ObjectiveDifferences in spatial distribution and quality of branches between two types of high-grafted loquat trees were examined.MethodsUsing 5-year-old high-grafted and replanted naturally round head and dwarf open heart-shaped multiple main branch Guifei loquat trees, an improved grid method was applied to compartmentalize into F1, F2, F3, and F4 layers according to plant height measured from the bottom to the top, as well as P1, P2, and P3 zones according to distance from the central trunk for the experimentation. Length, thickness, number of the leaves and angle of representative branches in the target measurement grids were collected. Numbers of the branches, spikes and heading rates of the branches were counted.ResultsThe plant height, curtain layer thickness, crown width, branch number, spike number, branch heading rate, branch angle, and internode distance of the natural round head trees were greater than those of the dwarf open heart-shaped counterparts. Horizontally, the number of branches and spikes of both types of Guifei loquat trees were mainly distributed in the P2, followed by the P1 zone. Vertically, the trees with a naturally round head were largely distributed in the F2 and F3 layers, while the dwarf trees with an open heart-shaped canopy were predominantly distributed in the F2 layer. The heading rate, length, and thickness of the round head-shaped branches were F4＞F3＞F2. The number, spikes, thickness, and angle of the branches in the F2 layer were P3＞P1. The heading rate, branch angle, and internode distance in the F3 layer were P3＞P1. The number of branches and spikes of the dwarf variety were F2＞F3, while the length and thickness of the branches F3＞F2. The number of leaves and internode distance in the F2 and F3 layers were P1＞P3; but the branch angle, P3＞P1. Conclusion The branches on the Guifei loquat trees of two differently shaped canopies grew in the sub-high and sub-outer layers of the plant. The branches and spikes on the canopy of the dwarf open heart-shaped trees were more evenly distributed and had less spaces that grew few or no branches in the inner chamber of the crown making the type of tree potentially more productive than the round head variety.
ObjectiveFunctions of a peptide transporter protein gene, OsPtr1, in rice were studied by means of T-DNA insertion mutation. Method The target RNA was extracted from the endosperm of Minghui 86 rice 12 d after flowering and reverse-transcribed into cDNA. By cloning the candidate gene P0421H01.23, named OsPtr1, and constructing the plant overexpression vector using the promoter Gt1 of endosperm-specific expressing, OsPtr1 was introduced into Nipponbare rice using an agrobacterium-mediated method. Nitrogen metabolism of the offspring and mutant w9101 was analyzed. A fusion expression vector of green fluorescent protein gene, GFP, and OsPtr1 was constructed and transferred to onion epidermal cells with a gene gun. In 24–48 h afterward, subcellular localization of OsPtr1 was examined under a fluorescence confocal electron microscope. ResultOsPtr1 was localized at the membrane and possibly involved in the transport of nitrogen substances. Knockout on OsPtr1 could cause a reduction on nitrogen-containing substances, such as amino acids and proteins, in the rice grains. Conversely, an overexpressed OsPtr1 would increase the accumulation.ConclusionOsPtr1 participated in the transmembrane transport of nitrogen substances in rice.
Objective Effects of straw-returning on phosphorus morphology and microbial phosphorus-cycling genes in paddy soil at rice tillering and maturing stages were investigated. Method In consecutive 7 years on a rice field in southern China under a positioning experiment, spent straws were returned to the acidic soil. The implemented treatments included: (1) chemical fertilizer without straw-returning (CK), (2) chemical fertilizer + 100% straw-returning in same season (CKS), (3) CKS+ straws to replace 10% potassium fertilizer (S10), (4) CKS + straws to replace 20% potassium fertilizer (S20) or (5) CKS + straws to replace 30% potassium fertilizer (S30). At end of the treatments, Guppy soil phosphorus continuous extraction method and metagenomic technology were applied to determine the composition of phosphorus of different forms and microbial phosphorus-cycling genes. Result Straw-returning significantly increased the available NaHCO3-Pi in soil (P＜0.05)—the S10 and S20 treatments resulted in an increase by 5.88%-8.73% over CK. NaOH-Pi was the main form of phosphorus in the acid paddy soil in southern China with a content ranging from 154.03 mg·kg−1 to 202.11 mg·kg−1. By turning the spent straws into the field, the abundance of phosphorus-cycling genes, especially the inorganic phosphorus dissolution gene pqqC under CKS, was significantly affected. The genes, such as phnW, phnO, pqqB, and pqqC, activated the conversion of hydrochloric acid phosphorus and residual phosphorus into available form; those like appA, phnX, and ppx, participated in the formation of stable phosphorus; and NaOH-Pi played a key role in the long-term transformation of the mineral. And the main factors that governed the abundance of the functional genes appeared to be the organic carbon and pH of the soil. Conclusion Through altering the soil physiochemical properties, returning spent straws to the ground significantly enriched the microbial phosphorus-cycling genes that promoted the mineral transformation of the acidic paddy soil in southern China.
