共查询到20条相似文献,搜索用时 31 毫秒
1.
Linda T. A. van Diepen Erik A. Lilleskov Kurt S. Pregitzer R. Michael Miller 《Ecosystems》2010,13(5):683-695
Increased nitrogen (N) deposition caused by human activities has altered ecosystem functioning and biodiversity. To understand
the effects of altered N availability, we measured the abundance of arbuscular mycorrhizal fungi (AMF) and the microbial community
in northern hardwood forests exposed to long-term (12 years) simulated N deposition (30 kg N ha−1 y−1) using phospholipid fatty acid (PLFA) analysis and hyphal in-growth bags. Intra- and extraradical AMF biomass and total microbial
biomass were significantly decreased by simulated N deposition by 36, 41, and 24%, respectively. Both methods of extraradical
AMF biomass estimation (soil PLFA 16:1ω5c and hyphal in-growth bags) showed comparable treatment responses, and extraradical
biomass represented the majority of total (intra-plus extraradical) AMF biomass. N deposition also significantly affected
the microbial community structure, leading to a 10% decrease in fungal to bacterial biomass ratios. Our observed decline in
AMF and total microbial biomass together with changes in microbial community structure could have substantial impacts on the
nutrient and carbon cycling within northern hardwood forest ecosystems. 相似文献
2.
Effects of arbuscular mycorrhizal fungus (Glomus mosseae) on the accumulation and speciation of selenium (Se) in alfalfa, maize, and soybean were investigated by using Se(IV)-spiked
soil. Mycorrhizal inoculation decreased Se accumulation in roots and shoots of all the plants at Se spiked level of 0 or 2 mg kg−1, while an increased Se accumulation was observed in alfalfa shoots and maize roots and shoots at the spiked level of 20 mg kg−1. Concentration of inorganic Se (especially Se(VI)) in roots and shoots of the three plants was much higher in mycorrhizal
than non-mycorrhizal treatment. Mycorrhizal inoculation decreased the portion of total organic Se in plant tissues with the
exception of alfalfa and maize shoots at Se spiked level of 20 mg kg−1, in which organic Se portion did not reduced greatly (<5%) for mycorrhizal treatment. Mycorrhizal effects on alfalfa and
maize were more obvious than on soybean in terms of root colonization rate, biomass, and Se accumulation. 相似文献
3.
Galván GA Kuyper TW Burger K Keizer LC Hoekstra RF Kik C Scholten OE 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2011,122(5):947-960
The response of Allium
cepa, A. roylei, A. fistulosum, and the hybrid A. fistulosum × A. roylei to the arbuscular mycorrhizal fungus (AMF) Glomus intraradices was studied. The genetic basis for response to AMF was analyzed in a tri-hybrid A. cepa × (A. roylei × A. fistulosum) population. Plant response to mycorrhizal symbiosis was expressed as relative mycorrhizal responsiveness (R′) and absolute
responsiveness (R). In addition, the average performance (AP) of genotypes under mycorrhizal and non-mycorrhizal conditions
was determined. Experiments were executed in 2 years, and comprised clonally propagated plants of each genotype grown in sterile
soil, inoculated with G. intraradices or non-inoculated. Results were significantly correlated between both years. Biomass of non-mycorrhizal and mycorrhizal plants
was significantly positively correlated. R′ was negatively correlated with biomass of non-mycorrhizal plants and hence unsuitable
as a breeding criterion. R and AP were positively correlated with biomass of mycorrhizal and non-mycorrhizal plants. QTLs
contributing to mycorrhizal response were located on a linkage map of the A. roylei × A. fistulosum parental genotype. Two QTLs from A. roylei were detected on chromosomes 2 and 3 for R, AP, and biomass of mycorrhizal plants. A QTL from A. fistulosum was detected on linkage group 9 for AP (but not R), biomass of mycorrhizal and non-mycorrhizal plants, and the number of
stem-borne roots. Co-segregating QTLs for plant biomass, R and AP indicate that selection for plant biomass also selects for
enhanced R and AP. Moreover, our findings suggest that modern onion breeding did not select against the response to AMF, as
was suggested before for other cultivated species. Positive correlation between high number of roots, biomass and large response
to AMF in close relatives of onion opens prospects to combine these traits for the development of more robust onion cultivars. 相似文献
4.
