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EFFECT OF MEDIA ON GROWTH AND INTERACTIONS BETWEEN A RANGE OF SOIL-BORNE GLASSHOUSE PATHOGENS AND ANTAGONISTIC FUNGI 总被引:10,自引:1,他引:9
JOHN M. WHIPPS 《The New phytologist》1987,107(1):127-142
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Folsomia Candida was maintained on potato dextrose agar (PDA) plates precolonised by the mycoparasite Coniothyrium minitans for 3 yr but the sciarid Bradysia sp. survived for a maximum of only three generations. Collembolans and sciarid larvae from these cultures were able to transmit C. minitans to uninoculated PDA plates through the survival of spores in faecal pellets. Adult and larval sciarids also transmitted C. minitans from PDA culture to uninoculated PDA plates by contamination on the cuticle. In soil and sand both sciarids and collembolans were able to transmit C. minitans from C. m/m'tans-inoculated to uninoculated sclerotia of Sclerotinia sclerotiorum. Inoculation of sclerotia with C. minitans enabled greater populations of larger collembolans to develop. In the glasshouse where C. minitans had been applied to the soil, one adult sciarid and four collembolans out of 70 and 101 insects collected respectively yielded C. minitans on placement onto PDA + Aureomycin. 相似文献
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Coniothyrium minitans, a mycoparasite with biocontrol activity against Sclerotinia sclerotiorum, was found to disperse during glasshouse trials where overhead irrigation was used. Consequently, the role of water splash in dispersal of C. minitans was investigated using soil-incorporated inoculum and a range of irrigation regimes found to occur in the glasshouse. The resulting inoculum deposition over horizontal distances up to 2 m was measured. Using drops < 6 mm diameter at 680 mm h-1, C. minitans was splash-dispersed at least 2.0 m, whereas with drops > 6 mm diameter at 30 mm h-1 it was dispersed to only 1.75 m. Irrigation with droplets < 1mm diameter at 49 mm h-1 failed to disperse inoculum beyond 0.5 m. The dispersal gradient produced by drops < 6 mm diameter at 680 mm h-1 was best described mathematically by the power function, whereas irrigation with drops > 6 mm diameter at 30 mm h- resulted in a gradient described well by power or exponential functions. The latter regime produced a significantly steeper gradient than irrigation with drops < 6 mm diameter at 680 mm h-1. C. minitans was isolated using an Andersen air sampler at concentrations of 2839 cfu m-3 or 22 cfu m-3 during irrigation with drops < 6 mm diameter at 680 mm h-1 or > 6 mm diameter at 30 mm h-1, respectively. After irrigation, deposition of C. minitans-canying aerosol particles declined exponentially and distance from source had no effect on the amount of inoculum isolated. Conidia of C. minitans, splash-dispersed by irrigation with drops < 6 mm diameter at 680 mm h-1 were able to infect sclerotia of S. sclerotiorum such that almost all sclerotia at 0.5 m from the inoculum source, and c. 50% of those at 2.0 m, became infected with the mycoparasite. 相似文献
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J. M. WHIPPS 《The Annals of applied biology》1993,122(1):173-187
The biology, aetiology and epidemiology of Puccinia horiana, the cause of white rust disease of chrysanthemum (Chrysanthemum spp.) is reviewed in relation to current environmental, cultural and chemical methods for its control. Importantly, basidiospore release, germination and infection can take as little as 5 h at optimum r.h. (96%) and temperature (between 17–24°C). Recent developments using the fungus Verticillium lecanii for the control of insects on glasshouse-grown all-year-round chrysanthemums rely upon the maintenance of r.h. during night periods in excess of 95%, thus predisposing plants to white rust attack. However, V. lecanii is unusual in that it can also parasitise spores and fruiting structures of a range of rust fungi including P. horiana. This mycoparasitic ability is also reviewed, and against this background, the potential for an integrated insect and white rust control programme on all-year-round chrysanthemums is assessed. 相似文献
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Environmental Factors Affecting the Loss of Carbon from the Roots of Wheat and Barley Seedlings 总被引:6,自引:0,他引:6
The amounts of carbon released into soil from roots of wheatand barley seedlings grown under three environmental conditionsfor 3 weeks with shoots in constant specific activity 14CO2are reported. This carbon loss was measured as respired 14CO2from both the root and the accompanying microbial populationand as root derived 14C-labelled organic C compounds in thesoil. With a 16 h photoperiod, growth at 15 ?C constant or 18?C day/14 ?C night gave a loss of 3340% of the totalnet fixed carbon (defined as 14C retained in the plant plus14C lost from the root). The proportion of 14C translocatedto the roots that was released into the soil did not changewith temperature, so carbon distribution within the plant musthave changed. With a 12 h photoperiod and a temperature regimeof 18 ?C/14 ?C carbon loss from the roots was decreased to 1725%of the total fixed carbon. Key words: Cereals, Roots, Carbon loss 相似文献
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Effect of CO2 Concentration on Growth, Carbon Distribution and Loss of Carbon from the Roots of Maize 总被引:2,自引:0,他引:2
The effects of three ranges of CO2 concentration on growth,carbon distribution and loss of carbon from the roots of maizegrown for 14 d and 28 d with shoots in constant specific activity14CO2 are described. Increasing concentrations of CO2 led toenhancement of plant growth with the relative growth rate (RGR)of the roots affected more than the RGR of the shoots. Between16% and 21% of total net fixed carbon (defined as 14C retainedin the plant plus 14C lost from the root) was lost from theroots at all CO2 concentrations at all times but the amountsof carbon lost per unit weight of plant decreased with time.Possible mechanisms to account for these observations are discussed. Key words: Growth, Roots, Carbon loss, [CO2] 相似文献
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SUBSTRATE FLOW AND UTILIZATION IN THE RHIZOSPHERE OF CEREALS 总被引:3,自引:1,他引:2