Effect of Lactic Acid Bacterial Inoculants on Rice Straw Silage

The trail was designed to study on technique aspects of ensiling rice straw （RS） appended amounts of lactobacillus. There were two groups according to silage ways, baled silage （BS） and chopped silage （CS）, in which lactobacillus was added at levels of 10, 15 and 20 mg·kg^-1, respectively and the mixtures were placed into a packed polyethylene bags and stored at room temperature for 45 days. The results showed that lactobacillus had remarkable effect on fermentation characteristics of RS. The quality of the silage was improved with the lactobacillus addition. In the experiment the optimal quality of rice straw silage （RSS） can be obtained when lactobacillus was added with 15 or 20 mg·kg^-1 level. The effect of different silage methods was very remarkable to the silage quality of same material. The quality of CS was better than that of long silage, at the same time, BS was feasible on condition of eligible level of lactic acid bacteria.

Preparation of slow-release regulated Rs-198 bilayer microcapsules and application of its lyophilized bacterial inoculant on Capsicum annuum L.under salt stress

The survival adaptation of bacteria in saline soil is poor.The bilayer microcapsules were prepared by secondary embedding of monolayer sodium alginate(NaAlg)-bentonite(Bent)-sodium carboxy-methylcellulose(CMC)microcapsules wrapped with plant growth promoting rhizobacteria(PGPR)Pseudomonas putida Rs-198 by chitosan solution to promote the synergistic effect of bilayer microen-capsulation and PGPR.The characterization of the Rs-198 bilayer microcapsules showed that the amino and carboxyl groups were cross-linked and a thin layer of chitosan was formed on the outside of the microcapsule.The bilayer microcapsule(Ch-d)with a chitosan concentration of 0.8 wt%and pH 6 showed a slow release of bacteria with a maximum release of 6.06 × 10^(9) cfu/g on the 7th day.The viable bacteria of Ch-d increased by 4.42%after 60 days of storage compared with monolayer microcapsules.The 0.9 wt%L-cysteine,10 wt%glycerinum,10 wt%trehalose and 12 wt%soluble starch were added as bacterial protective agents during the process of preparing the Ch-d lyophilized bacterial inoculant(Ch-d LBI).Pot experiments showed that Ch-d LBI exhibited better growth promotion of Capsicum annuum L.under salt stress.Therefore,the bilayer microcapsule as slow-release bacterial inoculant is a potential alternative for sustainable agriculture.

Ensiling Whipgrass in Large Containers with Lactobacilus plantarum andLactobacillus buchneri

[Objective]To compare the effectiveness of Lactobacillus buchneri（LB）,alone or in combination with Lactobacilllus plantarum（LP）at ensiling on the fermentation,aerobic stability and nutritive value of whipgrass（Hemarthria compressa（L.f.）R.Br.）silage in 1.5-l mili-silos and 50-l plastic containers.[Method]Treatments comprised control（no additives）,LP,LB and LP ＋ LB.After 90 d of storage,overall,inoculation increased the concentration of acetic and 1,2-propanediol,but it reduced the concentrations of lactic acid,water suluble carbohydrates and enthanol.[Result]The whipgrass silages treated with LB had higher acetic acid contents than the control or LP treated silages,and were free of mold,whereas the top layers of the control or LP-treated silages were moldly.In an aerobic stability test the LB-treated silages were stable,whereas those treated with LP deteriorated.In the whipgrass silages the effects of LB made less CO 2 production and stable pH.[Conclusion]It is concluded that LB has a potential as a whipgrass silage additive that protects the silage upon aerobic exposure.