We estimated the biomass and growth of arbuscular mycorrhizal (AM) mycelium in sand dunes using signature fatty acids. Mesh
bags and tubes, containing initially mycelium-free sand, were buried in the field near the roots of the dune grass Ammophila arenaria L. AM fungal mycelia were detected at a distance of about 8.5 cm from the roots after 68 days of growth by use of neutral
lipid fatty acid (NLFA) 16:1ω5. The average rate of mycelium extension during September and October was estimated as 1.2 mm
day−1. The lipid and fatty acid compositions of AM fungal mycelia of isolates and from sand dunes were analysed and showed all
to be of a similar composition. Phospholipid fatty acids (PLFAs) can be used as indicators of microbial biomass. The mycelium
of G. intraradices growing in glass beads contained 8.3 nmol PLFAs per mg dry biomass, and about 15% of the PLFAs in G. intraradices, G. claroideum and AM fungal mycelium extracted from sand dunes, consisted of the signature PLFA 16:1ω5. We thus suggest a conversion factor
of 1.2 nmol PLFA 16:1ω5 per mg dry biomass. Calculations using this conversion factor indicated up to 34 μg dry AM fungal
biomass per g sand in the sand dunes, which was less than one tenth of that found in an experimental system with Glomus spp. growing with cucumber as plant associate in agricultural soil. The PLFA results from different systems indicated that
the biomass of the AM fungi constitutes a considerable part of the total soil microbial biomass. Calculations based on ATP
of AM fungi in an experimental growth system indicated that the biomass of the AM fungi constituted approximately 30% of the
total microbial biomass.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
5.
We have studied how disturbance by ploughing and rotavation affects the carbon (C) flow to arbuscular mycorrhizal (AM) fungi
in a dry, semi-natural grassland. AM fungal biomass was estimated using the indicator neutral lipid fatty acid (NLFA) 16:1ω5,
and saprotrophic fungal biomass using NLFA 18:2ω6,9. We labeled vegetation plots with 13CO2 and studied the C flow to the signature fatty acids as well as uptake and allocation in plants. We found that AM fungal biomass
in roots and soil decreased with disturbance, while saprotrophic fungal biomass in soil was not influenced by disturbance.
Rotavation decreased the 13C enrichment in NLFA 16:1ω5 in soil, but 13C enrichment in the AM fungal indicator NLFA 16:1ω5 in roots or soil was not influenced by any other disturbance. In roots,
13C enrichment was consistently higher in NLFA 16:1ω5 than in crude root material. Grasses (mainly Festuca brevipila) decreased as a result of disturbance, while non-mycorrhizal annual forbs increased. This decreases the potential for mycorrhizal
C sequestration and may have been the main reason for the reduced mycorrhizal C allocation found in disturbed plots. Disturbance
decreased the soil ammonium content but did not change the pH, nitrate or phosphate availability. The overall effect of disturbance
on C allocation was that more of the C in AM fungal mycelium was directed to the external phase. Furthermore, the functional
identity of the plants seemed to play a minor role in the C cycle as no differences were seen between different groups, although
annuals contained less AM fungi than the other groups. 相似文献
6.
Zn uptake by maize plants may be affected by the presence of arbuscular mycorrhizal fungi (AMF). Collembola often play an important controlling role in the inter-relationship between AMF and host plants. The objective of this experiment was to examine whether the presence of Collembola at different densities (0.4 and 1 individuals g−1 dry soil) and their activity have any effect on Zn uptake by maize through the plant–AMF system. The presence of the AMF (Glomus intraradices) and of the Collembola species Folsomia candida was studied in a laboratory microcosm experiment, applying a Zn exposure level of 250 mg kg−1 dry soil. Biomass and water content of the plants were no different when only AMF or when both AMF and Collembola were present. In the presence of AMF the Zn content of the plant shoots and roots was significantly higher than without AMF. This effect was reduced by Collembola at both low and high density. High densities of Collembola reduced the extent of AMF colonization of the plant roots and hyphal length in the soil, but low densities had no effect on either. The results of this experiment reveal that the F. candida–G. intraradices interaction affects Zn uptake by maize, but the mechanisms are still unknown. 相似文献
7.
