查看更多>>摘要：Zn is an essential mineral nutrient for plant growth and development.Its effect on crop yield and quality has not been well documented.The objective of this study was to investigate the effects of foliar application of zinc fertilizers on yield and quality of millet (Pennisetum glaucum).Six levels of ZnSO4·7H2O (0,0.75,1.13,1.50,2.25,3.00 kg/hm2)were applied to two millet cultivars (Jigu 20 and Jiyou 2) to obtain 12 treatments.Zinc fertilization increased millet yield and improved quality when applied at a proper rate in both cultivars.The yield was the highest in Jigu 20 when applied at 1.50 kg/hm2,and in Jiyou 2 when treated with 1.50 kg/hm2.Zn application at 1.5 kg/hm2 increased protein content by 11.13％ for Jigu 20 and 10.53％ for Jiyou 2.The Zn application at all rates increased lysine acid and soluble sugar content in the grain in both cultivars.The results of this study suggest that foliar Zn application increases yield and also improves grain quality when applied at 1.50 to 2.25 kg/hm2 for soils with low zinc content.
查看更多>>摘要：This paper studied the variation characters on wheat and corn water consumption and irrigation watersaving amount under different water conditions (ample irrigation level,farmers conventional irrigation level and optimizing irrigation level).The water use efficiency and water saving potential of optimizing treatment and farmers' conventional irrigation treatment were analyzed respectively.The objective of this study was to provide theoretical supporting for popularization and application of optimizing irrigation measures.Crop water requirement under sufficient water supply was calculated by Penman equation.We obtained crop water consumption under conventional treatment and optimizing treatment by field experiment.The main results showed that the irrigation amount of wheat and corn was too much under farmers' conventional irrigation level and basically satisfied their water requirement,therefore,the water-saving amount was smaller while water-saving potential was bigger compared with the optimizing irrigation treatment.The grain yield under optimizing irrigation treatment was improved or appreciably reduced compared with that under conventional irrigation treatment,while the water consumption and irrigation amount of optimizing irrigation treatment was lower,with a higher water use efficiency.Therefore,the optimizing irrigation treatment could achieve a stable yield and high water efficiency at the same time.Moreover,when the optimizing irrigation measure was adopted,the grain yield reached 5940 kg/hm2,water-saving amount reached 91mm for winter wheat,and the grain yield reached 7743 kg/hm2,with water-saving amount of 49 mm for summer corn in the piedmont region of Taihang Mount.The grain yield got 7710 kg/hm2,with water-saving amount of 20 mm for winter wheat in Heilonggang Plain.Therefore,the water-saving amount in the piedmont region of Taihang Mountain was obviously higher than that in Heilonggang Plain.Thus,the piedmont region of Taihang Mountain in the North China Plain is viewed as the key district for water-saving.
查看更多>>摘要：With the aim of increasing the grain crop yield and the level of soil nutrition in the fluvo-aquic soil in North China,the effects of long-term application of K fertilizers and straw returning on crop yield and soil nutrient supplying capacity were investigated in the long-term K localization experiment (1992-2009).The results revealed that wheat and maize responded to K fertilizer in an identical manner and the average yield of wheat and maize for 17 years were NPKSr ＞ NPK ＞ NPSr ＞ NP.Application of K fertilizer on the basis of NP fertilizers could increase the yield of wheat and maize while the grain and straw yields in each treatment were significantly higher for maize than for wheat.The yield of wheat and maize was increased by 6.74％ and 22.32％ respectively when applied with NPK fertilizers compared to NP fertilizers.With the NPSr fertilizing mode,the yield of wheat and maize was increased by 2.84％ and 10.62％ compared to the NP mode respectively.The NPKSr fertilizing mode gave the best yield for wheat and maize,resulting in 10.34％ and 23.81％ increase respectively compared to the NP mode.The yield stability of wheat was significantly higher than that of maize.Under the condition of long-term fertilization,the K uptaken by wheat and maize was degressive by the sequence of NPKSr ＞ NPSr ＞ NPK ＞ NP,mainly deposited in the straw but not in the grain.In this work,the soil natural ability for applying K was gradually reduced as the planting years proceeded and the changes were fitted by linear equations.The natural supply ability of K element in land planted wheat was higher than that in land planted maize.
