Relative Mycorrhizal Dependency Research Articles

Effect of AM Fungi on Infectivity of Pythium Aphanidermatum in Curcuma Longa L.

Curcuma longa L. (Turmeric) a perennial herb belongs to Zingiberaceae. It’s highly grown for its remarkable medicinal uses. Apart from medicinal properties and importance; Turmeric has not been emphasized much with respect to agricultural view. Sustainable agriculture is need of hour and hence it must be brought in practice on large scale. Arbuscular Mycorrhizal (AM) fungi has mutually beneficial relationship with the roots and support plants during biotic and abiotic stress. The function of AM fungi in different morphological parameters when Turmeric under biotic stress shows scanty records so far. Existing research studies are intended to evaluate an influence of AM fungi on Turmeric plant during biotic stress. During this investigation Turmeric plants were assessed for Growth and Vigour Index, relative mycorrhizal dependency, some biochemical contents and fresh weight of the rhizome. Statistical analysis of the results obtained showed strongly significant results.

Detection of Tirmania pinoyi in Roots of Inoculated Cistaceae Plant Species by Nested Polymerase Chain Reaction

Desert truffles are edible hypogeous fungi, which grow in arid and semiarid areas of the Mediterranean region. They play an important role in the maintenance of rangelands by preventing erosion and desertification. In recent years, rangelands have experienced serious crises due to global warming and groundwater scarcity. One of the ways to improve rangelands is to use desert truffles as part of conservation or restoration efforts. For these reasons it is important to study the mycorrhizal association of these fungi with rangeland plants. For the first time, we investigated the mycorrhizal association of the desert truffle (Tirmania pinoyi) with the perennial plant species Helianthemum lippii, Helianthemum almeriense, Cistus laurifolius, and Cistus ladanifer. We inoculated all four plant species with T. pinoyi and found the presence of an ectendomycorrhizal association with varying degrees of sheath development. Our results shows that H. lippii is a suitable plant host for T. pinoyi, and the mycorrhization rate and relative mycorrhizal dependency in this native plant were about 90% and 57.85%, respectively, and higher than the other three plant species. The effect of the mycorrhizal fungus on host growth (root weight, root height, shoot weight, shoot height, plant height, and plant weight) was statistically significant compared with noninoculated plants. To detect the roots colonized by T. pinoyi, a polymerase chain reaction (PCR)-based diagnostic method was developed with the species-specific primer pairs FTiPi and RTiPi designed from the sequence of the internal transcribed space regions (ITS1 and ITS2). The specificity of the primers was verified by PCR analysis of DNA from T. pinoyi specimens and other desert truffles. The method detected T. pinoyi in inoculated root plants, and no cross-reactions were observed with any other tested desert truffles. This species-specific PCR method is suitable for quick, simple, and reliable detection of T. pinoyi mycorrhizas.

Response to Inoculation with Arbuscular Mycorrhizal Fungi of Two Tomato (<i>Solanum lycopersicum</i> L.) Varieties Subjected to Salt Stress under Semi-Controlled Conditions

