WANG Wence , XU Liwen , LIN Zhenping , XIONG Benhai , YANG Lin
2014, 35(6):1-7. DOI: 10.7671/j.issn.1001-411X.2014.06.001
Abstract:【Objective】 This study was conducted to investigate the effects of different dietary lysine levels on growth performance, serum biochemical indices and protein deposition of lion head geese aged from 1 to 21 days.【Method】 Eight hundred and twenty-eight one-day-old healthy lion head geese were randomly divided into 6 groups with 6 replicates per group and 23 geese in each replicate. Geese in control group were fed diets containing 0.75% lysine. Five treatment groups were fed diets containing 0.90%, 1.05%, 1.20%, 1.35%, 1.50% lysine, respectively. The experiment lasted for 21 days.【Result and conclusion】 These results showed that 1) With the increase of dietary lysine level, average daily gains of 21-day lion head geese in 1.05%~1.50% groups were significantly higher than those of control and 0.90% groups (P<0.05) whereas feed/gain ratio decreased compared to control and 0.90% groups (P<0.05); 2) The highest levels of total protein, albumin and globulin in lion head geese were observed in 1.20% group, which were higher than those of 0.90%, 1.05% and 1.35% groups (P<0.05). No significant difference of serum urea and triglyceride was observed in all groups, but these two indicated the lowest values in 1.05% group. Serum alkaline phosphatase in 1.20% group with the highest value was remarkably higher than those of 1.05%, 1.35% and 1.50% groups (P<0.05). There were no significant difference of serum growth horrnone and insulin growth factor-1 in all groups; 3) The absolute and relative protein depositions of lion head geese increased with the rise of dietary lysine level and resulted in a better performance in 1.20% group. In conclusion, dietary lysine supplementation can improve the growth performance of lion head geese aged from 1 to 21 days at the 1.05% optimum lysine level.
FENG Meiying , LI Guihuan , XU Zhenpeng , BAI Yinshan , WANG Wencong , LI Li , ZHANG Shouquan , WEI Hengxi
2014, 35(6):8-12. DOI: 10.7671/j.issn.1001-411X.2014.06.002
Abstract:【Objective】This study was conducted to explore the effect of different concentrations of L-carnitine on the maturation of porcine oocytes, the development of parthenogenetic (PA) embryos in vitro and the lipid metabolism in pig oocytes. 【Method】Different concentrations of L-carnitine were added into mature medium to observe the influence on porcine oocytes maturation and parthenogenetic embryos development. Oil red staining, triacylglycerol kit and quantitative RT-PCR were used to detect the lipid metabolism and the key hydrolase expression level in oocytes.【Result and conclusion】The rates of oocytes maturation and the subsequent PA blastocysts increased significantly when supplemented with 100 ng/mL L-carnitine to the IVM medium (P<0.05), and the oocytes lipid metabolism also increased significantly (P<0.001). The addition of 100 ng/mL L-carnitine into embryo culture medium significantly increased the cleavage rates (P<0.05) and contributed to the PA blastocyst rates and qualities. Further analyses of quantitative RT-PCR revealed that the mRNA expression levels of adipose triglyceride lipase gene (ATGL) and hormone-sensitive triglayceride lipase gene (HSL) both decreased significantly with 100 ng/mL L-carnitine treatment, which indicated that the L-carnitine could affect the lipid metabolism by regulating the key lipases gene expression. In conclusion, these results demonstrated that L-carnitine can improve porcine oocytes maturation and enhance the PA embryos developmental ability through lipid metabolism regulation.
