Technique for observation of mycorrhizal development under 0monoxenic conditions

1984 ◽  
Vol 62 (2) ◽  
pp. 251-254 ◽  
Author(s):  
Chin S. Yang ◽  
Hugh E. Wilcox

A culture system designed to study root growth and mycorrhizal formation is described. This technique allows shoots of seedlings to grow in the air while roots of the seedlings are growing in an aseptic condition where their growth and differentiation, fungal colonization, mantle formation, and mycorrhizal association can be observed. Packing vermiculite and ground peat moss into the tubes stabilized the pH. This technique has been successful with two pine species and three mycorrhizal fungi.

1988 ◽  
Vol 5 (1) ◽  
pp. 65-68 ◽  
Author(s):  
Gerry L. Simmons ◽  
Phillip E. Pope

Abstract A greenhouse study was conducted to determine if the root growth of yellow-poplar and sweetgum seedlings grown in compacted soil could be enhanced by inoculating the seedlings with the vesicular-arbuscular mycorrhizal fungi Glomus macrocarpum or G. fasciculatum. Root growth of both tree species was significantly reduced as bulk density increased. Inoculated yellow-poplar seedlings had greater root weight at each bulk density than noninoculated seedlings. Root length was not significantly influenced by mycorrhizal treatments at higher bulk densities, and fibrosity responses to mycorrhizal treatments varied at each bulk density. Mycorrhizal dependency, the degree to which a plant is dependent on the mycorrhizal association to produce its maximum growth, was the same for yellow-poplar seedlings inoculated with either fungal species. Results indicate that mycorrhizal colonization may not improve root growth of yellow-poplar at higher bulk densities. At each bulk density, sweetgum seedlings inoculated with G fasciculatum had the greatest root weight, length, and fibrosity, and the highest mycorrhizal dependency values, indicating that effects of compaction can be alleviated for sweetgum by inoculation with this mycorrhizal fungus. North. J. Appl. For. 5:65-68, March 1988.


2006 ◽  
Vol 32 (2) ◽  
pp. 62-66
Author(s):  
Balakrishna Rao ◽  
Donald Marx ◽  
Brian Jeffers

Live oak (Quercus virginiana), laurel oak (Q. laurifolia), and Drake elm (Ulmus parvifolia) seedlings were grown for 1 year in 4 L (1 gal) containers and then transplanted on 3 m (10 ft) centers at a nursery in Florida, U.S. Two years later, in April 2002, ten seedlings per tree species were treated by (1) soil injection with mycorrhizal fungi and rhizobacteria; (2) drenching with rhizobacteria and soil fungi applied monthly for 5 months; (3) a combination of (1) and (2); (4) drenching with Subdue® fungicide; or (5) nontreated controls. Root growth and mycorrhizal development were measured with root ingrowth cores. After 1 year (1 April, 2003), mycorrhizal development and root growth as well as stem calipers were greater in treatments containing the mycorrhizal fungi for all three species. The rhizobacteria treatment also increased root and stem growth on Drake elm. The fungicide, Subdue, did not significantly affect mycorrhizal development or root or stem growth. There were few naturally occurring mycorrhizae on roots of trees in this nursery.


2016 ◽  
Vol 62 (3) ◽  
pp. 263-271 ◽  
Author(s):  
Walid Ellouze ◽  
Chantal Hamel ◽  
R.M. DePauw ◽  
R.E. Knox ◽  
Richard D. Cuthbert ◽  
...  

The selection of genotypes under high soil fertility may alter the effectiveness of mycorrhizal symbioses naturally forming between crop plants and the mycorrhizal fungi residing in cultivated fields. We tested the hypothesis that the mycorrhizal symbiosis of 5 landraces functions better than the mycorrhizal symbiosis of 27 cultivars of durum wheat that were bred after the development of the fertilizer industry. We examined the development of mycorrhiza and the response of these genotypes to mycorrhiza formation after 4 weeks of growth under high and low soil fertility levels in the greenhouse. The durum wheat genotypes were seeded in an established extraradical hyphal network of Rhizophagus irregularis and in a control soil free of mycorrhizal fungi. The percentage of root length colonized by mycorrhizal fungi was lower in landraces (21%) than in cultivars (27%; P = 0.04) and in the most recent releases (29%; P = 0.02), which were selected under high soil fertility levels. Plant growth response to mycorrhiza varied from –36% to +19%. Overall, durum wheat plant breeding in Canada has increased the mycorrhizal development in wheat grown at a low soil fertility level. However, breeding had inconsistent effects on mycorrhizal development and has led to the production of cultivars with patterns of regulation ranging from unimproved to inefficient.


