Current issue

• 2018 Vol.34 No.17 Published:20 June 2018

  Low and Medium Cd Stress and Foliage Fertilizer: Effects on Growth and Cadmium Accumulation Regulation of Rice 2018, 34 (17):  1-7.  DOI: 10.11924/j.issn.1000-6850.casb17050041 Abstract + ( 998 )   To investigate the effects of self- made multi- nutrients foliar fertilizer on rice growth and Cd accumulation, a pot experiment was conducted with‘Zhongzao 39’rice variety. The effects of foliar fertilizer on rice growth, Cd distribution in different parts, Cd enrichment and transport were measured during the experiment. The relationship between the Cd content in grain and other organs was also analyzed. The effects of five foliar fertilizers on reducing Cd in rice grain was S> P> Se>Mg> Si, and the Cd content decreased by 73.50%, 66.41%, 58.55%, 58.50% and 46.86%, respectively. The enrichment coefficient of Cd in rice grain decreased by 73.5% and the Cd transport coefficient decreased by 72.9% under sulphur foliar fertilizer treatment. Compared with the other four foliar fertilizers, the sulphur foliar fertilizer has better effect on reducing Cd content, however, the effect of silicon foliar fertilizer on rice growth, yield and Cd reduction efficiency is the best among the five foliar fertilizers, rice stem is the most important part influencing the Cd content in grains, and one of the main pathways for Cd accumulation.

  Breeding and Application of Excellent Maize Inbred Line‘Zao48’ 2018, 34 (17):  8-11.  DOI: 10.11924/j.issn.1000-6850.casb17050099 Abstract + ( 945 )   For the narrow genetic basis of maize germplasm and the lacking of excellent resistant maize inbred lines in breeding and production, the domestic inbred line‘Ye478’and exotic hybrid progeny‘P249’with tropical germplasm were used to cross, backcross and multi-generation selfing, and breed the multi-resistant and high- quality inbred line‘Zao48’with the temperate- tropical background.‘Zao48’had high multidisease resistance to stem rot, dwarf mosaic disease, corn southern leaf blight, corn northern leaf blight and ear rot. It had high content of crude protein and crude starch in grain. It also had compact plant type, dwarf stalk with lodging- resistant, strong combining ability and wide adaptability. Six hybrid cultivars including ‘Qiangsheng31’,‘Jindan44’,‘Xinyu110’,‘Yongfeng No.1’,‘Jinyang No.2’and‘Jindan70’from‘Zao48’ inbred line combination were approved by the National or Provincial Crops Variety Approval Committee. These new cultivars have been promoted and applied widely in northeastern and northern early- maturity maize regions, Huanghuaihai summer maize region, and achieved huge social and economic benefits.

  Breeding of‘Yun Castor No.4’and‘Yun Castor No.5’ 王沛琦,郭丽芬,刘旭云 and 张锡顺 2018, 34 (17):  12-18.  DOI: 10.11924/j.issn.1000-6850.casb18010135 Abstract + ( 1092 )   ‘Yun Castor No.4’and‘Yun Castor No.5’are high-yielding, high-quality and high-resistance new varieties bred by the Institute of Industrial Crops of Yunnan Academy of Agricultural Sciences. The growth period of the two varieties was 148 days and 166 days respectively from the emergence to the main spike. In 2003, their average seed yield was 2993.55 and 2445.15 kg/hm2 respectively, which was higher than that of the control‘TCO- 202’by 48.40% and 21.27% . In 2014, it participated in the emonstration test of castor varieties in China.‘A131’was the second in Tongliao test spot and the second in Yunnan test spot.‘A133’ was the sixth in Tongliao test spot and the first in Yunnan test spot. The main characteristics of the two varieties are wax powder on stems and leaves, more branching, large ears, high yield and high oil content (57.53% and 56.66%, respectively), high ricinoleic acid (86.52% and 90.45%), disease-resistant, droughtresistant and wide adaptability. In Yunnan as well as other regions in southwest China, and Southeast Asian countries, the demonstration of castor production is very good. In 2015, a field identification was carried out on ‘A131’and‘A133’by the Seed Management Station in Yunnan Province, and the two varieties are named as ‘Yun Castor No.4’and‘Yun Castor No.5’. The varieties with supporting cultivation techniques have obvious economic and social benefits, they are suitable for planting in areas below 1800 m altitude in Yunnan Province and being promoted in southwest China and Southeast Asian countries.

