆地生态系统养分限制判断研究表明,N∶P比值是植物生长养分限制的敏感性指数,常被用于确定养分限制的阈值,同时N、P含量也可用于确定养分限制类型;气候、地理、土壤等因子是陆地植物生态化学计量学特征的主要影响因素。【结论】在陆地生态系统生态化学计量学研究进展中,C、N、P是学者们关注的重要因子,其比值在研究土壤质量评价、养分限制阈值等方面发挥重要作用。展开更多
基金This study was supported by the National Natural Science Foundation of China(31960306).
文摘To study non-structural carbohydrate character-istics and nutrient utilization strategies of Pinus yunnanen-sis under continuous drought conditions,2-year-old seed-lings were planted in pots with appropriate water,light and moderate and severe drought treatments[(80±5),(65±5),(50±5),and(35±5)%of field water-holding capacity].Non-structural carbohydrates,carbon(C),nitrogen(N),and phosphorus(P)concentrations were measured in each plant component.The results show that:(1)With increasing drought,non-structural carbohydrates gradually increased in leaves,stems,and coarse roots,while gradually decreased in fine roots;(2)C concentrations of all were relatively stable under different stress levels.Phosphorous utilization of each component increased under light and moderate drought conditions,while N and P utilization efficiency of each plant component decreased under severe drought.Growth was mainly restricted by N,first decreasing and then increasing with increased drought;(3)There was a correlation between the levels of non-structural carbohydrates and C,N,and P in each component.Changes in N concentration affected the interconversion between soluble sugar and starch,which play a regulatory role in the fluctuation of the concentration of non-structural carbohydrates;and,(4)Plasticity analysis showed that P.yunnanensis seedlings responded to drought mainly by altering starch concentration,the ratio of soluble sugar to starch in leaves and stems,and further by alter-ing N and P utilization efficiencies.Overall,these results suggest that the physiological activities of all organs of P.yunnanensis seedlings are restricted under drought and that trade-offs exist between different physiological indicators and organs.Our findings are helpful in understanding non-structural carbohydrate and nutrient adaptation mechanisms under drought in P.yunnanensis seedlings.
基金supported by the National Natural Science Foundation of China(Grant Numbers 31870603,41877341)the Youth Innovation Promotion Association CAS(Grant Number 2019200)。
文摘Background:Drought can exert a profound influence on soil nutrient availability,and understanding whether and how tree species adapt to this change is a critical priority for predicting the consequence of climate change on forest structure and function.The objective of this study was to examine the adaptability of Mongolian pine(Pinus sylvestris var.mongolica)to drought‑induced changes in soil nutrient availability from the perspective of root functions.Methods:We conducted a 7‑year precipitation manipulation experiment with three levels of throughfall reduction(0%,30%,and 50%)to simulate different drought intensities.We measured soil physicochemical properties and fineroot nutrient concentrations and biomass,and calculated the stoichiometric homeostatic regulation coefficient(1/H)of fine roots.Results:Drought reduced soil organic carbon(C),nitrogen(N),phosphorous(P)and inorganic N concentrations,as well as ratios of total N to total P,and available N to available P in the 0–20 cm soil layer.In contrast,drought had no significant effect on fine‑root N and P concentrations,and fine‑root biomass in the 0–40 cm soil layer.Fine roots displayed high homeostatic regulation coefficients of N(with 1/H values of 0.19 and 0)and P(with 1/H values of 0.33 and 0)concentrations in 0–20 and 20–40 cm soil layers,respectively.Conclusions:Our results indicate that drought leads to soil nutrient deficiency and the decoupling between N and P cycling,and provide evidence that Mongolian pine has high adaptability to drought‑induced decrease in soil nutrient availability by maintaining great fine‑root biomass to ensure sufficient nutrient uptake.
文摘【目的】探讨陆地生态系统生态化学计量学研究进展,以期推动对陆地生态系统物质循环及能量流动的进一步认识。【方法】利用Web of Science、CNKI等数据库,查阅相关文献,对陆地生态系统生态化学计量学研究进展进行综述。【结果】陆地植被生态化学计量学特征研究表明,C、N、P是生态化学计量学领域研究的主要对象,其中N和P是陆地植被生长2种最重要的限制元素;土壤中的碳氮磷比值是评价土壤质量重要指标,从全球尺度研究发现,土壤中的碳氮磷比值基本为恒值;陆地生态系统养分限制判断研究表明,N∶P比值是植物生长养分限制的敏感性指数,常被用于确定养分限制的阈值,同时N、P含量也可用于确定养分限制类型;气候、地理、土壤等因子是陆地植物生态化学计量学特征的主要影响因素。【结论】在陆地生态系统生态化学计量学研究进展中,C、N、P是学者们关注的重要因子,其比值在研究土壤质量评价、养分限制阈值等方面发挥重要作用。
