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Université du Hebei (2020)

Species Diversity and Salt Tolerance of Dark Septate Endophytes in Three Desert Plants

侯力峰;

Titre : Species Diversity and Salt Tolerance of Dark Septate Endophytes in Three Desert Plants

Auteur : 侯力峰;

Grade : Doctoral Dissertation 2020

Université : Université du Hebei

Résumé
Soil Salinization in desert is an important factor restricting the growth of plant and causing soil degradation.It is imperative to promote the restoration of vegetation and ecosystem in desert areas.Plant-microorganism combined bioremediation has been proven to be an economical and effective bioremediation approach.Dark Septate Endophytes(DSE)are a group of ascomycetes that grow on the root tissues of plant,which can improve the nutritional status of the host plant and the tolerance of host plant to stress.Psammochloa villosa,Artemisia ordosica and Hedysarum laeve are typical pioneer plants in the Mu Us sandland Land and are often used for desert vegetation restoration.In this study,the symbiotic relationship between desert plant and DSE fungi was taken as the entry point.The ecological distribution and species diversity of DSE fungi in the roots of three desert plants were systematically studied to clarify the effects of plant species,soil depth and environmental factors on the distribution of DSE fungi.Furthermore,we assessed the performance of DSE fungi and host plants inoculated with DSE species under different salt stress to explore the mechanism of DSE to salt tolerance and DSE improving plant salt tolerance.The research results can improve the understanding of the interaction mechanism of different plant-DSE in the desert environment and the mechanism of the symbiosis adapting to physiological drought caused by salt stress.Moreover,we hope to obtain more beneficial DSE fungal resources and explore the ecological functions of the DSE fungi in the desert environment,thus providing a theoretical basis for making full use of DSE fungi in vegetative restoration in arid ecosystem.The main results showed as follows:1.The root of P.villosa,A.ordosica and H.laeve can be infected by DSE fungi,and the predominant structure was Hyphae.There were significant differences in the colonization structure of DSE in different plants,and the average total colonization rates of P.villosa,A.ordosica and H.laeve were 79.66%,82.35%,and 70.45%,respectively.The maximum average colonization rate of P.villosa and H.laeve appeared in the 10-20 cm soil layer,while the maximum average colonization rate of A.ordosica was in 30-40 cm soil layer.The highest DSE colonization rates of the three plants occurred in 2016.2.Two-way analysis of variance(ANOVA)revealed that plant species and soil depth significantly affected the distribution of DSE.Plant species explained 47%of the variation in DSE distribution variation as the most important influencing factor.Correlation analysis showed that the colonization rate of DSE mycelium was significantly positively correlated with TN,and significantly negatively correlated with the C:N ratio.The colonization rate of microsclerotia was significantly positively correlated with SOC.The total colonization rate was significantly positively correlated with TN and TP,and significantly negatively correlated with C:N ratio.3.DSE isolates in the roots of three hosts were identified to 13 genera and 17 species,namely Leptosphaeria sp.、Phoma radicina、Paraphoma chrysanthemicola、Bipolaris zeae、Humicola sp.、Fusarium tricinctum、Alternaria chlamydosporigena、Darksidea delta、Phialophora mustea、Alternaria alternata、Bipolaris sorokiniana、Curvularia spicifera、Periconia macrospinosa、Paraphoma radicina、Paraphoma pye、Setophoma terrestris、Microdochium bolleyi.Five of them produce spores.Phoma radicina and Bipolaris zeae were reported here in desert ecosystems for the first time.4.The DSE fungal community composition presents the preference to host plants snd soil depths

Mots clés : Dark endophytic fungi; Ecological distribution; Species diversity; Desert plants; Soil depths; Salt tolerance;

Présentation (CNKI)

Page publiée le 22 octobre 2020