Abstract:Objective Rainfall characteristics during each growth period of early and late rice in South China region were studied to provide a decision-making basis and have an active meaning for double cropping rice production and disaster prevention and reduction in South China. Method Using daily precipitation data of 47 meteorology observational stations from 1960 to 2008 in South China, regional average cumulative precipitation and daily average percentage of rainstorm in each growth period of early and late rice were calculated, and annual average value and spatial distribution characteristic of rainfall were analyzed. Result There was almost the same accumulated rainfall with above 600 mm in early rice (673.5 mm) and late rice (611.5 mm)periods. The maximum accumulated rainfall occurred in seedling stage of late rice (256.6 mm), and the minimum value occurred in heading stage of late rice (26.9 mm). The maximum daily average precipitation in growth periods of early and late rice occurred in filling stage (8.2 mm) and seedling stage (8.3 mm) respectively, and the minimum value occurred in seedling stage (4.1 mm) and filling stage respectively. The daily average rainstorm and precipitation gradually increased with the growth stage for early rice, but decreased for late rice. The results of spatial distribution showed that the accumulated rainfall and frequency of heavy rainfall were closely related with the precipitation system in South China during the flood season. Early rice was mainly affected by the monsoon system,and late rice was mainly affected by the typhoon system. The high values of precipitation and rainstorm were mainly located in coastal areas. Conclusion Rainfall characteristics in the growth periods of early and late rice are different. The most important stage for preventing flood is filling stage for early rice, but tillering stage for late rice.

Abstract:Objective To analyze panicle trait combining ability and heritability of rice two-line sterile line ‘M20S’, and accelerate the application process of potential breeding value of ‘M20S’.Method Four light-sensitive rice sterile lines (‘Wang S’, ‘Deep 08S’, ‘Y58S’ and ‘M20S’) and three restoration lines (‘Hanghui 1173’, ‘Hanghui 91’ and ‘Hanghui 24’) were designed to combine according to 4×3 incomplete diallel cross (NCII), and the combining ability and heritability of panicle traits of sterile lines were analyzed.Result The variance differences of general combining ability and special combining ability of all traits were significant or extremely significant. The panicle length and primary branch number were mainly controlled by gene additive effects. Total grain number, seed setting rate, 1 000-grain weight, grain density and single panicle weight were mainly affected by non-additive effects. The generalized heritabilities of seven traits from large to small were 1 000-grain weight, grain density, total grain number, single panicle weight, primary branch number, panicle length and seed setting rate. The narrow heritabilities from large to small were the primary branch number, panicle length, grain density, 1 000-grain weight, total grain number, seed setting rate and single panicle weight. The general combining abilities of ‘M20S’ total grain number, primary branch number and grain density were 42.96, 17.69 and 45.35 respectively. The general combining ability of ‘M20S’ single panicle weight was positive. Conclusion ‘M20S’ has many traits that have good general combining abilities, and is an excellent parent. The special combining abilities of ‘M20S/Huihui 24’ total grain number, grain density and single panicle weight are higher, which is in line with the requirements of large panicle type breeding. Total grain number, 1 000-grain weight, grain density and single panicle weight are mainly controlled by genetic effects. The primary branch number, panicle length and other traits can be selected in early hybridization to improve breeding efficiency.

Abstract:Objective To investigate the effects of different rice planting years on physicochemical properties and fungi communities of soda saline-alkali soil, and provide a theoretical basis for saline-alkali soil improvement.Method Soda alkali-saline soil that had been planted with rice for 1, 3, 5, 15, 20 and 50 years respectively were chosen as research objects. The routine analysis and IlluminaMiSeq platform sequencing analysis were conducted to study the basic soil physicochemical properties, richness and diversity of fungi in ITS1+ITS2 domain in soda saline-alkali soil with different rice planting year.Result With the increase of rice planting year, pH, electrical conductivity, total alkalinity and water soluble total salt of saline-alkali soil decreased significantly; soil organic matter and microbial biomass carbon contents increased significantly; total nitrogen, ammonium nitrogen and nitrate nitrogen contents presented increasing trends; available phosphorus increased significantly first, reaching the maximum in the treatment of planting rice for 20 years, then decreased slightly; and available potassium content had no obvious changing pattern. The effective sequence numbers of fungi obtained in soil with 1-, 3-, 5-, 15-, 20- and 50- year rice planting periods were 56 942, 42 482, 45 987, 92 214, 64 665 and 68 515, including five phyla, 12 classes, 25 orders, 26 families, 45 genera and 59 species. Cladosporium, Holtermanniella and Massariosphaeria were dominant with relative abundance more than 2%. The α diversity indexes first increased and then decreased with the extension of rice planting years, reaching the largest in soil planted with rice for five years. Soil pH, electrical conductivity, total alkalinity, water soluble total salt and available potassium contents were the main environmental factors affecting fungi communities of soda alkali-saline soil after planting rice.Conclusion Planting rice can siginificantly change the basic physicochemical properties and fungi community structures of soda alkali-saline soil, and promote soil improvement.

