Abstract:【Objective】 To investigate the effects of straw returning and plastic film mulching on soil environment and rice growth.【Method】 ‘Jijing 88’ was selected as test material. The field experiments were conducted under three groups of straw returning amount and two kinds of cultivation mode (transplanting with plastic film mulching and transplanting without plastic film mulching) to measure soil temperatures, soil fertilities and rice growth traits.【Result】 The soil temperatures at 5 and 10 cm depths were significantly affected by plastic film at tillering stage. The soil temperatures of the treatments with plastic film mulching increased 0.2~2.0 ℃ (5 cm depth) and 0.3~1.7 ℃ (10 cm depth) respectively at the same straw returning amount. Compared with the treatments without plastic film mulching, the total nitrogen contents of soil at 20%, 40% and 60% straw returning amounts significantly increased 0.28, 0.26, 0.14 g·kg^–1 respectively at filling stage, the organic matter contents significantly increased 0.74, 0.65, 0.54 g·kg^–1 respectively at mature stage, the tillering numbers increased 9.1%, 22.7%, 17.4% respectively at late tillering stage, the leaf area indexes significantly increased 19.1%, 17.2%, 22.6% respectively at filling stage, the total accumulations of dry matter increased 4.5%, 31.7%, 16.5% respectively, while the actual yields increased 7.3%, 15.2%, 8.5% respectively in the whole growth period.【Conclusion】 Straw returning and plastic film mulching can increase soil temperature, soil organic matter and total nitrogen contents, tillering number, leaf area index and dry matter accumulation. Soil temperature, soil fertility and rice growth perform best while straw returning amount is 40%.

Abstract:【Objective】 To explore the fertilizer effect of new medium element fertilizer and its mechanism of increasing production.【Method】 The synergistic single superphosphate calcium was used to produce medium element coated fertilizer. The synergizing methods included single superphosphate calcium ammonization, humic acid, amino acid and binding agents were added for granulation; After drying, plant growth regulators, biological agents, anti-caking agents and parcel oil were added to coat the fertilizer. The pot experiment of lettuce and the field experiments of rape seed and peanut were carried out. The effect of new fertilizer was verified by analyzing the crop agronomic characteristics and physiological indexes. 【Result】 The scanning electron microscope (SEM) result showed that the specific coating layer of the new fertilizer played a slow release effect. The energy dispersive spectroscopy (EDS) result showed that the new fertilizer could provide various nutrients such as P, Ca, Mg and S for crops. The lettuce pot experiment showed that the yield of medium element coated fertilizer produced by synergistic single superphosphate calcium increased 10.8%–35.9% than that of common single superphosphate calcium. The field experiments showed that compared with simple synergistic single superphosphate calcium treatment, the medium element coated fertilizer increased the yield of rape seed and peanut by 64.5%–89.7% and 9.2%–11.1%, respectively, and the product efficiency was better than that of calcium-magnesium fertilizer on the market.【Conclusion】 Single superphosphate calcium fertilizer produced by synergistic techniques such as ammonization, granulation and coating can promote the absorption of Ca, Mg and S by crops and their transport and distribution efficiency in vivo. This product can be industrialized and brought to market.

Abstract:【Objective】 To examine the effect of biochar combining with micro-fertilizer on soil available heavy metal content.【Method】 Indoor simulation experiment was conducted. Pennisetum hydridum biochar, coffee grounds biochar, peanut shell biochar and micro-fertilizer (iron fertilizer, manganese fertilizer and silicon fertilizer) were added to the vegetable garden soils polluted by heavy metals, and the contents of available Cu, Pb, Zn, Cd and Ni were determined on the 14th and 28th days.【Result】 The available heavy metal contents in soils added with biochar or micro-fertilizer were lower than that of the control group. In single passivator treatments, P. hydridum biochar and silicon fertilizer had better heavy metal immobilization effects. In the blended passivator treatments, P. hydridum biochar combining with iron fertilizer had better Cu, Pb and Cd immobilization effects, the contents of available Cu, Pb, and Cd decreased by 32.94%, 31.26% and 21.21% respectively on the 14th day. The content of available Zn decreased by 6.82%, and the immobilization effect on Ni was not obvious. When coffee grounds biochar was added with iron fertilizer, the contents of available Ni and Zn decreased by 22.64% and 10.35% respectively on the 14th day. The immobilization effects were remarkable. On the 28th day, peanut shell biochar combining with iron fertilizer showed the best immobilization effect on Cu，the content of available Cu decreased by 49.06%. Coffee grounds biochar combining with silicon fertilizer had the best immobilization effect on Ni and Zn, the contents of available Ni and Zn decreased by 23.73% and 9.72% respectively.【Conclusion】 The reduction effects of biochar combining with micro-fertilizer on available heavy metal content in soil are better than that of single biochar or micro-fertilizer. P. hydridum biochar combining with iron fertilizer can be used to immobilize combined heavy metal pollution of Cu, Pb, Zn and Cd in soil.

