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入侵植物根茎的生长和竞争力因相邻植物的不同而不同

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Journal of Plant Ecology 2021年第4期14卷 638-647页

作者： Alyssa Laney Smith Daniel Z.Atwater Wonjae Kim David C.Haak Jacob N.Barney School of Plant and environmental sciences Virginia TechBlacksburgVAUSA department of Biology Earlham CollegeRichmondINUSA present address:department of Ecology and Evolutionary Biology University of ArizonaTucsonAZUSA

物种内的遗传和表型变异对进化过程的影响已众所周知,但人们对种内变异如何影响群落水平过程还知之甚少。在人类对自然系统造成影响的大背景下,由于人类活动可能会产生巨大的选择压力,因此具有生态意义的种内变异可能会特别重要。在一... 详细信息

物种内的遗传和表型变异对进化过程的影响已众所周知,但人们对种内变异如何影响群落水平过程还知之甚少。在人类对自然系统造成影响的大背景下,由于人类活动可能会产生巨大的选择压力,因此具有生态意义的种内变异可能会特别重要。在一项温室实验中,我们研究了一种分布广泛的入侵物种和农业杂草石茅(Sorghum halepense)在受到种间竞争、种内竞争和土壤肥力的影响时,其在生物量和根茎方面发生的种内变异和生态型变异。与我们的预期和此前的研究结果不同的是,我们并没有在这一早期生命阶段中发现石茅各生态型生物量的改变。然而,我们确实发现石茅的生物量会随着竞争植株种类和土壤施肥方式的不同而发生很显著的变化,同时不同株之间也存在很大差异。农业生态型的根茎较其它生态型大了11%,经施肥处理后的增大幅度更高至3倍;虽然施肥后的根茎生物量增加了~50%,但生态型之间却并无差异。有趣的是,当受到种内竞争时,与玉米(Zea mays)发生种间竞争时的情况相比,石茅的生物量和根茎生物量产出分别减少了32%和20%。我们的研究结果表明,针对相邻植株的种类而发生的物种特异性竞争响应以及根茎分配的改变,石茅在受竞争时可能会产生适应性响应,从而使分配情况发生改变。

关键词：适应农业竞争外来入侵选择石茅(Sorghum halepense)

Global case studies of soft-sediment deformation structures(SSDS): Definitions,classifications, advances, origins, and problems

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Journal of Palaeogeography 2017年第4期6卷 251-320页

作者： G.Shanmugam department of earth and environmental sciences The University of Texas at Arlington

Soft-sediment deformation structures（SSDS）have been the focus of attention for over 150 years.Existing unconstrained definitions allow one to classify a wide range of features under the umbrella phrase＂SSDS＂.As a consequence,a plethora of at least 120 different types of SSDS（e.g.,convolute bedding,slump folds,load casts,dish-and-pillar structures,pockmarks,raindrop imprints,explosive sandegravel craters,clastic injections,crushed and deformed stromatolites,etc.）have been recognized in strata ranging in age from Paleoproterozoic to the present time.The two factors that control the origin of SSDS are prelithification deformation and liquidization.A sedimentological compendium of 140 case studies of SSDS worldwide,which include 30 case studies of scientific drilling at sea（DSDP/ODP/IODP）,published during a period between 1863and 2017,has yielded at least 31 different origins.earthquakes have remained the single most dominant cause of SSDS because of the prevailing＂seismite＂mindset.Selected advances on SSDS research are：（1）an experimental study that revealed a quantitative similarity between raindrop-impact cratering and asteroid-impact cratering;（2）IODP Expedition 308 in the Gulf of Mexico that documented extensive lateral extent（〉12 km）of mass-transport deposits（MTD）with SSDS that are unrelated to earthquakes;（3）contributions on documentation of pockmarks,on recognition of new structures,and on large-scale sediment deformation on Mars.Problems that hinder our understanding of SSDS still remain.They are：（1）vague definitions of the phrase＂soft-sediment deformation＂;（2）complex factors that govern the origin of SSDS;（3）omission of vital empirical data in documenting vertical changes in facies using measured sedimentological logs;（4）difficulties in distinguishing depositional processes from tectonic events;（5）a model-driven interpretation of SSDS（i.e.,earthquake being the singular cause）;（6）routine application of the genetic term＂seismites＂to the＂SSDS＂,thus undermining the basic tenet of process sedimentology（i.e.,separ

