青藏高原多年冻土区两种典型高寒草甸根系觅食策略对增温的响应特征  

Responses of root foraging strategies to experimental warming in two typical alpine meadows in permafrost region of the Qinghai-Tibet Plateau

作　　者：吕雪丽 余万鹏 王岳 董逵才 胡明娟 杨凯[1,4] 唐川川 杨燕 LÜXueli;YU Wanpeng;WANG Yue;DONG Kuicai;HU Mingjuan;YANG Kai;TANG Chuanchuan;YANG Yan(Institute of Mountain Hazards and Environment,Chinese Academy of Sciences and Ministry of Water Conservancy,Chengdu 610299,China;Natural Resources,Forestry,and Grassland Bureau of Ledu District,Haidong 810799,China;Authority of Three-River-Source National Park,Xining 810003,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院、水利部成都山地灾害与环境研究所,成都610299 [2]青海省海东市乐都区自然资源和林业草原局,海东810799 [3]三江源国家公园管理局,西宁810003 [4]中国科学院大学,北京100049

出　　处：《应用与环境生物学报》2024年第3期458-466,共9页Chinese Journal of Applied and Environmental Biology

基　　金：中国科学院战略先导项目(XDA23060601);青海省“昆仑英才·高端创新创业人才”计划项目资助。

摘　　要：全球变暖背景下多年冻土融化导致的土壤水分状况的改变影响着植物的根系觅食行为.选取对气候变化十分敏感的青藏高原为研究区域,以多年冻土广泛分布的风火山地区高寒小嵩草(Kobresia pygmaea)草甸和藏嵩草(Kobresia tibetica)沼泽化草甸为研究对象,采用开顶式增温小室(open top chambers,OTCs)模拟气候变暖,开展增温试验(2012-2019年).监测和收集2019年生长季(5-9月)地上20 cm高度处的空气温度(AT)和地下5 cm深度处的土壤湿度(SM)数据,测定并计算得到2019年枯黄期两种草甸表层(0-10 cm)土壤根系形态塑性指标:衡量觅食尺度的总根长(TRL)、根直径(RD)、根表面积(RSA)、根体积(RV)、比根长(SRL)、比根面积(SRA)、根组织密度(RTD)和表征觅食精度的根系生物量(RB),根系生理塑性指标:碳含量(RCC)、氮含量(RNC)、非结构性碳水化合物含量(RNSCs)、可溶性糖含量(RSSC)、淀粉含量(RSC)和可溶性糖比淀粉(RSSC/RSC),以了解多年冻土存在时,青藏高原两种典型高寒草甸根系觅食策略对增温的响应特征.结果表明:(1)增温后小嵩草草甸和藏嵩草沼泽化草甸生长季月平均SM分别下降和上升;(2)增温显著增大了小嵩草草甸RB、SRA和藏嵩草沼泽化草甸RV、SRL,并显著减小了小嵩草草甸SRL和藏嵩草沼泽化草甸RTD;(3)增温显著升高两种草甸RCC、RNSCs、RSSC、RSC和小嵩草草甸RSSC/RSC;(4)增温对小嵩草草甸根系形态塑性指标(RB、SRL、SRA)和根系生理塑性指标(RCC、RNSCs、RSSC、RSC、RSSC/RSC)的影响效应均值分别为0.29和0.91,对藏嵩草沼泽化草甸根系形态塑性指标(RV、SRL、RTD)和根系生理塑性指标(RCC、RNSCs、RSSC、RSC)的影响效应均值分别为0.27和0.87;(5)增温对小嵩草草甸根系觅食精度(RB)和觅食尺度(SRL、SRA)的影响效应均值分别为0.66和0.10.研究结果表明了根系生理塑性在增温对多年冻土区两种高寒草甸表层土壤根系影响中的重要性,�Changes in soil moisture caused by permafrost melting under global warming affect plant root foraging.In this study,the Qinghai-Tibet Plateau,which is very sensitive to climate change,was selected as the research area,along with Kobresia pygmaea meadow and Kobresia tibetica swamp meadow in the Feng Huoshan region,where permafrost is widely distributed.We used open-top chambers(OTCs)to simulate climate warming and conducted artificial warming experiments from 2012 to 2019.Air temperature(AT)data at a height of 20 cm and soil moisture(SM)data at a depth of 5 cm were obtained using sensors and data collectors(MG-EM50)during the growing season(May-September 2019).The root morphological plasticity indices,including total root length(TRL),root diameter(RD),root surface area(RSA),root volume(RV),specific root length(SRL),specific root area(SRA),root tissue density(RTD)representing root foraging scale and root biomass(RB)characterizing root foraging accuracy,root physiological plasticity indices,such as root carbon content(RCC),root nitrogen content(RNC),root non-structural carbohydrate content(RNSCs),root soluble sugar content(RSSC),root starch content(RSC),and root soluble sugar to starch content ratio(RSSC/RSC)of root samples in soil surface layers(0-10 cm)of two meadows were measured using a scanner(Epson)and analyzing software(WinRHIZO)in the yellowing period of 2019 and was calculated to understand the response characteristics of root foraging strategies for two typical alpine meadows on the Qinghai-Tibet Plateau to warming in the presence of permafrost.The results showed that:(1)warming decreased and increased the average soil moisture(SM)in the soil shallow layer(5 cm depth)of the K.pygmaea meadow and K.tibetica swamp meadow,respectively;(2)warming significantly increased RB and SRA in the K.pygmaea meadow and RV and SRL in the K.tibetica swamp meadow,while significantly decreasing SRL in the K.pygmaea meadow and RTD in the K.tibetica swamp meadow;(3)warming remarkably increased the RCC,RNSCs,RSSC,and RSC in two

关 键 词：增温 青藏高原 多年冻土 高寒草甸 根系觅食策略 

分 类 号：S812[农业科学—草业科学]