Inheritance of Clubroot Resistance of Miniature Chinese Baby Cabbage and Molecular Markers-assisted Selection

[Objective] The paper was to analyze the inheritance of clubroot resistance of miniature Chinese baby cabbage,to shorten identification time and to improve breeding efficacy of new disease-resistant varieties. [Method] Taking clubroot-resistant Chinese cabbage CCR001,disease-susceptible baby cabbage CM002,and their F_1,F_2 and BC_1 offspring as the research objects,the inheritance of clubroot resistance of baby cabbage was studied. [Result]The clubroot-resistance of baby cabbage was controlled by a single dominant gene,which conformed to Mendel＇s Laws of inheritance. The molecular markers-assisted selection combing with bacterial soil inoculation confirmed that the disease-resistance indeed passed on from the parents,and was inherited in F_1 and F_2. [Conclusion]It is feasible to breed clubroot-resistant baby cabbage by using molecular markers-assisted selection.

Improvement of phosphorus uptake,phosphorus use efficiency,and grain yield of upland rice(Oryza sativa L.)in response to phosphate-solubilizing bacteria blended with phosphorus fertilizer

Phosphorus(P)limitation in soil is a major concern for crop productivity.However,the use of chemical fertilizer is hazardous to the environment and costly.Therefore,the use of phosphate-solubilizing bacteria(PSB)is an eco-friendly approach for a sustainable agricultural system.In the present study,a field trial was conducted for two consecutive years to study the effects of three PSB strains isolated,Bacillus licheniformis,Pantoea dispersa,and Staphylococcus sp.,with different P fertilizer rates on P uptake,P use efficiency(PUE),and grain yield of rice.The activities of soil enzymes were also studied in relation to PSB treatments.Comparative analysis of the yield and biochemical parameters revealed that inoculation of PSB consortium could reduce almost 50%of the recommended P dose in rice cultivation.Three PSB strains in combination with 50%P dose was most effective and showed the highest increases in P uptake and PUE as compared to the uninoculated control.Moreover,the PSB consortium combined with 50%P dose contributed to 50.58%and35.64%yield increases compared to the uninoculated control for 2018 and 2019,respectively.Significant increases in the activities of soil dehydrogenase,alkaline phosphatase,and acid phosphatase were also recorded under PSB treatment.

A highly effective polycyclic aromatic hydrocarbon-degrading bacterium,Paracoccus sp.HPD-2,shows opposite remediation potential in two soil types

Bioaugmentation is an efficient and eco-friendly strategy for the bioremediation of polycyclic aromatic hydrocarbons(PAHs).Since the degrading abilities of soils can greatly alter the abilities of PAH-degrading bacteria,illustrating the potential and mechanism of highly efficient degrading bacteria in different soil environments is of great importance for bioremediation.A PAH-degrading bacterium,Paracoccus aminovorans HPD-2,and two soil types,red and paddy soils,with distinct PAH-degrading abilities,were selected for this study.A soil microcosm experiment was performed by adding pyrene(PYR)and benzo[a]pyrene(B[a]P).Illumina sequencing was used to examine bacterial community structure.The results showed that inoculation with HPD-2 significantly elevated PYR and B[a]P degradation rates by 44.7%and 30.7%,respectively,in the red soil,while it only improved the degradation rates by 1.9%and 11%,respectively,in the paddy soil.To investigate the underlying mechanism,the fate of strain HPD-2 and the response of the indigenous bacterial communities were determined.Strain HPD-2 occupied certain niches in both soils,and the addition of the bacterium changed the native community structure more noticeably in the red soil than in the paddy soil.The addition of PAHs and strain HPD-2 significantly changed the abundances of 7 phyla among the 15 detected phyla in the red soil.In the paddy soil,5 of the 12 dominant phyla were significantly affected by PAHs and the inoculation of HPD-2,while 6new phyla were detected in the low-abundance phyla(<0.1%).The abundances of Massilia,Burkholderia,and Rhodococcus genera with PAH degradation efficiency were significantly increased by the inoculation of HPD-2 in the red soil during 42 d of incubation.Meanwhile,in the paddy soil,the most dominant effective genus,Massilia,was reduced by HPD-2 inoculation.This research revealed the remediation ability and inherent mechanism of the highly effective PAH-degrading strain HPD-2 in two different soil types,which would provide a theoretical basis for the application of degrading bacteria in different soils.