ObjectiveThe pathogen that caused the blueberry branch blight in Sanming, Fujian was identified.MethodMicrobes were isolated and purified from the blueberry branches showing anthracnose symptoms collected from the infected area. Pathogenicity of the isolates was tested by needle injection on the plant and verified by the Koch's method. Pathogen taxonomy was determined by morphological observations and molecular technology. ResultStrain KW1-4 was isolated from the diseased tissue and inoculated onto healthy blueberry branches to show on the inoculation site dry spots same as what produced by the strain from the infected plants. The white to gray, round colonies of KW1-4 had two types of conidia. The alpha conidia were elliptical or spindle in shape and 4.77-7.63 μm × 1.55-2.71 μm in size with two distinct oil globules, while the linear beta conidia sized 11.95-19.65 μm × 1.05-1.94 μm with no oil globule. The 3 fragments of the genes, ITS, TEF1-ɑ, and β-tubulin, were used to construct the phylogenetic tree that showed KW1-4 to cluster with Diaporthe australiana in a same branch, which agreed with the morphological characteristics. ConclusionIt was determinedD. australiana to be the pathogen that caused the blight on blueberry bushes in Sanming. The identification paved the way for the disease control.
Objective A variety of Paeonia lactiflora imported from abroad were evaluated for landscaping in Yangzhou, Jiangsu and for germplasm collection. Method The adaptability, characteristics, and ornamental quality of 21 peony varieties from foreign countries were examined based upon 12 selected criteria for a comprehensive evaluation using the analytic hierarchy process (AHP). Scores on the criteria were used to grade each variety for selection. [Result] The weighing of the scores on heat damage index, flower posture, bud differentiation, and florescence of single flower were more heavily among all indicators at 0.4180, 0.1496, 0.1393, and 0.0898, respectively. Of the 21 varieties, 8 (e.g., Peter Brand) scored greater than 3.5 were classified as Grade I and considered appropriated for promotion and application in the region; 6 (e.g., Buckeye Belle) between 3.0 and 3.5 as potentially applicable Grade II; and 7 (e.g., Teenage Boy) below 3.0 as Grade III not recommended for the introduction. Conclusion The comprehensive evaluation using the analytic hierarchy process classified the 21 peony germplasms for resource collection and introduction for landscape in Yangzhou and the middle and lower reaches of the Yangtze River regions.
ObjectiveAdaptability to environmental variations of Leptocybe invase Fisher et LaSalle for growth and survival was investigated based on the physiological mechanisms of the pest in dealing with the adverse conditions. Methods Geography-, temperature-, and host-specific morphological indicators, respiratory intensity, and activities of protective enzymes (such as, superoxide dismutase, catalase, peroxidase) and detoxification enzymes (such as, acetylcholinesterase, carboxylesterase, glutathione-S-transferase, polyphenol oxidase) of the insect were analyzed. ResultsThe morphological indicators of L. invase were inversely correlated to the latitude of the area it lived in. Its respiratory intensity and protective enzyme activity were relatively stable between 20 ℃ and 30 ℃. However, a surrounding temperature beyond 30 ℃ significantly raised the respiration rate and reduced the protective enzyme activity, while below 20 ℃ significantly decreased both. The diet also induced morphological differentiations in the insect. For instance, and the activities of 4 detoxification enzymes (acetylcholinesterase, carboxylesterase, glutathione-S-transferase, and polyphenol oxidase) were higher in the insects fed on DH201-2 (Eucalyptus grandis×E. tereticornis) than those on E. exserta.ConclusionL. invase found in areas of lower latitude were smaller in body size than those of higher latitude. They thrived between 20℃ and 30℃. And the host plants on which they infested affected their morphology as well as the detoxification enzymes in the insect.
