scholarly journals Vesicular-arbuscular Mycorrhizal Peat-based Substrates Enhance Symbiosis Establishment and Growth of Three Micropropagated Species

1993 ◽  
Vol 118 (6) ◽  
pp. 896-901 ◽  
Author(s):  
H. Wang ◽  
S. Parent ◽  
A. Gosselin ◽  
Y. Desjardins

Micropropagated plantlets of Gerbera jamesonii H. Bolus ex Hook. F. `Terra Mix', Nephrolepis exaltata (L.) Schott `Florida Ruffles', and Syngonium podophyllum Schott `White Butterfly' were inoculated with two vesicular-arbuscular mycorrhizal (VAM) fungi, Glomus intraradices Schenck and Smith and G. vesiculiferum Gerderman and Trappe. They were potted in three peat-based media to determine the effects of mycorrhizal peat substrate on acclimatization and subsequent growth of micropropagated plantlets under greenhouse conditions. Symbiosis was established between the three ornamental species and VAM fungi within 4 to 8 weeks of culture in the greenhouse, but not during acclimatization. Mortality of Gerbera and Nephrolepis mycorrhizal plantlets was reduced at week 8 compared to the noninoculated control. A peat-based substrate low in P and with good aeration improved VAM fungi spread and efficiency. Mycorrhizal substrates had a long-term benefit of increasing leaf and root dry weight of Gerbera and Nephrolepis. Mycorrhizal Gerbera plants flowered significantly faster than non-mycorrhizal plants.

1992 ◽  
Vol 1 (5) ◽  
pp. 527-535 ◽  
Author(s):  
Mauritz Vestberg

Ten strawberry cultivars, four early maturing, three late maturing and three “special” cultivars, were inoculated with six strains of vesicular-arbuscular mycorrhizal (VAM) fungi in a pot experiment. Growth effects and colonization of the VAM fungi were studied. Three strains, Glomus macrocarpum V3, G. mosseae Rothamsted and G. sp. V4, were highly efficient, causing significant growth increases in most cultivars. ’Jonsok’ showed the highest mycorrhizal dependency index, 648, and ’Ostara’ the lowest, 269, for the mean response of all six fungi. The fungal strains which increased shoot growth the most also increased the runner plant formation the most. Early cultivars showed higher colonization percentages than late maturing cultivars. Sporulation of the introduced VAM fungi was on average more abundant in early and special cultivars than in late cultivars. Root colonization and strawberry shoot dry weight correlated significantly in most cultivars, but the correlation between colonization and runner formation was generally poor.


HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 449e-449
Author(s):  
Martin Trépanier ◽  
Jacques-André Rioux

Roots of majority of natural shrubs are colonized by many species of vesicular–arbuscular mycorrhizal (VAM) fungi. These kinds of fungi form a symbiosis with the root system of the plant and give a better water and mineral absorption (P, Zn, N, Cu, etc.), and a better root disease resistance to the plant. However, the media usually used in ornemental plants nursery contain no or few mycorrhizal fungi. For now, new commercial inoculum are available and could be used to get the advantages provided by VAM fungi. In order to evaluate the potential of ornamental plants to be colonized, we have inoculated the rooting media with three VAM fungi (Glomus intraradices Schenk & Smith, Glomus etunicatum Becker & Gerdemann, and Glomus mosseae Nicol. & Gerd.; Premier Tech, Rivière-du-Loup, Québec). The inoculum proportion used contained about 1500 propagules/L. After 16 weeks, near 80% of the 200 species and cultivars tested have shown a colonization by at least one of the fungi. We shall present here a list of the results.


HortScience ◽  
1996 ◽  
Vol 31 (4) ◽  
pp. 680b-680
Author(s):  
G.S. Guzman ◽  
I.C.A Alvarez ◽  
L.J. Farias

In the commercial production of silver king plants and other ornate plants, the substrates are treated with fungicides, which affect the vesicular–arbuscular mycorrhizal (VAM) fungi and the plant growth negatively. The restoration of de VAM fungi to the substrate, after its disinfection, might improvement the development. The effectiveness and infectiveness of Glomus fasciculatum and Glomus aggregatum on silver king (Aglaonema commutatum) plants was evaluated in this work. Seedlings of 4-week-old, growing treated with mancozeb, were removed and planted in pots filled with a disinfected mixture of sand soil, cow manure and coconut powder (1:2:2), containing the inoculum of VAM fungi (soil with spores and colonized roots). After 3 and 4 months of the inoculation, plants were removed and dry weight of roots and shoot, number and length of leaves, and mycorrhizal colonization were evaluated. A better development was showed in plants inoculated, resulting highest values in number and length of leaves in relation to control plants. Both VAM fungi improvement the number and length of leaves. The percentage root length colonized (80%) and visual density of endophyte in roots was highest in plants inoculated with Glomus aggregatum in both sampling period.