XIAO He , WANG Weili , JIANG Lan , JU Jing , LUO Li , DENG Yuting , TAN Aiping
2014, 35(6):13-18. DOI: 10.7671/j.issn.1001-411X.2014.06.003
Abstract:【Objective】To investigate the pharmacokinetics and changes of sulfadiazine and trimethoprim in the blood of Oreochromis niloticus at different water temperatures.【Method】Compound sulfadiazine which contained two composition of sulfadiazine and trimethoprim was orally administered to O. niloticus at a single dosage of 120 mg/kg at 18,23,28 and 33 ℃.The concentration of sulfadiazine and trimethoprim in O. niloticus plasma was determined by HPLC method.【Result and conclusion】Results showed that higher peak plasma concentration(Cmax) of sulfadiazine was 12.41,19.60, 22.48 and 30.78 μg/mL at 18, 23, 28 and 33 ℃,the Cmax of trimethoprim was 1.22, 2.06, 2.44 and 2.70 μg/mL respectively,and a higher peak plasma concentration was found at a higher temperature. The elimination(t1/2 ke) of sulfadiazine was 18.22, 17.89, 16.90 and 12.99 h at 18, 23, 28 and 33 ℃;t1/2 ke of trimethoprim was 16.39, 7.08, 5.99 and 4.04 h respectively. Fast elimination of trimethoprim and sulfadiazine was observed at a higher temperature in O. niloticus. Concentration ratios of sulfadiazine/trimethoprim were 9.57∶1-11.01∶1, 6.30∶1-9.36∶1,5.40∶1-10.39∶1 and 4.20∶1-20.64∶1 within 10 h after administration at the synergistic activity ratios ranging of 1∶1-40∶1. The results show that the temperature can significantly affect the absorption and elimination of the drugs in O. niloticus, improving the maximum plasma concentration. It also speeds up the elimination of the drugs, but has little effect on the ratio of compound sulfadiazine.
YUAN Yan , FANG Jing , LIAO Tingbin , CUI Xue , CHEN Yue
2014, 35(6):19-23. DOI: 10.7671/j.issn.1001-411X.2014.06.004
Abstract:【Objective】 The immunohistochemical localization and developmental changes of ghrelin in the duck thymus were studied to provide the morphological effect of ghrelin on the physiological function of thymus. 【Method】 Tianfu ducks were divided into 19 groups as follows: 7 groups in the embryonic period (14, 16, 18, 20, 22, 24 and 26 days at embryonic stage), 12 groups after hatching (at neonatal stage, 1, 3, 5, 8, 11, 14, 17, 20, 26, 29 and 32 weeks). The immunohistochemical method associated with morphometric analysis was used. 【Result and conclusion】 The ghrelin immunoreactivity (-ir) cells with round, ovoid, stellate and irregular aspects were maily thymic epitheilial cells and macrophages, and diffusely distributed in the thymic cortex and medulla from embryonic 20 days to 32 weeks after hatching. The number of ghrelin-ir cells in the thymic cortex and medulla was unchanged during the embryonic development, presenting a wave-changed pattern during the continuous development (from neonatal stage to 8 weeks after hatching) and matured periods (from 11 to 17 weeks after hatching ), which decreased during the involution stage (from 20 to 32 weeks after hatching). These results suggested that ghrelin-ir cells existed in the duck thymus and their numbers exhibited obvious age-related changes, which can be closely related to the involution of the duck thymus.
YANG Zifeng , ZHU Haitao , LIU Ziqiang , ZENG Ruizhen , FU Xuelin , CHEN Xionghui , ZHANG Guiquan , JIN Lingling , LIU Guifu
2014, 35(6):24-28. DOI: 10.7671/j.issn.1001-411X.2014.06.005
Abstract:【Objective】 To explore the genetic basis on heading date in rice. 【Method】 Eight single segment substitution lines of Huajingxian 74 were applied as experimental materials to construct seven secondary F2 populations pyramiding dual QTL, in each of which nine marker genotypes were distinguished to allow estimations of epistatic components for the QTL pairs.【Result and conclusion】 All QTL pairs tested, except for QTL HD3 and HD8, exhibited significantly epistatic effects, accounting for 85.7%. There were 60.7% of 28 epistatic components to be detected with significant estimations at the probability levels of 5% or 1%, where three types of epistatic interactions, e.g. additive-additive, additive-dominance or dominance-additive, and dominance-dominance epistatic effects accounting for 71.3%, 42.8% and 85.6%, respectively. These results further confirmed that the universality and the importance of epistasis existed in genetic systems of quantitative traits, providing useful frames and materials for molecular marker assisted pyramiding breeding on heading date in rice.
