Coners, Heinz

[["dc.bibliographiccitation.firstpage","329"],["dc.bibliographiccitation.issue","3"],["dc.bibliographiccitation.journal","Environmental and Experimental Botany"],["dc.bibliographiccitation.lastpage","336"],["dc.bibliographiccitation.volume","71"],["dc.contributor.author","Graefe, Sophie"],["dc.contributor.author","Leuschner, Christoph"],["dc.contributor.author","Coners, Heinz"],["dc.contributor.author","Hertel, Dietrich"],["dc.date.accessioned","2018-11-07T08:54:55Z"],["dc.date.available","2018-11-07T08:54:55Z"],["dc.date.issued","2011"],["dc.description.abstract","Lowered temperatures may reduce the root water uptake of tropical trees at high elevations through several mechanisms; however, field studies to test their relevance are lacking. We measured sap flux density (J) in small-diameter tree roots across a 2000-m elevation transect in a tropical mountain forest for quantifying the effects of temperature (T(a)), VPD and soil moisture (theta) on root water flow and uptake at different elevations. Recently developed miniature heat balance-sap flow gauges were applied to roots of about 10 mm in diameter in mountain forest stands at 1050, 1890 and 3060m a.s.l. in the Ecuadorian Andes and the measured flow was related to anatomical properties of the root xylem. Between 1050 and 3060 m, mean J decreased to about a third. VPD was the most influential environmental factor controlling J at 1050 and 1890 m, while T(a) was the key determinant at 3060 in. Large vessels were absent in the root xylem of high-elevation trees which resulted in a 10-fold decrease of theoretical hydraulic conductivity (k(h)(theor)) between 1050 and 3060 in. We conclude that both physical limitations (reduced VPD, increased viscosity of water) and biological constraints (large decrease of k(h)(theor)) result in a significantly reduced J and root water uptake of the trees in high-elevation tropical forests. (C) 2011 Elsevier B.V. All rights reserved."],["dc.description.sponsorship","German Science Foundation (DFG) through Research Group [402, B6]"],["dc.identifier.doi","10.1016/j.envexpbot.2011.01.001"],["dc.identifier.isi","000290013500001"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/22785"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Pergamon-elsevier Science Ltd"],["dc.relation.issn","0098-8472"],["dc.title","Root functioning in tropical high-elevation forests: Environmental vs. biological control of root water absorption"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","602"],["dc.bibliographiccitation.firstpage","1"],["dc.bibliographiccitation.journal","Frontiers in plant science"],["dc.bibliographiccitation.lastpage","12"],["dc.bibliographiccitation.volume","8"],["dc.contributor.author","Kubisch, Petra"],["dc.contributor.author","Leuschner, Christoph"],["dc.contributor.author","Coners, Heinz"],["dc.contributor.author","Gruber, Andreas"],["dc.contributor.author","Hertel, Dietrich"],["dc.date.accessioned","2018-02-26T10:46:47Z"],["dc.date.available","2018-02-26T10:46:47Z"],["dc.date.issued","2017"],["dc.description.abstract","Low temperatures are crucial for the formation of the alpine treeline worldwide. Since soil temperature in the shade of tree canopies is lower than in open sites, it was assumed that self-shading may impair the trees' root growth performance. While experiments with tree saplings demonstrate root growth impairment at soil temperatures below 5-7°C, field studies exploring the soil temperature - root growth relationship at the treeline are missing. We recorded soil temperature and fine root abundance and dynamics in shaded and sun-exposed areas under canopies of isolatedPinus cembratrees at the alpine treeline. In contrast to the mentioned assumption, we found more fine root biomass and higher fine root growth in colder than in warmer soil areas. Moreover, colder areas showed higher fine root turnover and thus lower root lifespan than warmer places. We conclude thatP. cembrabalances enhanced fine root mortality in cold soils with higher fine root activity and by maintaining higher fine root biomass, most likely as a response to shortage in soil resource supply. The results from our study highlight the importance ofin situmeasurements on mature trees to understand the fine root response and carbon allocation pattern to the thermal growth conditions at the alpine treeline."],["dc.description.sponsorship","Open-Access-Publikationsfonds 2017"],["dc.identifier.doi","10.3389/fpls.2017.00602"],["dc.identifier.pmid","28469633"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/14495"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/12615"],["dc.language.iso","en"],["dc.notes.intern","Merged from goescholar"],["dc.notes.status","final"],["dc.publisher","Frontiers Media S.A."],["dc.relation.eissn","1664-462X"],["dc.rights","CC BY 4.0"],["dc.rights.uri","https://creativecommons.org/licenses/by/4.0"],["dc.title","Fine Root Abundance and Dynamics of Stone Pine (Pinus cembra) at the Alpine Treeline Is Not Impaired by Self-shading"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","330"],["dc.bibliographiccitation.journal","Frontiers in Plant Science"],["dc.bibliographiccitation.volume","10"],["dc.contributor.author","Göbel, Leonie"],["dc.contributor.author","Coners, Heinz"],["dc.contributor.author","Hertel, Dietrich"],["dc.contributor.author","Willinghöfer, Sandra"],["dc.contributor.author","Leuschner, Christoph"],["dc.date.accessioned","2019-07-09T11:51:18Z"],["dc.date.available","2019-07-09T11:51:18Z"],["dc.date.issued","2019"],["dc.description.abstract","In high-elevation grasslands, plants can encounter periods with high air temperature while the soil remains cold, which may lead to a temporary mismatch in the physiological activity of leaves and roots. In a climate chamber experiment with graminoid species from three elevations (4400, 2400, and 250 m a.s.l.), we tested the hypothesis that soil temperature can influence photosynthesis and stomatal conductance independently of air temperature. Soil monoliths with swards of Kobresia pygmaea (high alpine), Nardus stricta (lower alpine), and Deschampsia flexuosa (upper lowland) were exposed to soil temperatures of 25, 15, 5, and -2°C and air temperatures of 20 and 10°C for examining the effect of independent soil and air temperature variation on photosynthesis, leaf dark respiration, and stomatal conductance and transpiration. Soil frost (-2°C) had a strong negative effect on gas exchange and stomatal conductance in all three species, independent of the elevation of origin. Leaf dark respiration was stimulated by soil frost in D. flexuosa, but not in K. pygmaea, which also had a lower temperature optimum of photosynthesis. Soil cooling from 15 to 5°C did not significantly reduce stomatal conductance and gas exchange in any of the species. We conclude that all three graminoids are able to maintain a relatively high root water uptake in cold, non-frozen soil, but the high-alpine K. pygmaea seems to be especially well adapted to warm shoot - cold root episodes, as it has a higher photosynthetic activity at 10 than 20°C air temperature and does not up-regulate leaf dark respiration upon soil freezing, as was observed in the grasses from warmer climates."],["dc.identifier.doi","10.3389/fpls.2019.00330"],["dc.identifier.pmid","30936890"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/16097"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/59919"],["dc.language.iso","en"],["dc.notes.intern","Merged from goescholar"],["dc.publisher","Frontiers Media S.A."],["dc.relation.eissn","1664-462X"],["dc.rights","CC BY 4.0"],["dc.rights.uri","https://creativecommons.org/licenses/by/4.0"],["dc.subject.ddc","570"],["dc.title","The Role of Low Soil Temperature for Photosynthesis and Stomatal Conductance of Three Graminoids From Different Elevations"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]