Effect of Field Inoculation with Arbuscular Mycorrhizal Fungi on Rhizosphere Soil Structure of Paris polyphylla var. yunnanensis / 中国实验方剂学杂志

Objective:To investigate the effects of arbuscular mycorrhiza（AM） fungi inoculation on the rhizosphere soil of Paris polyphylla var. yunnanensis under field conditions，so as to provide a reference for the standardized cultivation and development of high-quality varieties of P. polyphylla var. yunnanensis. Method:The effects of inoculation with mycorrhizal fungi on the rhizosphere soil structure of P. polyphylla var. yunnanensis were observed through a combination of small-scale field inoculation test and laboratory analysis. Soil indexes were determined by soil agrochemical methods. Result:The treatment groups inoculated with exogenous AM fungi showed a regulatory effect on the infection rate and intensity of AM fungi infection in the root system of P. polyphylla var. yunnanensis. After treatment with AM fungi，the soil pH was basically not affected，and the contents of organic matter，available nitrogen，available phosphorus，and available potassium increased. Moreover，the number of fungi decreased，the number of bacteria and actinomycetes increased，and soil enzyme activities increased. The results of correlation analysis showed that there was a significant positive correlation among the soil physical and chemical indexes，especially the bacterial number and the three types of phosphatases showed extremely significant correlation （r=0.849，0.800，0.804，P<0.01）. Conclusion:The application of the two mixed fungicides could increase the number of microorganisms and enzyme activities in the rhizosphere of P. polyphylla var. yunnanensis， and there was a certain synergy effect among the soil factors. Among the three field trials，the effects in Anshun，Guizhou and Wanzhou，Chongqing were more ideal，which provided a theoretical and practical basis for large-scale promotion of P. polyphylla var. yunnanensis in the field.

Effect of Arbuscular Mycorrhizal Fungi Inoculation on Physical and Chemical Properties of Rhizosphere Soil of Paris polyphylla var. yunnanensis / 中国实验方剂学杂志

Objective:To investigate the infection rate of Paris polyphylla var. yunnanensis at different periods，the changes of mineral nutrients in rhizosphere soil and the correlation among the factors under different arbuscular mycorrhizal （AM） fungi conditions. Method:28 kinds of AM fungi were inoculated into the seedlings of P. polyphylla var. yunnanensis by single factor pot experiment. The samples were collected in August （fruit ripening period） and November （senescence period） to analyze the infection rate and the physical and chemical properties of rhizosphere soil. Result:The mycorrhizal infection rate of each treatment group was 75%-100% in the fruit ripening period and senescence period. The contents of easily extracted glomalin and total glomalin in rhizosphere soil increased to different degrees in these two periods as compared with CK group， the pH of rhizosphere soil in the two treatment groups showed an increasing trend， the content of organic matter in rhizosphere soil decreased significantly in the fruit ripening period in all the treatment groups，and the organic matter in rhizosphere soil in the senescence period showed no significant differences. The total N and K contents in rhizosphere soil decreased in both periods， and the other physical and chemical properties of rhizosphere soil increased or decreased without significant change regularity. Correlation analysis showed that the infection rate was correlated with the physical and chemical properties of rhizosphere soil to a certain degree. Conclusion:Inoculation of AM fungi can affect the physical and chemical properties of rhizosphere soil of P. polyphylla var. yunnanensis to some extent，and provide reference value for the application of AM fungi in the cultivation of traditional Chinese medicine.

Efectividad de hongos micorrizo-arbusculares nativos en suelos con diferentes usos agropecuarios / Native arbuscular mycorrhizal fungi effectiveness in soils with different agricultural uses

