Tripartite associations in snowbrush (Ceanothus velutinus): effect of vesicular–arbuscular mycorrhizae on growth, nodulation, and nitrogen fixation

1981 ◽  
Vol 59 (1) ◽  
pp. 34-39 ◽  
Author(s):  
S. L. Rose ◽  
C. T. Youngberg
Keyword(s):  
Host Plant ◽  
Mycorrhizal Fungi ◽  
Arbuscular Mycorrhizae ◽  
Nitrogenase Activity ◽  
Mycorrhizal Fungus ◽  
Nodule Formation ◽  
Nitrogen Fixing ◽  
Symbiotic Associations ◽  
Vesicular Arbuscular ◽  
Va Mycorrhizal Fungi

Symbiotic associations were established between nitrogen-fixing nonleguminous (actinorrhizal) snowbrush (Ceanothus velutinus Dougl.) seedlings and two categories of microorganisms: vesicular–arbuscular (VA) mycorrhizal fungi and a filamentous actinomycete capable of inducing nodule formation. The actinomycete is housed in nodules where fixation of atmospheric dinitrogen occurs and is made available to the host plant; the mycorrhizal fungus is both inter- and intra-cellular within the root tissue and may be found within the nodules. The two major nutrients, N and P, are made available and can be supplied to the host plant by these two symbiotic microorganisms. The root system of snowbrush seedlings was dually colonized by VA mycorrhizal fungi and a nitrogen-fixing actinomycete and the possibility of a direct interaction between the endophytes in the symbioses was investigated. Dually infected plants showed increases in total dry weight of shoots and roots, number of nodules, weight of nodular tissue, as well as higher levels of N, Ca2+, and P, and an increase in nitrogenase activity as measured by acetylene reduction.

Influence of increasing soil phosphorus levels on interactions between vesicular–arbuscular mycorrhizae and Rhizobium in soybeans

1980 ◽  
Vol 58 (20) ◽  
pp. 2200-2205 ◽  
Author(s):  
S. Asimi ◽  
V. Gianinazzi-Pearson ◽  
S. Gianinazzi
Keyword(s):  
Plant Growth ◽  
Arbuscular Mycorrhizae ◽  
Nitrogenase Activity ◽  
Mycorrhizal Fungus ◽  
Growth Stimulation ◽  
Growth And Yield ◽  
Nodule Formation ◽  
Growth Responses ◽  
Vesicular Arbuscular ◽  
Phosphate Fertilization

Growth and yield increases, obtained in nodulated soybeans growing in unamended sterile soil by inoculation with the vesicular–arbuscular (VA) mycorrhizal fungus Glomus mosseae, were accompanied by improved P uptake, lower root to shoot ratios, better nodulation with higher nitrogenase activity, and modifications in the pattern of the latter during plant growth. Stimulation of nitrogenase activity occurred early in plant development and preceded plant growth responses by about 2 weeks. Phosphate fertilization increased yield, percent P but not percent N of both mycorrhizal and nonmycorrhizal soybeans, and also modified the pattern and amount of nitrogenase activity during plant growth. Additions of 0.25 g KH2PO4/kg to the soil eliminated the mycorrhizal effect on plant growth, but nodule formation and nitrogenase activity were still significantly stimulated by the mycorrhizal infection. Mycorrhizal effects on nodulation were eliminated with 0.5 g KH2PO4 and on nitrogenase activity with the addition of 1.0 g KH2PO4. These higher levels of phosphate fertilization considerably diminished infection and, in particular, fungal spread within the roots.

Vesicular-arbuscular mycorrhizae of Easter lily in the northwestern United States

1977 ◽  
Vol 23 (12) ◽  
pp. 1663-1668 ◽  
Author(s):  
R. N. Ames ◽  
R. G. Linderman
Keyword(s):  
Root System ◽  
Mycorrhizal Fungi ◽  
Arbuscular Mycorrhizae ◽  
Lilium Longiflorum ◽  
Growing Season ◽  
Fungal Species ◽  
Easter Lily ◽  
Vesicular Arbuscular ◽  
Va Mycorrhizal Fungi ◽  
Isolated Species

