Survey of vesicular–arbuscular mycorrhizae in lettuce production in relation to management and soil factors

1998 ◽  
Vol 130 (2) ◽  
pp. 173-182 ◽  
Author(s):  
R. L. MILLER ◽  
L. E. JACKSON
Keyword(s):  
Arbuscular Mycorrhizae ◽  
Management Practices ◽  
Root Colonization ◽  
Soil Conditions ◽  
Multivariate Statistical ◽  
Spore Number ◽  
Vesicular Arbuscular Mycorrhizae ◽  
Wide Range ◽  
Vesicular Arbuscular ◽  
Vam Colonization

The occurrence of vesicular–arbuscular mycorrhizae (VAM) root colonization and spore number in soil was assessed for 18 fields under intensive lettuce (Lactuca sativa L.) production in California during July and August of 1995. Data on management practices and soil characteristics were compiled for each field, and included a wide range of conditions. The relationship between these factors and the occurrence of VAM in these fields was explored with multivariate statistical analysis. VAM colonization of lettuce tended to decrease with the use of chemical inputs, such as pesticides and high amounts of P and N fertilizers. Addition of soil organic matter amendments, the occurrence of other host crops in the rotation, and soil carbon[ratio ]phosphorus and carbon[ratio ]nitrogen ratios, were positively associated with VAM colonization of lettuce roots. The number of VAM spores in soil was strongly correlated with the number of other host crops in the rotation, the occurrence of weed hosts and sampling date, but was more affected by general soil conditions than by management inputs. Higher total soil N, C and P, as well as CEC, were inversely related to soil spore number. A glasshouse study of the two primary lettuce types sampled in the field showed no significant differences in the extent of root colonization under similar growing conditions. The results of this study are compared with other studies on the effects of management and soil conditions on mycorrhizal occurrence in agriculture.

Occurrence and isolation of vesicular–arbuscular mycorrhizae in cropped field soils of Saskatchewan, Canada

1993 ◽  
Vol 39 (6) ◽  
pp. 567-575 ◽  
Author(s):  
Narayan C. Talukdar ◽  
James J. Germida
Keyword(s):  
Arbuscular Mycorrhizae ◽  
Arbuscular Mycorrhizal ◽  
Triticum Aestivum L ◽  
Wheat Roots ◽  
Wheat Field ◽  
Vesicular Arbuscular Mycorrhizae ◽  
Vesicular Arbuscular ◽  
Field Soils ◽  
Vam Colonization ◽  
Study Sites

Soil and root samples collected from fields cropped to spring wheat (Triticum aestivum L. cv. Katepwa) and lentil (Lens esculenta L. cv. Eston) at 11 sites across four soil zones of Saskatchewan were analyzed for spore numbers, level of vesicular–arbuscular mycorrhizal (VAM) colonization, and VAM species. The number of VAM spores detected in field soils ranged from 78 to 272 per 100 g soil. Vesicular–arbuscular mycorrhizae colonized wheat and lentil at all the field study sites, but levels of colonization in the two crops varied from site to site and the differences were more pronounced in wheat than in lentil. Generally, lentil both exhibited a higher percentage of VAM colonized roots and contained more arbuscules and vesicles than wheat roots. However, wheat appeared to be colonized by different types of VAM depending on the field sites. Differences in VAM colonization were not related to the moisture and temperature gradient of the four soil zones or soil properties. Seven VAM species were isolated by enriching indigenous VAM mixtures (collected from wheat field soils of six field sites) on maize. The VAM isolated most closely resembled Acaulospora denticulata, Gigaspora decipiens, Glomus clarum, Glomus etunicatum, Glomus fasciculatum, Glomus mosseae, and Glomus versiforme. The species composition of the VAM community varied at the different field sites.Key words: VAM, Acaulospora, Gigaspora, Glomus.

scholarly journals The Effect of Four Composts on the Establishment of Vesicular–Arbuscular Mycorrhizae in Soilless Media

HortScience ◽  
1997 ◽  
Vol 32 (3) ◽  
pp. 539D-539
Author(s):  
Michelle Miller ◽  
Robert Linderman ◽  
Leslie Fuchigami
Keyword(s):  
Arbuscular Mycorrhizae ◽  
Growth Parameters ◽  
Fungal Spore ◽  
Exchange Capacity ◽  
Mycorrhizal Colonization ◽  
Mushroom Compost ◽  
Vesicular Arbuscular Mycorrhizae ◽  
Vesicular Arbuscular ◽  
Vam Colonization ◽  
Mineral Soils