ObjectiveStarvation tolerance of Gymnodiptychus dybowskii larvae was studied to determine the optimal time to start feeding larvae for the aquaculture.MethodMorphological development, growth, and survival rate of regularly fed G. dybowskii larvae and those under artificially imposed starvation were observed in separate fish tanks with a controlled water temperature at 15.2–16.4 ℃. The point of no return (PNR) under starvation of the larvae was determined by the percentage of the stressed fish that took daily feed initially.ResultThe normal mixed nutrition for the larvae lasted 5–6 d. In general, on the 7th day after hatching the larvae started natural feeding, and their yolk sac disappeared in 12–13 d. Approximately 5% of the larvae began to feed at the time of feeding initiation stage. The percentage of larvae started feeding reached 100% on the 11th day but was 50% at PNR after 17 d when deprived of food. Normally, it lasted for 10 d for the larva beginning to take the initial morsel of food. There was no significant difference found in the total length of the larvae fed regularly and under the starvation treatment up until the age of 9 d (P＞0.05). However, at 12-day-old, the two groups of larvae began to significantly widen the differentiation in body length (P＜0.05), and the starved fish started to show negative growth with physiological atrophy. After PNR, body distortion and deformities appeared on the starved larvae with the mortality rate gradually rising to 100% 25 d after hatching. Conclusion In a water of 15.2-16.4 ℃, G. dybowskii larvae displayed a tolerance to starvation with an apparent PNR. It showed that the optimal start time for feeding the larvae was 11 d after hatching.
ObjectiveImmune response of peroxiredoxin 4 gene of Procambarus clarki (Pc-prx4) after being stimulated by bacterial infection was studied. MethodsPc-prx4 were cloned before and after an artificial inoculation of Staphylococcusaureus or Edwardsiella ictaluri on the crayfish. Bioinformatic analysis was conducted with the aid of relevant online websites and software including Expasy, translate tool, SMART, Expasy ProtParam tool, BLASTx, and MEGA-X. Expressions of Pc-prx4 from the tissues of normal and pathogenically inoculated crayfish were detected by qRT-PCR. Antioxidant function of the constructed recombinant protein was determined.ResultsPc-prx4 had an open reading frame of 744 bp encoding 247 amino acids with an alkyl hydroperoxide reductase (AhpC) structural domain, a sulfhydryl-specific antioxidant structural domain, and a C-terminal structural domain of 1-Cys prx peroxisome iron oxidase. The predicted protein molecular formula was C1249H1934N330O357S10 with a molecular weight of 27.61 kDa and a pI of 5.88. Its signal peptide region was located at the N-terminal end, and the 1-Cys peroxiredoxin domain at the C-terminal end. The gene expressed in all sampled tissues—most highly in the hemolymph and high in the hemocytes, hepatopancreas, gills, and intestines of the crayfish inoculated by S. aureus or E. catarrhalis. In the plasmid DNA protection assay, rPc-PRX4 displayed varying degrees of antioxidant activity, especially in high concentrations. ConclusionA kind of 1-Cys prx, Pc-prx4 was highly expressed in the hemolymph of P. clarkii stimulated by S. aureus or E. catarrhalis. The protein exhibited a concentration-dependent activity associated with the antioxidant homeostasis of the crayfish.
