THE PEACH REPLANT PROBLEM IN ONTARIO: VII. THE PATHOGENICITY OF PRATYLENCHUS PENETRANS (COBB, 1917) FILIP. &amp; STEK. 1941

Mountain, W. B.; Patrick, Z. A.

doi:10.1139/b59-037

Cited by 51 publications

(27 citation statements)

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“…However, causes for peach replant prob lems have been studied from many different points of view such as nematodes (15,16,17), fungi (22, 23) and allelopathins (6,8,10,13,14,18,19,20). Therefore, it seems most reasonable that while in some cases a certain single factor may be predominant, in other cases other factors may complicate the problems.…”

Section: Resultsmentioning

confidence: 99%

Inhibition of ^|^beta;-Cyanoalanine Synthase Activity by Growth Inhibitors from Peach Roots

Mizutani

Hirota

Kadoya

1988

Engei Gakkai zasshi

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SummaryThe effect of growth inhibitors from peach roots on the activity of j3-cyanoalanine synthase was investigated. A positive correlation was found between the condensed tannin content and the inhibition of 13-cyanoalanine synthase activity in the fractions of extract of peach roots. Ethyl-acetate-soluble neutral fraction, which showed the highest content of condensed tannins and the greatest inhibition of the enzyme activity, was further separated by Sephadex LH-20 column chromatography. Fractions containing high condensed tannins reduced the growth of rice seedlings and suppressed the activity of Q-cyanoalanine synthase. One of the purified biflavanols, which were isolated from peach roots as growth inhibitors, also inhibited the /3-cyanoalanine synthase activity. We inferred that when the growth inhibitors suppress this activity, the normal cyanide metabolism is disturbed, resulting in the accumulation of hydrogen cyanide in the tissues. Thus from an allelopathic point of view, the growth inhibitors derived from the root residues of preplanted peach trees adversely affect the growth of replanted trees by causing cyanogenesis in their roots.

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Section: Resultsmentioning

confidence: 99%

Inhibition of ^|^beta;-Cyanoalanine Synthase Activity by Growth Inhibitors from Peach Roots

Mizutani

Hirota

Kadoya

1988

Engei Gakkai zasshi

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“…(Mountain and Patrick 1959;Traquair 1984), as nematode suppressors. Whether these compounds are stress metabolites (= phytoallexins) or simply toxins released as a result of natural degradation of decaying tissue in soil is unclear.…”

Section: Biodiversity and Biologymentioning

confidence: 99%

“…However, with particular respect to amygdalin, the root-lesion nematode P. penetrans is a serious pest of only some varieties of Prunus sp. fruit trees (Mountain and Patrick 1959) and is able to evade the toxic effect of this glycoside, depending on its concentration in the root tissues of the trees. Sensitive varieties react with a hypersensitive response to nematode probing, presumably because the nematode hydrolyzes the glycoside, releasing benzaldehyde and hydrogen cyanide.…”

Section: Biodiversity and Biologymentioning

confidence: 99%

“…What is still unknown, but would be interesting to prove, is whether hypersensitive Prunus spp. react to P. penetrans by production of enzymes such as phenylalanine ammonia-lyase (PAL) a key enzyme in phytoallexin synthesis (Lindgren et al 1992) or peroxidases (Sijmons et al 1994), or whether nematode-secreted β-glucosidase (Mountain and Patrick 1959;Townshend and Stobbs 1981;Townshend et al 1989) or a combination of plant-and nematode-secreted compounds interact in pathogenesis when nematodes attack such trees.…”

Section: Biodiversity and Biologymentioning

confidence: 99%

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Nematode biodiversity in Canadian agricultural soils

Potter¹,

McKeown²

2003

Can. J. Soil. Sci.

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The biodiversity of soil-inhabiting nematodes in Canada is incompletely known, as large areas of Canada’s landmass have not been surveyed for nematode fauna. Nematodes considered as indigenous are generally well adapted to a variety of ecological niches and climatic zones. Much of the available information is based on agricultural ecosystems and agricultural species, and thus is biased toward conditions in disturbed ecosystems and away from “primeval” ecology. Introduced nematode species are frequently quite pathogenic, even to exotic host plants from the same geographic point of origin. Estimates of crop loss due to single species infestations of pathogenic nematodes and the costs of nematode control using chemicals are reasonably well known, averaging about 10% of crop value, but ranging to 100% depending on the situation; the cost of damage by multiple-species infestations is less defined. Nematode-suppressive mechanisms are understood in only a few plant species; sulfur appears to be important as a constituent of active compounds in suppressive plants of agricultural origin. Similarly, some native plants are equally adapted with allelopathic chemicals that suppress nematodes. Management of nematode populations in agricultural soils by integrated crop management methods is at an early stage, requiring research to quantify effects of nematode-suppressive plants and soil amendments containing nitrogen. An integrated program could include nematode-suppressive plants, appropriate soil amendments, and the promotion of microbial antagonists. Different mathematical methods may be required to analyze and explain multi-factor nematode control systems. Less-toxic management systems could benefit the soil-inhabiting nematodes that predate arthropod soil pests. Further research on soil-borne nematodes may demonstrate the value of nematodes as indicators of agroecosystem health and environmental pollutants. Key words: Biocontrol, biodiversity, nematode distribution, nematode management, soil ecology

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“…Another report from California by De Vay et al (1967) stated that the decline of peach trees is a chronic root problem affecting 2-to 16-year-old trees, particularly in light soils. In Ontario, serious difficulties are frequent in the establishment of replants on old orchard sites (Koch 1955; Boyce 1957, 1958a,b;Mountain and Patrick 1959;Patrick 1955;Ward and Durkee 1956;Wensley 1956). Agrios (1971) reported from Greece that peach and apricot trees die within three to four years of first tree decline symptoms.…”

Section: Distributionmentioning

confidence: 99%