RESUMEN Objetivo. Determinar la efectividad de hongos micorrizo-arbusculares (HMA) de suelos con diferentes usos agropecuarios, en el valle medio del río Sinú, Colombia. Materiales y métodos. Bajo condiciones de invernadero se realizó el experimento, donde se utilizó como planta indicadora Leucaena leucocephala, la cual se sembró en materos con suelo de un Andisol (horizonte B) usado como sustrato. Este sustrato, se inoculó separadamente con muestras de siete suelos (horizonte Ap), como fuente de HMA, provenientes del Centro de Investigación Turipaná de Agrosavia. Como controles se incluyeron inoculación con HMA Glomus fasciculatum y uno no-inoculado El efecto de la inoculación micorrizal se evaluó mediante el monitoreo del contenido de P foliar en las plantas de L. leucocephala, en función del tiempo hasta 64 días cuando se determinó la masa seca de su parte aérea y la colonización micorrizal. Resultados. El crecimiento de L. leucocephala y el contenido de P foliar fue significativamente superior cuando el suelo se inoculó con G. fasciculatum, en comparación a aquel observado con los demás tratamientos. De igual forma, la colonización micorrizal fue muy alta en las raíces de L. leucocephala que crecieron en el suelo inoculado con G. fasciculatum e inferior en los otros tratamientos. Conclusiones. Los resultados indican que los HMA nativos de suelos con diferentes usos, provenientes del C.I Turipaná de Agrosavia, exhibieron bajo potencial para desarrollar simbiosis micorrizal, lo que limitó el crecimiento y la concentración de P foliar en la planta hospedera.

ABSTRACT Objective. To determine the effectiveness of mycorrhizal-arbuscular fungi (AMF) of soils with different agricultural uses, in the middle valley of the Sinú river, Colombia. Materials and methods. The experiment was carried out under greenhouse conditions, where Leucaena leucocephala was used as the indicator plant, which was planted in masons with an Andisol soil (horizon B) used as a substrate. This substrate was inoculated separately with samples from seven soils (Ap horizon), as a source of AMF, from the Turipaná Research Center in Agrosavia. As controls we included inoculation with HMA Glomus fasciculatum and one non-inoculated one. The effect of mycorrhizal inoculation was evaluated by monitoring the foliar P content in L. leucocephala plants, as a function of time to 64 days, when the dry mass of its aerial part and mycorrhizal colonization was determined. Results. The growth of L. leucocephala and the foliar P content was significantly higher when the soil was inoculated with G. fasciculatum, in comparison to that observed with the other treatments. Likewise, mycorrhizal colonization was very high in the roots of L. leucocephala that grew in the soil inoculated with G. fasciculatum and lower in the other treatments. Conclusions. The results indicate that the native AMF of soils with different uses, from Turipaná, exhibited low potential to develop mycorrhizal symbiosis, which limited the growth and concentration of leaf P in the host plant.

Maize Productivity, Mycorrhizal Assessment, Chemical and Microbiological Soil Attributes Influenced by Maize-Forage Grasses Intercropping

Abstract Mycorrhizae are important components of agroecosystems and the diversification of crops stimulates the abundance of arbuscular mycorrhizal fungi and the participation of symbiosis in plant growth. This experiment examined mycorrhizal assessment, chemical and microbiological soil attributes in a maize-forage grasses intercropping compared to a maize-monocropping system. A complete randomized block design was used with crop systems installed under no-till management with three replicates, as follow: Maize (Zea mays L.); Panicum maximum Jacq. cv. Aruana; Urochloa humidicola (Rendle.) Schweickerdt.; Maize-P. maximum intercropping and Maize-U. humidicola intercropping. In 2015/2016 season, intercropping maize with Panicum maximum Jacq. cv. Aruana or Urochloa humidicola (Rendle.) Schweickerdt. promoted similar effects (Tukey test, p<0.05) to monocropped maize under no-till system on soil chemical and biochemical parameters related to carbon cycling in the soil surface layer, as well as the dynamics of arbuscular mycorrhizal symbiosis in tropical soils, managed for a period of more than six years. Similar grain yield was verified among maize crop systems. This result indicates that intercropping maize-tropical forage grasses represents an alternative for monocropped grains, a very common practice that is used in intensive management, being able to guarantee equivalent productivities and to combine grain production with crop-livestock systems. As a result, intercropping promotes the diversification of the property's income source, adding environmental gains, such as more efficient land use by cultivated plants, keeping soil constantly cultivated, storing carbon and contributing to minimize the impact of climate change on agricultural systems and the sustainability of food production.