  Application of Nanotechnology in Seed Production, Process and Treatment 2018, 34 (17):  19-23.  DOI: 10.11924/j.issn.1000-6850.casb18020012 Abstract + ( 867 )   Seed is the first element of agricultural production, and the seed of high quality is the basis of the sustainable development of agriculture. The application of nanotechnology in crop breeding, seed processing and treatment is reviewed. Nanotechnology is still in the early stage of development, and has great potential for development in the future. But there are also some uncertain risks. Choosing safe and reliable nanotechnology is of great significance for the development of seed industry.

  Electronic Cloning and Bioinformatics Analysis of PaGAST Gene in Sweet Cherry (Prunus avium) 李洪雯 2018, 34 (17):  24-31.  DOI: 10.11924/j.issn.1000-6850.casb17050107 Abstract + ( 1029 )   To obtain the cDNA sequence of sweet cherry PaGAST gene and predict the structure and functions of the corresponding protein, PaGAST gene was cloned by electronic cloning technology based on EST sequences from NCBI databases using strawberry FaGAST1 gene sequence as a probe. The bioinformatics methods were utilized to analyze the physical and chemical properties, hydrophobicity and hydrophilicity, signal peptide sequence, transmembrane domain, subcellular localization, functions and other relevant characteristics of the corresponding protein. The results showed that sweet cherry PaGAST gene was 750 bp in length, and its open reading frame was 324 bp long, encoding a polypeptide of 107 amino acids with a signal peptide sequence in the N-terminal and a conserved GASA domain in the C-terminal. Because of high content of hydrophobic amino acid residues among peptide sequences, the PaGAST protein contained a transmembrane helical region, which meant it was a transmembrane protein with 10 presumed protein kinase phosphorylation sites. Subcellular localization analysis showed that the PaGAST protein was very likely to be localized outside the cell membrane. Functional prediction revealed that PaGAST gene had the greatest probability in participation of stress response, signal transduction and immune response. Phylogenetic analysis indicated that sweet cherry PaGAST protein was most closely related to peach. The results above lay a theoretical foundation for the cloning and functional identification of sweet cherry PaGAST gene to some extent.

  The Application of Nucleic Acid Dye Gelred in Two Gel Detection Systems 2018, 34 (17):  32-38.  DOI: 10.11924/j.issn.1000-6850.casb17080020 Abstract + ( 648 )   Because nontoxic nucleic acid dye Gelred has high cost, the minimum dosage of Gelred is investigated on non-denaturing polyacrylamide gel electrophoresis and agarose gel electrophoresis, without affecting the experimental results. 10000×Gelred was individually diluted to 1×, 10×, 20×, 30×, 40× and 50×, directly mixed with the PCR production of sugar beet, and then the mixture was directly detected by nondenaturing polyacrylamide gel electrophoresis and agarose gel electrophoresis. The detection was conducted with GEL imaging system. The other method was that the non-denaturing polyacrylamide gel and agarose gel were soaked in 1×Gelred and then showed by GEL imaging system. The results showed that 30×Gelred and above-30×Gelred were suitable for the detection of non-denaturing polyacrylamide gel electrophoresis and agarose gel electrophoresis, and 1×Gelred was more suitable for the soak of non-denaturing polyacrylamide gel. The dilute Gelred was mixed with PCR production, and then coordinated with non- denaturing polyacrylamide gel electrophoresis, which not only reduced the amount of Gelred, but also decreased the developing time.