CHEN Jiqun , LIU Lizhen , CHEN Jiezhong , ZHANG Hailan
2014, 35(6):29-32. DOI: 10.7671/j.issn.1001-411X.2014.06.006
Abstract:【Objective】 The objective of the study was to find the relationships among calcium contents, cell wall enzyme activities and fruit cracking. 【Method】 Two naval orange (Citrus sinensis) cultivars, ‘Skagg’s Bonanza’ and ‘Newhall’ were treated with exogenous calcium or calcium uptake inhibitor. The contents of calcium, the rate of fruit cracking and the activities of polygalacturonase (PG), cellulase (CX), and pectinmethylesterase (PE) were investigated in different periods.【Result and conclusion】 The contents of calcium in ‘Newhall’ was higher than that in ‘Skagg’s Bonanza’. The content of calcium in the normal fruits was higher than that in cracked fruits in the same cultivar. The mass fraction 2% Ca(OH)2 treatment increased significantly the calcium content in the pericarp and fruit firmness, reducing the rate of fruit cracking 150 days after anthesis. The mass fraction 2% Ca(OH)2 treatment reduced the activities of cellulase (CX). Calcium affected the incidence of fruit cracking through its effect on the activities of cell wall enzymes. Its effect was significant in ‘Skagg’s Bonanza’ but not in ‘Newhall’.
WANG Daobo , LI Fusheng , ZHOU Ruiyang
2014, 35(6):33-40. DOI: 10.7671/j.issn.1001-411X.2014.06.007
Abstract:【Objective】 The effects of NPK fertilizer management on nutrient contents and uptakes in different organs and soil available nutrient contents were studied to investigate the nutrient use of different kenaf varieties, so as to provide rational fertilization for high yield and high efficient cultivation of kenaf. 【Method】 The pot experiments included two kenaf varieties, i.e. Fuhong 992 and Hongyou 2, three fertilization levels, i.e. low fertilization (N 0.10 g·kg-1, P2O5 0.05 g·kg-1 and K2O 0.10 g·kg-1), medium fertilization (N 0.15 g·kg-1, P2O5 0.075 g·kg-1, K2O 0.15 g·kg-1) and high fertilization (N 0.20 g·kg-1, P2O5 0.10 g·kg-1, K2O 0.20 g·kg-1), and three fertilization methods, i.e. T1 (all N and K fertilizers as basal fertilizer), T2 (60% N and K fertilizers as basal fertilizer, 40% N and K fertilizers as topdressing) and T3 (all N and K fertilizers as topdressing).【Result and conclusion】 The contents of N, P and K in various organs, plant NPK uptakes and the contents of available N, P and K in soil increased with the increase of fertilizer rate. With the increase of the rate of NK for top dressing, N contents in various organs, P contents in root, leaf and pole and plant N and P uptakes reduced while P contents in bark, K contents in various organs, plant K uptakes and the contents of available N, P and K in soil increased. In this study, for Fuhong 992 and Hongyou 2, high fertilization with all N and K fertilizers as basal fertilizer can increase the nutrient absorption of kenaf and the contents of available nutrients in soil.
YAN Shen , FU Yunpeng , CAO Xiaotao , JING Shasha , WANG Weichao , ZENG Yu , LI Jianhua , LIU Guoshun
2014, 35(6):41-45. DOI: 10.7671/j.issn.1001-411X.2014.06.008
Abstract:【Objective】To explore the effect of growing period on upper leaf of tobacco in the center of Henan province.【Method】 With Zhongyan 100 as the experimental material, two experimental designs which included transplanting periods and maturity of leaves, were applied in 2012.【Result and conclusion】The effects of transplanting time and maturity on the chlorophyll and carotenoid content were significant, the chlorophyll content with the same maturity had a slight difference by postponing tobacco transplanting period, but carotenoid presented the tendency that rise firstly, then drop; with the increase of maturity of tobacco leaves, the contents of chlorophyll and carotenoid declined. The contents of degradation product in neophytadiene and carotenoid showed May 6th >May 15th >April 27th episode trend; the performance of content increased first and reduced then with the maturity. Upper leaf quality which is transplanted on May 15th and picked postponement 5 days than usual,is the best.
ZHOU Bo , WU Minghua , CHENG Jiong , DENG Nanrong , HU Yueming , DAI Jun
2014, 35(6):46-51. DOI: 10.7671/j.issn.1001-411X.2014.06.009
Abstract:【Objective】The relationships between arable land natural quality grade and main soil fertility indicators were studied. 【Method】Arable land quality monitoring indicators and the soil fertility indicators were investigated after the study area was divided into four monitoring partitions and 38 sampling points were laid, based on the work of Huazhou arable land quality grade monitoring. 【Result and conclusion】The results showed that the mathematical relationship between the arable land quality level(y) and the main soil fertility indicators[pH(x1); available nitrogen content(x2)] was y =1 300.15+630.33 x1+3.24x2. pH and available nitrogen significantly are correlated with ten original monitoring indicators of arable land, and the two fertility indicators and the natural quality grade index also have a significant linear relationship.