Salinity is a major problem that seriously impacts agricultural production, particularly that of tomato (Solanum lycopersicum L.). However, the plant has the ability to associate with Arbuscular Mycorrhizal Fungi to better tolerate salt stress. Thus, thanks to the extension of the AMF hyphae, the hydromineral nutrition and the tolerance to excess toxic ions (Na+ and Cl-) of the plant are optimized. In this context, the contribution of AMF to the salt stress tolerance of two tomato varieties under semi-controlled conditions was studied. To do this, the frequency and intensity of mycorrhization, the relative mycorrhizal dependency, the survival rates, the aerial and root dry weights, the mineral (P, K+, Na+) and proline contents of the plants subjected to four levels of salinity [0, 70, 140 and 210 mM of NaCl] were evaluated. All the parameters assessed appeared to be dependent on the variety, the fungal strain and the NaCl concentration. With the Lady Nema variety, inoculation with the Claroideoglomus etunicatum strain at [NaCl 140 mM] resulted in the highest frequencies (54%), intensities (40.47%), and relative mycorrhizal dependencies (19.65%). This same symbiotic couple recorded high survival rates (55%) and aerial (2.03 g) and root (0.50 g) dry weights. Significant contents of K+ (Leaves: 7.5 mg⋅g-1; Roots: 4.4 mg⋅g-1 of dry matter), P (Leaves: 15.15 mg⋅g-1 of dry matter) and proline (975 nmoles⋅g-1 of fresh matter) were also recorded by this pair, with the lowest Na+ contents (Leaves: 1.93 mg⋅g-1; Roots: 0.96 mg⋅g-1 of dry matter). For the Mongal variety, at [NaCl 140 mM], the highest frequencies (50.36%), intensities (35.14%) and relative mycorrhizal dependencies (43.95%) were obtained thanks to inoculation with Rhizophagus fasciculatus. The highest survival rates (59%) and aerial (2.58 g) and root (0.79 g) dry weights were also obtained with this symbiotic couple. The contents of K+ (Leaves: 6.1 mg⋅g-1; Roots: 3.09 mg⋅g-1 of dry matter), P (Leaves: 12.49 mg⋅g-1 of dry matter) and proline (942 nmoles⋅g-1 of fresh matter) the most important and those in Na+ the lowest (Leaves: 2.03 mg⋅g-1; Roots: 1.53 mg⋅g-1 of dry matter) were also recorded for this same pair. Thus, the best fungal partner for the Lady Nema variety is C. etunicatum, followed by F. mosseae and R. fasciculatus, while for the Mongal variety it is R. fasciculatus, followed by C. etunicatum and F. mosseae.

Response to Inoculation with Arbuscular Mycorrhizal Fungi of Two Tomato (<i>Solanum lycopersicum</i> L.) Varieties Subjected to Water Stress under Semi-Controlled Conditions

In arid and semi-arid regions, the growth and development of cultivated plants, especially tomato (Solanum lycopersicum L.), are severely limited by water deficit. Thus, to cope with this constraint, the plant establishes symbiotic relationships with arbuscular mycorrhizal fungi (AMF) in the soil whose extension of the hyphae allows a better and deeper exploration; this notably improves the hydromineral nutrition of the plant. Therefore, the choice of fungal partner becomes crucial for the establishment of a crop in water-deficient soil. In this context, the contribution of AMF to the water stress tolerance of two varieties of tomato plants was assessed under semi-controlled conditions. Parameters, such as the mycorrhizal frequency, intensity of mycorrhization, relative mycorrhizal dependency, growth, and biochemical parameters (carbon, nitrogen, phosphorus, and proline contents) of plants subjected to three levels of water stress (T100, T70, and T30), were evaluated. The highest frequencies and intensities of mycorrhization and relative mycorrhizal dependencies were obtained with plants of the Xewel variety inoculated with Rhizophagus fasciculatus (F: 95.24%, 88.35%, and 13.64%; M: 40.52%, 37.52%, and 11.22%; D: 23.7%, 54.4%, and 78.82%) and in those of the Lady Nema variety inoculated with Claroideoglomus etunicatum (F: 95.12%, 87.01%, and 15.25%; M: 40.66%, 37.99%, and 11.42%; D: 19.27%, 57.01%, and 70.98%), respectively at water regimes of T100, T70 and T30. These same symbiotic couples recorded, at T30, the best survival rates (+ 40%) and the higher aerial (77% and 74%) and root dry weights (80% and 59%). Plants of the Xewel variety inoculated with R. fasciculatus recorded the highest contents of carbon (T70: 30.59% and T30: 21.55%) and phosphorus (T70: 0.18% and T30: 0.17%). Plants of the Lady Nema variety recorded the highest nitrogen contents with 3.51% and 3.20%, respectively at T70 and T30. Plants of the Lady Nema variety, inoculated with C. etunicatum, also recorded the highest proline contents (572.25, 739.44, and 1165 nmoles•g−1 of fresh material), followed by those of the Xewel variety inoculated with R. fasciculatus (580.36, 763.65, and 1112.11 nmoles•g−1 of fresh matter), respectively at T100, T70, and T30. For the Lady Nema variety, the best fungal partner is C. etunicatum, followed by R. fasciculatus and, finally, Funneliformis mosseae. However, for the plants of the Xewel variety, R. fasciculatus is the most efficient, followed by F. mosseae and C. etunicatum. This suggests that, in tomatoes, the efficiency of mycorrhizal symbiosis under water stress conditions is not only dependent on the host plant but on both associated symbiotic partners. Hence, it is a need for screening to identify the best symbiotic couples in a stressful environment.