Abstract:【Objective】 To understand heavy metal content characteristics and pollution conditions in different forest soils in west Guangdong, and provide a theoretical basis for their ecology risk assessments.【Method】 Eucalyptus urophylla plantation, Pinus massoniana plantation, Cunninghamia lanceolata plantation, Acacia spp. plantation and broad-leaved mixed forest in West Guangdong were chosen to investigate heavy metal (Cu, Zn, Pb, Cd and Ni) contents in soil at the 0-20 cm depth. Single pollution index (P_i), Nemerow index (P_N) and Hakanson potential ecological risk index (RI) methods were used to assess heavy metal pollution conditions and potential ecological risks in different forest soils.【Result】 Cd content was the lowest while Zn content was the highest in all studied forest soils, but they were all below soil background value of Guangdong Povince. The values of pH ranged from 3.62 to 6.42, presenting acidic. Both Cu content (16.06 mg·kg^–1) in P. massoniana plantation soil and Pb content (12.37 mg·kg^–1) in E. urophylla plantation soil were significantly higher than those in broad-leaved mixed forest soil (9.21 and 6.87 mg·kg^–1). The correlations among five heavy metal contents in plantations were significant. All P_i values in five forests were lower than 1, indicating no contamination. Both P_i and P_N ranks in five forests were as follows: P. massoniana plantation>C. lanceolata plantation>E. urophylla plantation>Acacia spp. plantation>broad-leaved mixed forest. Except P. massoniana plantation, the pollution levels of all other forests were safe. The potential ecological risk assessment results of single and multiple heavy metals were slight risk. The potential ecological risk coefficients (E_i) of single heavy metal showed that Cd had the highest value while Zn had the lowest value. The results of RI showed that P. massoniana forest had the highest value and broad-leaved mixed forest had the lowest value.【Conclusion】 The E_i method can more comprehensively reflect the soil heavy metal contamination. According to its assessment results, it is still a long-term and necessary measure to prevent and reduce heavy metal pollution caused by human.

Abstract:【Objective】 To demonstrate the autotoxicity and allelopathic potentials of Celosia argentea L. against other plants, discuss the adaptive mechanism of C. argentea as a common field weed and co-existence with the invasive plant Bidens pilosa.【Method】 Laboratory bioassay was used to evaluate allelopathic potentials of aqueous leachate of C. argentea fresh leaves on seed germination and seedling growth of four different plants, including C. argentea, B. pilosa, Brassica campestris and Raphanus sativus. Meanwhile, pot experiments were conducted to determine the effects of aqueous leachate and litter mulching of C. argentea fresh leaves on itself growth, and mutual allelopathic potentials of C. argentea and B. pilosa litter.【Result】 The aqueous leachate of C. argentea leaves displayed varying inhibitory effects on seed germination and seedling growth of four tested plants, and this inhibition increased with increasing concentrations. The aqueous leachate of C. argentea leaves at 0.2 500 g·mL^–1 reduced itself root biomass by 37.5%. Litter mulching of C. argentea and B. pilosa significantly reduced the biomass of C. argentea after 40 days. Compared with the control, root biomass and total biomass of B. pilosa seedlings treated with litter mulching of B. pilosa decreased by 23.0% and 22.2% respectively.【Conclusion】 Not only C. argentea plant has autotoxicity, but also it has strong allelopathic effects on B. campestris and R. sativus. The large amount of C. argentea growth in field should be controlled, and monoculture and continuous cropping of C. argentea should be avoided. The mutual allelopathic inhibition was found between C. argentea and B. pilosa plants, and the co-existence of C. argentea with B. pilosa was conducted with the allelopathic effect.

