Arbuscular mycorrhizae of American ginseng (Panax quinquefolius) in cultivated field plots: plant age affects the development of a colonization lag phase

1999 ◽  
Vol 77 (7) ◽  
pp. 1028-1034 ◽  
Author(s):  
T P McGonigle ◽  
J P Hovius ◽  
R L Peterson
Keyword(s):  
Mycorrhizal Fungi ◽  
Arbuscular Mycorrhizae ◽  
Dry Mass ◽  
American Ginseng ◽  
Panax Quinquefolius ◽  
Root Turnover ◽  
Lag Phase ◽  
Seed Collection ◽  
Second Year ◽  
Hyphal Coils

Temporal patterns of colonization of roots of perennials by arbuscular mycorrhizal fungi are poorly understood because annual crops are more often studied. The objective was to monitor in detail the growth and mycorrhizae of the perennial American ginseng (Panax quinquefolius L.) over the first 2 years after seeding. In particular, the extent of carry-over of colonization into the second year was examined. Delayed germination of some seeds caused by chance-driven variability in the time needed for seed maturation after seed collection provided an opportunity to compare first- and second-year plants under identical conditions in the second year. For all plants, development of arbuscules rose to a maximum in mid-August, falling partially thereafter. Production of hyphal coils proceeded more slowly but steadily, so that end-of-season colonization was composed equally of arbuscules and hyphal coils. Between seasons, taproot dry mass was reduced by 18%, whereas lateral root length increased by 15%. These changes were probably caused by root turnover, which left little initial colonization of roots at the start of the second year. Strikingly, second-year plants did not exhibit a colonization lag phase, whereas a lag of 43 days was seen for the first-year plants alongside. Possible reasons for this difference are discussed.Key words: perennial, arbuscules, hyphal coils, taproot, Ontario.

Arbuscular mycorrhizae of Acer saccharum in different soil types

1995 ◽  
Vol 73 (11) ◽  
pp. 1824-1830 ◽  
Author(s):  
John N. Klironomos
Keyword(s):  
Arbuscular Mycorrhizal Fungi ◽  
Mycorrhizal Fungi ◽  
Acer Saccharum ◽  
Arbuscular Mycorrhizae ◽  
Arbuscular Mycorrhizal ◽  
Soil Types ◽  
Southern Ontario ◽  
Podzolic Soils ◽  
Hyphal Coils ◽  
Spore Densities

Differences in propagule levels and in the colonization of Acer saccharum feeder roots by arbuscular mycorrhizal fungi in maple forests distributed across three different soil types (brunisols, luvisols, podzols) were investigated. All forest stands were located in southern Ontario. Acer saccharum was the dominant tree species, making up at least 75% of all trees. Results show that arbuscular mycorrhizae can dominate in different soil types, even in podzolic soils with moder-type humus, which typically support ectomycorrhizal associations. In fact, total hyphal colonization of A. saccharum roots and the capacity of the soil to initiate infection units were highest in the podzolic soils compared with those in brunisolic and luvisolic soils. In brunisolic soils, the roots exhibited high arbuscular colonization, low coil colonization, low vesicular colonization, and relatively moderate sporulation levels. In luvisolic soils, colonization was similar to that of brunisols; however, spore densities were lower. Roots in podzolic soils showed very different trends, with a low occurrence of arbuscules, high levels of hyphal coils and vesicles, and much higher spore densities. Soil type can account for much of the variability in arbuscular mycorrhizal structure and functioning that occurs among different locations. Key words: arbuscular mycorrhizae, Acer saccharum, brunisol, luvisol, podzol.

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.

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.

scholarly journals Micorrizas arbusculares e absorção de fósforo em função da capacidade de fixação de fósforo do solo e da competição com a microbiota

2020 ◽  
Vol 13 (3) ◽  
pp. 1062
Author(s):  
Regina Lúcia Félix de Aguiar Lima
Keyword(s):  
Mycorrhizal Fungi ◽  
Dry Matter ◽  
Arbuscular Mycorrhizae ◽  
Specific Activity ◽  
Phosphorus Uptake ◽  
Dry Mass ◽  
Soil P ◽  
P Fixation ◽  
P Content ◽  
Fixation Capacity