Effect of single or dual inoculation of the arbuscular mycorrhizal fungus Glomus mosseae and root-nodulating rhizobacteria on reproduction of the burrowing nematode Radopholus similis on non-leguminous and leguminous banana intercrops

The bio-protective effect of either single or dual mycorrhizal (AMF) and rhizobial colonisation of the roots of non-leguminous and leguminous banana intercrops differing in host response to Radopholus similis on the reproduction of this important migratory endoparasitic nematode was examined. Included in the study were sorgho-Sudan grass (good R. similis host), sweet potato and common bean (intermediate hosts), soybean and sunn hemp (poor hosts), and marigold (non-host). Significant plant growth-promoting effect of single AMF and rhizobial colonisation in the good and intermediate R. similis hosts sorgho-Sudangrass (AMF) and common bean (AMF and rhizobium), respectively, was observed whereas this plant growth-promoting effect was absent in the other intercrops with the exception of sunn hemp with significant plant growth-promoting effect of AMF colonisation on fresh root weight. An additive plant growth-promoting effect of dual AMF and rhizobial colonisation (on fresh shoot weight) was only observed in the poor R. similis host soybean. Single AMF and rhizobial colonisation also resulted in a significant bio-protective effect against R. similis in sorgho-Sudangrass (AMF), sweet potato cv. Inzovu (AMF) and common bean (AMF and rhizobium). The growth-promoting and bio-protective effects of AMF colonisation were clearly present in the good and intermediate R. similis hosts with moderate to high relative mycorrhizal dependency (RMD) values ranging from 47% (sorgho-Sudangrass) to 65% (common bean) but absent in the intermediate R. similis host sweet potato, which had a negative RMD value, and in the poor and non- R. similis hosts. Overall, no suppressive effect of R. similis infection on AMF and rhizobial colonisation was observed except in soybean and sunn hemp in which AMF colonisation was significantly reduced.

Improvement of the yield-related response of mycorrhized Lallemantia iberica to salinity through sulfur-oxidizing bacteria.

To investigate the effects of salinity as a serious environmental limiter of productivity on the yield-related traits of Lallemantia iberica, a split-plot experiment was performed for 2 years (2017-2018) based on a randomized complete block design with three replications at Urmia University (37°33'09″N, 45°05'53″E). The main plots included salinity stress at two levels (6.72 dS m-1 , and 0.91 dS m-1 as control), and subplots were inoculants at four levels (Funneliformis mosseae, Thiobacillus sp., F.mosseae + Thiobacillus sp., and no inoculation). In the saline condition, serious reductions in yield and yield components (numbers of capsules per plant, seeds per capsule, and seeds per plant, 1000-seed weight, seed and biological yields), concentrations of leaf phosphorus and potassium, and relative mycorrhizal dependency were observed, but against the harvest index the leaf sulfur and sodium contents were increased. Moreover, all morphological traits (plant height, number of branches and leaves, leaf weight, stem weight, and ratio of leaf weight to stem weight) were decreased under salinity conditions. Mycorrhizal inoculation enhanced the salinity-induced reduction of yield and morphological traits to some extent. Inoculation with Thiobacillus had superiority in some of the yield and morphological characteristics compared with those in the non-inoculated plants. Salinity stress can significantly affect the yield, morphological characteristics, nutrients content, and mycorrhizal dependency of L.iberica plants. This study exhibited the significant effects of single and simultaneous applications of F.mosseae and Thiobacillus on plant growth and yield in saline soils. © 2020 Society of Chemical Industry.