Abstract:【Objective】 To study different methods of inserting bamboo poles in paddy field on spawning of Pomacea canaliculata.【Method】 Effects of four factors including position, distance, height and shape of inserting poles on trapping efficiency of P. canaliculata spawning were investigated.【Result】 The bamboo poles inserted in paddy field could lure P. canaliculata to spawn on them. The number of egg masses tended to decrease successively from reviving stage, jointing stage to heading stage. At reviving stage with the best trapping effect, more than 50% egg masses were found on the bamboo poles which were 1 m from the paddy ridge, and the number was significantly higher compared with bamboo poles at other positions and rice straws(control)(P<0.05). The bamboo poles at 3 m distance from the paddy ridge and rice straws had the least numbers of egg masses, followed by the bamboo poles at 2 m distance from the paddy ridge. The trapping efficiencies for bamboo pole layouts with 100 cm distance and 30 cm distance between poles were 41% and 33% respectively, which were significantly higher than those for bamboo pole layout with 70 cm distance between poles and the control (P<0.05). The trapping efficiencies for bamboo poles with the tops being 30 and 50 cm high above water surface were 43% and 40% respectively, which were significantly higher than those for bamboo poles with the tops being 10 cm high above water surface and the control (P<0.05). There was no significant difference in the numbers of egg masses between circular-shaped and flat-shaped bamboo poles. After transplanting the rice, high trapping efficiency of P. canaliculata spawning could be obtained by inserting bamboo poles at 1 m distance from paddy ridge, with 100 cm distance between poles and the tops being 30-50 cm high above water surface. Specially, at peak attack period of P. canaliculata, bamboo poles inserted at 30 cm distance between poles could realize efficient trapping of egg masses.【Conclusion】 Appropriately inserting bamboo poles in paddy field can help reduce the egg mass of P. canaliculata, hence reduce the reproductive rate of P. canaliculata and decrease the harm of P. canaliculata in practice. This research provides a new physical control approach of P. canaliculata.

Abstract:【Objective】 To investigate the effects of exogenous melatonin (MLT) and lipopolysaccharide (LPS) on the growth performance and immune function of ducks.【Method】 Eighty 28-day-old healthy Shanma ducks were randomly chosen and divided into four groups including control, MLT, MLT+LPS and LPS groups. The weight and food intake were measured throughout the experimental duration, and on the last day (the 50th day), organism and blood samples were collected to measure biochemical indexes and the levels of growth hormones.【Result】 Compared with control, LPS impaired growth performance of ducks while MLT had the opposite effect, but the difference was not significant (P>0.05). The levels of insulin-like growth factor and thyroxine in serum declined in LPS group (P>0.05), while the levels of serum growth hormone, insulin-like growth factor and thyroxine increased significantly in MLT group (P<0.05). LPS decreased the thymus index and raised the spleen index significantly (P<0.01). By observing tissue sections, a certain degree of damage was found in thymus, liver and spleen of LPS group, while MLT group had no obvious damage. LPS elevated AST content in serum significantly. MLT significantly lowered AST content (P<0.05) but elevated albumin content in serum (P>0.05).【Conclusion】 LPS impairs the growth performance and immune function of ducks, and MLT relieves the harmful effects such as slow growth and immunity decline caused by LPS.