Cardenas-Flores A Cranenbrouck S Draye X Guillet A Govaerts B Declerck S 《Mycorrhiza》2011,21(5):443-449
The vegetative compatibility of the arbuscular mycorrhizal fungus (AMF) Glomus clarum MUCL 46238 was evaluated after continuous exposure to fenhexamid, a sterol biosynthesis inhibitor (SBI). Three lineages of
this AMF were cultured in vitro for five generations in association with Ri T-DNA transformed carrot roots in the presence
of 0, 5 or 10 mg l−1 of fenhexamid. Whatever the AMF generation, fenhexamid at 5 and 10 mg l−1 had no significant impact on the number of spores produced. However, vegetative compatibility tests (VCT) conducted with
spores from the three lineages, in the presence of 10 mg l−1 of fenhexamid, impacted the anastomosis process. At this concentration, the morphology of the germ tubes was modified. In
addition, nitrotetrazolium–trypan blue staining revealed that 10 mg l−l of fenhexamid significantly reduced the probability of fusion between the germ tubes regardless of the culture conditions
(i.e. absence or presence of fenhexamid) preceding the VCT. Our results demonstrated that spore production was not affected
by fenhexamid, while anastomosis between germ tubes was decreased. This suggested that high concentrations, accumulation or
repeated application of this SBI fungicide may impact the community structure of AMF in soil. 相似文献
8.
Deciduous forests may respond differently from coniferous forests to the anthropogenic deposition of nitrogen (N). Since fungi,
especially ectomycorrhizal (EM) fungi, are known to be negatively affected by N deposition, the effects of N deposition on
the soil microbial community, total fungal biomass and mycelial growth of EM fungi were studied in oak-dominated deciduous
forests along a nitrogen deposition gradient in southern Sweden. In-growth mesh bags were used to estimate the production
of mycelia by EM fungi in 19 oak stands in the N deposition gradient, and the results were compared with nitrate leaching
data obtained previously. Soil samples from 154 oak forest sites were analysed regarding the content of phospholipid fatty
acids (PLFAs). Thirty PLFAs associated with microbes were analysed and the PLFA 18:2ω6,9 was used as an indicator to estimate
the total fungal biomass. Higher N deposition (20 kg N ha−1 y−1 compared with 10 kg N ha−1 y−1) tended to reduce EM mycelial growth. The total soil fungal biomass was not affected by N deposition or soil pH, while the
PLFA 16:1ω5, a biomarker for arbuscular mycorrhizal (AM) fungi, was negatively affected by N deposition, but also positively
correlated to soil pH. Other PLFAs positively affected by soil pH were, e.g., i14:0, a15:0, 16:1ω9, a17:0 and 18:1ω7, while
some were negatively affected by pH, such as i15:0, 16:1ω7t, 10Me17:0 and cy19:0. In addition, N deposition had an effect
on the PLFAs 16:1ω7c and 16:1ω9 (negatively) and cy19:0 (positively). The production of EM mycelia is probably more sensitive
to N deposition than total fungal biomass according to the fungal biomarker PLFA 18:2ω6,9. Low amounts of EM mycelia covaried
with increased nitrate leaching, suggesting that EM mycelia possibly play an important role in forest soil N retention at
increased N input. 相似文献
9.
The influence of Ni on arbuscular mycorrhizal fungi (AMF) has not been studied yet. We tested the tolerance to Ni of five
AMF isolates from New Caledonian ultramafic soils. Spore germination indicated that these isolates were clearly more tolerant
to Ni than three other isolates from non-ultramafic soils. They were able to germinate at 30 μg g−1 Ni, whereas spores of the non-ultramafic isolates were totally inhibited at 15 μg g−1 Ni. Among the ultramafic isolates, two were obtained from roots of Ni-hyperaccumulating plants. Their tolerance to Ni was
clearly higher than all the other isolates. The proportion of germinated spores of the different isolates in contact with
ultramafic soils showed the same tendencies as those observed with Ni solutions. Tolerance to Ni increased when spores were
produced from mycorrhiza on plants grown on sand containing 20 μg g−1 Ni, in comparison with those produced on sand without Ni. These results indicate that the tolerance to Ni of AMF spores can
be induced by the presence of this metal in the substrate.
