Analysis Of The Functional Traits Of Weed Suppression In Allelopathic Rice

As one of the most important chemoecological phenomenon, allelopathy refers to the favorable or deleterious effects of one plant on its neighboring plants (including microbes) through the release of secondary metabolism chemical compounds into the environment via volatilization, leaching, excretion, and decomposition. Using rice allelopathy to control weeds in agroecological system has been one of the hottest researching fields, which will be a key technology to control weed safely and friendly in 21^st century.Plant allelopathic trait not only manifests its adaptability to environment (such as weed competition), but also reflects its characteristics of ecological function in which the plant live, which involved in environment and ecological function was defined as plant functional trait. It is the sticking point of the application of allelopathy in practice to illustrate the process and mechanism of the functional traits for weed suppression mediated by allelopathic rice. Unfortunately, the previous study only focused on the biological characteristic of alleopathy such as the properties of genetics and physiology, however, less involved in the functional traits of weed suppression and the ecological function acting on the ecological system where allelopathic plants inhabited, especially, on the rhizospheric microbial ecological characteristics, since allelopathy is mainly a rhizospheric biological process. So it needs to have such a molecular evidence to further illuminate the chemoecological relationship, especially on the microbial properties in rhizosphere under environment stress.Hereby, in order to discuss the process and mechanism of the functional traits of weed suppression in allelopathic rice, take the international acknowledged allelopathic rice accession PI312777 and non-allelopathic rice accession Lemont as tested materials in the present study. The response trait and effect trait of different allelopathic potential rice and their relationship were studied, including two experiments, such as laboratory and field experiments. In the lab, we analyzed the molecular physiological properties of allelopathic rice regulated by different nitrogen concentrations, through comparing the phenotypic plasticity, nitrogen acquisition capacity, photosynthesis physiology and the differential expressions of the relevant genes using physioecological methods and fluorescence quantitative PCR approach. In the field, the structure and function of microorganism flora in the rhizosphere mediated by different allelopathic potential rice accessions were analyzed using terminal-restriction fragment length polymorphism combining the method of bioinformatics.The results obtained from the lab showed that allelopathic rice PI312777 put up stronger acclimation ability to the nutrient stress than non-allelopathic rice Lemont, which was attributed to its sound nutrient turnover efficiency. Moreover, the higher content of soluble sugars in allelopathic rice PI312777provided the basis of material and energy for establishing architecture of root system, when it exposed to nitrogen stress. The results of FQ - PCR suggested that the expression patterns of the related genes, which are involved in nitrogen absorption, carbon metabolism and secondary substance synthesis in the tested materials, were distinct, which approved the molecular ecological characteristics of the above physiological response. Consequaqntly, the allelopathic rice PI312777 was stronger than non-allelopathice rice Lemont in the capacity of nitrogen acquisition and chemical defense, in turn showing stronger ability of acclimation to nitrogen stress.In field trial, the results indicated that the microorganism diversity became greater than controlled soil after planted rice, while the structure and function of microorganism flora in the soil rhizosphere between different allelopathic potential rice were distinct. On the one hand, allelopathic rice PI312777 promoted the nutrient cycle in rhizosphere, and ensured itself healthy growing, on the other hand, it induced the inhabitation of actinomycete, which is closely related to allelopathy, to accomplish the purpose of inhibiting the co-cultured weeds. It was obvious that the structural and functional traits in rhizosphere soil were significantly affected by allelopathic rice.In summary, rice allelopathy was a functional trait which was closely correlative to nutrient environment and the function of rhizospheric microbial ecology. Moreover, the relationship among different response traits was tade-off, which was coorodinated and causal with effect traits.