Abstract:Objective To investigate the effects of main ecological factors on feature formation of strong-flavor flue-cured tobacco.Method ‘Yueyan 97’ was chosed as test material. According to the small differences on ecological condition and territory between two ecological subregions (Maozifeng and Gushi) in Nanxiong tobacco-growing area, four treatments by interchanging soil with the same texture were setted to study the effects of soil and climate on photosynthetic characteristics, chemical constituent contents and coordinations of strong-flavor flue-cured tobacco in different ecological subregions.Result On the 50th day after transplanting, compared with tobacco planted in Gushi with local sandy soil and climate condition (T2), the net photosynthetic rate of tobacco planted in Gushi with Maozifeng sandy soil (T1) increased by 3.66%; the contents of total sugar, reducing sugar and starch in middle leaves decreased by 5.74%, 4.77% and 10.73% respectively, and the contents of nicotine, K⁺ and total nitrogen increased by 6.49%, 11.07% and 11.34% respectively. Meanwhile, compared with tobacco planted in Maozifeng with local sandy soil and climate condition (T4), the net photosynthetic rate of tobacco planted in Maozifeng with Gushi sandy soil (T3) increased by 1.81%, the contents of reducing sugar and nicotine in middle leaves decreased by 10.02% and 13.14% respectively, and starch content increased by 9.30%. The climate had significant impacts on the contents of total sugar, reducing sugar, nicotine, total nitrogen and starch, nitrogen-nicotine ratio, stomatal conductance, transpiration rate, intercellular CO₂ concentration and net photosynthetic rate; soil and climate interaction had significant impacts on the contents of reducing sugar, nicotine, total nitrogen and starch, nitrogen-nicotine ratio and stomatal conductance; soil had significant impacts on the contents of K⁺ and total nitrogen and sugar-nicotine ratio. Conclusion Climate is the main factor affecting the feature formation of strong-flavor flue-cured tobacco, especially precipitation amount and mean temperature at root spreading and fast growing stages, followed by the interaction of soil and climate, and soil has the minimal role. The climate of Gushi is more suitable for production of superior strong-flavor tobacco leaves.

Abstract:Objective To explore the optimal coupled management mode of light intensity and nitrogen application for Coffea arabica seedlings.Method We set three shading levels:No shade (S₀, natural light), light shade (S₁, 65% natural light) and severe shade (S₂, 30% natural light), and three nitrogen levels:No nitrogen (N₀,0 g·kg⁻¹), medium nitrogen (N₁, 0.20 g·kg⁻¹), high nitrogen (N₂, 0.40 g·kg⁻¹). The effects of shading and nitrogen levels on growth, daily photosynthetic characteristics and biomass accumulation of C. arabica seedlings were studied.Result With the increase of shading degree, the total chlorophyll content increased. Compared with S₀ treatment, the net photosynthetic rate, stomatal conductance, light radiation use efficiency and total biomass of C. arabica in S₁ treatment increased by 13.54%, 18.54%, 127.77% and 12.41%, respectively. The total biomass decreased by 11.55% in S₂ treatment. Compared with N₀ treatment, the net photosynthetic rate, stomatal conductance, light radiation use efficiency and total biomass of C. arabica in N₁ treatment increased by 27.25%, 20.77%, 10.80% and 18.47%, respectively, and these traits in N₂ treatment increased by 14.85%, 25.99%, 41.65% and 21.02%, respectively. Compared with S₀N₀, with the increases of shading and nitrogen levels, leaf transpiration rate and light radiation use efficiency increased, leaf water use efficiency firstly increased and then decreased.Conclusion The optimal mode of light and nitrogen management of C. arabica is the combination of light shade and high nitrogen (S₁N₂). This mode is suitable for obtaining high leaf water-radiation use efficiency and biomass.

