Broomrape (Orobanche cumana Wallr.) can Influence the Microbial Cenosis in Sunflower Rhizosphere

Helia ◽  
2019 ◽  
Vol 42 (71) ◽  
pp. 145-159
Author(s):  
V. A. Lyakh ◽  
N. I. Kostyuchenko ◽  
I. A. Shevchenko

Abstract The bacterial and micromycete complexes in the rhizosphere of sunflower plants non-infected and infected with broomrape (Orobanche cumana Wallr.) have been compared. The investigations were carried out in the conditions of a stationary infectious field which was annually enriched with infected plant residues and broomrape seeds collected in different regions of Ukraine. Soil is leached, low-humic chernozem with acidic pH. The soil samples selected at the end of vegetation from the rhizosphere of healthy and infected with broomrape plants of sunflower breeding samples. The total number of bacteria found in the rhizosphere of sunflower plants infected by the parasite did not differ significantly from the control and was 11.7 and 12.1 million CFU / g of soil, respectively. The numbers of ammonifiers as well as bacterial microflora, using for its life mineral nitrogen, and pedotrophs and oligotrophs in the compared soil samples did not differ significantly, and generally corresponded to this type of soil. Although in general, both tested samples of soil were characterized by a low content of bacteria of the genus Azotobacter, the number of representatives of this genus in the rhizosphere of parasite-infected plants was somewhat less than in control (35 % and 21 %, respectively). However, unlike most bacteria, the number of micromycetes detected on Czapek-Dox and starch-ammonia agar media, in the rhizosphere of plants infected by broomrape almost twice exceeded the number of these microorganisms in the rhizosphere of healthy plants. Analysis of the generic and species composition of microscopic fungi showed that in the rhizosphere of sunflower plants infected by the parasite a very specific mycocenosis was formed that differ from a mycocenosis of healthy plants. This mycocenosis was characterized by a much smaller number of genera and species of micromycetes. At the same time for the structure of the fungal cenosis of diseased plants there was a characteristic increase in the proportion of toxin-forming fungi of the Aspergillus and Penicillium genera with active conidiogenesis. The obtained data testify not only to the differences in the microbial complexes in the rhizosphere of sunflower plants non-infected and infected by broomrape, but also indicate the direction of action of this parasite.

1998 ◽  
Vol 64 (2) ◽  
pp. 613-617 ◽  
Author(s):  
Morten Miller ◽  
Ansa Palojärvi ◽  
Andrea Rangger ◽  
Morten Reeslev ◽  
Annelise Kjøller

ABSTRACT Our objective was to determine if 4-methylumbelliferyl-labelled enzyme substrates could be used to detect and quantify specific components of chitinase and cellulase activities as specific indicators of the presence and activity of fungal biomass. The fluorogenic substrates 4-methylumbelliferyl (MUF)N-acetyl-β-d-glucosaminide and MUF β-d-lactoside were used for the detection and quantification of β-N-acetylglucosaminidase (EC 3.2.1.30 ) (NAGase) and endo 1,4-β-glucanase (EC 3.2.1.4 )/cellobiohydrolase (EC3.2.1.91 ) (CELase), respectively. Culture screenings on solid media showed a widespread ability to produce NAGase among a taxonomically diverse selection of fungi on media with and without added chitin. NAGase activity was expressed only in a limited number of bacteria and on media supplemented with chitin. The CELase activity was observed only in a limited number of fungi and bacteria. Bacterial CELase activity was expressed on agar media containing a cellulose-derived substrate. In soil samples, NAGase activity was significantly correlated with estimates of fungal biomass, based on the content of two fungus-specific indicator molecules, 18:2ω6 phospholipid fatty acid (PLFA) and ergosterol. CELase activity was significantly correlated with the PLFA-based estimate of fungal biomass in the soil, but no correlation was found with ergosterol-based estimates of fungal biomass.