Ketergantungan Tiga Jenis Tanaman Kehutanan terhadap Mikoriza pada Media Tanah Bekas Tambang Pasir Silika

One effort to support the success of reclamation and rehabilitation of ex-silica sand mines is to improve the quality of seedling planted with mycorrhizal inoculation. Each plant has a mycorrhizal dependency which varies depending on the plant species and the level of soil fertility. This study aimed to analyze the mycorrhizal dependency of Kadam (Anthocephalus cadamba), Red Sengon (Albizia chinensis), and Kaliandra (Calliandra calothyrsus) grown on soil growing media from post silica sand mining and amended with compost and lime. The study used completely randomized design with a split plot design consist of two factors, first factor was mycorrhizal inoculation in the form of MycoSilvi inoculum, consisting of two levels and the second factor was soil ameliorant in the form of lime and compost consisting of six levels, each treatment was repeated five times. The results showed that the treatment of lime and MycoSilvi addition showed the highest percentage of mycorrhizal dependency on Kadam, Red Sengon and Kaliandra seedlings, which were 76, 62, and 59% respectively. The addition of lime and compost decreased the degree of relative mycorrhizal dependency of three plants species tested, in line with increasing available P in soil growth medium. Keywords: mycorrhizal dependency, MycoSilvi, post mined soil, soil ameliorant

Variations in response of determinate common bean (Phaseolus vulgaris L.)genotypes to arbuscular mycorrhizal fungi (AMF) inoculation

This study evaluated seedling traits (shoot/root length, fresh and dry weights of shoots/roots, number of leaves, shoot diameter), phosphorus (P) content, mycorrhizal colonization (MC), and relative mycorrhizal dependency (RMD) of 21 common bean genotypes inoculated by 4 different arbuscular mycorrhizal fungi (AMF) [Glomus intraradices (Gi), Glomus mosseae (Gm), Gigaspora margarita (Gim), and commercial AMF (cAMF)] in a growth chamber under controlled growing conditions. With the exception of shoot diameter, inoculated plants had better seedling traits than noninoculated plants. P content of shoot was also higher in inoculated plants than in noninoculated plants. Of the 20 genotypes and Nadide cv. examined, 5 responded positively and 3 responded negatively to inoculation with all AMF types. Great variations in RMD and MC were observed, with the highest RMD and MC in the T120 (69.54%) and T71 (81.09%) genotypes and the lowest in the V77 (1.26%) and V78 (31.42%) genotypes. Positive correlations were found between RMD and seedling traits, with the exception of shoot length as well as root length, P content, and colonization. MC was significantly correlated only with P content.

PERTUMBUHAN KACANG HIAS (Arachis pintoi) PADA MEDIA TANAH PASCA PENAMBANGAN BATUBARA YANG DIPERKAYA MIKORIZA, KAPUR DAN PUPUK NPK

This study aimed to determine the effects of the provision of arbuscular mycorrhizal fungi (AMF), the provision of lime, and the provision of NPK fertilizer, and the interaction effect of the provision of Arbuscular mycorrhizal fungi (AMF), lime and NPK fertilizers in promoting the growth of pinto peanut in the soil media of post-mining land. The research method used was a completely randomized design (CRD) three-factor factorial with the first factor is the type of inoculant FMA (M) = 3 levels, the second factor is the provision of lime (K) = 3 levels, and the third factor is the NPK fertilizer (P) = 3 levels. These results indicated that the interaction between AMF Glomus sp. and NPK fertilizer dose of 1 gram/polybag can increase height increase pinto peanut plants for 34.16 % of the controls. The interaction between AMF Gigaspora sp. The lime dose of 50 % Al-dd and Fertilizers NPK dose of 1 gram/polybag can increase the growth of leaves pinto peanut plants at 108.33 % of the controls. The interaction between AMF Glomus sp. and NPK fertilizer dose of 2 grams/polybag can increase canopy and root biomass pinto peanut plants at 245.21 % of the controls. The interaction between AMF Glomus sp. and NPK fertilizer dose of 2 grams/polybag can increase canopy and root biomass pinto peanut plants at 245.21 % of the controls. Level relative mycorrhizal dependency (RMD) was influenced by the type of AMF plant inoculated host. Highest RMD shown in pinto peanut using AMF Glomus sp. is 31.99% at moderately dependent.

