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Phyton-International Journal of Experimental Botany 2022年第4期91卷 811-825页

作者： Cunyang Niu wenkai shou Li Ma Jianqiang Qian Department of Ecology College of ForestryHenan Agricultural UniversityZhengzhou450002China

Urban trees are sensitive to extreme weather events under climate ***-thaw induced hydraulic failure could induce urban tree dieback and nullify the services they *** height is a simple but significant trait for plant ecological *** how urban trees with different heights adapt to freeze-thaw stress is increasingly important under climate *** investigated the relationship between tree height and stem hydraulic functional traits of six common urban tree species in North China to explore tree height-related hydraulic strategies to cope with freeze-thaw *** showed that tall trees had wider vessels,higher hydraulic conductivity,more winter embolism,but lower vessel and wood *** relationships were found between tree height and vessel diameter,hydraulic conductivity,and freeze-thaw induced embolism,and negative relationships were found between tree height and vessel and wood densities,which implied that short trees employ more conservative ecological strategies than tall *** and short tree species were well separated by multiple stem hydraulic functional traits;this is consistent with the fact that tall and short trees occupy different niches and indicates that different hydraulic strategies for freeze-thaw stress exist between *** trees might face more pressure to survive under extreme cold weather caused by climate change in the ***,more attention should be paid to tall urban tree management in North China to cope with extreme cold weather.

关键词： Growth form height vessel size hydraulic conductivity freeze-thaw events

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Species composition and diversity,and carbon stock in a dune ecosystem in the Horqin Sandy Land of northern China

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Journal of Arid Land 2015年第1期7卷 82-93页

作者： FeiLong HU wenkai shou Bo LIU ZhiMin LIU Carlos A BUSSO State Key Laboratory of Forest and Soil Ecology Institute of Applied Ecology Chinese Academy of Sciences University of Chinese Academy of Sciences Agronomy Department National University of the South and CERZOS (CONICET)

In this study, we determined carbon allocation and carbon stocks in the plant-soil system of different dune ecosystems in northeastern China. We quantified the species composition, above and below-ground bio masses, and carbon stocks of three dune types （i.e. active dunes, semi-stabilized dunes and stabilized dunes） and their corresponding inter-dune lowlands （i.e. interdune lowlands of active dunes, interdune lowlands of semi-stabilized dunes and interdune lowlands of stabilized dunes） in the Horqin Sandy Land. The results showed that the succession series on interdune lowlands of the Horqin Sandy Land confirmed differences in species composition of the various dune types. Aboveground carbon （AGC） on the interdune lowlands of semi-stabilized dunes （33.04 g C/m2） was greater （P〈0.05） than that on the interdune lowlands of active dunes （10.73 g C/m2）. At the same time, the different dune types did not show any significant differences （/：〉〉0.05） in belowground plant carbon （BGC）. However, the percentage of plant BGC in interdune lowlands of active dunes （81.5%） was significantly higher （P〈0.05） than that in the interdune lowlands of semi-stabilized dunes （58.9%）. The predominant carbon pool in the study dune ecosystem was in the soil. It accounted for 95% to 99% of total carbon storage. Soil organic carbon （SOC） was at least 55% greater （P〈0.05） in the interdunes than in the dunes. Stabilized dunes showed at least a 37% greater （P〈0.05） SOC content than active dunes up to a 1-m soil depth. Meanwhile, SOC content of interdune lowlands of semi-stabilized dunes was greater （P〈0.05） than that of interdune lowlands of active dunes only up to a 20-cm soil depth. The dune ecosystem showed a great potential to store carbon when interdune lowlands of active dunes were conversed to interdune lowlands of semi-stabilized dunes, which stored up to twice as much carbon per unit volume as interdune lowlands of active dunes.

关键词： species diversity carbon storage sand dunes interdune lowlands semi-arid areas

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Level of habitat fragmentation determines its non-linear relationships with plant species richness, frequency and density at desertified grasslands in Inner Mongolia, China

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Journal of Plant Ecology 2018年第6期11卷 866-876页

作者： Zhimin Liu wenkai shou Jianqiang Qian Jing Wu Carlos Alberto Busso Xianzhang Hou Institute of Applied Ecology Chinese Academy of Sciences72 Wenhua RoadShenhe DistrictShenyang 110016China Faculty of Forestry Liaoning Forestry Vocation-Technical College186 Fengyang RoadSujiatun DistrictShenyang 110164China Departamento de Agronomia-CERZOS(CONICET) Universidad Nacional del Sur8000 Bahia BlancaProvincia de Buenos AiresArgentina