  Roles of RBR in Plant Growth and Development: Research Progress 2018, 34 (17):  39-46.  DOI: 10.11924/j.issn.1000-6850.casb18020041 Abstract + ( 822 )   Formation of plant new organs must be tightly controlled by cell division and differentiation during post-embryonic development. Retinoblastoma-Related (RBR) proteins are plant homolog of the human tumor suppressor Retinoblastoma (RB) protein. As a negative regulator of cell proliferation, it has been proved that RBR is involved in a wide range of plant growth and development processes. In order to gain insight into the mechanism of action of RBR, the authors summarized the characteristics of expression and regulation of RBR in different plants, and reviewed the research progress on the mechanism of RBR1 involved in regulating cell cycle and growth and development of Arabidopsis. The authors propose a regulatory network of RBR1 in which protein-protein interaction is mainly regulatory manner. Furthermore, the authors put forward some questions to be answered in the future and provide some valuable information for the continuous research of RBR in plants.

  Effects of Nutrient Elements on Activity of Protective Enzymes and Electrical Conductivity of Pinus tabulaeformis Under Water Deficiency 2018, 34 (17):  47-51.  DOI: 10.11924/j.issn.1000-6850.casb17050085 Abstract + ( 611 )   [Objective] The study in order to provide a theoretical basis for scientific fertilization which by means of analyzes effects of nutrient elements on drought resistance of Pinus tabulaeformis. [Methods] the test set 5 treatment as S1 (routine control), S2 (clean water control), S3 (N), S4 (NK), S5 (NPK) and repeat 3 times. [results] The S5 treatment SOD activity that was higher than S1 treatment 68.66%,64.54%,36.02%,30.03% when in May, June, July and August and then had significant difference; POD activity that S5 was higher than S1 treatment as 79.96%,117.82%,51.65%,41.28% and then had significant difference; CAT activity S5 was higher than S1 treatment as 35.86%,33.51% when in June and August and then had significant difference; PPO activity S5 was higher than S1 treatment as 92.18%,125.15%,74.95%,57.77% and then had significant difference; The conductivity of S5 was always at lowest level, at the same times, it was lower than control(S1)treatment 40.46%,24.73%,25.99%,55.55% and then had significant difference; [Conclusion] S5 was the best treatment as to enhance the activity of protective enzymes and decrease the conductivity of Pinus tabulaeformis seedlings under water stress.

  Effects of Planting Density on Quality and Economic Characters of‘Yunyan87’in Kunming 2018, 34 (17):  52-55.  DOI: 10.11924/j.issn.1000-6850.casb17080034 Abstract + ( 902 )   To explore appropriate cultivation measures of flue- cured tobacco in Kunming, the effects of planting density on neutral aroma components, chemical components and economic characters were studied with field experiments. The results showed that, with the increase of planting density, the contents of total sugar, reducing sugar and potassium increased first and decreased later, contrary to the content change of nicotine and chlorine, and the content of total nitrogen increased. The contents of maillard reaction productions, carotenoid degradation productions, phenylalanine degradation products, cembranoids degradation products, chlorophyll degradation products and neutral aroma components in tobacco leaves were the highest in treatment T2(120 cm× 60 cm), and all showed a first increase and then decrease tendency with the increase of planting density. The economic characters of T2 had the best performance. Therefore, the planting density of 120 cm×60 cm is more appropriate for‘Yunyan87’in Kunming, and could be popularized and applied.

  Screening and Application of SSR Markers’Polymorphism of Capsicum Whole Genome 2018, 34 (17):  56-61.  DOI: 10.11924/j.issn.1000-6850.casb17090062 Abstract + ( 616 )   The paper aims to further understand the genetic diversity of pepper germplasm resources. 152 pairs of SSR primers were designed based on the whole genome coding region sequence of pepper. 4 different species of Capsicum were used to screen 152 pairs of primers, to obtain clear bands, good stability of 14 SSR polymorphic primers. Then, the 14 pairs of SSR primers were used to analyze the genetic diversity of 26 accessions of pepper germplasm resources. The results showed that the 14 pairs of SSR primers amplified 39 polymorphic bands, with an average of 2.79 loci amplified by each pair of primers, which showed that the SSR primers had higher practicability in the genetic analysis of pepper. Phylip software was used to conduct the cluster analysis of the 26 accessions of pepper germplasm resources, and divided the accessions into seven categories, and the results were basically consistent with the source of pepper species. This study can lay a foundation for the study and rational utilization of genetic diversity of pepper germplasm resources.