DINÁMICA DEL CRECIMIENTO DE PAPAYA POR EFECTO DE LA INOCULACIÓN MICORRÍZICA Y FERTILIZACIÓN CON FÓSFORO

Papaya is a major fruit export for Mexico; however, the international market is increasingly demanding bio quality, representing a significant production challenge due to the need for bio-ecological and sustainable technologies. Arbuscular mycorrhizal fungi (AMF) can contribute significantly to plant nutrition, particularly in phosphorous (P) uptake. The use of AMF in papaya is yielding encouraging results, but there is a need to define certain aspects regarding agronomic management of AMF-based products. The aim of this study was to evaluate the effect of AMF Glomus sp. Zac-2 and P fertilization on the growth of Cera var. papaya during the nursery stage. For this, a 2 x 3 x 4 tri-factorial experiment (AMF inoculation, P source and P dose) was conducted in a completely randomized design. The variables plant height (PH) and stem diameter (SD) were evaluated every 15 days; dry biomass (DB) and spore density (SD) were assessed at the end of the experiment (90 days). From the DB of plants with and without mycorrhizal inoculation, the relative mycorrhizal dependency index (RMDI) was calculated. Data analysis showed significant differences (P ≤ 0.05) between papaya plants with and without AMF for PH, SD and DB, regardless of the P dose and source. At 75 days, growth increases of more than 500 % were recorded in plants with AMF compared to the non-inoculated plants; the RMDI was 99 %. These results suggest that AMF inoculation in papaya during the nursery phase can benefit further growth in the field. ADDITIONAL KEYWORDS: Carica papaya L., superphosphate, phosphate rock, mycorrhizae, mycorrhizal symbiosis, phosphorus uptake.

Response of Acacia senegal (L.) Willd. to inoculation with arbuscular mycorrhizal fungi isolates in sterilized and unsterilized soils in Senegal

The benefits of inoculation with six arbuscular mycorrhizal fungi (AMF) isolates (Glomus aggregatum, G. fasciculatum, G. intraradices, G. manihotis, G. mosseae, and G. verriculosum) were investigated on seedlings of Acacia senegal (L.) Willd., a multipurpose tree legume highly valued for arabic gum production. Mycorrhizal root colonization, plant growth and relative mycorrhizal dependency (RMD) were measured in A. senegal seedlings growing in soils from three geographical sites in Senegal (Dahra, Bambey and Goudiry) and two soil conditions (sterilized vs unsterilized) in the glasshouse. The impact of inoculation on mycorrhizal root colonization and plant growth depended on AMF isolates, soil origins and soil conditions. Mycorrhizal root colonization and plant growth were increased in sterilized soils regardless of soil origin and AMF isolates. The degree of RMD of A. senegal seedlings varied with soil origin, soil condition and AMF isolates. A. senegal showed the highest RMD values, reaching a maximum of 45 %, when inoculated with G. manihotis. However, in unsterilized soils, no significant effect of AMF inoculation on plant growth was observed despite significant root colonization with certain AMF isolates in Dahra and Goudiry soils. This indicates that the most infective AMF isolates were not the most effective and unsterilized soils may contain effective mycorrhizal propagules. In conclusion, it is important to consider the native mycorrhizal component of the soils before harnessing mycorrhizal inoculation programs for sustainable agroforestry systems.