2006 ◽  
pp. 76-82
Author(s):  
Zsolt Sándor

Sustainable plant growth, considering the difficulties of weed elimination, cannot be effective without the application of herbicides. However, these chemicals have enormous ecological implications, including effects on the microbiological communities of soils. It is advisable to use herbicides that have minimal secondary effects on the environment and soil-living microorganisms. In contrast, herbicides with prolonged growth stimulating or inhibiting effects are not suitable, because both types have strong influences on the number and activity of bacteria, thus causing changes in the ecological equilibrium.Preceding small plot experiments, laboratory tests were carried out to study the effect of herbicides used in maize cultures on the number of bacteria and growth of microscopic fungi.Substances that were observed to have stronger influences were applied in small plot experiments set up in the experimental garden of the Department of Plant Protection of the University of Debrecen. We studied the effects of four herbicides (Acenit A88EC, Frontier 900 EC, Merlin SC and Wing EC) on the microbiological properties of the soil. These herbicides were used in different concentrations in maize culture, and we investigated the effects in different soil layers.In the laboratory experiments, we determined the total number of bacteria and microscopic fungi and examined the growth of Aspergillus niger, Trichoderma sp. and Fusarium oxysporum on peptone-glucose agar containing herbicides.During the small plot experiments, soil samples were collected 3 times a year from 2-20 cm depth. The total numbers of bacteria and microscopic fungi were determined by plate dilution method, while the method of most probable number (Pochon method) was used to determine the numbers of nitrifying bacteria and cellulose decomposing bacteria. To evaluate the microbiological activity of the soil samples we measured carbon-dioxide release (after 10 days incubation), nitrate production (after 14 days incubation) and the concentration of C and N in the biomass.We can summarize our results as follows:• In laboratory experiments, herbicides caused a decrease in the number of bacteria and inhibited the growth of microscopic fungi.• Frontier 900 EC and Acenit A 880 EC had the strongest inhibiting effect on microorganisms.• In small plot experiments, herbicide treatment decreased the total number of bacteria and microscopic fungi.• Herbicides caused a significant increase in the number of nitrifying and cellulose decomposing bacteria.• Different herbicides containing the same active compound had similar influences on soil microoorganisms.• A significant increase was observed in the physiological processes of tolerant microorganisms surviving the effects of herbicides


2021 ◽  
Vol 55 (2 (255)) ◽  
pp. 172-180
Author(s):  
Iren V. Shahazizyan ◽  
Inessa M. Eloyan ◽  
Ruzanna E. Matevosyan ◽  
Siranoush G. Nanagyulyan

In this work we studied the effect of microscopic soil fungi on some lather samples. The species composition of micromycetes inhabiting the samples under study was revealed, and an assessment of the fungal resistance of the materials under study was given. In the process of work, species of microscopic soil fungi were isolated and identified from the soil. In order to determine the degree of resistance to fungi for the infection of samples, a water-spore suspension was obtained. The leather materials were partially destroyed by microscopic fungi, and mold resistance ranged from 2 to 3 on a 5-point scale.


Mycorrhiza ◽  
2020 ◽  
Vol 30 (6) ◽  
pp. 749-759
Author(s):  
Zerihun Belay ◽  
Mesele Negash ◽  
Janne Kaseva ◽  
Mauritz Vestberg ◽  
Helena Kahiluoto

Abstract The rapid conversion of native forests to farmland in Ethiopia, the cradle of biodiversity, threatens the diversity of the arbuscular mycorrhizal fungi (AMF) pivotal to plant nutrition and carbon sequestration. This study aimed to investigate the impact of this land-use change on the AMF species composition and diversity in southern Ethiopia. Soil samples were collected from nine plots in each of three land-use types: native forest, agroforestry, and khat monocropping. The plots of the three land-use types were located adjacent to each other for each of the nine replicates. Three 10 × 10m subplots per plot were sampled. AMF spores were extracted from the soil samples, spore densities were determined, and species composition and diversity were evaluated through morphological analysis. Both spore density and species richness were statistically significantly higher in the native forest than in the agroforestry plots with no clear difference to khat, whereas the true diversity (exponential of Shannon–Wiener diversity index) did not differ among the three land-use types due to high evenness among the species in agroforestry. In total, 37 AMF morphotypes belonging to 12 genera in Glomeromycota were found, dominated by members of the genera Acaulospora and Glomus. The highest isolation frequency index (78%) was recorded for Acaulospora koskei from native forest. Consequently, the agroforestry system did not appear to aid in preserving the AMF species richness of native forests relative to perennial monocropping, such as khat cultivation. In contrast, the native forest areas can serve as in situ genetic reserves of mycorrhizal symbionts adapted to the local vegetative, edaphic, and microbial conditions.


2019 ◽  
Vol 23 (10) ◽  
pp. 20-23
Author(s):  
L.V. Bryndina ◽  
O.V. Baklanova ◽  
N.M. Il’ina

Studies have been carried out to obtain combined biopreparats obtained on the basis of sewage sludge (WWS) and activated carbon (AC) from plant materials for cleaning soils from contaminants with herbicides. The content of organic matter in the settled sludge is 57.3 %. The organic matter of sewage sludge activates its enzymatic activity. Catalase activity in samples treated with combined sorbents, 2.5 to 2.9 times higher than in control soil samples. The combined use of WWS and activated carbons from plant residues significantly accelerates the decomposition of the herbicide. The presence of WWS increases the efficiency of detoxification of the herbicide (active substance metsulfuron-methyl) with active carbons by 1.7 times.