Fungos micorrízicos arbusculares (FMA) se associam às raízes das plantas e incrementam a absorção de fósforo (P), macronutriente com baixa mobilidade no solo. A capacidade de fixação de P do solo e a competição com a biota heterotrófica afetam sua disponibilidade para plantas. Visando avaliar a contribuição dos FMA na absorção de P em solos com capacidade crescente de fixação ou em situação de competição com a biota foram realizados experimentos em vasos compartimentalizados cultivados com braquiária associada a FMA, contendo substrato marcado com 32P. Foram quantificadas a massa seca das plantas, o conteúdo e a atividade específica do P. No experimento 1 avaliou-se a absorção de P por raízes e hifas de FMA ou somente por hifas em solos com alta, média e baixa capacidade fixação de P. No experimento 2 avaliou-se a absorção de P por raízes e hifas de FMA ou somente por hifas em solos com alta e baixa capacidade fixação de P em situação de competição com a biota do solo ativada por fontes de carbono. O aumento da capacidade de fixação de P pelo solo resultou em diminuição de massa seca, conteúdo de P e atividade específica nas plantas. No solo com alta fixação de P, plantas com absorção exclusiva por hifas de FMA tiveram aumento da massa seca e conteúdo de P. Em situação de competição, houve diminuição na massa seca e no conteúdo de P nas plantas. Plantas com absorção por raízes e hifas de FMA tiveram maior atividade específica de P. Arbuscular mycorrhizae and phosphorus uptake in soils as a function of adsorption capacity and competition with microbiota A B S T R A C TArbuscular mycorrhizal fungi (AMF) are associated with plant roots and increase the absorption of phosphorus (P), macronutrient with low soil mobility. Soil P fixation capacity and competition with heterotrophic biota affect its availability. To evaluate the contribution of AMF to P uptake in soils with increasing fixation capacity or in competition with biota, experiments were carried out in compartmentalized pots cultivated with AMF-associated Brachiaria decumbens containing 32P-labeled substrate. Plant dry mass, content and specific activity of P. were quantified. In experiment 1, the absorption of P by roots and hyphae of AMF or only by hyphae in soils with high, medium and low P. fixation capacity was evaluated. In experiment 2, the absorption of P by roots and hyphae of AMF or only by hyphae in soils with high and low P fixation capacity in competition with carbon-activated soil biota was evaluated. Increasing P fixation capacity by soil resulted in decreased dry matter, P content and specific activity in plants. In soil with high P fixation, plants with exclusive absorption by FMA hyphae had increased dry matter and P content. In a competition situation, there was a decrease in dry matter and P content in plants. Plants absorbed by roots and hyphae of AMF had higher P-specific activity.Keywords: 32P, P-soil fixing, AMF, extraradical mycelium, hyphal absorption

Vesicular–arbuscular mycorrhizal associations of American ginseng (Panax quinquefolius) in commercial production

1996 ◽  
Vol 74 (7) ◽  
pp. 1104-1112 ◽  
Author(s):  
Fraser Whitbread ◽  
R. Larry Peterson ◽  
Terry P. McGonigle
Keyword(s):  
Root Hairs ◽  
Arbuscular Mycorrhizal ◽  
Significant Degree ◽  
American Ginseng ◽  
Panax Quinquefolius ◽  
Vam Fungi ◽  
Cortical Cells ◽  
Vesicular Arbuscular ◽  
Commercial Farms ◽  
Hyphal Coils

Panax quinquefolius L. (American ginseng) roots collected from 1st year seedlings and 3-year-old plants on three commercial farms were colonized by vesicular–arbuscular mycorrhizal (VAM) fungi. Roots collected from ginseng plants in a managed maple–beech woodlot were also colonized by VAM fungi. Fungal hyphae entered roots either directly through root hairs or by forming appressoria on the surface of epidermal cells from which penetration hyphae formed. Hyphae colonized roots by passing intracellularly through cortical cells. Hyphal coils, from which arbuscular branches formed, were typical of the Paris-type of VAM association. The extent of colonization by hyphal coils and by arbuscules varied between 1-year-old and 3-year-old plants and among farms. The seasonal maxima for colonization differed among combinations of farms and plant age-classes in such a way as to suggest that a significant degree of the variability was due to characteristics of the individual seed beds. Over the season, we saw earlier development of hyphal coils that was only later exceeded by production of arbuscules; this pattern is consistent with the Paris-type morphology observed, in that arbuscule branches develop from hyphal coils. However, the speed at which arbuscules developed at some points in the season was so great that at those times the transition from newly formed hyphal coils to arbuscules must be extremely fast. Vesicles were rarely found in any root samples examined. Keywords: ginseng, Panax quinquefolius, vesicular–arbuscular mycorrhiza, commercial farms.

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