Effectiveness of arbuscular mycorrhizal fungi in protection of maize (Zea mays L.) against witchweed (Striga hermonthica Del Benth) infestation

Striga hermonthica is one of the most important obligate root hemiparasitic weeds of cereals such as maize and sorghum. This study investigated the impact of arbuscular mycorrhizal fungi (AMF) on theStriga-maize host interaction and its potential application in management of Striga infestation. Two maize varieties: Striga-susceptible Nyamilambo and Striga-tolerant KSTP94; three species of AMF; Glomus etunicatum, Scutellospora fulgida, Gigaspora margarita and Striga hermonthica seeds were used in a greenhouse experiment. Colonization of maize roots was fastest with Glomus spp. (51.98%) than other AMF species; however, Striga infestation reduced root colonization but conversely increased relative mycorrhizal dependency (Glomus spp. = 6.12%) in both maize cultivars. Inoculation of Nyamilambo maize cultivars with AMF reduced Striga plant incidence (9.50) and biomass (5.40 g) to significantly lower (4.90 and 3.82 g) levels. Mycorrhizal Nyamilambo and KSTP94 had higher nitrogen (154.01 and 116.88 mg) and phosphorus (25.33 and 31.07 mg) content compared to non-mycorrhizal cultivars (63.37 mg N and 16.81 mg P) in absence and presence of Striga infestation. While mycorrhizal maize had increased height (100.50 to 135.20 cm) and biomass (75.70 to 87.54 cm), their Striga damage score (4.07) was significantly lower than with non-mycorrhizal maize (8.10). Glomus spp. had most significant positive effect compared to both Gigaspora and Scutellospora spp. In conclusion, AMF inhibits germination and reduces growth of Striga hermonthica while enhancing maize host growth and development. Key words: Arbuscular mycorrhiza, Striga, maize growth.

The effects of arbuscular mycorrhizal fungi on the seedling growth of four hybrid cucumber (Cucumis sativus L.) cultivars

The effectiveness of different arbuscular mycorrhizal fungi (AMF) on different hybrid cucumber cultivars has not been well documented, even under normal seedling conditions. The present study therefore aimed to evaluate colonization, nutrient uptake, dependency, and other seedling traits of 4 cucumber hybrids (Ceren F_1, Beta F_1, Silyon F_1 and Maraton F_1) inoculated by 3 different AMF [Glomus intraradices (Gi), Glomus etunicatum (Ge) and Gigaspora margarita (Gm)]. Traits were evaluated in a growth chamber experiment consisting of a 4 × 4 factorial design (4 cucumber hybrids, 3 AMF plus 1 control) with 3 random replications. AMF-inoculated cucumber seedlings had shorter hypocotyledons and wider and longer cotyledons than non-inoculated seedlings. Gm-inoculated seedlings had the narrowest stem diameter and lowest leaf number. AMF-inoculated seedlings had shorter shoots and longer roots than noninoculated ones. There was significant mycorrhizal effect on the iron (Fe) content of shoots and the mycorrhizal colonization rate in roots. Relative mycorrhizal dependency (RMD) varied widely among the hybrid cucumber cultivars tested. It is thought that the determination of high-RMD cultivars could lead to improvements in cucumber seedling production in the future.