ObjectiveTo provide technological support for the development of A. auricula beverage, the rheological properties of the solution of the Auricularia auricula water extract (AWE) and A . auricula crude polysaccharide (ACP) were investigated, and the beverage formula was optimized.MethodIn this study, the effects of different mass concentrations and homogeneous pressure treatments on the rheological properties of AWE and ACP were studied. The formula of A. auricula beverage was optimized through single-factor and orthogonal experiments.ResultBoth 0.3%～1.5% AWE and ACP solution exhibited significant shear thinning characteristics, also demonstrated a pseudo-plastic fluid and non-Newtonian fluid. The result showed as the mass concentration of AWE and ACP solutions decreased, their flow behavior index increased, and their consistency coefficient decreased (P＜0.05). The 0.3%～0.6% AWE and 0.3% ACP solutions exhibited stable fluid characteristics. After homogenization at 4～12 MPa, it was found that the flow behavior index of 0.6% AWE solution and 0.6% ACP solution was improved and their consistency coefficient was reduced significantly with stable fluid characteristics. The result of average particle size (6.51 ± 0.02 μm) and stability coefficient (0.926 ± 0.024) of 0.6% AWE solution treated with 8 MPa homogeneous pressures achieved equilibrium. The A. auricula beverage formula optimized by single-factor and orthogonal experiments was 0.6% AWE, 6% rock sugar, and 0.1% citric acid. That production had a light brown color, a unique flavor of A. auricula and a delicate and silky taste.Conclusion0.3% ～1.5% AWE and ACP solution was both pseudo-plastic fluid and non-Newtonian fluid. 4 ～12 MPa high-pressure homogenization treatment on the 0.6% AWE and ACP solution exhibited fluid characteristics. The stability of the 0.6% AWE solution system was optimal when homogenized at 8 MPa, Thus 0.6% AWE solution was selected as the raw material and 8 MPa was selected as homogeneous pressure for beverage processing. The optimal formula for A. auricula beverage comprised 0.6% AWE, 6% rock sugar, and 0.1% citric acid.
ObjectiveEffects of tillage methods applied for maize cultivation in northern Liaoning on the crop productivity and soil conditions were studied in search of an improved agriculture practice for the region.MethodMaize yield and soil properties under various tillage methods were determined in a field experimentation. Means of tillage and ground preparation including (A) rotary tillage for 15 cm, (B) deep loosing tillage for 30cm, (C) smash ridging tillage for 30 cm, (D) smash ridging tillage for 50cm, (E) smash ridging tillage for 30cm combined with film mulching, and (F) smash ridging tillage for 50cm combined with film mulching were evaluated. Ground temperature and bulk density in different layers of soil at different maize growth periods as well as root number, length, and volume and yield of maize plants were monitored. ResultSmash ridging tillage on the field increased the ground temperatures in layers of the soil. Significant rises of the soil temperature by 14.14-23.75% in maize seedling stage were observed when the tillage method was applied with film mulching, and by 14.34-25.90% in the maize jointing stage. Smash ridging tillage also reduced the bulk density in 25-30cm layer of soil by 1.91-3.09% at the maize seedling, jointing, and mature stages, and in the 45-50cm layer soil by 2.91-5.21%, while significantly increased the root count by 13.21-47.55%, the root length by 7.14-38.83%, and the root volume by 20.63-110.04% from the maize jointing stage to maturity stage. By covering the ground with a mulching film after smash ridging tillage, maize yield was increased by 11.12-16.29%. And the greatest increase in yield was achieved by using the (C) method with a 30 cm tillage. ConclusionIt was preliminarily showed that the smash ridging tillage with film ground cover, especially the method (C), could materially benefit not only the soil conditions but also the growth of maize root system and crop yield.
