Root Exudates Interspecific Interactions Of Typha Domingensis And Phragmites Australis

In order to investigate the effects of interspecific interactions between Typha domingensis and Phragmites australis on plant growth and root exudates,a pot experiment technique was designed to study the interspecific competition characteristics of T.domingensis and P.australis under different root barriers,including plastic barrier,nylon mesh barrier and no barrier.The morphological characteristics and biomass were analyzed to explore the differences of interspecific competition between T.domingensis and P.australis.Nontargeted metabolomic was used to analyze the component characteristics of root exudates from monoculture and mixed culture of T.domingensis and P.australis.Significant differences in metabolites were identified and screened.The study of the interspecific interactions between T.domingensis and P.australis.It provides data support for controlling the growth of them and regulating the composition of plant community in wetland and agricultural ditches.The main research results showed that:1)The pot experiment results of different root barriers treatments showed that:(1)P.australis has obvious disadvantage in nylon mesh barrier and no barrier treatment.Compared with plastic barrier,the total biomass,plant density,total root length,root surface area and root volume of P.australis were 40%and 80% significantly lower under nylon mesh barrier and no barrier treatment,respectively.However,plant height,stem diameter and leaf number in our study were affected by root barrier treatments,following the order of nylon mesh barrier> plastic barrier>no barrier.(2)Nylon mesh barrier and no barrier treatment could improve the growth of T.domingensis.The total biomass of T.domingensis increased by 23.22% and 14.44%,compared to plastic barrier(P>0.05).Plant density and plant height of T.domingensis were higher in treatment of nylon mesh barrier and no barrier than plastic barrier treatment(P<0.05).Compared to plastic barrier,the total root length,root surface area and root volume of T.domingensis were increased by 41.9%,62.43% and 7.85% in nylon mesh barrier,respectively,but decreased by 6.54%,5.5% and 13.23% in no barrier treatment,respectively(P<0.05).The interaction of root substances promoted the growth of the root of T.domingensis,and the root interaction between plants,could weaken the growth of them.In no barrier treatment,the biomass and the plant density different of T.domingensis were 1.7 times and 6.74 times higher than that in P.australis.Our study indicated that the roots interaction between T.domingensis and P.australis significantly weakened the reproductive growth of P.australis,and increased the root tillers of T.domingensis.(3)The Interspecific interaction index(RII)analysis also showed that P.australis exhibited inhibitory effect(RII was negative)and T.domingensis exhibited promoting effect(RII was positive)under nylon mesh barrier and no barrier.In this study,the roots interaction of P.australis and T.domingensis affected the growth of P.australis,and significantly inhibited the biomass,root growth and growth density of P.australis.So that interspecific competition plays an important role in plant growth,which has a strong impact on species adaptability and species community reproduction.2)Based on nontargeted metabolomic analysis,this study investigated the response of root exudates of T.domingensis and P.australis to interspecific interactions.LC-MS was used to analyze the exudates,and a total of 410 metabolites were identified,of which 25.85% were fatty acids.Heterocycles11.46%,organic acids 10.73%,benzene and its derivatives 8.29%,amino acids 6.10%,flavonoids6.10%,phenylpropanoids 5.85%,nucleotides 5.85%,carbohydrates 4.63%,steroids 4.15%,phenols3.17%.The results of multivariate statistical analysis,identification of differentially expressed metabolites,correlation analysis of differentially expressed metabolites and KEGG enrichment analysis showed that the contents of 75 metabolites were significantly changed,among which 60 metabolites with mixed planting were higher than alone,and 15 metabolites with mixed planting were lower than alone,including amino acids,carbohydrates,fatty acids,phenols,alkaloids and phenylpropanes.Among them,P.australis with high contents and inhibition are 3-hydroxy-3-methylglutaric acid,hydroxycoumarin,benzoyl formic acid and cinnamic acid,and o-coumaric acid is the antioxidant.At present,there are 5 kinds of P.australis with no clear role.Emberic acid and Coirelachrylactonolactone,which had high expression level and inhibitory effect in T.domingensis,had no clear effect on 4kinds.Glycyrrhizin had low contents but inhibitory effect in the mixture of T.domingensis and P.australis.Therefore,our result provides an effective reference for the biodiversity conservation and protect the ecosystem functions by controlling and adjusting the rapid reproduction of T.domingensis and P.australis’ through root metabolites.