Aims This study aimed to examine the changes in plant species richness,frequency and density along a habitat fragmentation gradient(with varied degrees of habitat fragmentation[DHFs])in a desertified grass-land of Horqin Sandy Land,northeastern Inner Mongolia,*** In this study,six landscape plots(500×500 m each)along a habi-tat fragmentation gradient were established.A new fragmentation index was formulated to study the effects of habitat fragmentation on biodiversity indices(species richness,frequency and density).Regression analyses(linear-or non-linear regression)were con-ducted to assess the changes in species richness,frequency and density along the habitat fragmentation gradient at plant commu-nity,functional group and species scales,*** Findings There was a non-linear relationship(following a quadratic function)between total species richness and the *** species richness reached its peak when the DHF was 0.2,beyond which species richness decreased along the fragmentation *** func-tional groups showed their specific responses to habitat fragmenta-tion,and some non-linear relationships and thresholds *** relative richness of rare species also showed a non-linear response to habitat fragmentation,with the threshold being DHF=*** became rarer(both some common species and rare spe-cies)with the intensifying habitat *** study dem-onstrates the importance of the non-linear relationships and plant functional groups in exploring the effects of habitat fragmentation on biodiversity and implementing effective biological conservation in sand dunes.

关键词： density frequency functional group habitat fragmentation rare species species richness

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太行山南麓3种典型灌木枝-叶功能性状及其适应策略

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干旱区资源与环境 2023年第12期37卷 123-130页

作者：牛存洋寿文凯杨喜田钱建强杨建涛河南农业大学林学院郑州450002

研究荆条、扁担杆和酸枣枝条水力结构和叶片功能性状,探讨其适应策略,为太行山区植被恢复提供理论依据。以成龄荆条、扁担杆和酸枣为研究对象,测定多年生枝条水力结构,包括边材比导率、叶比导率、胡伯尔值和气穴化栓塞程度等,以及多年... 详细信息

研究荆条、扁担杆和酸枣枝条水力结构和叶片功能性状,探讨其适应策略,为太行山区植被恢复提供理论依据。以成龄荆条、扁担杆和酸枣为研究对象,测定多年生枝条水力结构,包括边材比导率、叶比导率、胡伯尔值和气穴化栓塞程度等,以及多年生枝条叶片厚度、比叶面积、叶片大小、水势、蒸腾速率和气孔导度日变化。利用光学显微镜和扫描电镜测定木质部导管和纹孔解剖性状。结果表明:1)荆条水力直径和纹孔密度均显著高于扁担杆和酸枣,因此荆条具有较高的水分传输效率,且荆条具有较高的气孔导度和蒸腾速率,体现出快速获取资源的适应策略。2)扁担杆导管水力直径较小、比导率较低,且叶片厚度显著高于荆条和酸枣,比叶面积显著低于荆条和酸枣,体现出较为保守的资源获取策略。3)酸枣水力直径和比导率最小,但是其抗气穴化栓塞能力最强,且水势日变幅最大,可忍耐较低的水势。另外酸枣比叶面积显著高于荆条和扁担杆,且具有较高的气孔导度和蒸腾速率,表明酸枣具有较强的碳获取能力。3种灌木具有不同的功能性状从而表现出多样化的适应策略,占据不同的生态位,因此可以较好的适应太行山区严峻的环境。。

关键词：水力结构导管纹孔比叶面积适应策略

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Tailoring Texture to Highly Strengthen AZ31 Alloy Plate in the Thickness Direction via Pre-tension and Rolling-Annealing

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Acta Metallurgica Sinica(English Letters) 2023年第2期36卷 266-280页

作者： Tianjiao Li Jiang Zheng Lihong Xia Haoge shou Yongfa Zhang Rong Shi Liuyong He wenkai Li International Joint Laboratory for Light Alloys(Ministry of Education) College of Materials Science and EngineeringChongqing UniversityChongqing400044China Shenyang National Laboratory for Materials Science Chongqing UniversityChongqing400044China College of Mechanical Engineering Chongqing Technology and Business UniversityChongqing400067China Zhejiang Provincial Engineering Center of Integrated Manufacturing Technology and Intelligent Equipment Zhejiang University City CollegeHangzhou310015China

Conventional wrought Mg alloys,such as AZ31 and ZK60 rolled plates,usually exhibit significantly low tensile yield strength in the thickness *** can be attributed to the high activity of{10-12}tension twinning due to the strong basal texture(//ND,normal direction).In this work,the tensile yield strength in the ND of the as-rolled(AR)AZ31 plate increased from 50 to 150 MPa(increased by 200%)via simple processing,i.e.,pre-tension and rolling-annealing(PTRA)*** strong basal texture(//ND)of the AR plate was changed into a weakened fiber texture(⊥ND).The evolution of microstructures during PTRA treatment and the activated deformation modes during uniaxial tension were studied quantitatively and statistically by the means of intergranular misorientation(IM)and in-grain misorientation axes(IGMA)*** results indicate that various twin variants,as well as{10-12}-{10-12}secondary twins,were activated during pre-tension and rolling,and most residual matrix was consumed by twins after *** dominated deformation modes in tension changed from{10-12}tension twinning(the AR sample)to prismatic slip(the PTRA sample)in the early tensile *** underlying formation mechanism of the fiber texture and corresponding strengthening mechanism were discussed.

关键词： Pre-tension Annealing Tailoring texture Texture strengthening Deformation modes

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