关键词： Soft-sediment deformation structures（SSDS） Prelithification deformation Liquidization Pockmarks Impact cratering Scientific drilling

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南极蓝冰用于第四纪古气候重建的进展

科学通报 2021年第21期66卷 2663-2670页

作者：颜余真 department of earth Environmental&Planetary SciencesRice UniversityHouston TX 77004USA

来自南北两极和山地的冰芯深刻揭示了第四纪气候与环境的演化,并提供了迄今为止最准确的大气成分历史记录.但是,传统深冰芯钻探面临着成本高和样品稀缺的局限,蓝冰区的浅层钻探由此成为了有效的补充研究手段.蓝冰研究最近在两个方面取... 详细信息

来自南北两极和山地的冰芯深刻揭示了第四纪气候与环境的演化,并提供了迄今为止最准确的大气成分历史记录.但是,传统深冰芯钻探面临着成本高和样品稀缺的局限,蓝冰区的浅层钻探由此成为了有效的补充研究手段.蓝冰研究最近在两个方面取得突破:首先,在蓝冰区发现了比最老深冰芯(800 ka)更老的冰样,揭示了中更新世转型期大气二氧化碳的浓度范围.其次,以相对较低的成本提供了大量末次间冰期以来的冰样,使新的分析方法得以实现.但是蓝冰研究也受到诸多因素的限制,无法取代深冰芯钻探.未来的蓝冰研究可围绕探索新的有价值蓝冰区、对现有蓝冰区展开进一步冰川动力学的研究,以及针对已有样品开发新的分析方法这3个思路进行突破.

关键词：冰芯蓝冰南极 Allan Hills Taylor Glacier 温室气体

Ambient noise H/V spectral ratio in site effects estimation in Fateh jang area, Pakistan

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earthquake Science 2015年第1期28卷 87-95页

作者： S.M.Talha Qadri Bushra Nawaz S.H.Sajjad Riaz Ahmad Sheikh department of earth sciences University of Sargodha College of earth and environmental sciences University of the Punjab

Local geology or local site effect is a crucial component while conducting seismic risk assessment studies. Investigations made by utilization of ambient noise are an effective tool for local site estimation. The present study is conducted to perform site response analysis at 13 different sites within urban settlements of Fateh jang area （Pakistan）. The aim of this study was achieved by utilizing Nakamura method or H/V spectral ratio method. Some important local site parameters, e.g., the fundamental fre- quencies f0 of soft sediments, amplitudes A0 of corre- sponding H/V spectral ratios, and alluvium thicknesses over 13 sites within the study area, were measured and analyzed. The results show that the study area reflects low fundamental frequency fo. The fundamental frequencies of the sediments are highly variable and lie in a range of 0.6-13.0 Hz. Similarly, amplification factors at these sites are in the range of 2.0-4.0.

关键词： Local site effectspectral ratios Fundamentalfactor Alluvium thickness Ambient noise H/Vfrequency Amplification

Preservation of a Paleoproterozoic rifted margin in the Himalaya:Insight from the Ulleri-Phaplu-Melung orthogneiss

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Geoscience Frontiers 2019年第3期10卷 873-883页

作者： K.Larson S.Piercey J.Cottle earth Environmental and Geographical Sciences IKBSAS University of British Columbia department of earth sciences Memorial University of Newfoundland department of earth Science University of CaliforniaSanta Barbara

Orthogneiss within the Paleoproterozoic strata of Lesser Himalayan sequence across the Himalaya has been variably linked to development in a continental arc setting, Indian basement, or a continental rift.New whole rock and trace element geochemical data and U/Pb zircon geochronology indicate that the granitoid protoliths to these rocks were derived from upper crustal sources in the Paleoproterozoic and have within-plate, A-type affinities. This is consistent with their generation in a rifted margin and is compatible with paleogeographic reconstructions that indicate an open boundary for present-day northern India in the Paleoproterozoic.

