Phytohormone changes in Bouteloua gracilis infected by vesicular–arbuscular mycorrhizae: I. Cytokinin increases in the host plant

1980 ◽  
Vol 58 (3) ◽  
pp. 371-374 ◽  
Author(s):  
Michael F. Allen ◽  
Thomas S. Moore Jr. ◽  
Martha Christensen
Keyword(s):  
Arbuscular Mycorrhizae ◽  
Callus Tissue ◽  
Axenic Culture ◽  
Bouteloua Gracilis ◽  
Cytokinin Activity ◽  
Mycorrhizal Infection ◽  
Soybean Callus ◽  
Vesicular Arbuscular ◽  
Leaves And Roots ◽  
Water Saturated

Bouteloua gracilis was grown in defined, axenic culture with and without vesicular–arbuscular (VA) mycorrhizae. Leaves and roots of mycorrhizal and nonmycorrhizal plants were harvested and assayed for cytokinin content using a soybean callus tissue bioassay. Total cytokinin activity was 57 and 111% greater in leaves and roots, respectively, in mycorrhizal over control plants. Cytokinin activities, separated using paper chromatography with water saturated n-butanol as a solvent, doubled in roots and leaves at Rf values of 0.3 and 0.9 and increased 9-fold in roots at an Rf value of 0.1 with infection. This appears to be the first demonstration of altered cytokinin levels in plants resulting from mycorrhizal infection.

Vesicular–arbuscular mycorrhizae in the Chenopodiaceae and Cruciferae: do they occur?

1978 ◽  
Vol 56 (22) ◽  
pp. 2813-2817 ◽  
Author(s):  
Marc C. Hirrel ◽  
H. Mehravaran ◽  
J. W. Gerdemann
Keyword(s):  
Arbuscular Mycorrhizae ◽  
Chenopodium Album ◽  
Mycorrhizal Infection ◽  
Va Mycorrhizae ◽  
Glomus Fasciculatus ◽  
Vesicular Arbuscular ◽  
Companion Plant ◽  
Resistance To Infection ◽  
Companion Plants ◽  
Test Plants

Members of the Chenopodiaceae and Cruciferae were reported to be nonmycorrhizal by early investigators; more recently, some species in these families have been reported to have low or in some cases high levels of vesicular–arbuscular (VA) mycorrhizal infection. In our experiments, a sparse vesicular (chlamydospore) infection by Glomus fasciculatus was found in four species of Chenopodiaceae and two species of Cruciferae but only when grown in the presence of a mycorrhizal companion plant, citrus or onion. No arbuscules were observed in infected roots. Chenopodium album had the highest incidence of infection (5%). Infection was restricted to older tissue and penetration of the vascular cylinder was common, which is atypical of VA mycorrhizae. As hyphae from mycorrhizal companion plants grew through the soil, they encountered older roots of the test plants which probably offered little or no resistance to infection. In documenting the occurrence of VA mycorrhizae in any species, it is important to observe whether the plant is growing by itself or if there are mycorrhizal plants closely associated with it. Also, care should be taken not to confuse common root parasites for the fungal structures of VA mycorrhiza.

Incidence and condition of vesicular–arbuscular mycorrhizae infections in the roots of sugar maple in relation to maple decline

1978 ◽  
Vol 8 (4) ◽  
pp. 375-379 ◽  
Author(s):  
Roberta A. Spitko ◽  
Terry A. Tattar ◽  
Richard A. Rohde
Keyword(s):  
Sugar Maple ◽  
Arbuscular Mycorrhizae ◽  
Mycorrhizal Infection ◽  
Fungal Symbiont ◽  
Crown Condition ◽  
Cortical Cells ◽  
Sugar Maples ◽  
Vesicular Arbuscular ◽  
University Of Massachusetts ◽  
The University

Twelve sugar maples (Acersaccharum Marsh.) on the campus of the University of Massachusetts were selected for the study in spring 1977. Trees chosen ranged from healthy to severely declined and were assigned to crown-condition classes of increasing severity from I to IV. Whole root samples from each tree were cleared in 10% KOH and stained in trypan blue to assess the degree of vesicular–arbuscular infection. Five sections of secondary feeder roots from each tree were selected at random and examined under a microscope. The number of infected cortical cells per centimetre of roots was counted to give an estimate of percent mycorrhizal infection for each tree. An inverse relationship was found between the degree of decline shown by the crown and the amount of mycorrhizal infection in the roots. Trees of class I had young infections showing extensive arbuscule development and few vesicles. In classes II to IV there was a decrease in the number of cortical cells infected by the fungus and an increase in vesicle formation, at times to the point where cortical cells were disrupted by their presence. In class IV, arbuscules that were present had undergone digestion of the fine branches so that only the collars were in evidence. Soil pH and nutritional status were determined but no relationship was found between these factors and the health of the fungal symbiont in the roots.

scholarly journals INFLUENCE OF PHOSPHATE SOURCE ON VESICULAR-ARBUSCULAR MYCORRHIZAE OF BOUTELOUA GRACILIS

1981 ◽  
Vol 87 (4) ◽  
pp. 687-694 ◽  
Author(s):  
MICHAEL F. ALLEN ◽  
JAMES C. SEXTON ◽  
THOMAS S. MOORE ◽  
MARTHA CHRISTENSEN
Keyword(s):  
Arbuscular Mycorrhizae ◽  
Bouteloua Gracilis ◽  
Vesicular Arbuscular Mycorrhizae ◽  
Vesicular Arbuscular ◽  
Phosphate Source

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.