Objective Effects of a highly reduced crude protein diet supplemented with glutamate (Glu) and arginine (Arg) on the intestinal metabolites and microbiota of weaned piglets were examined for aquaculture feed formulation. MethodOne-hundred-ninety-two healthy (26±2)-day-old crossbred (Duroc × Landrace × Large White) piglets with an average body weight of (6.96±0.29) kg were randomly divided into 4 groups. Each group contained 6 replicates of 8 piglets each. Group I (CK) was fed on the control diet that provided 21.16% crude protein (CP). Group II was on a low-protein diet containing 15.97% CP supplemented with some limiting amino acids. Added to the Group II diet, 1.50% Glu was included for feeding Group III and 1.50% Glu plus 1.00% Arg for Group IV. From 11th to 13th day in the 16 d feeding program, metabolites and microbial community in the piglet intestines were monitored.ResultThe fecal putrescine and spermidine of the treatment piglets were similar but significantly lower than those of CK (P＜0.05). The cadaverine in the Groups II and III piglets showed no significant differences but were significantly lower than that of CK or Group IV (P＜0.05), and that of Group I significantly lower than that of Group IV (P＜0.05). No significant differences were observed on the fecal acetic acid and propionic acid among all groups (P＞0.05), but the butyric acid in the piglets of all treatment groups was significantly higher than those of CK (P＜0.05). The intestinal microbiota richness and diversity of the animals under treatments were significantly higher than those of CK (P＜0.05). At phylum level, the relative abundance of Firmicutes in the fecal microbiota of the piglets were significantly higher under the treatments than CK (P＜0.05), but those of Bacteroidetes and Proteobacteria significantly lower than CK (P＜0.05). Significant differences were also observed among the groups at family and genus levels. The relative abundances of unspecified families and unspecified genera under clostridiales were significantly higher under the treatments than CK (P＜0.05), those of prevotellaceae, enterobacteriaceae, and lachnospiraceae were significantly lower under the treatments than CK (P＜0.05), those of lachnospiraceae, lactobacillaceae, blautia, and lactobacillus of Group IV significantly higher than those of CK (P＜0.05), and those of peptostreptococcaceae and terrisporobacter of Group IV were significantly lower than those of CK (P＜0.05). ConclusionA forage of CP being reduced from 21.16% to 15.97% and supplemented with Glu and Arg lowered the intestinal biogenic amines, increased the butyric acid, and enhanced the diversity and richness of microbiota in the weaned piglets.
Objective Germination, growth, and physiology of quinoa seeds and seedlings under salt stress were analyzed. Method Temuco Quinoa seeds and potted seedlings were treated with NaCl solutions of different concentrations (i.e., 0, 200, and 450 mmol·L−1). Physiological indexes on seed germination and seedling growth, agronomic traits of mature plants, contents of nutrients in the seeds or seedlings, and spatial-temporal expression of SOD, POD, and BADH in the seedlings, were monitored to determine the effects of the imposed salt stress. Result (1) Quinoa seed germination and seedling growth were significantly inhibited by the high NaCl concentration at 450 mmol·L−1. The N-uptake was ill-affected, the Na+/K+ ratio significantly increased, the activities of superoxide dismutase (SOD) and peroxidase (POD) significantly decreased, while malondialdehyde (MDA) content significantly higher than that of control. However, under 200 mmol NaCl·L−1, the quinoa plants grew and developed well. Aside from a declined germination index, the seed vigor index and fresh seedling weight were significantly increased, the content of all nutrients slightly raised, and the SOD and POD activities significantly elevated without a significant difference in MDA over control. (2) Under the salt stress of 200 mmol·L−1 and 450 mmol·L−1, the soluble sugar content increased by 68.06% and 41.67%, and the proline by 237.38% and 189.97%, respectively. As the salt concentration increased, they share a similar trend of firstly increasing then a decline. (3) In response to salt stress, BADH and SOD were more highly expressed in the root tissues than in the stems and leaves, while POD was highest in the leaves and lowest in the roots. Conclusion High salt concentration at 450 mmol·L−1 ill-affected the nutrient content in Temuco quinoa seeds, inhibited the germination, and hindered the seedling development. The temporal expression of BADH was more rapid and sensitive to salt stress than those of POD and SOD at either 200 mmol·L−1 or 450 mmol·L−1. Consequently, it could be served as an indicator in screening salt-tolerant quinoa germplasms.
