Involvement ofCylindrocarpon destructansin root death ofPinus sylvestrisseedlings: Pathogenic behaviour and predisposing factors
作者:
Torgny Unestam,
Liselotte Beyer‐Ericson,
Mats Strand,
期刊:
Scandinavian Journal of Forest Research
(Taylor Available online 1989)
卷期:
Volume 4,
issue 1-4
页码: 521-535
ISSN:0282-7581
年代: 1989
DOI:10.1080/02827588909382585
出版商: Taylor & Francis Group
关键词: Cylindrocarpon destructans;root death;nurseries;ecological niche;stress;predisposing agents;toxin;Pinus sylvestris;oxygen;light;fungicides;Trichoderma
数据来源: Taylor
摘要:
The common rhizospheric fungusCylindrocarpon destructanswas investigated in relation to its role in root death ofPinus sylvestrisin Nordic nurseries and plantations. Laboratory methods were developed for studying similar root problems as well as the early effects of phytotoxicity and fungal infection. Seedlings grown under standardized optimal conditions were exposed to controlled stress (known to occur in nurseries), with or withoutC. destructansin the rhizosphere. Low light conditions, anaerobic root environment, and fungicide treatment were each found to predispose pine seedlings to invasion by the pathogen. The pathogen was very sensitive to competition as well as antagonism on the root, and fungicide‐induced inhibition of antagonists such asTrichodermaspp. also increased the severity of attack by the pathogen. To compete successfully, the pathogen would have to invade and dominate weakened roots prior to the arrival of saprophytes. Toxic metabolites produced by the pathogen weakened or killed nearby root tissues, and pathogen metabolites seemed to prevent saprophytes from taking hold in the infected roots. Such heavily infected, dead roots may act as inoculum sources allowing the pathogen to invade adjacent living roots, even healthy ones. Dead roots left in nursery soil after earlier harvests may act as reservoirs of inoculum for long periods and pose a threat to new plants.
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