Relationship Between Microbial Community And The Volatile Oil Components In The Microscopic Soil Environment

Asarum sieboldii Miq. belongs to aristolochiacee (Asarum) plants. It is one of our traditional bulk herbs which contains essential oil. Some of them are provided with important medicinal properties, such as the central inhibition, antipyretic analgesic, dilating blood vessels and antifungal, etc.. Soil is one of the important ecological factors which affects the growth of Asarum sieboldii. Microorganisms play a most dynamic role in soil. The soil microbial community structure and its change will affect the growth of Asarum sieboldii and the accumulation of its active ingredients. Rhizosphere is a special area where plants and soil have the most important and closest relationship, so to study the relationship among growth of Asarum sieboldii, rhizosphere microbes and effective composition accumulation has important theoretical significance and practical value.This study chooses Asarum sieboldii in the wild and artificial planting environment as the object to collect samples of plants and their rhizosphere soil in different growth phase (months of May,June, July,9,11of2012and March of2013). Microbial cultures, denaturing gradient gel electrophoresis (DGGE) and chloroform fumigation-capacity analysis method are used to determine the rhizosphere microbial community characteristics and their change. The application of gas chromatography-mass spectrometry (GC-MS) method is adopted to obtain respectively the main volatile oil composition degrees of the aerial and underground part of Asarum sieboldii. Through mathematical statistics and multivariate analysis methods, we try to explore Asarum sieboldii rhizosphere microflora space-time structure characteristics and the relationships between the effective components in different soil environment. The main research results are as follows:1. Culturable microbial community characteristics and dynamic in rhizosphere areas of China asarumâ‘ overall performance for the three major microorganisms groups:Nbacteria>N actinomyces>Nfungi; and the main physiological group:N ammoniation bacteria> N nitrogen-fixing bacteria> N nitrite bacteria>N cellulose decomposition microbes.â‘¡In the wild environment, the number of bacteria, actinomyces and fungi peaked in July; Ammonifying bacteria, nitrogen-fixing bacteria and cellulose decomposing bacteria number also peaked in the same phase, but the highest number of nitrite bacteria appeared in November. In the artificial environment, the number of actinomycetes peaked in July, but bacteria and fungi quantity keep the highest in September and November respectively. Ammonifying bacteria, nitrogen-fixing bacteria and nitrite bacteria peak appeared in September, cellulose decomposing bacteria peak are in June and July.â‘¢In terms of microbial three groups, actinomycetes quantity give a minimum and the most stable performance in the wild environment (coefficient of variationCVwild=0.67); but is the largest and the most unstable in artificial environment(CVartificial=1.70).In terms of microbial physiological group, nitrous acid bacteria is the largest and the most unstable(CVwiid=2.44, CV artificial=2.43), but cellulose decomposing bacteria number volatility (CVartificial=0.79, CVanificiai=0.75) is relatively stable in the wild and artificial planting environment.2. The rhizosphere microbial biomass carbon (MBC) characteristics and the dynamicIn overall, rhizosphere microflora MBC is performed as:the MBCanificia>MBCwild. In the wild environment, the MBC peak appeared in June, July and November; and in the artificial environment, it is in June and July. As in change, the rhizosphere microorganism MBC volatility of the wild environment (CVwild=0.29) is less than that of the artificial environment (CVartificial=0.58), namely, rhizosphere microorganisms MBC is more stable in the wild environment.3. The rhizosphere bacteria community structure characteristics and hte dynamicâ‘ rhizosphere bacteria species and their dynamic:the numer of bacteria bands is29, with10unique ones and4-6priority ones in the wild environment; Samples of artificial environment to the total bands number of26, including7specific ones and4-5priority ones. The different bands feature reflects that bacterial communities have obvious different kinds of structure in the wild and artificial environment.â‘¡According to average Shannon-Weiner index of Asarum sieboldii in different growing period, we get a result that, for China asarum in wild environment rhizosphere bacteria diversity is lower than that of the artificial environment (Hwild<Hartificial).In the process of3to11months, rhizosphere bacteria Shannon-Weiner index is relatively more steady in the wild environment. As in change, the volatility of rhizosphere bacteria Shannon-Weiner index shows that the rhizosphere bacteria diversity of wild environment (CV=0.04)is more stable.than that of artificial environment (CV=0.05). â‘¢To take soil bacteria bands as a variable, with different months as the entity, the clustering results shows that samples in the wild environment can be divided into A (5-6-7), B (3months), C (9months) and D (November) class, and sanmples in artificial environment can be divided into A (3-9-11), B (may), C (June) and D (July) types. The time classification pattern reflects that the season factor may determine the similarity among microbial species compositions in a certain extent.4. seven main kinds of volatile oil relative content of Asarum sieboldii and its dynamics.:â‘ In overall, the percentage of7kinds of volatile oil components in ground parts overall performance is:component2> component7> component1> component5> component3> component4>component6both in the wild and artificial environment; Underground part performance is:the component2> component5>, component7> component3> component6> component1> component4both in the wild and artificial environment.â‘¡The peak of components relative contents appeared in different time.In the ground parts, month of the minimum relative content of volatile component are July, the underground part of the most volatile oil components in percentage of its minimum in May or March.â‘¢In the same environment, the percentage in volatile oil components of aerial and underground part shows that:in addition to the underground parts of the fartificial environment, components1of the rest of the samples relative content is more stable (CV ground in the wild=0.49, CV underground in the wild=0.19; CV ground in the artificial=0.36, CV underground in artificial=0.71) are stable.5. Asarum sieboldii rhizosphere microbial community characteristics and the relationship between plant volatile oil components:â‘ correlation between volatile oil components and the bacteria stripe number:7components field on the ground and the bacteria stripe number field is significantly negative correlation (r=0.884, P<0.01), the components of6field underground bands with the bacteria number field show significant positive correlation (r=0.764, P<0.05);Components of artificial ground and the bacteria stripe number4show significant positive correlation (r=0.747, P<0.05).â‘¡the volatile oil components correlation with bacterial community diversity index:in the wild environment, component1-7are not significantly correlated with the bacteria bands number (P>0.05); Component3ground in the artificial and the diversity index is significantly negative correlated (r=0.756, P<0.05), component4ground in the artificial and the diversity index was significantly positive correlated (r=0.728, P<0.05); Component1underground in the artificial and the diversity index is significantly negative correlated(r=0.084, P<0.05), component7underground in the artificial and diversity index of artificial environment shows significant correlation (r=0.835, P<0.05).â‘¢volatile oil components components and related relations between MBC:both in the wild and artificial environment, volatile oil components had no significant correlation with MBC (P>0.05).The research shows that:There are some differences with Asarum sieboldii rhizosphere microbial community structure types and quantity in the wild and artificial environment,.The complexity of the environment directly affects the diversity of microorganisms and their stability.Compared with the wild environment, the types of bacteria in the artificial environment is less, but the number, diversity index and the content of MBC are larger, and microbial community structure is more stable. Fertilization measures decreased the number of rhizosphere bacteria community and diversity index, but increased MBC content, and improved.microbial community structure stability. Parts of the main volatile oil components accumulation of Asarum sieboldii and bacterial community are closely related, but the correlation with the total microbial quantity is small.