LIU Xiaojia , TANG Xuedong , LIU Haiguang , WU Lin , ZHANG Zhidong , LI Yadong
2014, 35(6):52-57. DOI: 10.7671/j.issn.1001-411X.2014.06.010
Abstract:【Objective】 The contents and annual variations of cytokinins including zeatin (Z), zeatin riboside (ZR) and isopentenyl adenodine (iPA) were studied in the rhizosphere and non-rhizosphere of blueberry, Vaccinium vitis-idaea ‘Northland’ after the application of different soil amelioration materials in pots.【Method】Rhizosphere and non-rhizosphere soil samples with different root adhesion degrees were collected by rhizosphere soil stripping separation method,high performance liquid chromatography methods were used to investigate cytokinin contents in soil samples.【Result and conclusion】Cytokinin contents of corn stalks mixed with nitrogen fertilizer(k4) were the highest, followed by the application treatments of corn stalks(k3), peat(k2), and no added (k1,control). The general trend of cytokinin contents in blueberry rhizosphere and non rhizosphere soil were Z>ZR>iPA in different periods, such as k4 treatment the Z, ZR and iPA average content was 9.89, 9.76 and 3.57 ng/g respectively, which were higher than 67.9%,84.2% and 105.6% compared with the control, respectively. The annual variations of cytokinins in the root zone of blueberry were traced. The contents of cytokinins increased in early spring and declined in autumn, while between in early spring and late autumn they maintained high levels.
WANG Chunwei , WANG Yan , XU Yuncheng , CUI Lili , GAO Jie
2014, 35(6):58-62. DOI: 10.7671/j.issn.1001-411X.2014.06.011
Abstract:【Objective】 To investigate flusilazole residues in ginseng and to conduct risk assessment. 【Method】 A solid phase extraction (SPE) and high performance liquid chromatography coupled with mass spectrometry (SPE-HPLC-MS/MS) method was developed to determine the residual dissipation and final residues of flusilazole 400 g·L-1 EC in ginseng root and soil at Fusong County and Ji’an City in 2011 and 2012. The dietary risk assessment was also conducted using the calculation of risk quotient (RQ).【Result and conclusion】 The half-lives of flusilazole were 7.85-9.94 d in root and 5.59-7.13 d in soil at spraying dosage of 90 g·hm-2. Final residues of flusilazole were below 0.043 3 mg·kg-1 in root and below 0.037 5 mg·kg-1 in soil, and the risk was very low with 4.59×10-5 (much less than 1) of a risk quotient, and the residues could be declined to the safe level over 35 days after spraying once or twice at a dosage ranging from 60 to 90 g·hm-2. It is recommended that the MRL of flusilazole in ginseng should be 0.05 mg·kg-1 temporarily, and its preharvest interval should be set at 35 days.
QIU Xiaolong , ZHANG Bo , HE Yurong , GAO Yan , CHEN Ting , Lü Lihua
2014, 35(6):63-66. DOI: 10.7671/j.issn.1001-411X.2014.06.012
Abstract:【Objective】 To identify the foraging habits of the red imported fire antSolenopsis invicta Buren in newly invaded region of Guangzhou, and to provide scientific basis for researching and developing new baits to control the fire ant. 【Method】 The diurnal dynamics and body polymorphism of foragers in the colony of the red imported fire ant were observed by using directly-dissecting underground foraging tunnel at mulberry orchard and barren land in summer and autumn in Guangzhou.【Result and conclusion】 The results showed that foraging rates of fire ant workers for liquid-or solid-food were significantly different in habitats and seasons, but no difference in interaction of two treatments. The foraging rates of dietary preference for liquid food in all treatments were significantly higher than those for solid food. The average proportion of workers carring liquid food in crop [summer: (36.58±8.74)%, autumn: (37.60±5.16)%] was significantly higher than the proportion of workers carrying solid foods [summer: (8.03±1.66)%, autumn: (7.30±1.71)%].Individual polymorphism of workers feeding solid food, liquid food and responsible for defense showed a continuity of skewed distribution. Their average head width were (0.652 4±0.007 1), (0.636 1±0.006 2) and (0.636 3±0.006 4) mm, respectively, showing no significant difference among them.