相似文献
Hamid AmirEmail: |
10.
Citrus plants strongly depend on mycorrhizal symbiosis because of less or no root hairs, but few reports have studied if their
root traits and physiological status could be altered by different arbuscular mycorrhizal fungi (AMF). In a pot experiment
we evaluated the effects of three AMF species, Glomus mosseae, G. versiforme and Paraglomus
occultum on the root traits and physiological variables of the trifoliate orange (Poncirus trifoliata L. Raf.) seedlings. Root mycorrhizal colonization was 58–76% after 180 days of inoculation. AMF association significantly
increased plant height, stem diameter, leaf number per plant, shoot and root biomass. Mycorrhizal seedlings also had higher
total root length, total root projected area, total root surface area and total root volume but thinner root diameter. Among
the three AMFs, greater positive effects on aboveground growth generally ranked as G. mosseae > P. occultum > G. versiforme, whilst on root traits as G. mosseae ≈ P. occultum > G. versiforme. Compared to the non-mycorrhizal seedlings, contents of chlorophyll, leaf glucose and sucrose, root soluble protein were
significantly increased in the mycorrhizal seedlings. In contrast, root glucose and sucrose, leaf soluble protein, and activity
of peroxidase (POD) in both leaves and roots were significantly decreased in the mycorrhizal seedlings. It suggested that
the improvement of root traits could be dependent on AMF species and be related to the AMF-induced alteration of carbohydrates
and POD. 相似文献
11.
Song Quan Wu Mei Lan Lian Ri Gao So Young Park Xuan Chun Piao 《In vitro cellular & developmental biology. Plant》2011,47(6):719-724
Astragalus membranaceus is one of the most widely used traditional medicinal herbs in China, but the time required to generate a useful product in
the field production is long. The growth of adventitious root cultures was compared between cultures grown in solid, liquid,
or a 5-L balloon-type bubble bioreactor. The maximum growth ratio (final dry weight/initial dry weight) was determined for
adventitious roots grown in the bioreactor. Studies carried out to optimize biomass production of adventitious roots compared
adventitious root growth from various inoculum root lengths, inoculum densities, and aeration volume in the bioreactors. The
maximum growth ratio occurred in treatments with a 1.5-cm inoculum root length, with 30 g (fresh weight) of inoculum per bioreactor
or with an aeration volume of 0.1 vvm (air volume/culture medium volume per min). The polysaccharide, saponin, and flavonoid
content of roots from bioreactor-grown cultures were compared to roots from field-grown plants grown for 1 and 3 yr. Total
polysaccharide content of adventitious roots in the bioreactor (30.0 mg g−1 dry weight (DW)) was higher than the roots of 1-yr-old (13.8 mg g−1 DW) and 3-yr-old (21.1 mg g−1 DW) plants in the field. Total saponin (3.4 mg g−1 DW) and flavonoid (6.4 mg g−1 DW) contents were nearly identical to 3-yr-old roots and higher than that of 1-yr-old roots under field cultivation. 相似文献
12.
Rhizospheric soil samples were taken from Puna native grasses along an altitudinal gradient. Biodiversity of arbuscular mycorrhizal
fungi (AMF) and associated bacteria was analyzed considering altitude and grasses photosynthetic pathways (metabolic type
C3, C4). Cultivation-dependent approaches were applied to obtain further information about the phylogeny of the dominating cultivable
aerobic–heterotrophic bacteria communities present in rhizospheric soil samples. In average, the bacterial count ranged between
1.30 × 102 and 8.66 × 104 CFU g−1 of dry weight of soil. Individual bacterial colonies of aerobic heterotrophic bacteria grown on R2A medium were morphologically
grouped and identified as typical soil bacteria belonging to the genera Bacillus, Pseudomonas, and Arthrobacter. Ten AMF taxa were found: Acaulospora sp., A. laevis, A. spinosa, Gigaspora sp., Gi. ramisporophora, Glomus sp., Gl. aggregatum, Gl. ambisporum, Gl. sinuosum, and Scutellospora biornata. AMF diversity decreased with altitude. 相似文献
13.