Abstract:Objective To investigate the effect of astaxanthin (AST) treatment on acute liver injury induced by lipopolysaccharide (LPS) in mouse.Method Forty healthy male ICR mice were randomly allocated into four groups including control group(CK), AST group, LPS group and AST preprotection group (AST+LPS group). Body weight and liver index of mice were recorded. Myeloperoxidase (MPO) level in serum was measured by ELISA. Malondialdehyde (MDA) content and the activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-px) and catalase(CAT) were measured by biochemical methods. The relative mRNA expression levels of antioxidant enzymes including SOD, GSH-Px, CAT and glutamate cysteine ligase catalytic subunit (GCLC) were measured by fluorescence quantitative PCR. HE staining was used to observe the histopathological changes.Result The initial weight of mice in each group was 18 g. The final weight was 9−11 g higher than the initial weight, and there was no significant difference among groups(P>0.05). Compared with LPS group, the liver index (0.054), serum MPO level (10.20 ng·mL^-1), and MDA content (2.83 μmol·g^-1) in liver tissue were significantly reduced in AST+LPS group (P<0.05). Astaxanthin increased the activities of SOD(512.14 U·mg^-1), GSH-Px(848.91 U·mg^-1) and CAT (61.53 U·mg^-1) as well as the relative mRNA expression levels of tested antioxidases. In addition, the damage degree of liver in AST+LPS group was low, and hepatocyte structure was perfectly aligned.Conclusion Astaxanthin treatment can protect the morphology of hepatocyte, increase antioxidant level and the mRNA expression of antioxidase in liver, and thereby relive liver oxidative stress and alleviate LPS-induced acute liver injury in mice.

Abstract:Objective To study the effects of high protein diet on growth performance, blood biochemical parameters, liver and kidney tissues of goslings at the age of 1 to 14 days, and preliminarily investigate gout pathogenesis of high protein diet.Method Seventy-two one-day-old geese were randomly allocated into three groups with three replicates per group and eight geese per replicate. Group A, B and C were fed with diets containing 16%, 20% and 24% crude protein, respectively.Result The growth performance of geese in group A were higher than those in group B and C. Total protein, albumin and globulin levels of serum increased with the increase of dietary protein level, but the differences were not significant. Serum uric acid, alanine aminotransferase, urea nitrogen, and lactate dehydrogenase levels in group C were significantly higher than those in group A and B, while total bilirubin level in group C was significantly lower than those in group A and B. The interleukin-1β, interleukin-8 and xanthine oxidase activities of liver tissues and tumor necrosis factor-α activity of kidney tissues in group C were significantly higher than those in group A and B. In group A, the liver and kidney tissues were normal. In group B, there were mild inflammatory cells in liver tissues, and the kidney tissues were normal. In group C, necrosis, edema and inflammatory infiltration of liver cells and tubular vacuolar degeneration, glomerular atrophy of kidney were observed. The geese exhibited gout symptoms in group C.Conclusion Under the same feeding conditions, feeding with 24% crude protein can affect growth performance, serum uric acid and other blood biochemical indexes of goslings, cause some damage to liver and kidney tissue, and produce gout symptoms, such as urate deposition in the ureter.

Abstract:Objective To investigate the method of isolation, culture and identification of white king pigeon(Columba livia) skeletal muscle satellite cells, and establish a complete culture system of pigeon skeletal muscle satellite cells.Method We selected 16-day pigeon embryos as experimental materials. Skeletal muscle satellite cells were isolated from the pectoral muscle by the tissue explants adherent method and collagenase digestion method, and the growth curve was drawn. MyHC expression was detected by immunofluorescence assay after differentiation of the satellite cells into myotubes. We detected mRNA expression of Desmin, Pax7, MyoG and MyoD1 genes before and after cell differentiation into myotubes using RT-qPCR.Result Skeletal muscle satellite cells were successfully isolated by the tissue explants adherent method and collagenase method, and cell growth appeared in S-shaped curve. After seven days of culture in high glucose DMEM containing 20% fetal bovine serum(FBS), a large number of visible myotubes were observed, and the myogenic differentiation marker MyHC was expressed in differentiated cells. RT-qPCR results showed that the relative expressions of Desmin and MyoG genes in differentiated myotube cells were 5.68 and 10.38 times of those in skeletal muscle satellite cells before differentiation, while the relative expressions of Pax7 and MyoD1 genes in skeletal muscle satellite cells before differentiation were 7.01 and 5.51 times of those in differentiated myotube cells, respectively.Conclusion The culture method of pigeon skeletal muscle satellite cells has been established,which provides a cell model for future studies of muscle development in pigeons.