  Thermal Properties of Bilayer Mulching Plastic Film and Recycle-cotton Quilt for Grapevine Overwintering 2018, 34 (17):  62-68.  DOI: 10.11924/j.issn.1000-6850.casb17060028 Abstract + ( 520 )   To reduce the labor intensity of burying grapevine for overwintering in Turpan, Xinjiang, China, the values of daily soil temperature under bilayer mulching plastic film and recycle-cotton quilt as well as in burying soil in 2013/2014 winter were measured. The results revealed that the heat-insulating property of bilayer mulching plastic film was higher than that of recycle-cotton quilt and burying soil. The minimum temperature under the bilayer mulching plastic film was higher than the critical temperature of freeze injury (- 18℃), and there was a high compensation temperature of maximum temperature and average temperature. The grapevine germination under the bilayer mulching plastic film was obviously earlier than that under the recycle-cotton quilt and in burying soil, thus the growing period of grapevine was prolonged, and the grape yield and quality was increased. Moreover, the cost of bilayer mulching plastic film was cheaper than that of recycle-cotton quilt and re ycle-cotton quilt.

  Watermelon Rhizosphere Soil Bacterial Diversity Affects the Occurrence of Fusarium Wilt 2018, 34 (17):  69-76.  DOI: 10.11924/j.issn.1000-6850.casb17090154 Abstract + ( 800 )   To explore the effect of bacterial community diversity of watermelon rhizosphere soil on the occurrence of fusarium, the authors analyzed the rhizosphere bacterial of wilted and healthy plants under both the continuous cropping field soil and rotated cropping field soil. The V4 region of the 16S rRNA gene in bacterial DNA was amplified using the polymerase chain reaction technique, and sequenced by the Illumina Hiseq platform, to conduct a diversity analysis of the soil bacteria microbial community composition of different samples. A total of 234895 tags of high-quality reads were obtained in CH (continuous cropping, healthy), 224092 tags in CW (continuous cropping, wilted), 220963 tags in RH (rotated cropping, healthy), 231746 tags in RW(rotated cropping, wilted), respectively. And the tags were clustered into CH 11230, CW 11228, RH 10068, RW 10248 microbial operational taxonomic units (OTUs). At phylum level, Proteobacteria accounted for the highest ratio in all the four treatments, respectively as RH 55.61% , RW 60.84% , CH 46.06%, CW 47.21%, and the proportion in non-continuous cropping was averagely 11.59% higher than that of continuous cropping. In addition, there was a significant difference between CH and RH, Clostridia was specifically in CH, while Gammaproteobacteria existed only in RH. However, in the genus top 35 bacteria population, the abundance of Mizugakiibacter, Pandoraea, Thermomonas and Acidobacterium in rotate cropping was apparently higher than that in continuous cropping. And Taibaiella, Dyella and Chitinophaga in RH were more abundant compared with other treatments. The results showed that the bacterial community diversity in rhizosphere soil of continuous cropping was higher than that in rotate cropping; the structures of bacterial communities in rhizosphere soil of wilted plants and healthy plants were significantly different under rotate cropping condition; the structures of bacterial community were different under different cultivation conditions. In conclusion, the bacteria community structure, quantity and variety of rhizosphere soil are one of the main environmental factors that affect the occurrence of watermelon wilt.

  Evaluation of Chilling Tolerance of Melon Germplasm Resources 2018, 34 (17):  77-82.  DOI: 10.11924/j.issn.1000-6850.casb17050111 Abstract + ( 650 )   The aims are to screen the chilling-tolerant germplasm resources of melon and lay a foundation for melon chilling-tolerance breeding. In this study, 31 melon germplasms were used as materials. During the germination stage, the seeds were cultivated with 18℃ chilling stress. The relative germination percentage, relative germination index and relative vigor index were calculated and then analyzed by subordinate function analysis and cluster analysis. During the seedling stage, the seedlings of 31 melon germplasms were treated with 9℃/6℃ (day/night) chilling stress. The chilling injury index was calculated and then analyzed by cluster analysis. The results showed that, at germination stage, 31 melon germplasms could be divided into 5 chillingtolerance types, including high-tolerant type (2 lines), tolerant type (7 lines), moderately tolerant type (16 lines), susceptible type (3 lines) and high-susceptible type (3 lines). At seedling stage, 31 melon germplasms could be classified into 5 chilling-tolerant types, including high-tolerant type (2 lines), tolerant type (4 lines), moderately tolerant type (11 lines), susceptible type (10 lines) and high-susceptible type (4 lines).