Langenfeld-Heyser R Gao J Ducic T Tachd P Lu CF Fritz E Gafur A Polle A 《Mycorrhiza》2007,17(2):121-131
In order to characterise the effect of ectomycorrhiza on Na+-responses of the salt-sensitive poplar hybrid Populus × canescens, growth and stress responses of Paxillus involutus (strain MAJ) were tested in liquid cultures in the presence of 20 to 500 mM NaCl, and the effects of mycorrhization on mineral
nutrient accumulation and oxidative stress were characterised in mycorrhizal and non-mycorrhizal poplar seedlings exposed
to 150 mM NaCl. Paxillus involutus was salt tolerant, showing biomass increases in media containing up to 500 mM NaCl after 4 weeks growth. Mycorrhizal mantle
formation on poplar roots was not affected by 150 mM NaCl. Whole plant performance was positively affected by the fungus because
total biomass was greater and leaves accumulated less Na+ than non-mycorrhizal plants. Energy dispersive X-ray microanalysis using transmission electron microscopy analysis of the
influence of mycorrhization on the subcellular localisation of Na+ and Cl− in roots showed that the hyphal mantle did not diminish salt accumulation in root cell walls, indicating that mycorrhization
did not provide a physical barrier against excess salinity. In the absence of salt stress, mycorrhizal poplar roots contained
higher Na+ and Cl− concentrations than non-mycorrhizal poplar roots. Paxillus involutus hyphae produced H2O2 in the mantle but not in the Hartig net or in pure culture. Salt exposure resulted in H2O2 formation in cortical cells of both non-mycorrhizal and mycorrhizal poplar and stimulated peroxidase but not superoxide dismutase
activities. This shows that mature ectomycorrhiza was unable to suppress salt-induced oxidative stress. Element analyses suggest
that improved performance of mycorrhizal poplar under salt stress may result from diminished xylem loading of Na+ and increased supply with K+. 相似文献
14.
Hadeer Lazim Houda Mankai Nedra Slama Insaf Barkallah Ferid Limam 《Journal of industrial microbiology & biotechnology》2009,36(4):531-537
The purpose of the present research is to study the production of thermophilic alkaline protease by a local isolate, Streptomyces sp. CN902, under solid state fermentation (SSF). Optimum SSF parameters for enzyme production have been determined. Various
locally available agro-industrial residues have been screened individually or as mixtures for alkaline protease production
in SSF. The combination of wheat bran (WB) with chopped date stones (CDS) (5:5) proved to be an efficient mixture for protease
production as it gave the highest enzyme activity (90.50 U g−1) when compared to individual WB (74.50 U g−1) or CDS (69.50 U g−1) substrates. This mixed solid substrate was used for the production of protease from Streptomyces sp. CN902 under SSF. Maximal protease production (220.50 U g−1) was obtained with an initial moisture content of 60%, an inoculum level of 1 × 108 (spore g−1 substrate) when incubated at 45°C for 5 days. Supplementation of WB and CDS mixtures with yeast extract as a nitrogen source
further increased protease production to 245.50 U g−1 under SSF. Our data demonstrated the usefulness of solid-state fermentation in the production of alkaline protease using
WB and CDS mixtures as substrate. Moreover, this approach offered significant benefits due to abundant agro-industrial substrate
availability and cheaper cost. 相似文献
15.
Subramanian KS Virgine Tenshia JS Jayalakshmi K Ramachandran V 《Indian journal of microbiology》2011,51(1):37-43
A greenhouse experiment was conducted to examine the changes in antioxidant enzyme activities of arbuscular mycorrhizal (AM)
fungus Glomus intraradices Schenck and Smith inoculated (M+) and non-inoculated (M−) maize (Zea mays L.) plants (variety COHM5) under varying levels of zinc (0, 1.25, 2.5, 3.75 and 5.0 mg kg−1). Roots and shoots sampled at 45 days after sowing (DAS) were estimated for its antioxidant enzymes (superoxide dismutase,
peroxidase) IAA oxidase, polyphenol oxidase, acid phosphatase and nutritional status especially P and Zn concentrations. Mycorrhizal
inoculation significantly (P ≤ 0.01) increased all the four antioxidant enzymes in both roots and shoots at 45 DAS regardless of Zn levels. All enzyme
activities except SOD increased progressively with increasing levels of Zn under M+ and M− conditions. The SOD activity got
decreased in roots and shoots at 2.5 and 3.75 mg Zn kg−1. Acid phosphatase activity in M+ roots and shoots were higher in all levels of Zn but the values decreased with increasing
levels of Zn particularly in roots. Mycorrhizal fungus inoculated plants had higher P and Zn concentrations in both stages
in comparison to non-inoculated plants. Our overall data suggest that mycorrhizal symbiosis plays a vital role in enhancing
activities of antioxidant enzymes and nutritional status that enables the host plant to sustain zinc deficient conditions. 相似文献
16.