The arbuscular mycorrhizal fungi colonizing the roots of pre-nursery stage of oil palm seedlings: Elaeis guineensis in Malaysia

Aims@#Arbuscular mycorrhizal is an obligate mutualistic symbiosis fungus which survives by forming endomycorrhizal on plant roots. The arbuscular mycorrhizal fungi are not host-specific, allowing them to form a mutualistic symbiosis with a wide range of host plants including oil palm. In Malaysia, the arbuscular mycorrhizal fungi are used as a growth enhancer for the oil palm: Elaeis guineensis. The arbuscular mycorrhizal fungi are introduced only during transplantation to the field when the ages of the seedlings are approximately one year old. As such, this study is designed to investigate the ability of the arbuscular mycorrhizal fungi to form colonisation with pre-nursery oil palm seedlings. @*Methodology and results@#Here, the arbuscular mycorrhizal fungi were introduced at the pre-nursery stage oil palm seedlings. After inoculation, the seedlings were harvested on different days, i.e. on day-3, day-7, day-14, day-21, day-40 and day-60 to determine the colonisation of arbuscular mycorrhizal fungi. We found that the arbuscular mycorrhizal fungi are able to form a mycorrhizal association with the oil palm seedling at the pre-nursery stage after 40 days of inoculation, and the arbuscular mycorrhizal fungi that formed the association are Glomus sp. and Scutellospora sp. @*Conclusion, significance and impact of study@#This study suggested that the oil palm seedling can be made into a mycorrhizal plant as early as the nursery stage before transplanting them into the plantation.

ESTIMULACIÓN DE GERMINACIÓN Y COLONIZACIÓN RADICULAR DE Diversispora trimulares POR FLAVONOIDES DE EXUDADOS RADICULARES DE Nicotiana glauca / STIMULATION OF GERMINATION OF SPORES AND ROOT COLONIZATION OF Diversispora trimulares BY FLAVONOIDS IN Nicotiana glauca ROOT EXUDATES

Los metabolitos secundarios son señales importantes en la interacción planta-microrganismos; sin embargo, los datos que corroboran el rol de los flavonoides como señales entre plantas y la simbiosis micorrízica arbuscular son limitados y aún recientes. Este estudio tiene por objetivo evaluar el efecto de flavonoides presentes en exudados radiculares de Allium porrum L., Nicotiana gluaca y Brassica oleracea var. Itálica, en la germinación de esporas y establecimiento de colonización radicular de Diversispora trimulares. Se detectaron miricetina y canferol en exudados de A. porrum, con un contenido total de flavonoides de 23,80µg g-1, de raíz seca; quercetina, en N. glauca, con 23,35µg g-1 y crisina, en B. oleracea, con 14,71µg g-1. Quercetina estimuló la germinación y la vitalidad de esporas (24%, 40%), a diferencia de crisina, que presentó un efecto inhibitorio (4%, 20%). A. porrum y N. glauca incrementaron la germinación de esporas (54%, 56%) y porcentaje de colonización de micorriza arbuscular (72%, 75%). Los resultados de la investigación mostraron una evidencia sólida del efecto de los flavonoides como moléculas estimulantes en los procesos de germinación de esporas y colonización de micorriza arbuscular.

Secondary metabolites are important signals that could determine the outcome of the plant soil microbial interactions, however, the data available that support the leading role of flavonoids in the communication of arbuscular mycorrhizal symbiosis are recent and limited. The present study examines the effect of flavonoids detected in root exudates from Allium porrum, Nicotiana glauca y Brassica oleracea var. italica on spore germination and mycorrhizal root colonization of Diversispora trimulares. Myricetin and kaempferol were detected in A. porrum root exudates with a total flavonoid content of 23.80µg g-1 dried root, quercetin in N. glauca with 23,35µg g-1 and chrysin in B. Oleracea with 14.71 µg g-1. Quercetin increased the spore germination and vitality (24%, 40%). In contrast, chrysin showed an inhibitory effect (4%, 20%). A. porrum and N. glauca increased spore germination (54%, 56%) and root mycorrhizal colonization (72%, 75%). This results evidence the effect of flavonoids on the stimulization of spore germination and stablishment of root colonization of arbuscular mycorrhizal fungi.