Abstract:【Objective】 To investigate the effect of astaxanthin (AST) on IPEC-J2 cell inflammation induced by lipopolysaccharide (LPS) via TLR4/MyD88/NF-κB signaling pathway.【Method】 MTT assay was performed to determine the optimal time and concentrations of astaxanthin and LPS for treating IPEC-J2 cells and transfected IPEC-J2 cells. Fluorescent quantitative RT-PCR was performed to determine the relative mRNA expressions of inflammatory factors including NF-κB, TNF-α, IL-6 and IL-1β in IPEC-J2 cells and transfected IPEC-J2 cells stimulated by LPS. ELISA assays were carried out to determine the secretion amounts of these inflammatory factors.【Result】 The vitality of IPEC-J2 cells and transfected IPEC-J2 cells reached the peak when treated with 150 μmol·L^–1 astaxanthin for 3 h or 100 ng·mL^–1 lipopolysaccharide for 6 h. Compared with control group, the relative mRNA expressions and secretions of NF-κB, TNF-α, IL-6 and IL-1β in IPEC-J2 cells significantly increased in LPS treatment group (P<0.05). Compared with LPS treatment group, the relative mRNA expressions and secretions of NF-κB, TNF-α, IL-6 and IL-1β in LPS+AST group were significantly lower in IPEC-J2 cells (P<0.05), but did not differ significantly in transfected IPEC-J2 cells (P>0.05).【Conclusion】 Astaxanthin can inhibit cell inflammation, and its protective effect on cells is related to TLR4/MyD88/NF-κB signaling pathway.

Abstract:【Objective】 To investigate the infection states of Giardia duodenalis and the infected G. duodenalis genotype in adult goats in Sichuan partial areas.【Method】 The fecal samples of 342 adult goats were collected from 12 different farms of Sichuan, and subjected to nested PCR to amplify bg, tpi and gdh gene loci through multilocus genotyping technique. PCR products of positive samples were sequenced and further analyzed.【Result】 The infection rate of G. duodenalis in 342 adult goat fecal samples was 14.91% (51/342) and the infected G. duodenalis genotype in all positive samples was assemblage E. Fifty-one positive samples were respectively identified four (assemblage E5, E8, E17 and E18), two (assemblage E2 and E4), and two (assemblage E3 and E4) subtypes in bg, tpi and gdh gene loci. Two novel genotypes (assemblage E17 and E18) were detected at bg locus.【Conclusion】 There are serious G. duodenalis infection in adult goats in Sichuan partial areas. The infected G. duodenalis genotype is mainly assemblage E which has the genetic diversity at a certain level.

Abstract:【Objective】 To explore the effects of chlortetracycline on microflora diversity and tetracycline resistance gene (TRG) abundance in manure-soil environment.【Method】 Four different chlortetracycline dosages were adopted, including 0 (control), 10, 100, 1 000 μg. Samples were collected on the 1st, 7th, 14th, 28th and 56th day. High-throughput sequencing and qPCR were utilized to investigate the changes of microbial community diversity and TRG abundance.【Result】 Firmicutes could tolerate toxic effect of 10 μg chlortetracycline, and was sensitive to 100 and 1 000 μg chlortetracycline. Actinobacteria could tolerate toxic effects of 100 and 1 000 μg chlortetracycline, its survival and reproduction had some advantages. The relative abundances of proteobacteria in all chlortetracycline groups on the 28th day were significantly lower than that of control group, and usually significantly higher than control group on other sampling dates. Three TRGs (tetO, tetT and tetW) were detected in chlortetracycline-manure-soil model, their changing trends of abundance were similar. Compared with the 1st day, the relative abundances in all groups on the 56th day decreased significantly. The day dissipation rates in 10 μg chlortetracycline group were significantly higher than other groups in period Ⅱ, while their relative abundances on the 7th day were significantly higher. The day dissipation rates in 100 μg chlortetracycline groups were significantly lower than other groups in period Ⅳ, while the relative abundances on the 56th day were significantly higher.【Conclusion】 In manure-soil environment, the sensitivity degrees of different bacterium communities to chlortetracycline stress were different, chlortetracycline can change microbial community composition by changing the relative abundances of dominant bacteria. Chlortetracycline stress can change the day dissipation rates of TRGs, thereby affect the relative abundances of TRGs. The results can provide a basis for further research on ecological risk evaluation of antibiotic residue in poultry raising.

