The influence of vesicular–arbuscular mycorrhizae on biomass production in willow

1986 ◽  
Vol 16 (1) ◽  
pp. 103-108 ◽  
Author(s):  
Georg F. Backhaus ◽  
Per Häggblom ◽  
Lars Owe Nilsson
Keyword(s):  
Arbuscular Mycorrhizal Fungi ◽  
Mycorrhizal Fungi ◽  
Arbuscular Mycorrhizae ◽  
Arbuscular Mycorrhizal ◽  
Dry Mass ◽  
Commercial Fertilizer ◽  
Available Nutrients ◽  
Vesicular Arbuscular Mycorrhizae ◽  
Vesicular Arbuscular ◽  
Fertilizer Solution

Cuttings of Salixdasyclados and Salixdaphnoides were grown in clay, peat, or sand under greenhouse conditions and inoculated with endomycorrhizal roots. Uninoculated cuttings in the same substrates served as controls. All plants were fertilized with a commercial fertilizer solution. Shoot dry mass and colonization by vesicular–arbuscular mycorrhizal fungi were measured during the experiment. At the end of the experiment growth of inoculated plants was significantly enhanced in peat (p < 0.001) and sand (p < 0.01), while in clay, no effect of inoculation on growth was found. In peat and sand increased growth of plants could be correlated with frequency of vesicular–arbuscular mycorrhizal colonization. No significant differences in concentrations of P or N in leaves and stems were noted between mycorrhizal and nonmycorrhizal plants at the end of the experiment. It is concluded that vesicular–arbuscular mycorrhizae stimulate growth of willow under greenhouse conditions despite application of easily available nutrients.

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.

The influence of fixation procedure on the ultrastructure of the host–endophyte interface of vesicular-arbuscular mycorrhizae

1977 ◽  
Vol 55 (1) ◽  
pp. 48-51 ◽  
Author(s):  
D. E. Carling ◽  
J. A. White ◽  
M. F. Brown
Keyword(s):  
Arbuscular Mycorrhizal Fungi ◽  
Granular Material ◽  
Mycorrhizal Fungi ◽  
Arbuscular Mycorrhizae ◽  
Arbuscular Mycorrhizal ◽  
Interfacial Zone ◽  
Fixation Procedure ◽  
Vesicular Arbuscular Mycorrhizal Fungi ◽  
Host Cytoplasm ◽  
Vesicular Arbuscular

The ultrastructure of the interfacial zone which separates the intracellular structures of vesicular-arbuscular mycorrhizal fungi from host cytoplasm has been described in a variety of ways by recent investigators. Evidence is presented here which suggests that previous interpretations of the ultrastructure of the interfacial zone have been based on an artifact of fixation. Using an improved procedure, a dense, granular material was found in the interfacial zone. This material was preserved by simultaneous glutaraldehyde-osmium fixation but not by conventional prefixation and postfixation in glutaraldehyde and osmium, respectively.

A new method for observing the morphology of vesicular–arbuscular mycorrhizae

1984 ◽  
Vol 62 (10) ◽  
pp. 2128-2134 ◽  
Author(s):  
M. C. Brundrett ◽  
Y. Piché ◽  
R. L. Peterson
Keyword(s):  
Arbuscular Mycorrhizal Fungi ◽  
Mycorrhizal Fungi ◽  
Arbuscular Mycorrhizae ◽  
Arbuscular Mycorrhizal ◽  
Staining Procedure ◽  
Acid Fuchsin ◽  
Vesicular Arbuscular Mycorrhizal Fungi ◽  
Vesicular Arbuscular ◽  
Contrast Microscopy ◽  
Interference Contrast Microscopy

A new procedure using chlorazol black E has been developed for staining vesicular–arbuscular mycorrhizal fungi in cleared roots. In a comparative study, chlorazol black E was found to be much superior to previously used stains (acid fuchsin, trypan blue, aniline blue) for showing details of internal hyphae and particularly arbuscules. This clearing and staining procedure, combined with Nomarski interference contrast microscopy, revealed details of arbuscule structure not evident with previous techniques. Field-collected samples were also stained well by this procedure. The procedure should allow more accurate assessment of roots for colonization by vesicular–arbuscular mycorrhizal fungi.