  Morphology and Interconversion Factor of Selenium in Soil 邢 颖,,,,, and 2018, 34 (17):  83-88.  DOI: 10.11924/j.issn.1000-6850.casb17060087 Abstract + ( 629 )   In recent years,production and processing of natural selenium-rich agricultural products become a research hotspot. The main factor affecting the selenium content in soil was effective form . So it was particularly important to understanding the conversion relationship of selenium forms in the soil and find ways to improve selenium effectiveness. By analyzing the past research on selenium in soils, this paper analyzes the classification of soil selenium morphology, the transformation of soil selenium morphology and the factors that improved the validity of selenium. Insight into the relationship between chemical form and leaching form of selenium in soil,study the conversion factors of different forms of selenium. Looking for ways to improve selenium effectiveness in rich selenium areas. Combining soil and crop characteristics of different rich selenium regions,taking different selenium activation methods, provide more scientific evidence for the research.

  Rhizosphere Soil Microorganism Quantity and Enzyme Activity of 3 Tree Species in Daqing Mountain 刘雷,姚庆智,铁英,李敏 and 魏杰 2018, 34 (17):  89-94.  DOI: 10.11924/j.issn.1000-6850.casb17060039 Abstract + ( 601 )   The paper aims to reveal the effect of altitude gradient on soil microorganism quantity and enzyme activity of 3 kinds of native drought-resistant tree species, and to provide a theoretical basis for accurate assessment of the role and rational utilization of different tree species in Daqing Mountain ecosystem. The authors measured and analyzed the rhizosphere soil microorganism quantity and enzyme activity by traditional plate colony technique and 96 microtiter plate fluorescence method. The results showed that: the number of microbes in the 3 species showed bacterial>actinomycete>fungi, but there were significant differences (P < 0.05); the activity of protease, N - acetylglucosidase, alkaline phosphatase and peroxidase in soil of the 3 species decreased with the increase of altitude; the correlation analysis showed that: there were some correlations between soil microorganism quantity, soil enzyme activity and soil physical and chemical properties. The research provides a theoretical basis for soil improvement, afforestation and protecting the ecosystem of Daqing Mountain Nature Reserve in Inner Mongolia.

  Maize Straw Returning for Three Consecutive Years: Effects on Soil Physical and Chemical Properties and Crop Yield 2018, 34 (17):  95-98.  DOI: 10.11924/j.issn.1000-6850.casb17060098 Abstract + ( 581 )   Straw returning could increase soil organic matter content, improve soil nutrients, reduce soil bulk density, and enhance soil physical and chemical properties. In this paper, the effects of corn straw returning on soil physical and chemical properties and crop yield were studied by fixed-point monitoring method. The results showed that compared with the soil basal background value before returning and the conventional fertilization without straw (CK), conventional fertilization with straw returning could effectively improve soil nutrients content; soil organic matter, available nitrogen, available phosphorus and available potassium content increased in different degrees; soil bulk density decreased, soil physical and chemical properties were improved, the after crop lettuce yield increased. In addition, corn straw returning could effectively reduce the environmental pollution caused by straw burning, and was worth popularizing.