2021 ◽  
Author(s):  
Robert Reuter ◽  
Olga Ferlian ◽  
Mika Tarkka ◽  
Nico Eisenhauer ◽  
Karin Pritsch ◽  
...  

Abstract Mycorrhizal fungi play an important role for the nitrogen (N) supply of trees. The influence of different mycorrhizal types on N acquisition in tree-tree interactions is, however, not well understood, particularly with regard to the competition for growth-limiting N. We studied the effect of competition between temperate forest tree species on their inorganic and organic N acquisition in relation to their mycorrhizal type (i.e., arbuscular mycorrhiza or ectomycorrhiza). In a field experiment, we quantified net N uptake capacity from inorganic and organic N sources using 15N/13C stable isotopes for arbuscular mycorrhizal tree species (i.e., Acer pseudoplatanus L., Fraxinus excelsior L., and Prunus avium L.) as well as ectomycorrhizal tree species (i.e., Carpinus betulus L., Fagus sylvatica L., and Tilia platyphyllos Scop.). All species were grown in intra- and interspecific competition (i.e., monoculture or mixture). Our results showed that N sources were not used complementarily depending on a species´ mycorrhizal association, but their uptake rather depended on the competitor indicating species-specific effects. Generally, ammonium was preferred over glutamine and glutamine over nitrate. In conclusion, our findings suggest that inorganic and organic N acquisition of the studied temperate tree species is less regulated by mycorrhizal association, but rather by the availability of specific N sources in the soil as well as the competitive environment of different tree species.


2021 ◽  
Author(s):  
Xuhui Zhou ◽  
Lingyan Zhou ◽  
Yanghui He ◽  
Yuling Fu ◽  
Zhenggang Du ◽  
...  

Abstract Biomass allocation in plants is fundamental for understanding and predicting terrestrial carbon storage. Recent studies suggest that climate warming can differentially affect root and shoot biomass, and subsequently alter root: shoot ratio. However, warming effects on root: shoot ratio and their underlying drivers at a global scale remain unclear. Using a global synthesis of >300 studies, we here show that warming significantly increases biomass allocation to roots (by 13.1%), and two factors drive this response: mean annual precipitation of the site, and the type of mycorrhizal fungi associated with a plant. Warming-induced allocation to roots is greater in relatively drier habitats compared to shoots (by 15.1%), but lower in wetter sites (by 4.9%), especially for plants associated with arbuscular mycorrhizal fungi compared to ectomycorrhizal fungi. Root-biomass responses to warming predominantly determine the biomass allocation in terrestrial plants suggesting that warming can reinforce the importance of belowground resource uptake. Our study highlights that the wetness or dryness of a site and plants’ mycorrhizal associations strongly regulate terrestrial carbon cycle by altering biomass allocation strategies in a warmer world.


1997 ◽  
Vol 75 (11) ◽  
pp. 1903-1912 ◽  
Author(s):  
Kyeong W. Yun ◽  
M. A. Maun

Greenhouse studies were conducted to test allelopathic effects of Artemisia campestris ssp. caudata on seed germination and seedling growth of several sand-dune species and colonization by mycorrhizal fungi. The aqueous extracts of A. campestris showed no inhibitory effect on seed germination, seedling elongation, or dry-weight growth of plants at lower concentrations (10 and 50%), but 100% concentration of the extracts caused varying degrees of inhibition depending on the test species. The mixing of dry leaves of seedlings of A. campestris to the sand showed severe inhibition of Elymus canadensis seedlings. The percent germination of test species in soil from the rhizosphere of A. campestris was significantly lower than that of the control. The leaf area and dry weight were also lower but the differences were not significant. The aqueous extract inhibited mycorrhizal fungal colonization in roots of three sand-dune grasses. Key words: allelopathy, Artemisia campestris ssp. caudata, seed germination, seedling growth, mycorrhizal fungi.


2021 ◽  
Vol 12 ◽  
Author(s):  
Ricardo Alexander Peña Venegas ◽  
Soon-Jae Lee ◽  
Moses Thuita ◽  
Deusdedit Peter Mlay ◽  
Cargele Masso ◽  
...  