Cytokinin production by the fungi Taphrina cerasi and T. deformans

1974 ◽  
Vol 52 (7) ◽  
pp. 1583-1589 ◽  
Author(s):  
James C. Johnston ◽  
Edward J. Trione
Keyword(s):  
Culture Medium ◽  
Callus Tissue ◽  
Zeatin Riboside ◽  
Cytokinin Activity ◽  
Liquid Media ◽  
Migration Patterns ◽  
Soybean Callus ◽  
Isopentenyl Adenine ◽  
Isopentenyl Adenosine ◽  
Solvent Systems

Cytokinins were released into chemically defined liquid media by cultures of Taphrina cerasi and T. deformans. The presence of the cell-division factors was demonstrated with the soybean callus tissue assay, which is specific for the detection of cytokinins. Paper chromatography in four solvent systems, in conjunction with bioassays, revealed that T. cerasi produced compounds that have migration patterns similar to those of zeatin, zeatin riboside, N6-(Δ2-isopentenyl) adenine, and N6-(Δ2-isopentenyl)adenosine. T. deformans produced compounds with chromatographic properties similar to those of zeatin, zeatin riboside, and a substance(s) the migration of which is correlated with the Rf interval that included the positions of N6-(Δ2-isopentenyl) adenine and its riboside. A third type of cytokinin, the mobility of which differs from those of the cytokinin standards used, was also produced by T. deformans. The total cytokinin activity in cultures of T. cerasi was calculated to be about 2 μg kinetin-equivalents per liter of culture medium, and the amount released by T. deformans was about 4 μg kinetin-equivalents per liter of medium.

Competition between plants of different successional stages: mycorrhizae as regulators

1984 ◽  
Vol 62 (12) ◽  
pp. 2625-2629 ◽  
Author(s):  
Edith Bach Allen ◽  
Michael F. Allen
Keyword(s):  
Stomatal Conductance ◽  
Mixed Culture ◽  
Mycorrhizal Fungi ◽  
Pure Culture ◽  
Arbuscular Mycorrhizae ◽  
Bouteloua Gracilis ◽  
Dry Mass ◽  
Mycorrhizal Infection ◽  
Agropyron Smithii ◽  
Salsola Kali

Salsola kali, a colonizing annual which does not form vesicular–arbuscular mycorrhizae (nonmycotrophic), was grown in pure culture and in mixtures with two mycotrophic grasses which are late successional dominants, Agropyron smithii and Bouteloua gracilis. Soils were either left sterile or inoculated with mycorrhizal fungi. In pure culture mycorrhizae caused no significant increase in dry mass of either grass, but in mixed culture with S. kali, mycorrhizal infection was significantly related to increased mass of grasses. Mycorrhizal infection was related to increased stomatal conductance of the grasses in both pure and mixed culture. Salsola kali had lower stomatal conductance but not a significantly reduced mass with mycorrhizal fungi. Hyphae of mycorrhizal fungi, but not vesicles or arbuscules, were observed in the rhizosphere and occasionally the cortex of S. kali. Where competition between colonizing nonmycorrhizal species and later successional mycorrhizal species is a mechanism which drives succession, the inoculum density may determine the rate of succession.

Vesicular-arbuscular mycorrhizae of winter and spring cereals

1985 ◽  
Vol 105 (3) ◽  
pp. 649-657 ◽  
Author(s):  
J. G. Buwalda ◽  
D. P. Stribley ◽  
P. B. Tinker
Keyword(s):  
Mycorrhizal Fungi ◽  
Arbuscular Mycorrhizae ◽  
Field Experiments ◽  
Sowing Date ◽  
Phosphorus Concentration ◽  
Mycorrhizal Infection ◽  
Stages Of Growth ◽  
Early Stages ◽  
Vesicular Arbuscular ◽  
Spring Cereals

SUMMARYThe importance of mycorrhizal infection for the growth of wheat and barley sown in winter and spring was assessed in two field experiments. Low temperatures during winter restricted the development of mycorrhizal infection, and calculations of ‘thermal time’ indicated that the percentage of root length infected did not increase when mean temperatures were less than 5 °C. Hence infection was less in the winter-sown crops than in the spring-sown crops at early stages of plant development. However, the effects of mycorrhizal infection on growth were greater in winter-sown than in spring-sown wheat.At all levels of applied phosphorus up to 60 kg P/ha, artificial inoculation with mycorrhizal fungi increased the yields of both cereals at each sowing date by 17–25% after indigenous mycorrhizal fungi had been removed by fumigation, but the effects were smaller on non-fumigated plots. The results confirmed the potential importance of mycorrhizal infection for the growth of cereals.Mycorrhizal infection increased the phosphorus concentration in the plant tissue at very early stages of growth, but the effect generally declined with time.

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