关键词： Himalaya Geochemistry Paleogeography Rifting Geochronology

Campaign-style U-Pb titanite petrochronology:Along-strike variations in timing of metamorphism in the Himalayan metamorphic core

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Geoscience Frontiers 2019年第3期10卷 827-847页

作者： Catherine M.Mottram John M.Cottle Andrew R.C.Kylander-Clark School of earth and environmental sciences University of Portsmouth department of earth Science University of CaliforniaSanta Barbara

present-day along-strike heterogeneities within the Himalayan orogen are seen at many scales, from variations within the deep architecture of the lithospheric mantle, to differences in geomorphologic surface processes. Here, we present an internally consistent petrochronologic dataset from the Himalayan metamorphic core(HMC), in order to document and investigate the causes of along-strike variations in its Oligocene-Miocene tectonic history. Laser ablation split-stream analysis was used to date and characterise the geochemistry of titanite from 47 calc-silicate rocks across >2000 km along the Himalaya.This combined U-Pb-REE-Zr single mineral dataset circumvents uncertainties associated with interpretations based on data compilations from different studies, mineral systems and laboratories, and allows for direct along-strike comparisons in the timing of metamorphic processes. Titanite dates range from ～30 Ma to 12 Ma, recording(re-)crystallization between 625 ℃ and 815 ℃. Titanite T-t data overlap with previously published P-T-t paths from interleaved peltic rocks, demonstrating the usefulness of titanite petrochronology for recording the metamorphic history in lithologies not traditionally used for thermobarometry. Overall, the data indicate a broad eastward-younging trend along the orogen.Disparities in the duration and timing of metamorphism within the HMC are best explained by alongstrike variations in the position of ramps on the basal detachment controlling a two-stage process of preferential ductile accretion at depth followed by the formation of later upper-crust brittle duplexes.These processes, coupled with variable erosion, resulted in the asymmetric exhumation of a younger,thicker crystalline core in the eastern Himalaya.

关键词： Himalaya Petrochronology Titanite Metamorphic petrology

Acorn size and tolerance to seed predators:the multiple roles of acorns as food for seed predators,fruit for dispersal and fuel for growth

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Integrative Zoology 2018年第3期13卷 251-266页

作者： Andrew W.BARTLOW Salvatore JAGOSTA Rachel CURTIS Xianfeng YI Michael ASTEELE department of Biology and The WIESS Institute for environmental Science and Sustainability Wilkes UniversityWilkes BarrePennsylvaniaUSA present address:department of Biology University of UtahSalt Lake CityUtahUSA Center for environmental Studies and department of Biology Virginia Commonwealth UniversityRichmondVirginiaUSA present address:department of Veterinary Integrative Biosciences Texas A&M UniversityCollege StationTexasUSA College of Life sciences Jiangxi Normal UniversityNanchangJiangxiChina.

Fitness of parents and offspring is affected by offspring size.In oaks(Quercus spp.),acorns vary considerably in size across,and within,species.Seed size influences dispersal and establishment of oaks,but it is not known whether size imparts tolerance to seed predators.Here,we examine the relative extent to which cotyledon size serves as both a means for sustaining partial consumption and energy reserves for developing seedlings during early stages of establishment.Acorns of 6 oak species were damaged to simulate acorn predation by vertebrate and invertebrate seed predators.Seedling germination/emergence and growth rates were used to assess seedling performance.We predicted that if cotyledons are important for dispersal,acorns should show tolerance to partial seed consumption.Alternatively,if the cotyledon functions primarily as an energy reserve,damage should significantly influence seedling performance.Acorns of each species germinated and produced seedlings even after removing>50%of the cotyledon.Seed mass explained only some of the variation in performance.Within species,larger acorns performed better than smaller acorns when damaged.Undamaged acorns performed as well or better than damaged acorns.There was no pattern among individual species with increasing amounts of damage.In some species,simulated invertebrate damage resulted in the poorest performance,suggesting alternative strategies of oaks to sustain damage.Large cotyledons in acorns may be important for attracting seed dispersers and sustaining partial damage,while also providing energy to young seedlings.Success of oak establishment may follow from the resilience of acorns to sustain damage at an early stage.