Formononetin associated with phosphorus influences soybean symbiosis with mycorrhizal fungi and Bradyrhizobium / Formononetina associada com fósforo influencia a simbiose de soja com fungos micorrízicos e Bradyrhizobium

Arbuscular mycorrhizal fungi play an important role on nutrient supply to plants, specially P. However, the availability of inoculants for large-scale usage in agriculture is still limited because these organisms are obligatory symbionts. The use of symbiosis stimulants such as flavonoids can be an alternative to improve the beneficial effects of mycorrhiza for plant nutrition. The aim of this study was to evaluate the effect of the isoflavonoid biostimulant formononetin (7-hydroxy, 4'-methoxy isoflavone) in combination with three levels of phosphorus fertilization on mycorrhizal colonization, nodulation, and productivity of soybean, under field conditions. A 3 x 4 factorial scheme (levels of P: 0, 60 and 120 kg ha-1 P2O5 and doses of formononetin: 0, 25, 50 and 100 g ha-1) was used with five replicates. The following parameters were quantified at full bloom: plant height, shoot dry weight, nodule number, nodule dry weight, mycorrhizal colonization, and shoot N and P concentrations. Productivity was also evaluated at the end of the crop cycle. Formononetin stimulated mycorrhizal colonization at lower levels of P (0 and 60 kg ha-1), with colonization increasing from 56 to 64%. When applied with 60 kg ha-1 P2O5, formononetin increased soybean productivity to values similar to those observed when 120 kg ha-1 de P2O5, was applied. At doses above 50 g ha-1, formononetin applied to the seeds can reduce the need of P fertilization by 50%.

Os Fungos micorrízicos arbusculares desempenham papel importante no fornecimento de nutrientes para as plantas, especialmente P. No entanto, a disponibilidade de inoculantes com esses fungos, para o uso em larga escala na agricultura é ainda limitada, porque estes organismos são simbiontes obrigatórios. O uso de estimulantes simbióticos, como os flavonóides, podem ser uma alternativa para melhorar os efeitos benéficos da micorrrização na nutrição das plantas. O objetivo neste estudo foi avaliar o efeito do isoflavonóide bioestimulante formononetina (7-hidroxi, 4'-metoxi isoflavona) em combinação com três níveis de adubação fosfatada sobre a colonização micorrízica, a nodulação e a produtividade da soja, em condições de campo. Um esquema fatorial 3 x 4 (níveis de P: 0, 60 e 120 kg ha-1 de P2O5 e doses de formononetina: 0, 25, 50 e 100 g ha-1) foi utilizado, com cinco repetições. Os seguintes parâmetros foram quantificados em plena floração: altura da planta, matéria seca da parte aérea, número e matéria seca de nódulos, colonização micorrízica, e concentrações de N e P na parte aérea das plantas. A produtividade também foi avaliada no final do ciclo da cultura. A Formononetina estimulou a colonização micorrízica em níveis mais baixos de P (0 e 60 kg ha- 1), com aumentos de 56-64%. Quando aplicado com 60 kg ha-1 de P2O5, a formononetina aumentou a produtividade da soja, alcançando valores semelhantes aos observados quando foi aplicado 120 kg ha-1 de P2O5. Em doses acima de 50 g ha- 1, a formononetina aplicada na semente pode reduzir a necessidade de fertilização fosfatada em 50%.

Effects of Arbuscular Mycorrhiza on Osmotic Adjustment and Photosynthetic Physiology of Maize Seedlings in Black Soils Region of Northeast China

ABSTRACT To investigate the effect of arbuscular mycorrhiza fungi on maize growth, osmoregulation substances and photosynthetic physiology, a popular maize variety ZD 958 was measured under potted condition. Arbuscular mycorrhiza (AM) symbiosis promoted plant growth, and enhanced plant height, leaf length, mean leaf width and dry weight. Higher soluble sugar and protein, but lower proline concentrations were detected in AM seedlings than corresponding non-AM seedlings. Quantum yield of PSII photochemistry and potential photochemical efficiency increased by arbuscular mycorrhiza fungi, meanwhile, AM plants had lower primary fluorescence but higher maximal fluorescence and variable fluorescence than non-AM plants. AM enhanced apparent quantum efficiency, maximum net photosynthetic rate, dark respiration rate and light saturation point, but reduced light compensation point. The conclusion was that, after the seedling inoculated with Glomus. tortuosum, AM symbioses could protect cell from being hurt through regulating substances related to osmotic adjustment, besides, the efficiency of light utilization, the capacity of using low light and the capacity of fitting and using high light were all increased by AM symbiosis.