Abstract:Objective To investigate a better model to support crossing system of Green-shell chickens.Method The hens of Green-shell chicken (LK) and two cross combinations of Jiuyuan black cocks×Green-shell layers (JL) and Green-shell cocks×Luhua layers (LL) at the age of 300-day-old were randomly sampled. Their body sizes and slaughter performance were measured. The correlations between body sizes and slaughter performance were analyzed and the best regression equations for carcass traits were established.Result The chest depth and shinbone girth of LL were shorter compared with LK and JL, while the shank length was longer. The comb height of LK was the highest among three groups. The average living body weights for 300-day-old hens from three populations were more than 1 700 g, their slaughter rates were over 87%, and the eviscerated rates of LK,JL and LL were 53.50%, 59.35% and 61.39%, respectively. As for LL, its subcutaneous fat thickness was greater compared with other groups, its breast muscle rate was higher than that of JL, and its abdominal fat weight and abdominal fat rate were less than those of JL (P<0.05). The eviscerated carcass rates of LL and JL were greater than that of LK, and the breast muscle rates of LK and LL were greater than that of JL. The correlations between slaughter performance and some body size traits such as shinbone girth, keel length and chest depth were significant (P<0.05). The optimal linear regression equations of slaughter performance and body measurement traits were established. The R² for regression models of half-eviscerated weight, eviscerated weight, subcutaneous fat thickness, eviscerated rate and breast muscle rate were above 0.4.Conclusion LL has better meat performance compared with LK and JL. Shinbone girth, keel length, and chest depth can be used as indirect indexes for selecting slaughter performance of Green-shell chickens. We have successfully established regression equations for evaluating slaughter performance through body size traits.

Abstract:Objective To investigate the etiology and pathologic features of two cases of hemorrhagic ulcer happened on channel catfish (Ietalurus punetaus).Method The gill tissue and body mucus were compressed by wet film method to detect potential parasite. Pathogen isolation was conducted using liver, spleen and kidney of diseased fish to detect potential bacterial infection. The homogenate of liver, spleen and kidney from diseased fish was detected for the channel catfish virus (CCV) by PCR. The pathologic features of diseased fish were observed by histopathology, and the causes of this disease were analyzed comprehensively.Result The spleen, kidney, hepatopancreas, intestine, skin and muscle were the main target organs of hemorrhagic ulcer. The main syndrome was severe vascular response with degeneration and necrosis of the parenchymal cells. Stomach, brain and heart had minor damages with slight inflammation, and gill filaments, eyeballs and swim bladder did not have obvious pathological changes. The diseased individuals displayed moderate to severe hemorrhagic necrotic spleen inflammation, moderate nephritis, and mild to moderate necrotic hepatopancreatitis and necrotic enteritis. No parasite, bacteria, or CCV was detected in diseased catfish.Conclusion Based on the results of pathological, bacteriological and virological examinations, it is inferred that the fulminant disease of catfish was caused by some non-CCV virus infection, and temperature stress may be the conditional incentive of this disease.

Abstract:Objective To develop a method for determining trifloxystrobin and its metabolite trifloxystrobin acid simultaneously in coffee by liquid chromatography-mass spectrometry (LC-MS).Method The sample was ultrasonically extracted with acetonitrile (including φ=1% acetic acid), and salted out with sodium chloride and anhydrous magnesium sulfate. After high-speed centrifugation, the supernatant was purified by C₁₈ dispersive solid-phase extraction and detected by LC-MS. The quantitative determination was conducted by ESI (+) ionization mode and multi-reaction monitoring (MRM).Result The recovery rates of trifloxystrobin in coffee fruits ranged from 87.8% to 106.7%, and the relative standard deviation (RSD) ranged from 1.3% to 5.8% when the additive amount of trifloxystrobin ranged from 0.01 to 2.00 mg·kg^-1. The recovery rates of trifloxystrobin in coffee beans ranged from 83.2% to 88.1%, and the RSD ranged from 2.0% to 6.2%. The recovery rates of trifloxystrobn acid in coffee fruits ranged from 71.5% to 106.0%, and the RSD ranged from 1.0% to 6.1%. The recovery rates of trifloxystrobn acid in coffee beans ranged from 84.4% to 105.2%, and the RSD ranged from 1.0% to 5.2%. The minimum detectable amounts of both trifloxystrobin and trifloxystrobin acid in coffee were 2.5 × 10^-12 g, and the minimum limits of quantitation were 0.01 mg·kg^-1.Conclusion This method is simple, rapid and stable, and can meet the requirement for detecting the residues of trifloxystrobin and its metabolites in coffee samples.

