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Symbiotic microorganisms such as arbuscular mycorrhizal fungi (AMF) and rhizobia (Rh) both promote host plant N acquisition, but whether and how the combination affects host plant nitrogen (N) assimilation remains unclear. To clarify the role of AMF and rhizobia on N assimilation in white clover (Trifolium repens), the effect of single or combined inoculation with an arbuscular mycorrhizal fungus Paraglomus occultum and a rhizobium Rhizobium trifolii on plant growth, photosynthesis, leaf N and amino acid contents, and the activities of N assimilation-related enzymes were analyzed in white clover under potted conditions. The results obtained were as follows: (1) The plant height, stolon length, leaf number, shoot biomass, total biomass, chlorophyll b and total chlorophyll contents, steady-state light quantum efficiency, and leaf N contents of white clover were significantly increased by single inoculation with Paraglomus occultum, single Rhizobium trifolii, and combined inoculations of Paraglomus occultum and Rhizobium trifolii, along with the order of combined inoculations of Paraglomus occultum and Rhizobium trifolii > single Paraglomus occultum > single Rhizobium trifolii > non-inoculation control. (2) Combined inoculations of Paraglomus occultum and Rhizobium trifolii significantly increased the contents of various amino acids including alanine, arginine, asparagine, aspartate, glutamine, glutamic acid and histidine in leaves of white clover, and distinctly improved the activities of nitroreductase, nitrite reductase, glutamine synthetase, glutamate synthetase, glutamate dehydrogenase, asparagine synthetase, and aspartate aminotransferase. In addition, the introduction of Rhizobium trifolii significantly promoted the colonization of Paraglomus occultum to roots of white clover, suggesting the partnership between the two. Therefore, it is concluded that combined inoculations of AMF and rhizobia promote N assimilation, generate more amino acids, and further promote the growth of white clover by activating the activities of N assimilation-related enzymes. It is further demonstrated that AMF and rhizobia have synergistic effects on promoting N assimilation of white clover. [ABSTRACT FROM AUTHOR]

The response of arbuscular mycorrhizal fungi(AMF)colonization rate to slope position and shrub species in karst slope and the key influencing factors were identified, which is the prerequisite for rational utilization of soil AMF to promote karst vegetation restoration. Based on field investigation of typical shrub communities and environmental variables on slopes of a karst peak cluster depression. The fine root samples of three typical shrub species(Vitex negundo, Alchornea trewioides and Pyracantha fortuneana)were collected from three positions(upper, middle and lower)along three slopes. The frequency, intensity and abundance of AMF colonization were detected and calculated by the Trypan blue-microscope method. The results were as follows:(1)The colonization frequency, colonization intensity and abundance of AMF for Vitex negundo and Alchornea trewioides were higher than those for Pyracantha fortuneana in the same slope. The colonization intensity for Vitex negundo and Pyracantha fortuneana in the lower slope was higher than that in the upper and middle slopes. The abundance of AMF for Alchornea trewioides in the middle slope was significantly higher than that in the upper and lower slopes(P<0.05).(2)Shrub species had significant effect on the colonization frequency, intensity and abundance of AMF, and slope position only had significant effect on the colonization intensity of AMF. Slope position and shrub species had significant interactive effect on the abundance of AMF(P<0.05).(3)Soil depth and total potassium content were identified as the two strongest explanatory factors on AMF colonization rate according to the redundancy analysis(P<0.05). Therefore, the rational use of soil AMF to promote vegetation restoration in karst areas needs to consider the choice of terrain and species, and should pay attention to the water and soil conservation. The results of this study provide a scientific basis for rational utilization of the symbiotic relationship between soil AMF and plants and promoting ecological restoration of karst peak cluster depression. [ABSTRACT FROM AUTHOR]

The mutually beneficial symbiosis system formed between arbuscular mycorrhizal fungi(AMF)and host plants is one of the representative types of symbiosis systems widely distributed in various ecosystems. In addition to promoting the growth and development of host plant, AMF can also have various effects on the reproduction process of host plants. Studying the changes of reproduction strategies of host plants infected by AMF has important theoretical significance for in-depth understanding of changes in plant reproductive fitness. In this article, we review the related researches on the effects of AMF on the reproduction of host plant, including the effects of AMF infection on reproductive allocation, floral characteristics, insect-pollination and anthesis of host plants. Although current studies have found that AMF can promote the increase of host plant reproduction input, increase the size and number of flowers, increase the number of pollen and nectar secretion, affect the behavior of flower visitors, and cause early flowering and prolonged flowering, the specific mechanism of AMF affecting reproduction of flowering plant is still unclear, and there is currently no unified conclusion due to differences between host plants. However, due to the ubiquity of AMF symbiosis with plant, its important role in the process of plant reproduction cannot be ignored. In the future, more researches should be conducted to investigate the influence mechanism of AMF on the reproductive traits of host plants, the resource allocation of male and female functions in the process of plant sexual reproduction, asexual reproduction and offspring fitness in addition to conducting more in-depth studies in the above-mentioned aspects. [ABSTRACT FROM AUTHOR]

To find microbes promoting the biosynthesis of active metabolites in medicinal plants, with Polygonatum sibiricum as materials, the ITS region of fungi form rhizosphere, rhizome and root was sequenced by Illumina MiSeq to analyze the diversity and community composition, and FUNGuild was used to analyze the ecological function categories of endophytes fungi in rhizome. The results were as follows:(1)A total of 1 023 operational taxonomic units(OTUs)were obtained from all samples of P. sibiricum. The numbers of OTU from rhizosphere, rhizome and root fungi were 703, 128 and 141, respectively. The composition of fungal community in three samples was significantly different, and there was specific fungi Chytridiomycota in root.(2)There was 41 OTU in common of three samples, and Ascomycota accounted for the highest proportion(58.15%).(3)In ecological functional, endophytic fungi of rhizome in P. sibiricum contained six functions groups, undefined saprotroph, mycoparasites, plant pathogen, animal pathogen, arbuscular mycorrhizal fungi, lichenized fungi, and 37 undefined species(34.91%)had no reference information in the FUNGuild database. It is suggested that the dominant endophytic fungi like Setophoma and Neocosmospora in rhizome may be important microbial communities affecting the biosynthesis of the active products, which provides data reference for the exploration of medicinal functional microorganisms in P. sibiricum. [ABSTRACT FROM AUTHOR]

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Copyright of Guihaia is the property of Guihaia Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Guihaia is the property of Guihaia Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)