Abstract:【Objective】 To elucidate the inhibitory activities of the secondary metabolites of Bacillus amyloliquefaciens gfj-4 and their mixtures with chemical fungicides against Exserohilum turcicum.【Method】 Based on the mycelium growth rate, we determined the effects of different culture and fermentation times of seed broth and fermentation time on the production of antifungal substances, and evaluated the inhibition effects of fermentation supernatant, lipopeptide crude extracts, and mixtures of fermentation supernatant and seven chemical fungicides.【Result】 The most suitable incubation time of seed broth was 6 h and the appropriate fermentation time was 72 h. The EC₅₀ against E. turcicum of the fermentation supernatant and lipopeptide crude extract were 0.32 and 0.11 μL·mL^–1, respectively. E. turcicum showed a high sensitivity to difenoconazole, tebuconazole, procymidone and myclobutanil. Among them, difenoconazole had the highest inhibitory activity against E. turcicum with EC₅₀ of 0.10 μg·mL^–1. Themancozeb and thiram had similar inhibitory activities with EC₅₀ of 12.03 and 12.08 μg·mL^–1, respectively. The inhibitory effect of propineb on E. turcicum was the worst with EC₅₀ of 24.73 μg·mL^–1. The gfj-4 fermentation supernatant and difenoconazole had the additive effect, and the mixture with a volume ratio of 3∶7 had the highest toxicity ratio of 1.28. The fermentation supernatant mixed with mancozeb or propineb in a volume ratio of 2∶8 both had the highest toxicity ratio of 1.28 or 1.67, respectively.【Conclusion】 B. amyloliquefaciens gfj-4 and its mixture with difenoconazole or propineb have important application values in pesticide reduction and synergism.

Abstract:【Objective】 To discover suitable adsorbents of quinclorac and atrazine and to reduce injury to crops caused by their residues.【Method】 The methanol elutions of the adsorbents ( mixtures of soil and different adsorbents) containing quinclorac or atrazine were concentrated, and then analyzed by high-performance liquid chromatography.【Result】 When each adsorbent was used alone, the adsorption rates of active charcoals with different particle sizes (F280, F380, F580) to quinclorac and atrazine were all above 80% indicating excellent adsorption effects. When the adsorbents were mixed with soil, the adsorption rates of F580 active charcoal to quinclorac and atrazine were 73.85% and 59.49%, respectively, indicating relatively good adsorption effects.【Conclusion】 F580 active charcoal can absorb the residues of quinclorac and atrazine in water and soil, and it has great value for application and popularization.

Abstract:【Objective】 To increase the activity of 10-deacetyl baccatin Ⅲ-10β-O-acetyl transferase (DBAT) and the efficiency of in vitro enzymatic synthesis of baccatin Ⅲ.【Method】 Computer simulation of molecular docking between DBAT and its natural substrate acetyl CoA was performed. Three amino acid residues including C165W, N300I and F160C were chosen for site-directed mutation. The recombinant mutants were expressed in Escherichia coli and their enzymatic properties were determined by reactions in vitro.【Result】 The relative molecular mass of each of the three mutant enzymes was 67 000, and the optimum reaction temperature was 32.5 ℃ which was consistant with that of the wild type enzyme (DBAT). The optimum reaction pH of DBAT^F160C or DBAT was 7.5, slightly higher than that of DBAT^C165W or DBAT^N300I (pH 7.0). Compared with DBAT, DBAT^C165W, DBAT^F160C and DBAT^N300I had 61.5%, 59.6% and 19.2% higher specific activities, 55.4%、35.1% and 2.9% higher catalytic efficiency, as well as higher K_m and v_max.【Conclusion】 Hydrophobic mutations lead to significantly increased specific activities for mutant enzymes compared with the wild type enzyme. This study provides a basis for efficient in vitro enzymatic synthesis of baccatin Ⅲ, a direct precursor for chemical semi-synthesis of anti-cancer drug paclitaxel.