LIU Feifei , WANG Jianpan , LIN Yuan , BI Shoudong , ZHOU Xiazhi , ZOU Yunding , LENG Peng , HUA Yuqin , JIANG Yunya , LI Xia
2014, 35(6):67-73. DOI: 10.7671/j.issn.1001-411X.2014.06.013
Abstract:【Objective】The major insect pests in the Huangshan large leaf tea gardens are Empoasca vitis, Toxoptera aurantii, Aulcophora femoralis and Ricaniaspeculum. To investigate the population dynamics between the four major pests and their natural predators. 【Method】 The quantity, and the temporal and spatial relationships of the four pests and their predators were analysed using grey correlation degree and ecological niche analyses. The dominant natural predator of each pest was evaluated using the sum of close index.【Result and conclusion】 There were greater differences for dominant natural predators of four pests between spring-summer season and autumn-winter season. In spring-summer season the three dominant natural predators of Empoasca vitis were Oxyopes sertatus, Neoscona theisi and Tetragnatha maxillosa; the dominant natural predators of Toxoptera aurantii were Leis axyridis, Propylea japonica and Tetragnatha maxillosa; for Galerucinae, the main natural predators were Propylea japonica, Leis axyridis and Erigonidium graminicolum; and for Ricaniaspeculum, the predators were Clubiona japonicola, Tetragnatha maxillosa and Xysticus ephippiafus. In autumn-winter season, the three dominant natural predators of Empoasca vitis were Tetragnatha maxillosa, Theridion octomaculatum and Tetragnatha squamata; the three dominant natural predators of Toxoptera aurantii were Tetragnatha maxillosa, Theridion octomaculatum and Tetragnatha squamata; for Galerucinae, the main natural predators were Propylea japonica, Leis axyridis and Tetragnatha maxillosa; and for Ricaniaspeculum, the predators were Neoscona theisi, Oxyopes sertatus and Xysticus ephippiafus.
ZHANG Zhidan , JIANG Haichao , LUO Xiangli , LIU Xin , DONG Rui , LI Qiao , XU Liying , LIU Shuxia , ZHAO Lanpo , WANG Jihong , YANG Da
2014, 35(6):74-78. DOI: 10.7671/j.issn.1001-411X.2014.06.014
Abstract:【Objective】 To reveal the variation law of black soil enzyme of Songliao Plain and provide reference to establish an effective fertilization system. 【Method】 Black soil under continuous maize cultivation was taken in the corn belt of Songliao Plain as materials. Enzyme activities in different areas and sections(“plant type ” and “wave type”) were determined based on field surveys and sampling correlation analyses between enzyme activities and soil nutrient contents were obtained.【Result and conclusion】 Soil enzyme acted as the biological catalyst in a soil cycle. The activities of different kinds of enzymes were significantly correlated with the soil nutrient, so enzyme activities could be used to indicate the soil fertility. Furthermore, urease could indicate the soil fertility well.
KUANG Lei , DENG Xiaomei , YU Fei , LIU Xiaorui , ZHANG Shuo , CHEN Xiaoyang
2014, 35(6):79-82. DOI: 10.7671/j.issn.1001-411X.2014.06.015
Abstract:【Objective】Changes of seeding height, ground diameter, biomass, leaf area and chlorophyll content in different proportions of fertilizers were investigated to find out the optimum fertilization scheme. 【Method】Through orthogonal experimental design, experiments of N, P, K fertilization were carried out in container seedlings of Zenia insignis.【Result and conclusion】Fertilization could promote the growth of seedlings and different nutrient elements, and their ratios had a different influence on the growth of seedlings. The treatment of N4P4K2 and N3P4K3 played a greater role in promoting the growth of seedling height and ground diameter. Compared with the control group, it increased by 251.99% and 214.75%, respectively. Total biomass reached the maximum in the treatment of N2P4K1, increasing 298.03% compared with the control group. N is the biggest influence on the growth of Z. insignis seedling, followed by P. Reasonable ratio of N and P, which can effectively improve the quality of Z. insignis seedlings.