查看更多>>摘要：The external morphology of the compound eye of the winged female and male Solenopsis invicta Buren and its microstructure in light and dark adaptations were observed using scanning electron microscopy and optical microscopy.The results indicated that the compound eye located on the lateral side of its head,is the a shape of a half ellipsoid and composed of approximately 510 ommatidia in the female,and a near hemisphere with about 805 ommatidia in the male.The ommatidium was made of a corneal lens,crystalline cone,8 to 9 retinula cells and basement membrane.The cornea was a colorless,transparent and double convex lens.The crystalline cone,with an inverted cone shape,was approximately 14.50 m long,formed by four equal parts,and surrounded by many pigment granules.The rhabdom beneath the crystalline cone,was about 75.00 m long,with a thicker middle part and thinner ends.More pigment granules were scattered in the distal and proximal ends and less in the middle,and the basement membrane was on the most bottom area of the ommatidium.The primary pigment cells moved horizontally along the crystalline cone from its distal to proximal end during dark adaptation or moved reversely during light adaptation.There was no significant difference between the pigment granule distribution and the structure of the crystalline cone between female and male ommatidium under the same light or dark adaptation.It is concluded that the fire ant compound eye is an apposition eye,whose light-tuning mechanism is accomplished by the change of crystalline cone and the movement of the pigment cells.
查看更多>>摘要：To clone the antibiotic biosynthesis gene cluster ofStreptomyces roseoflavus Men-myco-93-63,we constructed a Fosmid genomic library.The genomic DNA of the strain Men-myco-93-63 was isolated by the modified CTAB procedure,and the size of most genomic DNA fragments was larger than 150 kb.Then,a Fosmid genomic library containing more than 6000 clones was constructed.The average size of the inserted DNA in recombinant plasmids was 38.1 kb,and the probability of harboring any gene in the genome of the strain Men-myco-93-63 was 99.99％.The library coverage was at least a 10-fold genome equivalent.Therefore,the constructed Fosmid library meets the requirements as a standard genomic library
查看更多>>摘要：The aim of this study was to screen the antagonistic spore-forming bacteria of Alternaria brassicae and to assess their control effect.The test microorganism was A.brassicae in this experiment.One spore-forming strain named DL-59 with a rather stronger antagonistic activity than ever reported was obtained by using an improved agar plate diffusion method.Morphological,physiological and biochemical tests combined with 16S rDNA sequence analysis were carried out to identify DL-59.Its control effect was studied in the basin culture and the plot trials.Two hundred strains were isolated form soil and 20 antagonistic bacteria strains were obtained through preliminary screen.After the secondary screening,a strain named DL-59 with a rather stronger antagonistic activity was obtained and identified as B.velezensis with the largest diameter of inhibition zone of 23 mm.The control efficacy was 79.07％.The plot trials showed that DL-59 had a visible preventive effect on cabbage black spot disease.This can be applied for biological control of plant disease.The strain can produce spores,which is important for the storage of its preparation.
查看更多>>摘要：This paper aims at studying the effect of steam-flaked corn instead of corn in the diet for finishing steers on the growth performance and blood biochemical parameters.A single-factor design was used.There were 28 simmental crossbred steers with the similar bodyweight (414.4±29.3 kg,P＞0.05) selected and allotted to four groups with seven duplicates in each group.Steam-flaked corn replaced the proportion of normal cracked corn,which was of 0,30％,60％,or 90％ in the concentrate of Groups 1,11,111,or ⅣV,respectively.The results showed that the steam-flaked corn replacing ordinary cracked corn could significantly improve the growth of steers.The daily growth rate (ADG) was increased by about 37.16％ from 985.3 g/d to 1351.4 g/d.The feed efficiency was significantly improved by 27.46％.The feed to gain ratio was decreased from 5.68 to 4.12.Serum urea nitrogen was decreased from 4.59 mmol/L to 3.66 mmol/L.Under the experiment conditions,steam-flaked corn replacing ordinary cracked corn could increase the feed efficiency with an optimal replacing ratio of 90％.