Abstract:【Objective】 To investigate the molecular mechanism of flavonol synthase (FLS) gene in peony flower (Paeonia lactiflora) color formation.【Method】 We cloned PlFLS gene and carried out bioinformatics analysis. The over-expression vector of PlFLS gene was constructed and transformed as heterologous gene into Arabidopsis by floral-dip method with recombinant agrobacterium transformants.【Result】 The bioinformatics analysis results suggested that the amino acid sequence of PlFLS gene was highly similar with Camellia sinensis, and there were two structure domains but no potential signal peptide. The tertiary structure prediction of PlFLS protein showed that there was a 2-oxoglutaric acid ligand connecting with several peptide chains. Transgenic Arabidopsis plants expressing homologous PlFLS gene were obtained successfully. GUS staining and PCR detection confirmed the integration of PlFLS gene into Arabidopsis genome, and qRT-PCR analysis showed PlFLS gene was expressed at significantly higher level in transgenic lines compared with wide type (P<0.05). Through HPLC detection, the anthoxanthin content in transgenic plants significantly increased compared with wide type (P<0.05).【Conclusion】 PlFLS gene has been transformed into Arabidopsis successfully and it plays an important role in regulating the synthesis of flavonoids.

Abstract:【Objective】 To realize the automatic walk and uniform application of mobile robot in the greenhouse, a kind of spraying robot capable of navigating autonomously between crop lines was designed.【Method】 Aiming at the problem that the recognition of navigation path was greatly affected by light changes, HIS space was selected from the color images acquired by Kinect camera. The clustering center and number were optimized for K-means algorithm. Using the improved K-means algorithm，the components of H and S were segmented and the complete road information was obtained. The method of Candy operator was used to detect the edge，and the method of improved Hough change was used to fit the navigation path. The method of fuzzy control was used to correct robot walking offset by adjusting the rotating angle and turn in real time. A self-tuning fuzzy PID control algorithm was selected for this spraying system to meet application requirements of different crops.【Result】 The system could effectively adapt to different light conditions. On average, it took 12.36 ms to extract the center line of crop. The navigation deviation does not exceed 5 cm. The coverage rate of plant leaves on upper, middle and lower layers was 63.26%, 50.89% and 75.82% respectively, and the droplet number per square centimeter was 55, 42 and 78 respectively.【Conclusion】 This system can meet the need of pesticide application of mobile robot to prevent pests and diseases in greenhouse.

Abstract:【Objective】 To detect the anthocyanin contents of winegrape skins during ripening stages using hyperspectral imaging technology.【Method】 The 900-1 700 nm near-infrared hyperspectral imaging technology and multiple regression methods were used to build prediction models for anthocyanin contents in skins of different winegrape varieties during ripening stage. Totally 75 groups of grape samples belonging to 6 varieties were collected at 4-5 phases of mature stage, and their hyperspectral images were scanned. The spectrum data were enhanced by different preprocessing methods. Dimensionality reduction was then performed by principal component analysis (PCA) and successive projections algorithm (SPA). The anthocyanin contents measured by chemical method were used as reference values, and the prediction models of anthocyanin contents were built using support vector regression (SVR) method.【Result】 The SPA-SVR model had the best performance of prediction with the determination coefficient (R_p²) being 0.869 1 and the root mean square error of prediction (RMSEp) being 0.135 9.【Conclusion】 It is feasible to use the hyperspectral imaging technology to realize non-destructive and fast detection of the anthocyanin contents in winegrape skins of different varieties during ripening.

Abstract:【Objective】 To propose a method to detect feed intake based on broiler chicken feeding audio, overcome the situation that feed intake data of broiler chickens in China nowadays were mainly population feed intake measured manually and provide a strong technical support for accurately measuring broiler chicken feed intake.【Method】 The feed intake audio collected by voice recorder was conducted framing, windowing, endpoint detection and other preprocessings, the effective sound fragments were picked up. Then one-class support vector machine (OC-SVM) was used to classify extracted sound fragments based on power spectral density curve differences of different sounds. The pecking number during feeding process was detected through audio technology. The relationship between pecking number and feed intake was explored, and the feed intake was calculated by their strong correlation.【Result】 The pecking number of broiler chicken detected through audio technology was highly correlated with feed intake, and the determination coefficient (R²) was 0.982 5. The calculation accuracy rates of pecking number and feed intake were 94.58% and 91.37% respectively.【Conclusion】 This method can be used for feed intake measurement of broiler chicken.