SUN Peiguang , XI Ruchun , Li Juncheng , OUYANG Kunxi , ZHONG Yanmei , CHEN Xiaoyang
2014, 35(6):83-88. DOI: 10.7671/j.issn.1001-411X.2014.06.016
Abstract:【Objective】This study aimed to lay a theoretical foundation for rational use of Camellia oleifera germplasm resource and provide technical support for the conservation of elite C.oleifera varieties. 【Method】SRAP molecular markers were used to assess the genetic diversity and molecular identification of 25 superior clones of C.oleifera from Jiangxi Province.【Result and conclusion】Three hundred ard forty seven sites were amplified by 11 primer combinations of SRAP, among which 332 were polymorphic sites. The percentage of polymorphic sites was 95.68%. The result of cluster analysis indicated that the genetic distance of the 25 superior clones ranged from 0.255 6 to 0.738 4, and the average genetic distance was 0.599 9, indicating that these cultivars had similar geographical origins. The 25 superior clones were divided into five groups by cluster analysis according to genetic distance 0.528 0. DNA fingerprints of the 25 superior clones were constructed using the screened primer combinations. The fingerprint constructed by each primer combination can be used for molecular identification of the 25 superior clones.
LIU Dehao , ZHANG Weihua , ZHANG Fangqiu
2014, 35(6):89-93. DOI: 10.7671/j.issn.1001-411X.2014.06.017
Abstract:【Objective】In order to rapidly and precisely identify the excellent gene for the breeding of Eucalyptus urophylla, the construction of core collection of E.urophylla was necessary. Establishing a core collection of E.urophylla could simplify the management and enhance the utilization of genetic resources in E.urophylla research programs. 【Method】Based on 17 quantitative traits, height, diameter and volume of 194 families from 27 provenances of E.urophylla, core collections were constructed using different sampling proportions (5%, 10%, 20%, 30%, and 40%), 3 distances (Euclidean distance, Standardized Euclidean distance, and Mahalanobis distance), 4 hierarchical clustering methods (Single distance method, Complete distance method, Unweighted pair-group average method and Ward’s method), and 2 sampling strategies (random sampling and least distance stepwise sampling) were employed. The genetic variation of the quantitative traits among these core collections was compared by evaluating the mean difference percentage (MD), variance difference percentage (VD), changeable rate of coefficient of variation (VR) and coincidence rate of range (CR) of the traits.【Result and conclusion】The results showed that the primary core collection was constructed with 10% sampling proportion, standardized Euclidean distance, Single distance method,and least distance stepwise sampling, which was composed of 100 families from 27 provenances of E.urophylla and the best representative of total germplasm.
CHEN Ying , ZHANG Juntao , RUAN Lin
2014, 35(6):94-98. DOI: 10.7671/j.issn.1001-411X.2014.06.018
Abstract:【Objective】A strain with the ability of lignin degradation was screened from landscaping waste compost.【Method】The obtained isolates were identified by molecular identification; the lignin degradation isolates were inoculated into sterilized Ficus microcarpa var. pusillifolia wattle to study the degradation ability, including analyses of the content of lignin, cellulose and hemicellulose of the wattle respectively.【Result and conclusion】The results showed that the lignin degradation isolates were identified as Streptomyces sp. Compared with non-inoculated treatments, samples inoculated with different dosages (5%, 10%, 15%) of the bacteria fermentation liquid into Ficus microcarpa broken branches, respectively, the lignin content could be reduced by 22.48%, hemicellulose content could be reduced by 26.60% after 45 d incubation.
XIA Hongmei , LI Zhiwei , ZHEN Wenbin , ZHANG Bingchao
2014, 35(6):99-103. DOI: 10.7671/j.issn.1001-411X.2014.06.019
Abstract:【Objective】To optimize chamber structure parameters of the pneumatic plate-type vegetable seed metering device, and to simplify the vacuum flow field in the air chamber as steady, regular, incompressible and turbulent fluid.【Method】The FLOTRAN module of ANSYS software was applied to simulate and analyze the air chamber with different structure parameters.【Result and conclusion】Compared to the rectangular cavity air chamber structure, the rectangular groove connected air chamber structure could save more gas flow and improve the overall strength. Pressure loss of double outlet was less than single outlet, and flow field uniformity of double outlet was better. The optimized air source location was between the fourth and the fifth suction holes calculated from both sides of the metering device. Increasing channel depth could reduce pressure loss at transition region and ensure more uniform pressure and velocity distribution. But if channel depth increased, the size of metering device would increase correspondingly, and the time for forming steady flow would be longer. According to simulation results, 4 mm channel depth was optimized. Verifying tests of the air flow field in the vacuum chamber of seed metering device show that the simulation analysis results are comparatively consistent with the actual measurement results, with a consistent pressure distribution trend. This proves the feasibility of the numerical simulation method.
