Fungi associated with roots of cucumber grown in different greenhouse root substrates

2005 ◽  
Vol 83 (1) ◽  
pp. 80-92 ◽  
Author(s):  
J G Menzies ◽  
D L Ehret ◽  
C Koch ◽  
J W Hall ◽  
K A Seifert ◽  
...  
Keyword(s):  
Root Zone ◽  
Pythium Aphanidermatum ◽  
Common Species ◽  
Penicillium Oxalicum ◽  
Trichoderma Spp ◽  
Pythium Irregulare ◽  
Penicillium Janthinellum ◽  
Cucumber Seedlings ◽  
Root Diseases ◽  
Cucumber Roots

Hydroponic soilless culture systems are commonly used in the greenhouse industry to mitigate soilborne root pathogens, but root diseases continue to be a major problem. A thorough knowledge of the root zone ecology of greenhouse crops is needed for the successful biological control of root diseases. The objectives of this study were to characterize the fungi associated with symptomless cucumber roots grown using different greenhouse substrates and to determine the effects of these fungi on plant growth. A total of 1250 fungal isolates were collected from cucumber roots grown in soil, rockwool, sawdust, or nutrient film and identified to genus and species. There was a greater density of fungal colonies on roots grown in soil than on roots grown in other substrates. Penicillium (87.2% of all isolates), Trichoderma (4.6%), and Pythium (3.0%) were the most common genera isolated from the cucumber roots. The two most common species were Penicillium oxalicum Currie & Thom (69.9%) and Penicillium janthinellum Biourge(13.4%). Pythium group F, Pythium group G, Pythium aphanidermatum (Edson) Fitzp., and Pythium irregulare Buisman were also isolated from healthy cucumber roots and all except Pythium group F were pathogenic to germinating cucumber seedlings. Treatment of cucumber seeds with Penicillium spp. resulted in significantly greater shoot length, root length, and seedling fresh weight of the resulting cucumber seedlings than did treatment with Trichoderma spp. One isolate of Penicillium janthinellum and one of Aspergillus sp. significantly improved survival of cucumber seedlings growing in a Pythium aphanidermatum-infested medium.Key words: hydroponics, Penicillium, Trichoderma, Pythium, Cucumis sativus.

scholarly journals Колонизация ризопланы корней огурцов микроорганизмами, входящими в состав микробного препарата «Эмбико®»

2013 ◽  
Vol 4 (2) ◽  
pp. 63-70
Author(s):  
V.S. Rzhevskaya ◽  
L.M. Teplitskaya ◽  
I.P. Oturina
Keyword(s):  
Microbial Consortium ◽  
Root Zone ◽  
Apical Part ◽  
Yeast Cells ◽  
Cultivated Plants ◽  
Yeast Saccharomyces Cerevisiae ◽  
Entire Volume ◽  
Cucumis Sativus L ◽  
Cucumber Seedlings

The ability of microorganisms belonging to the microbiological preparation “Embiko®” to colonize the rhizoplanes and rhizospheres of the Competitor and Phoenix Plus types of cucumber (Cucumis sativus L.) in vitro was investigated. The objects of study were the cultures of the lactic homofermentative streptobacteria Lactobacillus plantarum 20 and L. casei 6 and the homofermentative lactic streptococcus Lactococcus lactis 4/6, the yeast Saccharomyces cerevisiae 75 and the microbiological preparation “Embiko®” which includes the above-mentioned microorganisms. Germinated seeds were placed aseptically in biological test-tubes with starvation agar, where a suspension of the microbiological consortium of microorganisms had been added before. The ability of bacteria to colonize the root zone of plants was assessed visually by the intensity of formation of bacterial microcolonies on the surface of the roots of the seedlings and on the crushed micropreparations. The strain of S. cerevisiae colonized the entire volume of the agar along the entire length of the root, in the apical part of the root colonization was shown to be less active. With increasing duration of cultivation the intensity of colonization of the root zone by microorganisms was increased – colonies became larger. In various areas of the root the diameter of the cloud colonies S. cerevisiae was different in size. The strains of L. casei 6 and L. plantarum 20 colonized all the root zones, forming a cloud of small colonies around them. The strain of L. lactis 4/6 did not form colonies in the starvation agar and didn’t colonize the root surface of the cucumber seedlings. The microbiological preparation “Embiko®” colonized the root throughout its length, gradually narrowing in the apical zone. When inoculated with a pure culture of isolated strains the cloud was composed of monotypic colonies and looked homogeneous. When inoculated with the microbial consortium the cloud of the colonies looked heterogeneous, colonies of different sizes and colors were clearly visible. Under microscopy the preparations of the roots of the cucumber seedlings inoculated with the microbial preparation “Embiko®” yeast cells and cells of the lactic acid bacteria were found. This study of the ability of microorganisms from the preparation “Embiko®” to colonize the rhizoplanes and rhizospheres of roots of cultivated plants in vitro showed that the different strains of microorganisms form clouds of colonies around the roots which were distinct in turbidity and size: the strain of L. plantarum – almost transparent, and S. cerevisiae – very dense. The lowest growth rate of microorganisms was observed at the apex of the root, the highest – in the zone of root hair. Clearly, root exudates of plants are the main source of carbon and energy for the inoculated bacteria. The results indicate that the investigated microbial consortium has a promising potential to inoculate plants in order to stimulate their growth and development.