ObjectiveA new deep learning network was designed to improve the often-inaccurate identification of diseases and pest infestations on rice.MethodThe coordinate attention mechanism (CA) was introduced under the residual convolution block of RestNet-50 using the LeakyRelu activation function to replace the Relu activation function as well as the three 3×3 convolution kernels to replace the original 7×7 convolution kernel under the first convolution layer. Result The newly designed ResNet-50-CA effectively balanced the detection accuracy and model simplicity the original method lacked. The improved model was further fine-tuned with experiments to achieve a much-improved detection accuracy of 99.21% in identifying the diseases and infestations on a batch of 16 specimens with a learning rate of 0.0001. ConclusionThe superior deep learning algorithm of the current ResNet50-CA system extracted more detailed and accurate information on the diseases and infestations than did the previous model. It could be applied for field and/or clinic diagnosis on rice plants.
ObjectiveDegree and distribution of tea plantations soil fertility in Anxi County, Fujian were determined and statistically analyzed.MethodSoil specimens were collected from plantations in 22 major tea-producing towns in Anxi. pH, organic matter, total NPK, alkaline N, available P, and available K of the soils were measured. Fertility IFI for each sampling site was calculated by the fuzzy comprehensive evaluation method. Result From the randomly sampled 243 specimens, the following results were obtained. (1) pH of the plantation soils ranged 3.79-4.97 averaging 4.36 with a coefficient of variation of 11.51%. There were significant differentiations among the towns (P＜0.05). (2) On the content of organic matter, only one town did not meet the Grade I standard of being higher than 20.00g·kg-1. (3) Alkaline N, available P, and available K in the soils ranged 109.70-184.70 mg·kg-1, 5.34-257.21 mg·kg-1, and 78.18-272.20 mg·kg-1, respectively. Hence, the alkaline N in all specimens reached the Grade I level, but the available P and K left two localities fall into Grade II. (4) The total N, P, and K at all sites were 0.38-2.05 g·kg-1, 0.14-1.76g·kg-1, and 4.83-24.06 g·kg-1, respectively. On account of total N, two towns were rated Grade II and two Grade III; on total K, 4 were Grade II and one Grade III; and on P, only one qualified for Grade I and 68.18% of the towns rated Grade II and 27.27% Grade III. Significant differences were evident among the towns and villages. And (5) on account of IFI, 81.82% of the sites belonged to Grade I, 4.55% Grade II, 9.09% Grade III, and 4.55% Grade IV. ConclusionSoil acidification was severe at the tea plantations in the county. The soil was generally rich in organic matter and available nutrients, but deficient in total nutrients, especially P. The IFI at the plantations was generally of acceptable grades, however, the structure and spatial distribution of soil fertility were not well balanced. To overcome such shortcomings, it was recommended the following measures be implemented for the region: (1) using green manure to enrich organic matter content mitigating soil acidification, (2) increasing NPK application to enhance total nutrient reserve, and (3) formulating precise and efficient fertilization with routine soil testing to foster technical advancements.
Objective Physiological functions of the Sec pathway subunit secD of Aeromonas hydrophila were studied.MethodAn secD-knockout A.hydrophila was constructed by homologous recombination with pRE112 suicide vector. Effects of the genetic deletion on the physiological phenotypes including hemolytic and extracellular protease activities were determined on sheep’s blood and skim milk agar plates; on the biofilm formation, by crystal violet staining combined with SpectraMax® i3; on the bacterial acid-base and hyperosmolarity tolerance, according to the growth curve; and on the minimal inhibitory concentration (MIC) of antibiotics, using the broth microdilution method.Result Compared to wild-type, the constructed ∆secD A.hydrophila showed no significant differences in growth and tolerance to pH 5, 6, 7, and 8. The activities of hemolytic and extracellular protease, as well as the resistance to high osmotic pressure or pH 9 were enhanced. The biofilm forming ability significantly declined. And the resistance to antibiotics varied, as the MIC increased 4 times on oxytetracycline, tetracycline, enoxacin, or meropenem and two times on ciprofloxacin and norfloxacin, but decreased 2 times on erythromycin and 4 times on cefotaxime.ConclusionThe Sec pathway subunit secD was confirmed to be involved in the transport of virulence factors and resistance to antibiotics in A.hydrophila. It could be a key element in studies for developing antimicrobial applications and prevention of disease infected by the pathogen.