XIE Shicong , HUANG Zhihui , LI Changzhu , XIAO Zhihong , BAI Pengzhan , YANG Xingxing , LIU Rükuan
2014, 35(6):104-107. DOI: 10.7671/j.issn.1001-411X.2014.06.020
Abstract:【Objective】To predict the temperature distribution on the inner surface of the spiral oil press. 【Method】The finite element method was used to analyze the squeezing chamber’s thermal. The objective function of the squeezing chamber’s outside surface’s temperature distribution was established and a method was put forward to solve the temperature distribution of the squeezing chamber’s inner surface. 【Result and conclusion】The effective of this method was varifed. Analysis results show that this method can provide the theoretical basis for the development of a squeezing chamber and the design of high performance oil press.
LI Xiaoxia , CHEN Feng , PAN Qing , CHEN Cuiying , TAN Yuwen , LEI Xiaoting , CAO Junming
2014, 35(6):108-112. DOI: 10.7671/j.issn.1001-411X.2014.06.021
Abstract:【Objective】The effects of dietary yeast selenium on the growth and antioxidant performance were studied in Litopenaeus vannamei. 【Method】Seven hundred and twenty healthy Litopenaeus vannamei with an initial average body mass of (0.41±0.01) g were randomly stocked into 6 groups with 3 replicates per group and 40 shrimps per replicate in re-circulated water system. The basal diet was supplemented with 0, 0.15, 0.30, 0.45, 0.60 and 1.00 mg·kg-1 selenium (yeast selenium) respectively and these shrimps were fed with 6 semi-purified diets containing graded levels of 0.25, 0.41, 0.56, 0.68,0.84,1.20 mg·kg-1 of selenium, respectively for 56 d.【Result and conclusion】The results showed that mass gain rate (MGR), specific growth rate (SGR), feed conversion rate (FCR), survival rate (SR) had no significant difference among all groups (P>0.05), but with the increase of yeast selenium levels, MGR and SGR increased and the highest value was found in the 0.84 mg·kg-1 group. The total antioxidative capacity (T-AOC) and superoxide dismutase (SOD) of shrimp in hepstopsncreas were higher than those of the control group, while the malondialdehyde (MDA) content was lower than that of the control group. But there were no significant differences (P>0.05).A quadratic linear regression analysis showed that using MGR and SGR as response criteria in cultured condition, the optimum dietary selenium content for the highest growth in Litopenaeus vannamei was 0.98 mg·kg-1 of dietary mass.
WANG Yunhe , WANG Zhichun , YANG Fan , AN Fenghua , YANG Hongtao , BAO Da
2014, 35(6):113-116. DOI: 10.7671/j.issn.1001-411X.2014.06.022
Abstract:【Objective】 To explore the effects of desulfurized gypsum application on soluble salt in sodic soil and drainage water in paddy field.【Method】 A field experiment with three different application rates of desulfurized gypsum [29.17(S1),16.68(S2) and 4.17(S3)t·hm-2]was carried out to assess the improvement effect of sodic soil and soluble salt ions concentration.【Result and conclusion】 The results showed that the soluble salt ions concentration except for carbonate in drainage water remained constant after rice tillering rear, and pH, electrical conductivity (EC) and residual sodium carbonate (RSC) in drainage water basically stayed unchanged. Differences in soil EC between S1 and S2 treatments were statistically significant at 10-20 cm soil depth (P<0.05); soil EC increased with the increase of desulfurized gypsum application rates at 0-20 cm soil depth, however, the opposite trends were found for soil pH and sodium adsorption ratio (SAR). Improvement effects of S1 treatment on sodic soil were better than those of S2 and S3 treatments for 0 to 40 cm soil depth.
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