Effect of Naptalam on Chloramben Toxicity, Uptake, Translocation, and Metabolism in Cucumber (Cucumis sativus)

Weed Science ◽  
1991 ◽  
Vol 39 (1) ◽  
pp. 27-32
Author(s):  
Larry D. Knerr ◽  
Herbert J. Hopen ◽  
Nelson E. Balke
Keyword(s):  
Root Growth ◽  
Cucumis Sativus ◽  
Shoot Growth ◽  
Petri Dish ◽  
Dry Weight ◽  
Laboratory Studies ◽  
Cucumber Seedlings ◽  
Plant Parts ◽  
Cucumber Roots ◽  
Hydroponically Grown

Laboratory studies demonstrated that naptalam safens cucumber against the phytotoxic effects of chloramben. In petri dish studies, cucumber seedlings grown from seeds exposed to chloramben plus naptalam had greater shoot growth, root growth, and dry weight than seedlings grown from seeds exposed to chloramben alone. Naptalam also partially reversed the reduction in dry weight of various plant parts caused by exposure of roots of hydroponically grown seedlings to chloramben. More radioactivity from root-applied14C-chloramben remained in cucumber roots and less was translocated to shoots with a14C-chloramben plus naptalam treatment than with a14C-chloramben alone treatment. Naptalam appeared to influence chloramben metabolism. In various plant parts, concentrations of chloramben and its metabolites differed between the two treatments.

Control of root diseases with Trichoderma spp. in forest nurseries of Central Siberia.

2009 ◽  
pp. 197-202 ◽  
Author(s):  
T. I. Gromovykh ◽  
V. A. Tyulpanova ◽  
V. S. Sadykova ◽  
A. L. Malinovsky
Keyword(s):  
Trichoderma Spp ◽  
Central Siberia ◽  
Root Diseases ◽  
Forest Nurseries

Control of root zone pH is not effective in preventing Pythium aphanidermatum disease in cucumber

2010 ◽  
Vol 117 (6) ◽  
pp. 244-247
Author(s):  
Milena A. Dimova ◽  
Carmen Büttner ◽  
Jutta Gablers ◽  
Rita Grosch ◽  
Benayahu Bar-Yosef ◽  
...  
Keyword(s):  
Root Zone ◽  
Pythium Aphanidermatum

Evaluation of a method for quantification of Pythium aphanidermatum in cucumber roots at different temperatures and inoculum densities

2006 ◽  
Vol 113 (3) ◽  
pp. 113-119 ◽  
Author(s):  
M. A. Kyuchukova ◽  
C. Büttner ◽  
J. Gabler ◽  
B. Bar-Yosef ◽  
R. Grosch ◽  
...  
Keyword(s):  
Pythium Aphanidermatum ◽  
Different Temperatures ◽  
Cucumber Roots

scholarly journals Bacillus sp. L324-92 for Biological Control of Three Root Diseases of Wheat Grown with Reduced Tillage

1997 ◽  
Vol 87 (5) ◽  
pp. 551-558 ◽  
Author(s):  
Dal-Soo Kim ◽  
R. James Cook ◽  
David M. Weller
Keyword(s):  
Biological Control ◽  
Root Rot ◽  
Gaeumannomyces Graminis ◽  
Limiting Factors ◽  
Bacillus Species ◽  
Bacillus Sp ◽  
Pythium Irregulare ◽  
Root Diseases ◽  
Rhizoctonia Root Rot ◽  
Take All

Strain L324-92 is a novel Bacillus sp. with biological activity against three root diseases of wheat, namely take-all caused by Gaeumannomyces graminis var. tritici, Rhizoctonia root rot caused by Rhizoctonia solani AG8, and Pythium root rot caused mainly by Pythium irregulare and P. ultimum, that exhibits broad-spectrum inhibitory activity and grows at temperatures from 4 to 40°C. These three root diseases are major yieldlimiting factors for wheat in the U.S. Inland Pacific Northwest, especially wheat direct-drilled into the residue of a previous cereal crop. Strain L324-92 was selected from among approximately 2,000 rhizosphere/rhizoplane isolates of Bacillus species isolated from roots of wheat collected from two eastern Washington wheat fields that had long histories of wheat. Roots were washed, heat-treated (80°C for 30 min), macerated, and dilution-plated on 1/10-strength tryptic soy agar. Strain L324-92 inhibited all isolates of G. graminis var. tritici, Rhizoctonia species and anastomosis groups, and Pythium species tested on agar at 15°C; provided significant suppression of all three root diseases at 15°C in growth chamber assays; controlled either Rhizoctonia root rot, takeall, or both; and increased yields in field tests in which one or more of the three root diseases of wheats were yield-limiting factors. The ability of L324-92 to grow at 4°C probably contributes to its biocontrol activity on direct-drilled winter and spring wheat because, under Inland Northwest conditions, leaving harvest residues of the previous crop on the soil surface keeps soils cooler compared with tilled soils. These results suggest that Bacillus species with desired traits for biological control of wheat root diseases are present within the community of wheat rhizosphere microorganisms and can be recovered by protocols developed earlier for isolation of fluorescent Pseudomonas species effective against take-all.

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