  Effects of Intercropping Green Manure on Soil Available Zinc and Nutrient Content of Young Tea Garden 2018, 34 (17):  99-103.  DOI: 10.11924/j.issn.1000-6850.casb17050089 Abstract + ( 603 )   The effects of intercropping green manure on soil available zinc and nutrient content of young tea garden are studied in this paper. Field experiments were conducted with four kinds of green manure (peanut, soybean, mung bean and‘chafei No.1’), the effects of intercropping green manure on soil pH value, organic matter, available zinc, nitrogen, phosphorus, potassium, plant height, plant width and other growth indexes were studied. The results showed that intercropping green manure was beneficial to the increase of soil zinc content in young tea garden, and the improvement effect was obvious after one month of green manure buried, the effects were in sequence of mung bean＞soybean＞‘chafei No.1’＞peanut. Intercropping green manure increased the contents of available nitrogen, available phosphorus and available potassium in young tea garden soil. The correlation analysis showed that soil zinc content was significantly and negatively correlated with soil available nitrogen and available phosphorus, with the correlation coefficients of - 0.888** and - 0.941** respectively. The four kinds of green manure improved plant height, plant width, stem and branch and survival rate of tea, and the effect of intercropping peanut was the most obvious. Mung bean and peanut are screened out to improve soil fertility and enhance the growth of tea tree.

  Effect of Biochar Pyroligneous on Conventional Five Items of Tobacco Soil Under Reducing Fertilizer 2018, 34 (17):  104-109.  DOI: 10.11924/j.issn.1000-6850.casb18010165 Abstract + ( 579 )   To seek the method of reducing fertilization in field and verify the practical application effect of the mixture of biochar and pyroligneous, three plots experiment on‘Tobacco K326’was conducted in one year, to study the effect of mixture of biochar and pyroligneous, and reducing fertilization on dynamic change of soil. The results of Yongren County showed that: compared with reducing conventional fertilizer, the mixture of biochar and pyroligneous under reducing fertilization could improve the sustained-release effect of nitrogen and potassium, and enhance the activity of phosphorus. The results in Yaoan County and Wuding County showed that compared with the normal fertilization with biochar and pyroligneous, the mixture had better release and excitation effect under reducing fertilization, and the advantage was obvious at reducing fertilization 10%-20%. Therefore, the method of reducing fertilization combined with the mixture of biochar and pyroligneous may be an effective one to reduce the amount of chemical fertilizer.

  Climate Change in Four Seasons in Qingyang: Analysis and Its Impacts on Crop Planting 2018, 34 (17):  110-114.  DOI: 10.11924/j.issn.1000-6850.casb17060134 Abstract + ( 889 )   According to the QX/T 152-2012 division standard of four seasons in climate issued by the China Meteorological Administration in 2012, the authors divided climate seasons in Qingyang based on the daily average temperature data of 8 stations in Qingyang from 1981 to 2016, finding that the annual climate of this region was divided into no summer zone and four distinctive seasons zone. The results showed that: the beginning date of spring time was between the end of mid-April to the early late-April, earlier in southwestern region than that in northeastern region; the beginning date of summer time was between the end of June to late- July, earlier in northwestern region than that in south-central region; the beginning date of autumn time was between the end of mid-July to mid-August, earlier in eastern region than that in western region; the beginning date of winter time was between mid-October to early late-October, earlier in northeastern region than that in southwestern region. The authors analyzed the beginning date of each season in four distinctive seasons zone by the methods of linear correlation analysis. The results showed that the beginning date of spring and summer had an advanced trend, the beginning date of winter had a postponed trend; the duration of autumn showed an extended trend, and the duration of winter showed a shortened trend. In response to climate change, this region has adjusted the planting structure in recent years, introduced hardy and drought-resistant quinoa, expanded alfalfa cultivation, developed animal husbandry, and increased the input to facility agriculture.

  Hydrolysis of Yak Blood Protein into Polypeptide with Protease 2018, 34 (17):  115-121.  DOI: 10.11924/j.issn.1000-6850.casb17060110 Abstract + ( 505 )   The yak hemoglobin from blood was hydrolyzed in order to produce protein polypeptide with neutral protease. The factors influencing neutral protease to hydrolyze yak hemoglobin and their relationships with hydrolysis degree were explored by single factor experiments and orthogonal design [L16(45)]. And the effect of activated carbon on decolorization was analyzed. The results showed that the optimum hydrolysis conditions were as follows: pH 7.0, temperature 45℃, enzyme activity 4000 U/g substrate, substrate concentration 5%, hydrolysis duration 7 h. The optimum parameters for decolorization were determined to be active carbon consumption of 4%, temperature of 75℃, pH 5.0 and decolorization duration of 60 min.