Abstract:目的 克隆荸荠Eleocharis tuberosa苯丙氨酸解氨酶基因（PAL），分析其序列特征及其在荸荠不同组织中和鲜切荸荠贮藏过程中的表达情况，为揭示鲜切荸荠黄化机理提供理论依据。方法 通过RT-PCR和RACE技术从荸荠中克隆PAL基因的cDNA全长，采用生物信息学方法对其序列和所编码的蛋白进行预测分析，利用荧光定量PCR技术分析PAL基因在荸荠不同组织和鲜切荸荠贮藏过程中的表达情况。结果 克隆得到荸荠PAL基因全长cDNA，将其命名为CwPAL，该序列长度为2 485 bp，含有1个2 142 bp的完整开放阅读框，共编码713个氨基酸。CwPAL蛋白分子式为C₃₄₃₇H₅₅₁₄N₉₄₄O₁₀₅₈S₃₄，相对分子质量为78 079，等电点为5.97，原子总数为10 987个。CwPAL包含PAL-HAL和PLN02457结构域及典型的PAL酶活性中心序列（GTITASGDLVPLSYIAG）。CwPAL的二级结构以α-螺旋为主，其三维结构模型呈典型的“海马状”结构。系统进化分析表明，CwPAL与菠萝Ananas comosus和海枣Phoenix dactylifera的PAL蛋白亲缘关系较近。荧光定量PCR分析表明，CwPAL基因在荸荠皮中的表达量最高，鲜切荸荠贮藏过程中CwPAL基因表达量快速上升，水杨酸处理显著抑制了CwPAL基因的表达。结论 CwPAL属于典型的苯丙氨酸解氨酶家族，该基因可能通过调控苯丙烷代谢从而影响鲜切荸荠的黄化。

Abstract:Objective To screen efficient cellulose degrading bacteria, and develop a bacterial agent for rice straw degradation and in situ returning to field.Method The efficient cellulolytic bacterium CX1 was screened from soil in Wuhu area by using rice straw powder medium and Congo red-cellulose selective medium. The cellulase activity under different substrate conditions and different reaction temperatures were determined. We performed the filter paper disintegration test, soil degradation test, experiment on synergistic degradation of rice straw by bacterium and chemical substances, and tested the effect of fermentation broth on growth of wheat seedlings. The decomposition characteristics of strain CX1 were analyzed.Result Strain CX1 was identified as Thermophilic Bacillus sp. based on morphology and 16S rDNA sequence similarity (99%). Using rice straw powder as the substrate, the activity of cellulase from CX1 reached 13.87 U·mL^-1 at 50℃ and 9.73 U·mL^-1 at 65℃. The filter paper completely disintegrated after 4 days of culture with CX1. The degradation rate of rice straw cellulose reached 52.55% after 15 days of culture with CX1. The relative degradation rate of rice straw reached 25.38% after 40 days of degradation in soil. The rice straw immersed with 0.05 g·mL^-1 NaOH solution in advance was more easily to be degraded by strain CX1, and its weight loss rate increased by 6.69% compared with the control group. The addition of fermentation broth from rice straw degradation with strain CX1 obviously promoted the growth of wheat seedlings, and the germination rate, seedling height, root fresh weight and seedling fresh weight increased by 9.66%, 55.55%, 59.71% and 118.84%, respectively.Conclusion Strain CX1 has high temperature resistance and can efficiently degrade cellulose. It can be used for promoting rice straw returning to field in agricultural production.

