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Title: Peridermium pini (Pers.) Lev. : a study of aeciospores in vitro, mode of infection and resistance in Pinus silvestris
Author: Olembo, Titus Wycliffe
Awarding Body: University of Aberdeen
Current Institution: University of Aberdeen
Date of Award: 1970
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The effect of temperature, pH, humidity and spore density on the germination of aeciospores of Peridermium pini were studies in vitro and the optimum conditions for germination determined. Inoculation of scalpel wounds 2 mm deep on current year's shoots gave higher infections than wounds 1 mm deep. Some lesions resulting from these infections developed pyenidial droplets, and a few also produced social blisters within the first year after infection. Counts of aeciospores at various times after placement showed that they do not adhere firmly to needle surfaces and that many are rapidly lost. The reminder tond to drift down and to accumulate in the needle fascicles. Infection of P. sylvestris by aeciospores of P. pini can take place by direct stomatal penetration. This was observed only inside the needle sheaths and not above them. The hyphae developing from these penetrations pass intercellularly through the mesophyll to the vascular tissue of the needles where they proliferate and grow to the shoots and stems thus establishing infection. Internal needle extracts and needle and shoot juices taken from a healthy tree standing beside diseased trees showed a marked retarding effect on the germination of aeciospores and subsequent germ tube development compared with those from an already infected tree. Chromatography work showed that quantitative differences between the phenolic content of needles from both the healthy and the infected trees did not exist. Resistance of P. sylvestris to P. pini infection may be due either to qualitative phenolic differences or to other substances.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available