Defence responses of non-mycorrhizal and mycorrhizal seedlings of Pinus sylvestris L. to fungal pathogensReportar como inadecuado




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Reference: Bonello, Pierluigi., (1991). Defence responses of non-mycorrhizal and mycorrhizal seedlings of Pinus sylvestris L. to fungal pathogens. DPhil. University of Oxford.Citable link to this page:

 

Defence responses of non-mycorrhizal and mycorrhizal seedlings of Pinus sylvestris L. to fungal pathogens

Abstract: The defence mechanisms expressed in roots of Pinussylvestris seedlings challenged with fungal pathogens wereinvestigated, and a comparison was made between the expressionof defences in non-mycorrhizal and mycorrhizal seedlings.Papillae were formed by cortical cells of non-mycorrhizalseedlings infected with Cylindrocarpon destructans.Histochemical evidence was obtained for pectic materialscomprising an important polysaccharide component of thesestructures, and for the deposition of polyphenolic compoundsalso. Proton induced X-ray emission (PIXE) microanalysisindicated that insoluble calcium levels were elevated inpapillae relative to normal cell walls. Although papillaeappeared important in protecting cortical cells againstpenetration by fungal hyphae, a primary role for the wallappositions in the resistance of seedlings of Scots pineagainst root pathogens could not be proven.Although phytoalexins were not detected in the roots ofScots pine seedlings following infection with C. destructans,the mean content of an abietic acid fraction (comprising sixcompounds, of which only dehydroabietic acid could bepositively identified), increased from 5.2 to 9.7mg g-1 dryweight. This fraction exhibited some antifungal activity.-related proteins induced de novo byinfection could not be detected, but several constitutiveapoplastic proteins, including some with chitinase activity,appeared to increase in the needles of root-infectedseedlings.The formation of ectomycorrhizae with Pisolithustinctorius, Suillus bovinus and Hebeloma crustuliniforme didnot itself induce papilla formation in the roots of P.sylvestris. Evidence was obtained to suggest that the responsewas suppressed when mycorrhizal seedlings were challenged withC. destructans.Results highly suggestive of the induction of systemicresistance in P. sylvestris seedlings, consequent uponmycorrhizal infection, were obtained. In seedlings grown invitro the survival rate of mycorrhizal seedlings challengedaerially with Botrytis cinerea was 37.5% compared with 7.1 inseedlings grown gnotobiotically. However, the physiologicalmechanisms by which this protection was imparted remain to bedetermined.

Type of Award:DPhil Level of Award:Doctoral Awarding Institution: University of Oxford Notes:The digital copy of this thesis has been made available thanks to the generosity of Dr Leonard Polonsky

Contributors

Pearce, Ray B.More by this contributor

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Dr. Ray B. PearceMore by this contributor

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 Bibliographic Details

Issue Date: 1991Identifiers

Urn: uuid:83f17126-ed81-4060-9e5f-714814faada1

Source identifier: 603853183 Item Description

Type: Thesis;

Language: eng Subjects:



Autor: Bonello, Pierluigi. - institutionUniversity of Oxford facultyDept. of Plant Sciences facultyLife and Environmental Sciences Divis

Fuente: https://ora.ox.ac.uk/objects/uuid:83f17126-ed81-4060-9e5f-714814faada1



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