The vesicular-arbuscular (VA) mycorrhizal fungi of commercially grown Easter lily (Lilium longiflorum Thunb.) were studied. Soil and root samples were collected monthly from March through September 1975 from five fields in the coastal area of southern Oregon and northern California. Soil seivings were inoculated onto clover, onion, and lily to cause infections resulting in the production of many new mycorrhizal spores facilitating identification. Four VA mycorrhizal species were found: Acaulospora trappei, A. elegans, Glomus monosporus, and G. fasciculatus. All four VA species infected Easter lily, clover, and onion. Acaulospora trappei and G. fasciculatus were the most commonly isolated species from all five fields.Mycorrhizal infections in roots of field-grown lilies were sparse and presumably young in March and gradually increased in size and number until September when bulbs were harvested. Over 75% of each root system became infected with mycorrhizae in fields with all four fungal species, and those levels were reached by July. In fields with only two mycorrhizal species, usually 50% or less of each root system was infected, even by the end of the growing season.

Bacteria and actinomycetes associated with pot cultures of vesicular–arbuscular mycorrhizas

1987 ◽  
Vol 33 (12) ◽  
pp. 1069-1073 ◽  
Author(s):  
Jean Secilia ◽  
D. J. Bagyaraj
Keyword(s):  
Mycorrhizal Fungi ◽  
Xanthomonas Campestris ◽  
Mycorrhizal Fungus ◽  
Arbuscular Mycorrhizas ◽  
Bacterial Populations ◽  
Phytopathogenic Bacterium ◽  
Nitrogen Fixers ◽  
Acaulospora Laevis ◽  
Vesicular Arbuscular ◽  
Va Mycorrhizal Fungi

The bacteria and actinomycetes associated with pot cultures of the vesicular–arbuscular (VA) mycorrhizal fungi Glomus fasciculatum, Gigaspora margarita, Acaulospora laevis, Sclerocystis dussii, and of a control without VA mycorrhizal fungus were studied. Total bacterial populations and numbers of nitrogen fixers were significantly higher in the pot cultures of G. fasciculatum, G. margarita, and S. dussii. There were more gram-negative bacteria in these three pot cultures. Spore formers decreased and urea hydrolysers increased in all four pot cultures. The pot cultures of A. laevis harboured fewer bacteria compared with the control. The occurrence of amino acid requiring bacteria increased in all the pot cultures, except that of A. laevis. Pot cultures of G. fasciculatum and A. laevis had significantly more actinomycetes than the control. Streptomyces, series Rectus flexibilis, was selectively stimulated. These two pot cultures also had more actinomycetes antagonistic to the pathogens Fusarium solani and Pseudomonas solanacearum than the control. Glomus margarita pot cultures harboured more actinomycetes antagonistic to the phytopathogenic bacterium Xanthomonas campestris pv. vignicola.

Phytohormone changes in Bouteloua gracilis infected by vesicular–arbuscular mycorrhizae. II. Altered levels of gibberellin-like substances and abscisic acid in the host plant

1982 ◽  
Vol 60 (4) ◽  
pp. 468-471 ◽  
Author(s):  
Michael F. Allen ◽  
Thomas S. Moore Jr. ◽  
Martha Christensen
Keyword(s):  
Abscisic Acid ◽  
Mycorrhizal Fungi ◽  
High Performance ◽  
Arbuscular Mycorrhizae ◽  
Mycorrhizal Fungus ◽  
Arbuscular Mycorrhizal ◽  
Bouteloua Gracilis ◽  
Defined Medium ◽  
Liquid Chromatograph ◽  
Vesicular Arbuscular

Bouteloua gracilis (H.B.K.) Lag ex Steud (blue grama) was grown in a defined medium with and without the vesicular–arbuscular mycorrhizal fungus Glomus fasciculatus for 50 days. Levels of gibberellin-like substances (GA) and a substance like abscisic acid (ABA) of mycorrhizal and nonmycorrhizal plants were measured using the barley half-seed bioassay and UV detection of peaks from a μ-Bondapak–NH2 anion exchange high-performance liquid chromatograph column, respectively. Infection by mycorrhizal fungi resulted in significantly increased GA activity in the leaves and a tendency for decreased activity in the roots. ABA concentration decreased in leaves of infected plants but remained unchanged in roots. Increased levels of GA with reduced ABA in the leaves may alter substantially the physiology of B. gracilis.