关键词： acorns damage tolerance dispersal Quercus seed size

Solutes in native plants in the Arabian Gulf region and the role of microorganisms: future research

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Journal of Plant Ecology 2018年第5期11卷 671-684页

作者： Roda Fahad Al-Thani Bassam Taha Yasseen department of Biological and environmental sciences College of Arts&SciencesQatar UniversityDohaQatar present address:8 James Court Dunstable RoadLuton LU40HNUK.

Aims One of the outstanding challenges facing humankind is increas-ing crop production under various types of severe environmental conditions.Many measures have been taken to adopt molecular and biotechnological approaches that lead to the development of transgenic plants able to deal with such harsh and polluted envi-ronments.However,such solutions could be very expensive and require considerable efforts and time to achieve these objectives.The main objective of this review is to discuss the new biological solutions that have emerged in the last decade,as environmentally friendly approaches,perhaps to support and/or replace the present efforts.These solutions based on plant-microbe interactions could be a lifeline and promising alternative strategy to create plants with a high resistance to the extreme environments.Methods During the last two decades research projects have been conducted to study the ecology,identify the features,and the ecophysiology of native plants and the associated microorganisms in the Arabian Gulf region and particularly in Qatar.Many physiological and bio-chemical parameters have been determined,including organic sol-utes(amino acids like proline,glycinebetaine,soluble sugars,etc.),photosynthetic pigments,organic acids and inorganic ions espe-cially heavy metals,along with the physical and chemical proper-ties of the soil in various locations of the State of Qatar.Also,the microorganisms adjacent to and associated with these native plants were identified to elucidate the possible roles in the soil biota in supporting these plants against extreme environmental conditions.Important Findings Investigations of native plants in the Arabian Gulf states during the last decade have shown that wild plants exhibit different abili-ties to accumulate organic solutes to cope with the harsh natural environments.Pollution is a major factor stressing wildlife in this region due to the expansion of urban sectors and industrial activi-ties of oil and ***patible osmolytes,like proline,accumu-late in wild p

关键词： Arabian Gulf region arid lands compatible solutes drought microorganisms modern approaches pollution salinity

From Mantle Transition Zone with Microstructures: A New Paradigm in Ophiolite Studies

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Acta Geologica Sinica(English Edition) 2020年第S01期94卷 53-54页

作者： Souvik DAS department of earth and environmental sciences University of Texas at ArlingtonTX 76019USA

The SE Ladakh(India) area displays one of the best-preserved ophiolite sections in this planet, in places up to 10 km thick, along the southern bank of the Indus River. Recently, in situ ultra-high pressure(UHP) microstructural evidences from mantle transition zone(MTZ ~ 410–660 km) with diamond and reduced fluids were discovered from two peridotite bodies in the basal mantle part of this Indus ophiolite(Das et al., 2015;2017). Ultrahigh-pressure phases were also found by early workers from podiform chromitites of another equivalent Neo–Tethyan ophiolite in southern Tibet(e.g., Yang et al., 2007;Yamamoto et al., 2009). However, the MTZ phases in the Indus ophiolite are found in silicate peridotites not metallic chromitites and the peridotitic UHP phases show systematic and contiguous phase transitions from the MTZ to shallower depth, unlike the discrete ultrahighpressure inclusions, all in Tibetan chromitites. The gradual change in oxygen fugacity(fo2) and fluid composition from(C-H + H2) to(CO2 + H2O) in the upwelling peridotitic mantle causing melting to produce MORB. At shallow depths(present in Neo-Tethyan ophiolites(Zhang et al., 2005). Recently, continental materials(quartz, k-feldspar etc.) bearing old zircons(up to 2700 Ma) are also recovered from UHP chromitite of Tibetan ophiolite(Yamamoto et al., 2013). Eventually, the presence of older continental material can produce non-MORB like basalts in

关键词： mantle transition zone Neo-Tethyan ophiolites diamond oxygen fugacity historical contingency