The beneficial use of vesicular–arbuscular mycorrhizae (VAM) in mineral soils is well-documented, but little is known about the effect of soilless mixes on mycorrhizal colonization of roots. Previous research indicates that mycorrhizal colonization is affected by pH, soluble salts, phosphorus levels, cation exchange capacity, percent organic matter, and some peats. No other research has been published, to our knowledge, on the role of commonly used horticultural composts and mycorrhizal establishment. This study examined four different composts for their effect on VAM establishment using onion roots as an indicator. The composts used in the study were vermicompost, spent mushroom compost, yard waste compost, and processed manure fiber. Plant growth parameters, phosphorus (P) levels and rate of desorption, and microbial populations were analyzed in relation to the percent of VAM colonization of the roots. Significant differences were found in percent VAM colonization between composts. The primary factors influencing VAM colonization were the initial levels of P in the blends and the rate and amount of P released. The experiment raised questions about the balance between mineralized P and organic P in composts and their effect on VAM fungal spore germination.

Development of vesicular-arbuscular mycorrhizae in crop plants

1973 ◽  
Vol 51 (12) ◽  
pp. 2487-2493 ◽  
Author(s):  
J. C. Sutton
Keyword(s):  
Arbuscular Mycorrhizae ◽  
Mycorrhizal Fungus ◽  
Crop Plants ◽  
Lag Phase ◽  
Vesicular Arbuscular Mycorrhizae ◽  
Wide Range ◽  
Vesicular Arbuscular ◽  
Glycine Max L ◽  
Mycorrhizal Development ◽  
Relationship Of

Vesicular-arbuscular mycorrhizae developed extensively in a wide range of crop plants grown in field plots and in controlled environment. At 25–28 days after sowing, generally few roots (0.6–19%) were colonized by the mycorrhizal fungus Endogone. The proportion of roots colonized subsequently increased rapidly to maximum levels ranging from 48 to 84%. A three-phase pattern of mycorrhizal development involving sequentially a lag phase, a phase of extensive development, and a phase of constancy in the proportion of mycorrhizal to non-mycorrhizal roots was found in bean (Phaseolus vulgaris L.) and soybean (Glycine max (L.) Merr.). A similar multiphase development of mycorrhizae was evident also in some other hosts. The relationship of the different phases of mycorrhizal development to physiological changes in the host is discussed.

Vesicular – arbuscular mycorrhizae in disturbed and revegetated sites from La Gran Sabana, Venezuela

1992 ◽  
Vol 70 (1) ◽  
pp. 73-79 ◽  
Author(s):  
Gisela Cuenca ◽  
Milagros Lovera
Keyword(s):  
Arbuscular Mycorrhizae ◽  
Plant Cover ◽  
Ground Cover ◽  
Arbuscular Mycorrhizal ◽  
Most Probable Number ◽  
Probable Number ◽  
Organic Layers ◽  
Vesicular Arbuscular Mycorrhizae ◽  
Disturbed Areas ◽  
Vesicular Arbuscular

Savannas growing on stony, old and nutrient-poor soils of southern Venezuela were severely disturbed by removal of the soil organic layers with bulldozers for road building. Introduced species Brachiaria decumbens, Brachiaria humidicola, Pueraria phaseoloides, and Calopogonium sp. were sown. The substrate was fertilized and limed. Plant cover, vesicular – arbuscular mycorrhizae colonization, spore number, and most probable number of propagulels in undisturbed savanna, disturbed nonrevegetated savanna, and six revegetated savannas were assessed. The perturbation reduced the mycorrhizal propagule number in comparison with the undisturbed savanna. In the nonrevegetated areas the mean percent ground cover 2 years after disturbance was low (0.04%). In revegetated areas an increase in mycorrhizal propagule number occurred and the mycorrhizal colonization of the sown species was high. In restored areas there was an increase in species of nonmycotrophic Amaranthaceae. The results support other predictions on the mycorrhizae in successional biomes, because in the extremely nutrient-poor soils studied the colonizing species were mainly mycotrophic. The reclamation program applied in disturbed areas was useful because it has allowed the recovery of vesicular – arbuscular mycorrhizal inoculum and there was an increase in the recolonization of native plants. Key words: disturbance, endomycorrhizae, revegetation, savanna, vesicular – arbuscular mycorrhizae.

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