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Effects of biotic and abiotic factors on the spatial distribution of enzyme activities in the soil

dc.contributor.advisorDippold, Michaela Prof. Dr.
dc.contributor.authorMa, Xiaomin
dc.date.accessioned2018-11-27T09:59:31Z
dc.date.available2018-11-27T09:59:31Z
dc.date.issued2018-11-27
dc.identifier.urihttp://hdl.handle.net/11858/00-1735-0000-002E-E516-B
dc.identifier.urihttp://dx.doi.org/10.53846/goediss-7163
dc.language.isoengde
dc.rights.urihttp://creativecommons.org/licenses/by-nc-nd/4.0/
dc.subject.ddc630de
dc.titleEffects of biotic and abiotic factors on the spatial distribution of enzyme activities in the soilde
dc.typecumulativeThesisde
dc.contributor.refereeDippold, Michaela Prof. Dr.
dc.date.examination2018-11-21
dc.description.abstractengEnzymes produced by plant and microorganisms are crucial to soil functions as they decompose insoluble macromolecules organic compound to smaller, soluble molecules which can be assimilated by cells. The enzymes are spatial and temporal heterogeneously distributed in soil as affected by microbial and root activity. It is imperative to measure biotic and abiotic factors affected the spatial and temporal distribution of enzyme activity in order to reveal complex interactions between enzymes, macromolecules organic compound decomposition and plant, microbial nutrient acquisitions. Among various factors we selected three biotic factors: root morphology (root hairs and root radius), root architectures (lateral root and taproot), and plant development and two abiotic controls: phosphorus availability and temperature. Therefore, this thesis aimed to visualize and localize distribution of various enzymes activities in two hotspheres in soil: rhizosphere, root-detritusphere depending on biotic and abiotic controls. Directly soil zymography were established to investigate: 1) the root morphology (root hairs and root radius) and root architectures (taproots and lateral roots) effects on the spatial distribution of enzyme activity in the rhizosphere; 2) plant development (reproductive stage and vegetative stage) effects on the spatial distribution and temporal dynamic of enzyme activity in two legume species; 3) the temperature effects on hotspot areas of enzyme activity and the duration of hot moments in the root-detritusphere. Beside, zymography was combined with enzyme kinetics to test the substrate turnover in the rhizosphere of maize with and without root hairs zone and in the root-detritusphere under a series of temperatures. Moreover, zymography was combined with pH planar optode to investigate the spatial distribution phosphatase activity and pH in the rhizosphere of lupine in response to phosphorus availability and cluster root formation. The abiotic effects: root morphology (root hairs and root radius) and architectures (lateral root and taproots) and plant development influenced the in situ and the spatial distribution of enzyme activity as well as the substrate turnover in the rhizosphere: 1) the rhzosphere extent of enzyme activity and the substrate turnover depended on the root hairs: the rhizosphere extent of β-glucosidase activity in wheat root regions with hairs was 1.5-fold broader and substrate turnover was 2 times faster than in root regions without hairs; 2) the rhizosphere extent relative to root radius and the enzyme activity per root surface area in plant with thin root (wheat) were higher than in plant with thick root (maize): the rhizosphere extents relative to root radius of β-glucosidase and phosphatase activity in wheat were nearly 2 times broader than in maize; and the leucine aminopeptidase activity per root surface area in wheat was 7 times higher than that in maize; 3) the rhizosphere extent relative to root radius and enzyme activity per root surface area in plant with long and dense root hairs (lupine) was significantly higher than in plant with short and sparse root hairs (lentil): the rhizosphere extent relative to root radius of acid phosphatase in lupine was 1.5 times broader than in lentil; the β-glucosidase and cellobiohydrolase activity per root surface area in lupine was 2-3 times higher than in lentil; 4) the rhizosphere volume per root length was 30-70 times higher and enzyme activity per root surface area was 6-14 fold higher for lateral roots than for taproots; 5) the spatial distribution of enzyme activity in situ in the rhizosphere depended on plant development and growth stage: Lentil kept as vegetative growth and the rhizosphere extent was constant; lupine entered reproductive growth in the 7th week after planting companied with broader rhizosphere extent, however, the enzyme activity decreased by 10-50% compared to the vegetative stage. Moreover, the spatio-temporal patterns of phosphatase activities and pH in the rhizosphere depending on biotic and abiotic interaction effects such as P availability and cluster root formation: 1) before cluster root formations, phosphorus deficiency increased acid phosphatase activities by 20%, decreased pH by 0.8 units and broadened the rhizosphere extent by about 0.4 mm around taproot; 2) after cluster root formation, the rhizosphere extent of phosphatase activity around taproot of lupine was 0.2 mm narrower, while the hotspot areas of alkaline phosphatase activity was 40% larger for lupine grown under P-deficiency than amended with Ca(H2PO4)2. These indicate that lupine used various strategies to conquer P deficiency during growth: increased phosphatase activity, soil acidification and broaden their rhizosphere extent around taproot are the mechanisms before cluster root formation. After cluster root development, the main mechanism is increase of hotspot area of phosphatase activity to explore larger soil volume for P acquisition. Beside, abiotic factors such as temperature affected the enzyme activity hotspot area formation, the duration of hot moment, enzyme kinetics and the substrate turnover: 1) the hotspot areas increased by 2-24 times from 10 to 30 °C, however, the hotspots area decreased by 5-73% for all enzymes at 40 °C compared to at 30 °C; 2) Vmax increased with temperature from 10 to 30 °C by 1.5-6.6 times but decreased at 40 °C ; 3) The turnover time of all substrates were shorter at warm compared to cold temperatures: the turnover time of substrates decomposed by phosphatase, cellobiohyrolase and leucine-amino peptidase at 30 °C were 1.7-6.7 folds faster than at 10 °C. Overall, this thesis developed new concepts and developed numbers of approaches dedicated to investigate the abiotic and biotic effects on spatial distribution, hotspot area formation of soil enzyme activities. The effect of abiotic and biotic controls on spatial distribution of the enzyme hotspots has important consequences not only for soil science, but also for ecology, plant-soil-microbial interactions, nutrients and element cycles.de
dc.contributor.coRefereePausch, Johanna Prof. Dr.
dc.contributor.thirdRefereeBlagodatskaya, Evgenia PD Dr.
dc.subject.engEnzyme spatial distributionde
dc.identifier.urnurn:nbn:de:gbv:7-11858/00-1735-0000-002E-E516-B-8
dc.affiliation.instituteFakultät für Forstwissenschaften und Waldökologiede
dc.subject.gokfullForstwirtschaft (PPN621305413)de
dc.identifier.ppn1041147287


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