[目的]建立基于SYBR Green I嵌合染料法的灌溉水源中沙门氏菌实时荧光定量PCR(Quantitative Real-time PCR,qPCR)检测方法.[方法]以沙门氏菌侵袭蛋白A(invA)基因为靶基因,设计 1对特异性qPCR检测引物,在对qPCR反应体系和反应条件进行优化后,通过特异性实验和灵敏度实验对qPCR方法进行验证,并制作灌溉水源中沙门氏菌qPCR定量标准曲线,最后与国标方法对比检测灌溉水源中沙门氏菌污染来验证该方法的准确性.[结果]经过优化的qPCR检测方法灵敏度检测结果显示最低检测限量为 1×10-1 pg·μL-1,特异性检测结果显示具有良好的特异性,干扰菌株对本qPCR检测方法无影响,所制作的qPCR扩增标准曲线在 2×100～2×105 cfu·mL-1有较好的线性关系,相关系数为 0.9996,能对沙门氏菌进行准确的定量分析.该方法在与国标方法对比检测灌溉水源中沙门氏菌污染时具有同等准确性.[结论]本研究建立的基于SYBR Green I嵌合荧光法的实时荧光定量PCR检测方法,可以满足灌溉水源中沙门氏菌的定量检测要求.
[目的]鉴定影响普城沙雷氏菌ACCC 02146产灵菌红素能力的基因,构建ACCC 02146的转座子突变体文库,为进一步研究普城沙雷氏菌ACCC 02146灵菌红素合成机制奠定基础.[方法]采用平板划线法从菌种保藏中心购买菌株和实验室保藏菌株中获得 15株产灵菌红素的菌株.采用 16S rRNA基因测序法鉴定各菌株,邻接建树将其分类,并比较不同类别菌株灵菌红素合成基因簇启动子序列差异,观察各菌株产色能力.对 16S rDNA序列和灵菌红素合成基因簇启动子序列均有异于其他菌株的普城沙雷氏菌ACCC 02146合成灵菌红素的调控基因展开研究.构建ACCC 02146的转座子突变体文库,筛选出产色能力明显改变的克隆子并鉴定出对应的转座子插入突变基因.[结果]该突变体文库中有 74个突变体表现出产灵菌红素能力的变化.其中 25个突变体转座子插入发生在pigA、pigB、pigC、pigD和pigH 等 5个灵菌红素合成簇基因上,49个突变体转座子插入基因为灵菌红素合成基因簇之外的基因.在鉴定到的产色能力改变的突变体中,麦芽糖O-乙酰基转移酶基因突变菌株有 6个,二氢乳清酸脱氢酶基因突变菌株有 4个,MarR家族转录因子SlyA基因突变体有 3个,winged helix家族的双组分转录调控因子RstA基因突变体有 3个,H-醌氧化还原酶亚基I基因突变菌株有 3个,NADH-醌氧化还原酶G链基因突变菌株有 3个,肽基脯氨酰异构酶B基因突变菌株有 3个,其他突变基因对应的克隆子数量为 1～2个.[结论]在沙雷氏菌中,除了灵菌红素合成簇基因调控灵菌红素合成,推测灵菌红素合成簇外编码相关酶、转录调控因子和一些结构蛋白的基因通过直接或间接途径在不同程度上调控了灵菌红素的合成.