查看更多>>摘要：Aflatoxin-detoxifizyme (ADTZ) was evaluated for its ability to reduce the deleterious effects of aflatoxin B1 (AFB1) in broiler diets.A total of 624 one-day-old AA broilers were randomly divided into 3 treatment groups with 8 replicates each.The control,AFB1 and ADTZ treatments were fed with basal diet,basal diet + 0.1 mg/kg AFB1 and basal diet + 0.1 mg/kg AFB1 + 0.3％ ADTZ,respectively.The trials lasted 42 days.The results showed that:(1) AFB1diminished the growth performance of broilers significantly (P＜0.01).(2) The AFB1 supplement caused significant alteration of related liver enzyme activities and significantly decreased the body's antioxidant capacity.(3) Related parameters were returned to normal levels by a 0.3％ ADTZ addition to the AFB1-contaminated diet.All the results in the trials indicate that ADTZ has the ability to detoxify AFB1 and recover the negative effects of AFB1.
查看更多>>摘要：Twelve dual-flow continuous culture fermenters (culture 8 d with 5 d for adjustment and 3 d for sample collection) were used to evaluate the effects of rumen-degradable protein balance (RDPB) on rumen fermentation.The different RDPB levels in six diets were as follows:- 16.84,-8.87,- 0.87,+ 7.13,+ 15.13,and + 23.12 g RDPB/kg DM.Results indicated that RDPB had a significant effect on fermenter NH3-N (P ＜ 0.0001),but had less effect on the fermenter pH (P=0.058),total VFA concentration (P=0.57),or acetate molar proportion (P=0.70).The decrease in rumen-available N in the diets with the RDPB levels at + 15.13,+ 7.13,- 0.87,- 8.87,- 16.84 g RDPB/kg DM resulted in NH3-N concentration decreasing at 9％,52％,104％ and 118％ in rumen compared with the diet of+ 23.12 g RDPB/kg DM.Total VFA concentration,acetic acid and valeric acid at different time points was altered (P＜0.05) by the treatment.With the increase of dietary RDPB,the total NH3-N flowing out of fermenters linearly increased,and the N losses also increased.
查看更多>>摘要：An experiment was conducted to assess the effects of different sources of fats added with an external emulsifier (lecithin) on the performances of Khaki Campbell Ducks in an eight-week trial.Ducks were grouped into five dietary groups with three replicates (n =10) in each group.The ducks were fed with a basal diet supplemented with 3％ soybean oil and without emulsifier (C1),3％ palm oil without emulsifier (C2),3％ soybean oil with emulsifier (T1),3％palm oil with emulsifier (T2) and 3％ lard with emulsifier (T3).The growth performance of ducks did not vary (P＞ 0.1)among the dietary treatments.Feed intakes by ducks were also similar (P＞0.1) among treatments within the periods.Similarly,feed intake to gain ratios were not affected by any dietary treatments.The metabolizability of dry matter,crude protein and nitrogen free extract also did not change (P＞0.1) due to various dietary treatments.However,the metabolizability of fats in all the emulsifier added groups (T1,T2 and T3) was greater (P＜ 0.05) than the dietary groups without emulsifier (C1 and C2).Various carcass traits such as percentages of hot carcass,breast,legs,lungs,hearts,gizzard,giblets weights relative to bodyweights did not vary (P＞ 0.1) among the groups.The carcass yield tended (P =0.06) to be greater in the T1 than in the C1 group.The moisture,fats,protein and ash composition of meat (percent on fresh basis) was similar (P＞ 0.1) among treatments.In conclusion,supplementation of lecithin as an emulsifier to the diets containing different sources of fats (3％) appears to have no major impact on the overall performances of Khaki Campbell ducks in their grower phase.
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