Mycorrhizal associations of some actinomycete nodulated nitrogen-fixing plants

1980 ◽  
Vol 58 (13) ◽  
pp. 1449-1454 ◽  
Author(s):  
Sharon L. Rose
Keyword(s):  
United States ◽  
Mycorrhizal Fungi ◽  
The United States ◽  
Flowering Plants ◽  
Atmospheric Nitrogen ◽  
Nitrogen Fixing ◽  
Mycorrhizal Associations ◽  
Vesicular Arbuscular ◽  
Distributional Patterns ◽  
Va Mycorrhizal Fungi

Flowering plants that fix atmospheric nitrogen in actinomycete-induced nodules were sampled for mycorrhizal associates. Twenty-five species from seven families (Betulaceae, Casuarinaceae, Myricaceae, Rhamnaceae, Rosaceae, Elaeagnaceae, and Datiscaceae) were examined. Samples included were from the United States, Japan, and England.Both mycorrhizae and actinomycete-induced nitrogen-fixing nodules were present on: (i) four species of Alnus, (ii) two species of Casuarina, (iii) eight species of Ceanothus, (iv) four species of Myrica, (v) and one species each of Shepherdia, Hippophae, Cercocarpus, Dryas, Purshia, Comptonia, and Datisca. Soil sieving revealed species of the following genera of vesicular–arbuscular (VA) mycorrhizal fungi: Gigaspora, Glomus, Acaulospora, Entrophospora, and three undescribed taxa soon to be described. Spores of species in the first three genera of fungi were found most frequently from soil sievings. The VA mycorrhizal fungi exhibited distinct distributional patterns when associated with nonleguminous nitrogen-fixing hosts in different habitats. The ectomycorrhizae were not characterized.

scholarly journals Effect of Vesicular–Arbuscular Mycorrhizal Fungi on Rooting of Sciadopitys verticillata Sieb & Zucc. Cuttings

HortScience ◽  
1995 ◽  
Vol 30 (1) ◽  
pp. 133-134 ◽  
Author(s):  
D.D. Douds ◽  
G. Bécard ◽  
P.E. Pfeffer ◽  
L.W. Doner ◽  
T.J. Dymant ◽  
...  
Keyword(s):  
Arbuscular Mycorrhizal Fungi ◽  
Host Plant ◽  
Mycorrhizal Fungi ◽  
Arbuscular Mycorrhizal Fungus ◽  
Mycorrhizal Fungus ◽  
Arbuscular Mycorrhizal ◽  
Root Number ◽  
Vesicular Arbuscular Mycorrhizal Fungi ◽  
Vesicular Arbuscular ◽  
Sciadopitys Verticillata

A vesicular–arbuscular mycorrhizal fungus in a peat-based medium significantly increased survival, callus development, and rooting percentage of Sciadopitys verticillata cuttings over noninoculated cuttings. The presence of a nurse host plant for the mycorrhizal fungi to colonize in the absence of S. verticillata roots decreased survival and rooting percentage, but not callus development, relative to the fungus without the nurse host. Among plants that did produce roots, however, there were no significant differences among treatments for root number, weight, or length per cutting.

Vesicular–arbuscular endomycorrhizal associations of some desert plants of Baja California

1981 ◽  
Vol 59 (6) ◽  
pp. 1056-1060 ◽  
Author(s):  
Sharon L. Rose
Keyword(s):  
Mycorrhizal Fungi ◽  
Sonoran Desert ◽  
Baja California ◽  
Fungal Spores ◽  
Desert Plants ◽  
Endemic Plants ◽  
Mycorrhizal Associations ◽  
Glomus Spp ◽  
Vesicular Arbuscular ◽  
Va Mycorrhizal Fungi

Endemic plants of the Sonoran Desert of Baja California were sampled for mycorrhizal associations. Eight of the 10 plant species examined were colonized by vesicular–arbuscular (VA) mycorrhizal fungi. Soil sievings revealed chlamydospores of three VA mycorrhizal Glomus spp.; G. microcarpus, G. fasciculatus, and G. macrocarpus. At the time of sampling, the populations of VA fungal spores in the soil were low, with one to five chlamydospores per 100 g soil sample.