1969 ◽  
Vol 72 (2) ◽  
pp. 191-199
Author(s):  
Stan Michelini ◽  
Stan Nemec

A citrus seedbed was established August 1984 on the west coast of Barbados. Before being planted and inoculated with vesicular-arbuscular mycorrhizal (VAM) fungi, one-half the seedbed was fumigated with methyl bromide; the other half was untreated. Four weeks after fumigation, four treatments, Glomus intraradices, G. mosseae, indigenous VAM fungi, and a noninoculated control were established in each half of the test. Early vigorous plant growth in the nonfumigated half of the plot suggested that indigenous VAM may have colonized and stimulated plant growth earlier than the treatments in the fumigated portion. Three months after inoculation, plants in both portions of the plot were growing well. In the fumigated area, application of two Glomus species, which were introduced from Florida, resulted in a significant improvement in plant growth over the control. This occurred in spite of the fact that infection levels in control roots were similar to those in inoculated roots. This study suggests that, when possible, alternative pesticides not harmful to VAM fungi should be used in place of methyl bromide fumigation to conserve these fungi in agricultural soils.


HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 893G-894
Author(s):  
G.S. Guzmán ◽  
O.C.E. Cuevas ◽  
L.J. Farias ◽  
S.M. Orozco

Citrus macrophylla is an important citrus rootstock for Mexican lemon (Citrus aurantifolia S.). Citrus are highly dependent of vesicular–arbuscular mycorrhizal (VAM) fungi. Four Glomus species were screened for their symbiotic response with C. macrophylla. Seedlings were inoculated with VAM fungi in pots containing sterilized soil. After 3 and 4 months, plants were harvested. Glomus fasciculatum (following by G. intraradices) gave the greatest improvements in growth, resulting in larger plant height and higher shoot dry weight. Glomus aggregatum, G. mosseae, and control plants showed the lowest rates of growth. Plants inoculated with the first three species showed the highest percent of root length colonized. However G. aggregatum gave the highest values of visual density of endophyte in root and soil hyphae. Root colonization and soil hyphae were lowest in plants with G. mosseae.


2001 ◽  
Vol 52 (7) ◽  
pp. 731 ◽  
Author(s):  
R. M. Kelly ◽  
D. G. Edwards ◽  
J. P. Thompson ◽  
R. C. Magarey

The presence of vesicular-arbuscular mycorrhizal (VAM) fungi in long-term cane-growing fields associated with yield decline led to the supposition that VAM fungi may be responsible for the poor yields. A glasshouse trial was established to test the effectiveness of a species of VAM fungi, Glomus clarum, extracted from one of these North Queensland fields on the growth of sugarcane (Saccharum interspecific hybrid), maize (Zea mays), and soybean (Glycine max) for 6 phosphorus (P) rates (0, 2.7, 8.2, 25, 74, 222 mg/kg). For maize and soybean plants that received VAM (+VAM), root colonisation was associated with enhanced P uptake, improved dry weight (DW) production, and higher index tissue-P concentrations than those without VAM (–VAM). By comparing DW responses of maize and soybean for different P rates, savings in fertiliser P of up to 160 and 213 kg/ha, respectively, were realised. Sugarcane plants were generally less responsive. Apart from a 30% DW increase with VAM when 2.7 mg P/kg was added, DW of +VAM plants was equivalent to, or worse than in the case of 222 mg P/kg, DW of –VAM plants. For all 3 host species, colonisation was least at the highest P application, presumably from excessive P within the plant tissue. Critical P concentrations for the 3 host species were below those reported elsewhere, and for soybean and sugarcane, the critical concentration for +VAM plants was lower than that of –VAM plants. There are 3 implications that arise from this study. First, VAM fungi present in cane-growing soils can promote the growth of maize and soybean, which are potential rotation crops, over a range of P levels. Second, the mycorrhizal strain taken from this site did not generally contribute to a yield decline in sugarcane plants. Third, application of P fertiliser is not necessary for sugarcane when acid-extractable P is <30 mg/kg if sufficient VAM propagules are present, or mp;lt;47 mg/kg if a mycorrhizal response is not anticipated.


1995 ◽  
Vol 75 (1) ◽  
pp. 269-275 ◽  
Author(s):  
S. M. Boyetchko ◽  
J. P. Tewari

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


1998 ◽  
Vol 28 (1) ◽  
pp. 150-153
Author(s):  
J N Gemma ◽  
R E Koske ◽  
E M Roberts ◽  
S Hester

Rooted cuttings of Taxus times media var. densiformis Rehd. were inoculated with the arbuscular mycorrhizal fungi Gigaspora gigantea (Nicol. & Gerd.) Gerd. & Trappe or Glomus intraradices Schenck and Smith and grown for 9-15 months in a greenhouse. At the completion of the experiments, leaves of inoculated plants contained significantly more chlorophyll (1.3-4.1 times as much) than did noninoculated plants. In addition, mycorrhizal plants had root systems that were significantly larger (1.3-1.4 times) and longer (1.7-2.1 times) than nonmycorrhizal plants, and they possessed significantly more branch roots (1.3-2.9 times). No differences in stem diameter and height or shoot dry weight were evident at the end of the experiments, although the number of buds was significantly greater in the cuttings inoculated with G. intraradices after 15 months.


1985 ◽  
Vol 79 (2) ◽  
pp. 562-563 ◽  
Author(s):  
Christopher van Kessel ◽  
Paul W. Singleton ◽  
Heinz J. Hoben

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