We studied the nutritional modes of the orchid Serapias strictiflora and its mycorrhizal fungus Epulorhiza sp. using the differences in carbon isotopic composition (δ13C) of C3 orchid and C4 maize tissues. We found that if cultivated in substrate lacking any organic compounds, the mycorrhizal extraradical mycelia
(δ13C = −26.3 ± 0.2 ‰) developed well, despite being fully dependent on nutrition from orchid roots (δ13C = −28.6 ± 0.1 ‰). If the mycorrhizal fungus had additional access to and colonized decaying maize roots (δ13C = −14.6 ± 0.1 ‰), its isotopic composition (δ13C = −21.6 ± 0.4 ‰) reflected a mixture of biotrophy and saprotrophy. No statistically significant differences in δ13C of new storage tubers were found between Epulorhiza-associated orchids with (δ13C = -28.2 ± 0.1 ‰) and without access to maize roots (δ13C = −28.6 ± 0.2 ‰). We conclude that autotrophy is the predominant nutritional mode of mature S. strictiflora plants and that they supply their mycorrhizal fungus with substantial amount of carbon (69 ± 3 % of the fungus demand), even
if the fungus feeds saprotrophically. 相似文献
17.
Acquisition of Cu, Zn, Mn and Fe by mycorrhizal maize (Zea mays L.) grown in soil at different P and micronutrient levels 总被引:3,自引:0,他引:3
Sustainability of soil-plant systems requires, among other things, good development and function of mycorrhizal symbioses.
The effects of P and micronutrient levels on development of an arbuscular mycorrhizal fungus (AMF) and uptake of Zn, Cu, Mn
and Fe by maize (Zea
mays L.) were studied. A pot experiment with maize either inoculated or not with Glomus intraradices was conducted in a sand:soil (3 :1) mix (pH 6.5) in a greenhouse. Our goal was to evaluate the contribution of mycorrhizae
to uptake of Cu, Zn, Mn and Fe by maize as influenced by soil P and micronutrient levels. Two levels of P (10 and 40 mg kg−1 soil) and three levels of a micronutrient mixture: 0, 1X and 2X (1X contained, in mg kg−1 soil, 4.2 Fe, 1.2 Mn, 0.24 Zn, 0.06 Cu, 0.78 B and 0.036 Mo), were applied to pots. There were more extraradical hyphae at
the low P level than at the high P level when no micronutrients were added to the soil. Root inoculation with mycorrhiza and
application of micronutrients increased shoot biomass. Total Zn content in shoots was higher in mycorrhizal than non-mycorrhizal
plants grown in soils with low P and low or no micronutrient addition. Total Cu content in shoots was increased by mycorrhizal
colonization when no micronutrients were added. Mycorrhizal plants had lower Mn contents than non-mycorrhizal plants only
at the highest soil micronutrient level. AMF increased total shoot Fe content when no micronutrients were added, but decreased
shoot Fe when plants were grown at the high level of micronutrient addition. The effects of G. intraradices on Zn, Cu, Mn, and Fe uptake varied with micronutrient and P levels added to soil.
Accepted: 27 December 1999 相似文献
18.