Use of the arbuscular mycorrhizal fungus Glomus intraradices as biological control agent of the nematode Nacobbus aberrans parasitizing tomato

The plant-parasitic nematode Nacobbus aberrans is an endoparasite that induces gall formation in the roots and causes severe losses to diverse crops. Some populations of this nematode show preference for certain hosts, revealing the existence of "races/groups" with different behaviour and making nematode management difficult. A possible biological control alternative to reduce the damage caused by this species may be the use of arbuscular mycorrhizal fungi (AMF). In the present work, the effect of Glomus intraradices on tomato plants inoculated with the nematode at transplanting and three weeks later was tested. At 60 days, the following parameters were estimated: percentage of AMF colonization, root and aerial dry weight, number of galls and egg masses, and reproduction factor (RF=final population/initial population) of N. aberrans. AMF colonization was higher in the presence of the nematode. The use of AMF favoured tomato biomass and reduced the number of galls and RF on the plants inoculated with the nematode at transplanting.

Resposta do cafeeiro à inoculação de fungos micorrízicos arbusculares, em latossolo vermelho, do cerrado / Response of coffee plants colonized inoculation with arbuscular mucorrhizal fungi, red latosol, in cerrado

O objetivo deste trabalho foi verificar a resposta de dois cultivares de café (sensível e tolerante ao alumínio - Al), à inoculação de Gigaspora margarita e Glomus etunicatum, em Latossolo Vermelho do cerrado, com diferentes saturações por bases (30, 45 e 53 %). O experimento foi realizado em casa de vegetação, com delineamento inteiramente casualizado e em esquema fatorial 2x3x3, consistindo de 2 cultivares de (tolerante e sensível a Al), 3 tratamentos com micorriza (com inoculação de duas espécies de FMA e sem inoculação) e 3 níveis de saturação por bases do solo (V%), com cinco repetições por tratamento. As variáveis foram: altura da planta, diâmetro do caule, área foliar, massa da matéria seca da parte aérea, massa da matéria fresca de raiz, atividade da redutase do nitrato, teor de clorofila, colonização micorrízica e número de esporos. Os isolados de micorrizas proporcionaram maior crescimento do cafeeiro em solo ácido com alta concentração de Al, porém esta resposta foi verificada para ambos os cultivares quando colonizados por G. margarita. Os cultivares avaliados não mostraram diferenças quanto à tolerância ao Al quando não micorrizados.

The aim of this study was evaluate the response of two coffee cultivars (tolerant and sensitive to aluminum - Al), inoculated or not by two arbuscular mycorriza fungi (AMF), Gigaspora margarita and Glomus etunicatum, in cerrado Oxisol, with different base saturation. This experiment was conducted under greenhouse conditions, with a complete randomized design, in a 2x3x2 factorial scheme, consisting of 2 cultivars (tolerante and sensitive to Al), 3 treatments with mycorrhizal (inoculated with two species of AMF and without inoculation) and 3 levels of soil base saturation (30, 45 and 53 V%), with five replicates per treatment. The variables were: plant height, stem diameter, leaf area, shoot dry weight, root fresh weight, nitrate reductase activity, chlorophyll concentration, root colonization and number of AMF spores. Mycorrhizae isolates promoted greater response of coffee plants, in acid soil with high concentration of Al, but this response was observed for both cultivars when plants were colonized by G. margarita. The cultivars evaluated showed no differences in Al tolerance when non inoculated.

Arbuscular mycorrhizal fungi in saline soils: vertical distribution at different soil depth

Arbuscular mycorrhizal fungi (AMF) colonize land plants in every ecosystem, even extreme conditions such as saline soils. In the present work we report for the first time the mycorrhizal status and the vertical fungal distribution of AMF spores present in the rhizospheric soil samples of four species of Chenopodiaceae (Allenrolfea patagonica, Atriplex argentina, Heterostachys ritteriana and Suaeda divaricata) at five different depths in two saline of central Argentina. Roots showed medium, low or no colonization (0-50%). Nineteen morphologically distinctive AMF species were recovered. The number of AMF spores ranged between 3 and 1162 per 100 g dry soil, and AMF spore number decreased as depth increased at both sites. The highest spore number was recorded in the upper soil depth (0-10 cm) and in S. divaricata. Depending of the host plant, some AMF species sporulated mainly in the deep soil layers (Glomus magnicaule in Allenrolfea patagonica, Septoglomus aff. constrictum in Atriplex argentina), others mainly in the top layers (G. brohultti in Atriplex argentina and Septoglomus aff. constrictum in Allenrolfea patagonica). Although the low percentages of colonization or lack of it, our results show a moderate diversity of AMF associated to the species of Chenopodiaceae investigated in this study. The taxonomical diversity reveals that AMF are adapted to extreme environmental conditions from saline soils of central Argentina.