Mycorrhizal dependency of mangaba tree under increasing phosphorus levels

The objective of this study was to evaluate the mycorrhizal dependency of mangaba tree (Hancornia speciosa) plantlets, under increasing levels of phosphorus fertilization. The experimental design was completely randomized in a 4×5 factorial arrangement with three mycorrhizal fungi inocula - Gigaspora margarita, Glomus etunicatum, or a pool of native mycorrhizal fungi (Acaulospora longula, Glomus clarum, Gigaspora albida, Paraglomus sp.) -, and a nonmycorrhizal control, in combination with five levels of phosphorus applied to the substrate: 0, 25, 50, 75, and 100 mg kg-1. After 180 days of growth, plantlets with inoculation of native mycorrhizal pool produced more shoot and root dry biomass and had higher shoot phosphorus content and accumulation. The noninoculated control showed the lowest values, independently of the phosphorus level. The highest relative mycorrhizal dependency occurred with the inoculation of native mycorrhizal fungi. Plants with mycorrhizal fungi did not respond to phosphorus addition above 50 mg kg-1. Mangaba tree is highly dependent on mycorrhiza, but the degree of dependency varies according to phosphorus levels and fungal inocula. In general, mangaba tree is more responsive to mycorrhizal fungi inoculation than to phosphorus addition.

Responses of some different pepper ( Capsicum annuum L.) genotypes to inoculation with two different arbuscular mycorrhizal fungi

Eight different pepper genotypes inoculated by two different arbuscular mycorrhizal fungi (AMF) [ Glomus intraradices ( Gi) and Gigaspora margarita ( Gm)] in a growth chamber experiment under normal seedling growing conditions were evaluated for seedling traits, colonization and relative mycorrhizal dependency (RMD). In general, inoculated plants had greater dry weights compared to non-inoculated plants. Five cultivars responded positively to inoculation with AM fungi and three responded negatively. A great variation in mycorrhizal colonization dependency was observed among the pepper genotypes, with the N52 genotype showing the highest RMD and the Karaisali genotype the lowest. RMD and dry weights of pepper genotypes were inversely correlated.

Contrasting responses to ectomycorrhizal inoculation in seedlings of six tropical African tree species

Five caesalpinioid legumes, Afzelia africana, Afzelia bella, Anthonotha macrophylla, Cryptosepalum tetraphylum and Paramacrolobium coeruleum, and one Euphorbiaceae species, Uapaca somon, with a considerable range in seed sizes, exhibited different responses to inoculation by four species of ectomycorrhizal (ECM) fungi, Scleroderma dictyosporum, S. verrucosum, Pisolithus sp. and one thelephoroid sp. in greenhouse conditions. Thelephoroid sp. efficiently colonized seedlings of all of the five caesalpinioid legumes except U. somon, but provided no more growth benefit than the other fungi. Thelephoroid sp. and S. dictyosporum colonized seedlings of U. somon poorly, but stimulated plant growth more than the other fungi. The relative mycorrhizal dependency (RMD) values of the caesalpinioid legumes were never higher than 50%, whilst U. somon had RMD values ranging from 84.6 to 88.6%, irrespective of the fungal species. The RMD values were negatively related to seed mass for all plant species. Potassium concentrations in leaves were more closely related than phosphorus to the stimulation of seedling biomass production by the ECM fungi. Our data support the hypothesis that African caesalpinioid legumes and euphorbe tree species with smaller seeds show higher RMD values than those with the larger seeds.

English

  A greenhouse experiment was carried out in a sandy soil with a low available phosphorus to evaluate responsiveness of four Solanum aethiopicum cultivars to indigenous arbuscular mycorrhizal fungi. Results showed clear interaction between genetic variability of cultivars and fungal isolates on shoot biomass and on mineral status. Arbuscular mycorrhizal fungi can be ranked as Glomus aggregatum > Glomus mosseae > Glomus versiforme for improving yield as well as nitrogen, phosphorus, and potassium acquisition of Solanum cultivars.   Key words: Arbuscular mycorrhizal fungi, Solanum aethiopicum, sterile soil, relative mycorrhizal dependency.