The effect of the fungicide, chlorothalonil, on vesicular-arbuscular mycorrhizal (VAM) symbiosis was studied in a greenhouse
using Leucaena leucocephala as test plant. Chlorothalonil was applied to soil at 0, 50, 100 and 200 μg g−1. The initial soil solution P levels were 0.003 μg mL−1 (sub-optimal) and 0.026 μg mL−1 (optimal). After 4 weeks, the sub-optimal P level was raised to 0.6 μg mL−1 (high). The soil was either uninoculated or inoculated with the VAM fungus, Glomus aggregatum. The fungicide reduced mycorrhizal colonization of roots, development of mycorrhizal effectiveness, shoot P concentration
and uptake and dry matter yields at all concentrations tested, although the highest inhibitory effect was noted as the concentration
of the fungicide was increased from 50 to 100 μg g−1. Phosphorus applied after four weeks tended to partially offset the deleterious effects of chlorothalonil in plants grown
in the inoculated and uninoculated soil which suggests that the fungicide was interfering with plant P uptake. The results
suggest that the use of chlorothalonil should be restricted to levels below 50 μg g−1 if the benefits of mycorrhizal symbiosis are to be expected.
Contribution from Hawaii Institute of Tropical Agriculture and Human Resources Journal Series No. 3464.
Contribution from Hawaii Institute of Tropical Agriculture and Human Resources Journal Series No. 3464. 相似文献
19.
Sánchez Fernández JF González-López CV Acién Fernández FG Fernández Sevilla JM Molina Grima E 《Applied microbiology and biotechnology》2012,94(3):613-624
This paper focuses on modelling the growth rate and exopolysaccharides production of Anabaena sp. ATCC 33047, to be used in carbon dioxide removal and biofuels production. For this, the influence of dilution rate, irradiance
and aeration rate on the biomass and exopolysaccharides productivity, as well as on the CO2 fixation rate, have been studied. The productivity of the cultures was maximum at the highest irradiance and dilution rate
assayed, resulting to 0.5 gbio l−1 day−1 and 0.2 geps l−1 day−1, and the CO2 fixation rate measured was 1.0 gCO2 l−1 day−1. The results showed that although Anabaena sp. was partially photo-inhibited at irradiances higher than 1,300 μE m−2 s−1, its growth rate increases hyperbolically with the average irradiance inside the culture, and so does the specific exopolysaccharides
production rate. The latter, on the other hand, decreases under high external irradiances, indicating that the exopolysaccharides
metabolism hindered by photo-damage. Mathematical models that consider these phenomena have been proposed. Regarding aeration,
the yield of the cultures decreased at rates over 0.5 v/v/min or when shear rates were higher than 60 s−1, demonstrating the existence of thus existence of stress damage by aeration. The behaviour of the cultures has been verified
outdoors in a pilot-scale airlift tubular photobioreactor. From this study it is concluded that Anabaena sp. is highly recommended to transform CO2 into valuable products as has been proved capable of metabolizing carbon dioxide at rates of 1.2 gCO2 l−1 day−1 outdoors. The adequacy of the proposed equations is demonstrated, resulting to a useful tool in the design and operation
of photobioreactors using this strain. 相似文献
20.
Nakatani AS Mescolotti DL Nogueira MA Martines AM Miyauchi MY Stürmer SL Cardoso EJ 《Mycorrhiza》2011,21(6):515-522
The controlled disposal of tannery sludge in agricultural soils is a viable alternative for recycling such waste; however,
the impact of this practice on the arbuscular mycorrhizal fungi (AMF) communities is not well understood. We studied the effects
of low-chromium tannery sludge amendment in soils on AMF spore density, species richness and diversity, and root colonization
levels. Sludge was applied at four doses to an agricultural field in Rolandia, Paraná state, Brazil. The sludge was left undisturbed
on the soil surface and then the area was harrowed and planted with corn. The soil was sampled at four intervals and corn
roots once within a year (2007/2008). AMF spore density was low (1 to 49 spores per 50 cm3 of soil) and decreased as doses of tannery sludge increased. AMF root colonization was high (64%) and unaffected by tannery
sludge. Eighteen AMF species belonging to six genera (Acaulospora, Glomus, Gigaspora, Scutellospora, Paraglomus, and Ambispora) were recorded. At the sludge doses of 9.0 and 22.6 Mg ha−1, we observed a decrease in AMF species richness and diversity, and changes in their relative frequencies. Hierarchical grouping
analysis showed that adding tannery waste to the soil altered AMF spore community in relation to the control, modifying the
mycorrhizal status of soil and selectively favoring the sporulation of certain species. 相似文献