Role of arbuscular mycorrhiza fungi on tolerance to salinity of the tree legume Albizia lebbeck (L.) inoculated by Rhizobium.

Myrica esculenta (Myricaceae) and Syzygium cumini(Myrtaceae), the Indian traditional fruits The effect of different level of salinity on growth, nodulation and Nitrogen fixation of single and dual inoculated tree legumes which help arbascular mycorrhizal fungi (AMF) Acaulospora laevis Gerd. and Trappe with Rhizobium bacteria in the presence of different levels of salinity (concentration of NaCl) conducted in earthen pots in a completely randomized block design with three replications resulted in effective plant growth, shoot and root biomasses, nodulation and N2 fixation. The effect of different levels of salinity (concentration of NaCl) on growth, nodulation and N2 fixation of single (Rhizobium or AMF alone) and dual inoculated (Rhizobium + AMF ) tree legume has a pot culture experiment using The parameter growth , nodulation, nitrogen fixation and % AMF colonization of roots were considerable influenced with the increase in salt concentration from 0.5 % to 4.0 % NaCl. It was observed that the mycorrhizal tree legume (inoculated with the most preferred AMF Acaulospora laevis) performed better in the increasing levels of salinity in comparison to non-mycorrhozal ones. These investigations suggested a protective role play by AMF in providing resistance to the tree legume against injurious effects of salinity. Inoculation of efficient strain of AMF (Acaulospora laevis) during the course of study, prevented the injurious effects of salinity in the test plants due to enhanced water and sustainable nutrient uptake thereby promoting growth, nodulation and biogeochemical N2 cycle (fixation of nitrogen) of the tree legume under investigation.

Triple inoculation with Bradyrhizobium, Glomus and Paenibacillus on cowpea (Vigna unguiculata) [L. ] walp. )development. (au)

The use of microorganisms to improve the availability of nutrients to plants is of great importance to agriculture. This study aimed to evaluate the effect of triple inoculation of cowpea with arbuscular mycorrhizal fungi (AMF), plant growth-promoting bacteria (PGPB) and rhizobia to maximize biological nitrogen fixation (BNF) and promote plant growth. The experiment was conducted in a greenhouse using cowpea plants (Vigna unguiculata L. Walp cv. IPA 206). The treatments included inoculation with strains of Bradyrhizobium sp. (BR 3267 and EI - 6) individually and as a mixture, an absolute control (AC) and mineral nitrogen control (NC), all combined with the presence or absence of native AMF (Glomus etunicatum) and PGPB (Paenibacillus brasilensis - 24) in a 5x2x2 factorial design. All treatments were replicated three times. Contrasts were performed to study the treatment of variables. Inoculation with Bradyrhizobium sp. (BR 3267 and EI - 6) and G. etunicatum favored nitrogen acquisition and phosphorus availability for the cowpea plants. Inoculation with P. brasilensis - 24 increased colonization by Bradyrhizobium sp. and G. etunicatum and promoted cowpea growth, while the nitrogen from symbiosis was sufficient to supply the plants nutritional needs.

Relación entre ssociación micorrícica con el esado fitosanitario en el arboladdo urbano de bogotá dc.. / Relationsip betwween mycorrhizal association with the stae woody plant hhealth in the city of bogota dc

En parques y zonas verdes de Bogotá DC., se evaluó la densidad de esporas y la colonización radical en la rizosfera de tres especies comunes del arbolado urbano: Eugenia myrtifolia, Ficus soatensis y Croton bogotensis, con el fin de determinar si el grado de micorrización está relacionado con el estado fitosanitario y si existe diferencias en el grado de micorrización entre dos zonas climáticas distintas. Se comprobó que la especie y el clima son fuentes significativas de variabilidad en el estado general de micorrización. Eugenia myrtifolia presentó la mayor colonización radical promedio pero el más bajo promedio de densidad de esporas, mientras C. bogotensis tuvo la respuesta contraria. En general los ambientes secos y semisecos favorecieron la micorrización. Considerando los datos de todas especies, se comprobó una relación positiva entre el estado fitosanitario general y la colonización radicular, y al evaluar la relación con la afectación de síntomas específicos se encontró que la clorosis, la quemazón y la herbivoría mantienen una relación negativa con la micorrización en E. myrtifolia y C. bogotensis. Los resultados sugieren que la asociación con hongos de micorriza arbuscular ayuda de algún modo a reducir esos síntomas, presentando un potencial importante para mejorar la sanidad y vida media de las especies arbóreas en la ciudad.