Susceptibility of barley cultivars to vesicular-arbuscular mycorrhizal fungi

1995 ◽  
Vol 75 (1) ◽  
pp. 269-275 ◽  
Author(s):  
S. M. Boyetchko ◽  
J. P. Tewari
Keyword(s):  
Mycorrhizal Fungi ◽  
Mycorrhizal Fungus ◽  
Arbuscular Mycorrhizal ◽  
Growth And Yield ◽  
Vam Fungi ◽  
University Of Alberta ◽  
Barley Cultivars ◽  
Vesicular Arbuscular ◽  
Glomus Species ◽  
The University

The relative susceptibility of selected barley cultivars produced in western Canada to vesicular-arbuscular mycorrhizal (VAM) fungi under field and greenhouse conditions was evaluated in this study. Cultivars tested under field conditions at the University of Alberta and Lacombe research stations showed no significant differences in VAM colonization of barley roots; colonization was light. Greenhouse trials at the University of Alberta with eight cultivars inoculated with individual mycorrhizal species illustrated significant differences among the barley cultivars in their reactions to Glomus dimorphicum, G. intraradices, and G. mosseae. Distinct differences were observed in the ability of each Glomus species to colonize the barley cultivars. The VAM fungi increased growth and yield in some cultivars, depending on the Glomus species. This study indicates that a degree of host-specificity exists in VAM fungi and that the host-mycorrhizal fungus genotypes may influence the effectiveness of the symbiosis. Key words: Barley, cultivars, susceptibility, VA mycorrhizal fungi

The effect of soil pH on the formation of VA mycorrhizas by two species of Glomus

Soil Research ◽  
1985 ◽  
Vol 23 (2) ◽  
pp. 253 ◽  
Author(s):  
LK Abbott ◽  
AD Robson
Keyword(s):  
Soil Ph ◽  
Mycorrhizal Fungi ◽  
Subterranean Clover ◽  
Vesicular Arbuscular ◽  
Va Mycorrhizal Fungi ◽  
Four Levels ◽  
Ph Level ◽  
Ph Range ◽  
Spread Of Infection ◽  
Glomus Sp

Two species of vesicular-arbuscular (VA) mycorrhizal fungi differed in their ability to infect subterranean clover roots when soil pH was changed by liming. In a glasshouse experiment, Glomus fasciculatum infected extensively at each of four levels of soil pH (range 5.3-7.5). Glomus sp. (WUM 16) only infected extensively at the highest pH level. Liming the soil depressed plant growth, but this effect was almost entirely overcome by inoculation with G. fasciculatum. In the second experiment, Glomus sp. (WUM 16) failed to spread from existing infection within roots of subterranean clover when soil pH was 5.3 or lower. The lack of spread of infection was associated with an inability of hyphae of this fungus to grow in the soil used unless it was limed to give a pH at least greater than 5.3.

Development of vesicular–arbuscular mycorrhizae in a young sweetgum plantation

1985 ◽  
Vol 15 (6) ◽  
pp. 1061-1064 ◽  
Author(s):  
Paul P. Kormanik
Keyword(s):  
Mycorrhizal Fungi ◽  
Arbuscular Mycorrhizae ◽  
Fungal Spores ◽  
Arbuscular Mycorrhizal ◽  
Available Phosphorus ◽  
Vesicular Arbuscular Mycorrhizae ◽  
Vesicular Arbuscular ◽  
Mycorrhizal Development ◽  
Crown Closure ◽  
Arbuscular Mycorrhizal Fungal

Sweetgum seedlings with vesicular–arbuscular mycorrhizae formed by Glomusetunicatum or Glomusdeserticola in nursery soil with 30 ppm available phosphorus (P) and nonmycorrhizal seedlings grown in nursery soil with 800 ppm available P were outplanted and whole trees were excavated periodically over the next 5 years in the plantation to follow mycorrhizal development. Four months after outplanting, roots of all initially nonmycorrhizal seedlings had formed vesicular–arbuscular mycorrhizae and the degree of root colonization was comparable to that of initially vesicular–arbuscular mycorrhizal seedlings. New feeder roots did not develop on seedlings of any treatment until almost 5 months after planting. By the end of the first growing season and for the remainder of the study, vesicular–arbuscular mycorrhizae development was approximately the same on all seedlings. The proportion of feeder roots colonized by vesicular–arbuscular mycorrhizal fungi stabilized at 65 to 70%; approximately 56% of the cortical tissues of all feeder roots were colonized with arbuscles, vesicles, and hyphae. Periodic assays of the soil in the plantation showed that vesicular–arbuscular mycorrhizal fungal spores gradually declined from an initial high of 3600 spores to 620 spores per 100-cm3 soil sample after 5 years. This decline was probably caused by crown closure of the sweetgum trees which gradually suppressed understory vegetation.

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