1932 ◽  
Vol 22 (4) ◽  
pp. 797-810 ◽  
Author(s):  
Jadwiga Ziemięcka

Summary and abstract1. The kneaded plate (plaque moulée) method of detecting deficiency in lime and available phosphate was applied to seventy-nine soil samples taken from the classical Rothamsted arable plots, and the Azotobacter population from some of these samples was estimated by counts on silica jelly.2. The silica jelly counts showed that Azotobacter cells were very much reduced in number, or even absent in soil receiving 86 lb. per acre or more of mineral nitrogen. It is suggested that this is due to competition with other organisms whose growth is stimulated by added nitrogen compounds.3. The kneaded-plate test correctly indicaṫed whether phosphate had been applied in soils receiving little or no nitrogen manures.4. In those soils receiving 86 lb. or more of mineral nitrogen, the kneaded-plate test usually showed little or no Azotobacter growth even in the presence of phosphate and calcium carbonate. This failure was probably due to the paucity of Azotobacter cells originally present in such soil samples. In some cases the test was modified by inoculating the sample with a culture of Azotobacter and it then gave correct indications as to phosphate content.


1952 ◽  
Vol 24 (3) ◽  
pp. 127-134
Author(s):  
Armi Kaila ◽  
Pertti Kivinen

In the experiments reported above the effect of organic material upon the aggregation of soil particles and the simultaneous immobilization of mineral nitrogen by microorganisms were studied. The relative amount of water-stable aggregates larger than 0.5 mm in diameter was considered to indicate the aggregation state of the soil samples. Probably, somewhat different results were obtained if the crumb formation had been determined by some other method, but it is not sure that these would have been more reliable. Since the incubation of soil samples were performed under aerobic conditions, and all the samples were mineral soils, it seemed justifiable to take the nitrate-nitrogen content of the soil samples to characterize the amount of mineral nitrogen in them. On the basis of the results the general conclusion may be drawn that the more favourable the conditions are for the development of an active and large microflora in the soil, the more intensively the crumb formation and the immobilization of nitrogen takes place, but also the destruction of aggregates begins the more rapidlv. This appeared to be true with regard to the indigenous fertility of soil as well as to the fertilization. Liming, however, did not improve the conditions in these experiment, probably due to the rather slight acidity of the soil samples used. Under otherwise similar conditions the larger amount of straw produced larger amount of aggregates, but the differences in the nitrate-nitrogen content of soil in the presence of various amounts of straw were neglibigle. Generally, the degree of immobilization of soil nitrogen seemed largely to depend on the properties of soil and on other environmental conditions, and nitrogen applications, theoretically enough for the needs of microorganisms that decomposed the straw, could not always prevent an intensive absorption of soil nitrogen. The crumb formation appeared to need mere energy-yielding material than the immobilization of nitrogen, or the destruction of crumbs occurred more rapidly than the nitrification of microbiologically bound nitrogen.


2020 ◽  
Vol 27 (1) ◽  
Author(s):  
Alvyra Šlepetienė ◽  
Kazimiež Duchovski ◽  
Jonas Volungevičius

The aim of this study – to evaluate the status of organic carbon (OC) under different land uses of soils formed in alluvial deposits. The soil samples were collected from 0–10, 10–20 and 20–30 cm depths in three field replicates.Three land uses were investigated: arable land, grassland and forest. The experimental site is situated near Surviliškis, Kėdainiai District (55°26′08.37′′N, 24°02′27.75′′Y) in Central Lowland of Lithuania. A total of 27 soil samples, collected from 0–10, 10–20 and 20–30 cm depths in three field replicates, were analysed for OC. The samples were prepared for analysis by removing plant residues, grinding and sieving through a 0.25 mm sieve. For all land uses, the highest content of OC was found in the upper 0–10 cm soil layer of the soil, with the highest values found in the forest land use. Fast-growing deciduous trees are an effective means to increase the content of OC in alluvial soil, especially in the 0–10 cm layer. The distribution of OC in the soil layers depended on the land use. Grassland and forest land uses allow OC to be preserved throughout the 0–30 cm layer, with less OC differentiation than in arable land. This could be attributed to the specificities of organic matter accumulation and degradation in different land uses. Not only the amount of labile organic carbon (similar to total organic carbon) was highest (0.392 g kg–1) in forest soil in the 0–10 cm layer, it also had a higher relative share in the total organic carbon (2.9%) than in other land uses – arable land and grassland (2.3–2.4%).


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