Spore number and root infection by arbuscular mycorrhizal fungi were evaluated in Eugenia myrtifolia, Ficus soatensis and Croton bogotensis, in parks and green zones of urban woodlands of Bogotá DC . The aim was to investigate relations between mycorrhizal associations and tree phyto-sanitary conditions, and effects of two distinct climatic zones. It was demonstrated that plant species and climate are significant sources of variations in the general mycorrhizal state. Eugenia myrtifolia showed the highest degree of root colonization but the lowest number of spores, while C. bogotensis had the opposite response. In general, dry environments favored the mycorrhizal infection levels. By considering overall data, there was a positive relation between the general phytosanitary status of the urban trees and the mycorrhizal colonization. The evaluation of the relationship with the incidence of specific foliar symptoms showed that chlorosis, bight and herbivory maintained a negative relation with the mycorrhization in E. myrtifolia and C. bogotensis. Results suggest that association with AM fungi helps in any way for reducing those symptoms, showing an important strategy to improve the sanity of urban trees.

Mycorrhizal-like interaction between gametophytes and young sporophytes of the fern Dryopteris muenchii (Filicales) and its fungal endophyte

The morphology of a Glomus-like fungus-host interaction in chlorophyllous gametophytes and young apogamic sporophytes of Dryopteris muenchii A.R. Sm. was studied from ferns cultivated in laboratory, using soil as substrate. An aseptate fungus colonized the gametophytes’ tissue through the rhizoids, developing vesicles. The fungus penetrated the young sporophytes primary roots by developing appressoria. It spread forming inter- and intra-cellular hyphae through the epidermis and the outermost cortical cell layers, where it formed vesicles, hyphal coils-like and arbuscules. The fungus hyphae never colonized the gametophyte-sporophyte cellular junction. The fungal structures observed on D. muenchii during this study, are rather similar to those reported for the plant host-arbuscular mycorrhizal fungus (AMF) interaction, where the AMF described belonged to Phylum Glomeromycota. Therefore, this study is a contribution to the scarce knowledgement of the association between AMF and chlorophyllous gametophytes and young apogamic sporophytes of ferns. Rev. Biol. Trop. 56 (3): 1101-1107. Epub 2008 September 30.

Se describe la morfología de un hongo endófito afín al género Glomus, como colonizador de gametofitos clorofílicos y de esporofitos apogámicos jóvenes del helecho Dryopteris muenchii A.R. Sm.; el estudio se llevó a cabo con helechos cultivados en el laboratorio y utilizando tierra como substrato. El tejido del gametofito fue colonizado, a través de los rizoides, por un hongo miceliar aseptado, el cual formó vesículas. El hongo logró penetrar las raíces primarias de los esporofitos jóvenes desarrollando apresorios. El hongo se dispersó formando hifas inter- e intra-celulares a través de la epidermis y de la capa de células corticales más externas, donde produjo vesículas, estructuras similares a ovillos y arbúsculos. Las hifas del hongo nunca colonizaron las células de la unión entre el gametofito y el esporofito. Las estructuras observadas durante este estudio en D. muenchii, son muy similares a las de la interacción planta hospedera-hongo micorrícico arbuscular (HMA), en donde el HMA descrito corresponde al Phylum Glomeromycota. Por lo anterior, este estudio es una contribución al escaso conocimiento que se tiene sobre la asociación entre los HMA y gametofitos clorofílicos y esporofitos apogámicos de helechos jóvenes.