Abstract:Objective To understand the population genetic structure, gene flow, strain differentiation of Beauveria bassiana in Guangdong Province, analyze the correlation between genetic variation and host type, ecological environment, and provide a large number of reserved germplasm resources for screening and production of superior strains.Method The genetic variation and diversity of 81 B. bassiana isolates from Dinghu Mountain National Nature Reserve of Guangdong Province (DHS) were assessed using SSR markers.Result Eight SSR primers were amplified to produce 58 polymorphic points, the percentage of polymorphic loci was 100%, and the number of polymorphic points of primer Ba12 was the largest (10). Nei's genetic diversity index (h) was 0.212 6 and Shannon's information index (I_s) was 0.348 7 based on the analysis using the Popgene 32 software package, which indicated the genetic diversity and population heterogeneity levels of B. bassiana were high in DHS. Eighty-one strains of B. bassiana were divided into different subpopulations according to host/soil and insect order respectively. The genetic diversity of soil subpopulation (h=0.192 5, I_s=0.309 9) was slightly higher than that of host subpopulation (h=0.176 9, I_s=0.278 3), suggesting a generally low genetic differentiation among subpopulations (N_m=1.662 9, G_st=0.130 7).Genetic differentiation among subpopulations in different insect order was low and was associated with strong gene flow. The distribution of isolates had no obvious correlation with isolation medium or insect orders based on UPGMA clustering.Conclusion The genetic lineage of B. bassiana in DHS is not correlated with isolation medium or insect orders. The diversification of B. bassiana population in DHS is maintained by different ecological environment and host type.

Abstract:Objective To analyze genetic variation in growth traits of Tectona grandis clone and interaction between clone and site, and to select superior teak clones.Method Regional field tests of teak clones at two sites were carried out by using randomized complete block design.Result Analysis of variance results showed that tree height, DBH, individual volume of teak at 3.5 years old were all significantly different among site, clones and clone×site interaction. The variation coefficient of tree height for teak clones in Ding'an was relatively small (0.092), and the variation coefficients of DBH in Ding'an and both tree height and DBH in Jinggu were relatively large (0.118−0.167). The variation coefficients of individual volume in Ding'an and Jinggu were 0.327 and 0.305, respectively. The repeatability of tree height and DBH in Ding'an were 0.873 and 0.852, respectively. The repeatability of tree height and DBH in Jinggu were 0.851 and 0.773, respectively. The repeatability of individual volume for teak clones at 3.5 years old in Ding'an and Jinggu were 0.863 and 0.784, respectively.Conclusion The selected fast-growing clones for Ding'an area in Hainan were 3078-5, 7029, 7122, 7514 and 7559. The mean tree height, DBH and individual volume for the selected clones were 21.11%, 19.82% and 60.53% higher than that of the control, respectively. The superior clones of fast-growing for Jinggu area in Yunnan were 7029, Z408, 7509, 7559 and 8301. The mean tree height, DBH and individual volume for the selected clones were 31.69%, 33.66% and 128.24% higher compared with control, respectively. The genetic gain of individual volume in Ding'an and Jinggu reached 40.26% and 34.57%, respectively. The clone 7029 and 7559 were the shared superior clones in both sites.

Abstract:Objective To define the conditions suitable for somatic embryogenesis of Pinus elliottii and its hybrids, and develop a mature protocol for somatic embryogenesis maturation and germination.Method The immature zygotic embryos (with endosperm) of two P. elliottii families (EE1, EE2) and two P. elliottii hybrid (EC, EH) were sampled in June 2016. Three series of medium from induction, proliferation maturation to germination were set to compare the effects of explant collection date, family and basal medium on embryogenic callus induction. The embryogenic callus were identified through microscopic observation, and choosen for proliferation, maturation and germination culture. Finally the regenerated plantlets were developed.Result The zygotic embryo development processes of P. elliottii and hybrids were divided into eight stages. The immature embryos at stage Ⅱ and Ⅲ were suitable for somatic embryogenesis. The embryos at stage Ⅲ first appeared in EC. The embryogenic callus with embryonal suspensor mass (ESM) could be further proliferated. The induction mediums (T1, T2 and T3) played vital roles in callus formation and embryogenic callus proportion. T1 medium had the highest callus induction efficiency (49.0%), and T2 medium had the highest embryogenic callus proportion (22.4%).The mediums had genotype-specific induction rates. The overall induction rate of T1 medium was low, and T2 medium had the highest induction rate (5.82%) for EE1. T3 medium was suitable for all tested materials, with the highest mean induction rate of 3.75%. The somatic embryo induction rates of EE1 and EH gradually increased with the sampling time extension, while the somatic embryo induction rates of EE2 and EC gradually decreased. The results of somatic embryo induction rate were basically corresponded with zygote development stages. The stage Ⅲ zygotic embryo appeared late, and its induction rate was low in early stage. After the embryogenic callus were subcultured for 24 times, the embryo activities progressively decreased. The maturation medium T1S and T3S could accomplish embryo maturation. Their average ripening efficiencies in per gram of mature medium were 23.3 and 15.9 cotyledons, respectively. The germination rate was 32.1% and the transplanting rate was 47.8%.Conclusion All tested materials can induce somatic embryo in T3 medium. T3 medium is widely applicable, and all materials have high induction rates when zygotic embryo appears at stage Ⅲ, illustrating that stage Ⅲ may be the optimal for somatic embryo induction. The experiment establishes the protocol for somatic embryogenesis and plantlet regeneration.