Effects of an arbuscular mycorrhizal fungus and two plant-parasitic nematodes on Musa genotypes differing in root morphology

In this study, the effect of an arbuscular mycorrhizal fungus (AMF) and two migratory endoparasitic nematodes on Musa plant growth, including the root system, were examined. In addition, the AMF-nematode interaction was studied. Seven Musa genotypes with different root systems were selected. Based on their relative mycorrhizal dependency, two genotypes (Calcutta 4 and Obino l'Ewai) were selected for AMF-nematode interaction studies. The experiments were performed under greenhouse conditions. Mycorrhization with Glomus mosseae resulted in a significantly better plant growth even in the presence of nematodes. The effect of AMF on the root system was genotype-dependent and seemed to be related to the relative mycorrhizal dependency of the genotype. The nematodes also affected the root system, decreasing branching. Nematode population densities were significantly reduced in the presence of AMF, except for Pratylenchus coffeae in Obino l'Ewai. In the root system, it appeared that the decreased branching caused by the nematodes was counterbalanced by the increased branching caused by the AMF.

Relative mycorrhizal dependency and mycorrhiza-nematode interaction in banana cultivars ( Musa spp.) differing in nematode susceptibility

Four Musa cultivars, differing in nematode susceptibility, were selected to study their relative mycorrhizal dependency and to study the interaction between the arbuscular mycorrhizal fungus (AMF), Glomus mosseae, and two migratory endoparasitic nematodes, Radopholus similis and Pratylenchus coffeae. Mycorrhization with G. mosseae resulted in significantly better plant growth, even in the presence of R. similis and P. coffeae. No differences in relative mycorrhizal dependency (RMD) were observed among the four cultivars. G. mosseae suppressed nematode population build-up in Grande Naine and Pisang Jari Buaya. Only in the case of R. similis (Indonesian population) in Pisang Jari Buaya, no significant suppression was observed. In the case of P. coffeae, the AMF reduced the damage in the roots, caused by the nematodes. For R. similis, no reduction of damage was observed. In all, except one experiment, the frequency of the mycorrhizal colonisation was negatively affected by the nematodes.

Mycorrhizal dependency of passion fruit (Passiflora edulisf.flavicarpa)

Mycorrhizal dependency of passion fruit (Passiflora edulis f. flavicarpa). Abstract — Introduction. Brazil is one of the most important producers of passion fruits. Inoculation with arbuscular mycorrhizal fungi (AMF) may reduce or eliminate the need for phosphate fertilization on this crop. We investigated the response of passion fruit seedlings to inoculation with AMF and phosphorus (P) supply. Materials and methods. A greenhouse experiment was carried out in a factorial design. The seedlings were inoculated with 100 spores per plant of single or mixed AMF inoculum on sterilized or non-sterilized soil which was amended with (11 or 30) mg P 〈 dm -3 soil applied as superphosphate or used unfertilized (4 mg P 〈 dm -3 soil). Relative mycorrhizal dependency (RMD) of passion fruit was estimated for each treatment of inoculation, soil sterilization, and P level, by expressing the difference between the dry mass of mycorrhizal plants and non-mycorrhizal plants as a percentage of the dry mass of mycorrhizal plants. Results. Inoculation was effective only on plants grown in sterilized soil with (4 or 11) mg P 〈 dm -3 soil. Plants were facultatively mycotrophic when associated with AMF and when receiving a supply of 30 mg P 〈 dm -3 soil. Seedlings in unfer- tilized soil with 4 mg P 〈 dm -3 soil were excessively dependent on the mycorrhizal associa- tion. In soil with 11 mg P 〈 dm -3 soil, seedlings were marginally to moderately dependent, depending upon the AMF species used. All inoculated seedlings, without considering soil sterilization, were marginally dependent in soil with 30 mg P 〈 dm -3 soil. In sterilized soil, independently of P, they were moderately dependent. However, in the same soil, with 30 mg P 〈 dm -3 soil, the seedlings were marginally dependent. Discussion - conclusion. The relative mycorrhizal dependency (RMD) of the passion fruit cultivar used was influenced by the species of the inoculated AMF, soil sterilization and soil P level. Passion fruit obtained significant benefit from inoculation with AMF; thus, these fungi can be used to improve plant growth even without P fertilization. Brazil / Passiflora edulis / fertilizer application / phosphate fertilizers / phosphorus / vesicular arbuscular mycorrhizae / biomass