Advances of Study on Arbuscular Mycorrhizal Symbiotic Phosphate Transporter in Plants / 中国生物工程杂志

The arbuscular mycorrhizal(AM)symbiosis is a mutualistic endosymbiosis formed by plant roots and AM fungi.The AM symbiosis is manifested in bidirectional nutrient exchange: AM fungi obtain carbon from their plant host while assisting the plant with the acquisition of mineral nutritions(in particular phosphate)from the soil.AM symbiosis facilitate phosphate uptake is the central reason of plant growth and development.Phosphate transport into the root is mediated by phosphate transporters,and phosphate transporters play a role in the acquisition of phosphate released by the fungus in the AM symbiosis.The molecular biology of arbuscular mycorrhizal symbiotic phosphate transporters in plants was summarized.AM phosphate transporter belong to Pht1 family,is not only essential for the acquisition of phosphate,also critical to AM symbiosis.Study of phosphate transport roles and their gene regulation will further our knowledge of the interaction between the two symbiotic partners,and so as to provide innovative approach to improving phosphate efficiency and agricultural yield.

Molecular Identification of Arbuscular Mycorrhizal Fungal Spores Collected in Korea

Arbuscular mycorrhizas (AM) have mutualistic symbiosis with plants and thus efforts have been placed on application of these symbiotic relationships to agricultural and environmental fields. In this study, AM fungi were collected from 25 sites growing with 16 host plant species in Korea and cultured with Sorghum bicolor in greenhouse condition. AM fungal spores were extracted and identified using both morphological and molecular methods. Using morphological characters, total 15 morpho-speices were identified. DNA was extracted from single spore of AM fungi and a partial region on 18S rDNA was amplified using nested PCR with AM fungal specific primers AML1/AML2. A total of 36 18S rDNA sequences were analyzed for phylogenetic analysis and 15 groups of AM fungi were identified using both morphological and molecular data of spores. Among the species, 4 species, Archaeospora leptoticha, Scutellospora castanea, S. cerradensis, S. weresubiae were described for the first time in Korea and two species in Glomus and a species in Gigaspora were not identified. Morphological and molecular identification of AM fungal spores in this study would help identify AM fungal community colonizing roots.

Effects of Interspecific Interactions of Arbuscular Mycorrhizal Fungi on Growth of Soybean and Corn

Growth responses of Zea mays and Glycine max to colonization by mixture of combination of three species of arbuscular mycorrhizal (AM) fungi, two species of Glomus and a species of Scutellospora were compared. In Zea mays, plants inoculated with single species of AM fungi showed significantly higher in dry weight than non-mycorrhizal plant for all three AM fungal species. Also, growth of plants inoculated with spores of two species of AM fungi was significantly higher than nonmycorrhizal control except for plants inoculated with two Glomus species. When three species of AM fungi were inoculated, the plants showed the highest growth. In Glycine max, plants with single AM fungal species inoculation were not significantly different in plant growth from nonmycorrhizal plants. When the plants were inoculated with combination of two or more AM fungal species, their growth significantly increased compared to nonmycorrhizal plants. In both plant species, mycorrhizal root colonization by Scutellospora species was significantly lower than by Glomus species.

Effects of Soils Containing Arbuscular Mycorrhizas on Plant Growth and Their Colonization

Four arbuscular mycorrhizal fungal (AMF) inocula collected from three arable sites in Korea were used to determine plant growth, mycorrhizal root colonization rate and spore production in three different host plant species; Sorghum bicolor, Allium fistulosum, Tagetes patula. Growth of plant treated with AMF differed from those without AMF. Different AMF inocula showed significantly different root colonization rates and spore production of AMF on the wild plants, A. fistulosum and T. patula, but did not on the cultivated plant, S. bicolor. Results suggested that indigenous mycorrhizal fungal community would be important factors in mycorrhizal symbiosis, and play important roles in the plant succession.

The Observation of Arbuscular Mycorrhizal Roots in Horticultural Plants

To determine the degree of variability among the host plant species in their abilities to become colonized by arbuscular mycorrhizal fungi (AMF), the inoculum for AMF was collected from the various sites in Korea and was inoculated to the three horticultural plants; Tagetes patula, Torenia fournieri, and Salvia splendens. After 4-month growth under greenhouse, mycorrhizal root colonization rates and spore density were measured. The roots of T. patula showed higher colonization rate than both plants of T. fournieri and Salvia splendens. The mycorrhizal root colonization was influenced by both of the AM fungal inoculum and the host species or their interactions. The combination of the host and fungal species was suggested to be important for the application of AMF to horticultural crops.