A vast majority of terrestrial plants are dependent on arbuscular mycorrhizal fungi (AMF) for their nutrient acquisition. AMF act as an extension of the root system helping phosphate uptake. In agriculture, harnessing the symbiosis can potentially increase plant growth. Application of the AMF Rhizophagus irregularis has been demonstrated to increase the yields of various crops. However, there is a paradigm that AMF colonization of roots, as well as the plant benefits afforded by inoculation with AMF, decreases with increasing phosphorus (P) supply in the soil. The paradigm suggests that when fertilized with sufficient P, inoculation of crops would not be beneficial. However, the majority of experiments demonstrating the paradigm were conducted in sterile conditions without a background AMF or soil microbial community. Interestingly, intraspecific variation in R. irregularis can greatly alter the yield of cassava even at a full application of the recommended P dose. Cassava is a globally important crop, feeding 800 million people worldwide, and a crop that is highly dependent on AMF for P uptake. In this study, field trials were conducted at three locations in Kenya and Tanzania using different AMF and cassava varieties under different P fertilization levels to test if the paradigm occurs in tropical field conditions. We found that AMF colonization and inoculation responsiveness of cassava does not always decrease with an increased P supply as expected by the paradigm. The obtained results demonstrate that maximizing the inoculation responsiveness of cassava is not necessarily only in conditions of low P availability, but that this is dependent on cassava and fungal genotypes. Thus, the modeling of plant symbiosis with AMF under different P levels in nature should be considered with caution.


2021 ◽  
Vol 22 (11) ◽  
Author(s):  
Maria Viva Rini ◽  
Fitri Yelli ◽  
Darwin Leonardo Tambunan ◽  
Inggar Damayanti

Abstract. Rini MV, Yelli F, Tambunan DL, Damayanti I. 2021. Morphological and molecular identifications of three native arbuscular mycorrhizal fungi isolated from the rhizosphere of Elaeis guineensis and Jatropha curcas in Indonesia. Biodiversitas 22: 4940-4947. Molecular analysis has been widely used to provide more accurate identification within arbuscular mycorrhizal fungi (AMF) species than identification based on morphology. However, morphological analysis is essential for a basic preliminary of classification studies. Therefore, a study is needed to complete the identification of AMF isolates through morphological and molecular analyses. This research used three AMF isolates, namely MV 5, MV 17, and MV 18, which were isolated from Indonesian agricultural land. Spore-based taxonomy (shape, size, color, ornamentation, PVLG, and Melzer’s reaction) and fungal colonization on roots of maize trap plants were employed for the morphological studies. AMF species identification was performed using molecular analysis through nested-Polymerase Chain Reaction (PCR) to amplify a fragment of SSU rRNA followed by sequencing and phylogenetic tree construction. Morphological analysis showed that MV 5 had spores borne from the neck of the sporiferous saccule, MV 17 was found to have a bulbous suspensor without a germination shield, and MV 18 had spores borne from subtending hyphae. The SSUR rRNA analysis revealed that MV 5, MV 15, and MV 18 were identified as Acaulospora longula, Gigaspora margarita, and Glomus etunicatum, respectively. Both morphological and molecular methods demonstrated reliable and consistent results that complement AMF taxonomy studies.


Author(s):  
Maria Theresia Sri Budiastuti ◽  
Djoko Purnomo ◽  
Supriyono Supriyono ◽  
Bambang Pujiasmanto ◽  
Desy Setyaningrum

<p class="Default"><em>Indigofera tinctoria</em> is a legume that is cultivated as a source of natural indigo dyes. As a legume, <em>Indigofera tinctoria</em> is capable of symbiosis with soil microbes. This study evaluates the effects of light intensity and microbial inoculation on root growth and nodulation. The study used a complete randomized block design with a split-plot pattern. Light intensity was the main plot with four levels of light intensity 100%, 50%, 25%, and 10%. Microbial inoculation was a subplot with four levels without inoculation, mycorrhizae inoculation, rhizobium inoculation, and double inoculation with both mycorrhizae and rhizobium. The results obtained show that light intensity and microbial inoculation affected root length, root fresh weight, root biomass, and the number of nodules. 50% light intensity was optimum for root length, while 100% light intensity was optimum for root fresh weight, root biomass, and a number of nodules. Root growth and nodulation were further increased with double inoculation. The combination of light intensity and microbial inoculation affected root biomass and nodulation. The combination of 100% light intensity and double inoculation resulted in the highest root biomass and nodule numbers. Mycorrhizae and rhizobium have a synergistic relationship to nodulation and root growth. Double inoculation with mycorrhizae and rhizobium efficiently increased root biomass and the number of nodules under low or high light intensity.</p>


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