Abstract:Objective To test and compare the operation effects of single-rotor unmanned aerial vehicle (UAV) type HY-B-15L and multi-rotor UAV type MG-1S on pest and disease control in rice field.Method The mixing solution of rhodamine-B and nano-pesticide was selected to spray in rice field, and field spraying experiments were carried out by changing the working altitude of helicopter and the amount of pesticide spraying. The polyester fiber cards and water-sensitive papers deposited by droplets were collected and analyzed by fluorescence spectrophotometer and image analysis software "DepositScan" to obtain deposition effects of the droplets.Result The deposition of droplets increased with the increase of pesticide application. Compared with 46.67 mL·hm^-2 pesticide, when pesticide application was 66.67 or 100.00 mL·hm^-2, the deposition of droplets sprayed by single-rotor UAV increased by 48.50% or 137.73% respectively, while the deposition of droplets sprayed by multi-rotor UAV increased by 66.60% or 111.88% respectively. The spraying height of UAV influenced the deposition and uniformity of droplets on the sampling point. When the spraying height ascended from 1.5 m to 2.5 m, the deposition and uniformity of droplets decreased by 19.3% and 53.6% respectively for single-rotor UAV, and decreased by 48.7% and 22.9% respectively for multi-rotor UAV. The spraying performances of single-rotor UAV were better than those of multi-rotor UAV under four spraying conditions. Compared with multi-rotor UAV, the deposition of single-rotor UAV increased by 85.8%, 26.5%, 59.4% and 123.4% from treatment 1 to treatment 4. When single-rotor UAV worked at the height of 1.5 m and a dosage of 46.67 mL·hm^-2, the preventive effect of pesticide was the best which were 87.63%, 76.67%, 84.08%, 59.26% and 82.33% respectively against Nilaparvata lugens, Cnaphalocrocis medinalis, Chlorops oryzae, bacterial leaf streak and rice blast. When multi-rotor UAV worked at 1.5 m and a dosage of 66.67 mL·hm^-2, the preventive effects against those rice pests and diseases were close to the former and were 86.54%, 78.62%, 89.47%, 66.67% and 83.33% respectively.Conclusion Because of different wind field below the UAV rotor, the droplet deposition of two UAVs are different. The spraying effect of single-rotor UAV is better than that of multi-rotor UAV, but there is no significant difference of control effect between two UAVs. The preventive effects of pesticides sprayed by both UAVs can reach the criterion of China.

Abstract:Objective To reduce the cost of processing, and obtain high quality dried Lentinus edodes.Method On the basis of single-factor experiment, Box-Behnken Design (BBD) was used to study the effects of heat pump temperature(A), vacuum degree(B) and conversion point moisture content(C) on unit energy consumption, sense judgment, rehydration ratio and hardness. We deduced a multinomial regression model, optimized the combined drying technology and compared with single heat pump drying and single vacuum drying.Result The optimal parameters were obtained as follows:The heat pump temperature was 49℃, the vacuum degree was 110 Pa, and the conversion point moisture content was 56%. Under these conditions, the tested unit energy consumption was 345.01 kJ·g^-1, the sense judgment was 8.3, the rehydration ratio was 2.72, and the hardness was 3.61 N, which were close to the predicted values. The relative errors were 0.19%, 3.61%, 1.47% and 1.66% respectively. The unit energy consumption of combined drying was 37.69% less than that of vacuum drying and higher than that of heat pump drying. The sense judgment and rehydration ratio of combined drying were close to those of single vacuum drying and higher than those of heat pump drying. The hardness was slightly larger than that of vacuum drying and less than that of heat pump drying.Conclusion The method combining heat pump drying and vacuum drying obtained dried L. edodes with low energy consumption and good quality. It solves the poor quality in heat pump drying and high energy consumption in vacuum drying. This study can provide a theoretical basis for heat pump-vacuum combined drying of L. edodes.