[目的]黄胸蓟马(Thrips hawaiiensis)是为害枇杷的重要害虫,本研究旨在明确单一色板、色板+单组分信息化合物和色板+双组分信息化合物对黄胸蓟马和有益昆虫的诱集作用,为枇杷园蓟马种群监测与防控及有益昆虫保护提供科学依据.[方法]通过田间试验比较3种颜色粘虫板(黄色、蓝色和白色)和悬挂高度(225 cm、150 cm、75 cm)对黄胸蓟马的诱集效果,在此基础上比较色板+单组分信息化合物(异烟酸甲酯、烟酸甲酯、异烟酸乙酯和烟酸乙酯)和色板+双组分信息化合物(异烟酸甲酯+烟酸乙酯、异烟酸甲酯+异烟酸乙酯、异烟酸甲酯+烟酸甲酯、烟酸甲酯+烟酸乙酯、烟酸甲酯+异烟酸乙酯、烟酸乙酯+异烟酸乙酯)对黄胸蓟马和有益昆虫的诱集效果.[结果]白色粘虫板在悬挂高度 150 cm对黄胸蓟马诱集数量显著高于其他处理组.单组分信息化合物异烟酸甲酯对黄胸蓟马引诱效果最强,诱集雌、雄成虫和黄胸蓟马总成虫数量分别为空白对照组的 4.68倍、8.45倍和 5.56倍;比较 6种双组分信息化合物与对应单组分信息化合物对黄胸蓟马的诱捕效果,发现均对雌成虫呈拮抗作用.10种信息化合物处理组对有益昆虫食蚜蝇、寄生蜂类、草蛉、蜜蜂和胡蜂的诱集数量均较低,食蚜蝇诱集数量最多仅2.73头·板-1·d-1,各处理组益害比值均低于空白对照组,其中异烟酸甲酯处理组最小(1∶285.33).[结论]白色粘虫板与异烟酸甲酯组合对枇杷园花期黄胸蓟马的诱集效果最强,且对有益昆虫影响最小.
[目的]在滇杨幼苗时期和开花前利用形态差异对雌雄株进行性别鉴定极为困难,因此亟需探明对其性别进行快速鉴定的分子标记方法.[方法]以滇杨雌雄各 30株为材料,利用简单重复序列(SSR)筛选与滇杨性别相关的分子标记,并利用所获得的SSR标记对未知性别滇杨幼苗进行鉴定,分析滇杨苗期的性别分化情况.[结果]从已报道的相关文献中选出 15对与植物性别连锁的SSR引物,经试验筛选出 1对(BPCA90)在琼脂糖凝胶检测中显现清晰条带且反应稳定的SSR引物,并将这对引物经聚丙烯酰胺凝胶电泳进行复筛,经PCR扩增后在滇杨雄株中出现 1条特异性条带,大小在 680 bp左右.利用这对SSR引物对 30株滇杨幼苗进行性别鉴定,结果表明雄株明显多于雌株,且比例为 13∶2.[结论]试验筛选所得到的SSR引物可以用于滇杨早期进行性别鉴定.研究结果可作为滇杨早期性别鉴定的遗传标记,为今后滇杨在生产中的分性别利用提供技术支持.
[目的]通过对伏牛山 3种针叶林植物器官、枯落物和土壤中植硅体及植硅体碳的研究,探讨不同林分间植硅体碳的封存特性及稳定性差异,为长期固碳提供理论依据.[方法]在伏牛山的雪松(Cedrus deodara)、圆柏(Sabina chinensis)、侧柏(Platycladus orientalis)3种森林中对植物各器官、枯落物和 0～50 cm深的土壤剖面进行采样,基于质量平衡法研究了土壤与植物体内的植硅体、植硅体碳和二氧化硅(SiO2)的含量.[结果]雪松各器官植硅体含量在 1.49～3.27 g·kg-1,植硅体碳含量在 0.030～0.114 g·kg-1.圆柏各器官植硅体含量在 1.44～2.56 g·kg-1,植硅体碳含量在 0.036～0.085g·kg-1.侧柏各器官植硅体含量在 1.86～2.90 g·kg-1,植硅体碳含量在0.038～0.083 g·kg-1.本研究估算了植硅体碳在各林分中的生产通量与周转时间,圆柏林中土壤植硅体碳储量(1.64 t·hm-2)高于雪松林(1.17 t·hm-2)和侧柏林(0.77 t·hm-2),且圆柏林植硅体碳周转时间(1813.16 a)长于雪松林(218.78 a)和侧柏林(556.44 a).[结论]不同的森林类型对植硅体及植硅体碳的生产速率和周转时间会有显著影响,在未来的针叶林森林管理计划中优化圆柏的造林/再造林会显著增强未来几个世纪的生物地球化学碳汇.