Colonization of crop and pasture species with vesicular–arbuscular mycorrhizal fungi and a negative correlation with root infection by Bipolaris sorokiniana

1989 ◽  
Vol 67 (3) ◽  
pp. 687-693 ◽  
Author(s):  
J. P. Thompson ◽  
G. B. Wildermuth
Keyword(s):  
Arbuscular Mycorrhizal Fungi ◽  
Mycorrhizal Fungi ◽  
Arbuscular Mycorrhizae ◽  
Arbuscular Mycorrhizal ◽  
Bipolaris Sorokiniana ◽  
Mycorrhizal Colonization ◽  
Root Infection ◽  
Vesicular Arbuscular Mycorrhizal Fungi ◽  
Vesicular Arbuscular ◽  
Mycorrhizal Roots

The roots of 37 crop and pasture species were assessed for vesicular–arbuscular mycorrhizae in a vertisol containing spores of vesicular–arbuscular mycorrhizal fungi mainly Glomus mosseae, and of the pathogenic fungus, Bipolaris sorokiniana. The level of mycorrhizal colonization of different hosts is an important aspect of managing crop sequences to reduce "long fallow disorder." All species except rapeseed in the Cruciferae and lupin in the Leguminosae were hosts, although perennial rye grass in the Gramineae had only very slight colonization. The percent root length colonized as assessed by the grid-intersect method ranged up to 60.5% for wheat in the winter series and up to 98.4% for mungbean in the summer series. Greatest weights of mycorrhizal roots were produced by phalaris grass, chickpea, safflower, cocksfoot, lucerne, and barley in the winter series and by lucerne, maize, canary seed, Sudan grass, grain sorghum, and buffel grass in the summer series. Although Gramineae as a group tends to have fine roots with a low percentage of mycorrhizal colonization, the total weight of mycorrhizal roots can be large, and they should be at least equal to legumes in effectiveness for breaking long fallow disorder. Percentages of mycorrhizal colonization determined by the grid-intersect and three slide methods were generally well correlated with one another, but all were less strongly correlated with weight of mycorrhizal roots for winter crops and were entirely uncorrelated with weight of mycorrhizal roots for summer crops. Significant inverse-regression relationships were obtained between infection of root segments (but not of stem bases) by B. sorokiniana and root colonization with vesicular–arbuscular mycorrhizae, indicating that vesicular–arbuscular mycorrhizal fungi antagonise root infection by B. sorokiniana.

Utilization of vesicular–arbuscular mycorrhizal fungi in agriculture

1983 ◽  
Vol 61 (3) ◽  
pp. 1015-1024 ◽  
Author(s):  
J. A. Menge
Keyword(s):  
Mycorrhizal Fungi ◽  
Large Scale ◽  
Arbuscular Mycorrhizae ◽  
Crop Yields ◽  
Natural Populations ◽  
Arbuscular Mycorrhizal ◽  
Vam Fungi ◽  
Vesicular Arbuscular Mycorrhizae ◽  
Vesicular Arbuscular ◽  
Direct Inoculation

Commercial use of vesicular–arbuscular mycorrhizae (VAM) may be an alternative to rising agricultural energy and fertilizer costs. Vesicular–arbuscular mycorrhizae may be able to increase crop yields while reducing fertilizer and energy inputs. Since mycorrhizal fungi are naturally present in most soils, their unique fertilizer abilities are already being utilized by most crop plants. Commercial uses of VA mycorrhizal fungi are therefore currently restricted to situations where the natural populations of VAM fungi have been destroyed or damaged such as in fumigated or chemically treated areas, greenhouses, and disturbed areas such as coal spoils, strip mines, waste areas, or road beds. Commercial production of VAM inoculum is presently being attempted at several locations in the U.S. Vesicular–arbuscular mycorrhizal inoculum is produced by growing VAM fungi on the roots of suitable host plants under aseptic greenhouse conditions The inoculum consists of the host-plant growth medium and host roots associated with VAM hyphae and spores which have been ground and dried. Most large-scale uses of VAM involve the establishment of the mycorrhizae on seedlings which will be transplanted to the field. Large-scale methods for direct inoculation with VAM have not yet been devised, but in small trials, layering, banding, broadcasting, and pelleting seed with VAM inoculum have proved effective. Methods for determining what soils are most likely to benefit from applications of VAM fungi are available. The potential for employing VAM fungi on a wide scale in agriculture is dependent on the development of crop growth-promoting strains of VAM which are superior to native soil populations of VAM fungi.

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