  Different Lysine Levels Affecting Productive Performance and Serum Biochemical Parameters of Two-line Crossbred Gilts Feeding Low-Protein Diets 2018, 34 (17):  122-128.  DOI: 10.11924/j.issn.1000-6850.casb17040072 Abstract + ( 743 )   The study was conducted to evaluat the effects of different lysine levels in low crude protein on the growth performance and serum biochemical parameters of replacement gilts from 70 to 100 kg and 100 to 125 kg. A total of 96 two-line crossbred gilts(Landrace x Large White), with 69.01 kg of average bodv weigh and similar body conditions, were allocated to four groups with four replicates per group. The gilts were fed four digestible lysine levels of diets in low crude protein based on isoenergetic and ideal amino acid pattern. The results showed that average daily gain (ADG) (908.33 g) was hightest and feed/gain (F/G) (2.77) was lowest in trial group 2 of 70~100 kg gilts (P<0.05). The concentration of serum urea nitrogen (UN) in trial group 2 was significantly lower than that in trial group 1 and 4 (P< 0.05), and there was no significant difference than that in trial group 3 (P>0.05), the concentration of INS and IGF-Ⅰincreased,then decreased whth increasing levels of Dlys (P>0.05),the concentration of serum lysine,threonine in trial group 1 were significantly lower than those in group 4 (P< 0.05),the concentration of others serun amino acid decreased,then increased with increasing levels of Dlys(P>0.05).The ADG (863.14 g) was hightest and F/G (3.08) was lowest in trial group 2 of 100~125 kg gilts (P<0.05). The concentration of UN in trial group 3 was significantly lower than that in trial group 1 and 4 (P< 0.05), and there was no significant difference than that in trial group 2 (P>0.05), the concentration of INS in trial group 3 was significantly higher than that in trial group 1 (P< 0.05), and there was no significant difference than that in trial group 2 and 4(P>0.05),the concentration of IGF-Ⅰincreased,then decreased whth increasing levels of Dlys (P>0.05).the concentration of serum lysine in trial group 1 and 2 were significantly lower than those in group 3 and 4 (P< 0.05),the concentration of others serun amino acid decreased,then increased with increasing levels of Dlys(P>0.05). In conclusion，based on low-protein diets with ideal amine acid patter，when the daily total DLys intake were 16.57 g/d and 15.96 g/d（DLys level in the low-protein diets should be 0.66% and 0.60%）respectively,the gilts with BW of 70 to 10 kg and 100 to 125 kg could have the higher growth performance.

  The Present Situation and Developing Trend of Laying Hens ’Welfare in China 2018, 34 (17):  129-134.  DOI: 10.11924/j.issn.1000-6850.casb17060043 Abstract + ( 764 )   Welfare rearing of laying hens combines welfare with production of laying hens, and is the developing trend of laying hen industry. At present, cage rearing is dominant in China, welfare rearing of laying hens needs to be carried out. First, we clarified the definition and modes of welfare rearing of laying hens. Second, we summarized the current status of welfare rearing from the following aspects, i.e. enrichment of rearing environment, rearing equipment, rearing density, management (beak broken, forced moulting, ventilation, light, etc.), transportation, and slaughter. Finally, we pointed out the existing problems for welfare rearing of laying hens and put forward corresponding countermeasures, aiming to provide a reference for the welfare rearing and promote the healthy and stable development of laying hen industry in China.

  Nutrition Analysis on Leaves of Forage Grasses as Feedstuffs 2018, 34 (17):  135-139.  DOI: 10.11924/j.issn.1000-6850.casb17100031 Abstract + ( 642 )   To study the nutrient composition of leaves from five kinds of forage grasses, evaluate the nutrition value of amino acid, and provide a scientific basis for the development and utilization of forage grasses fodder, crude protein, amino acid, crude fat, Ca and P were measured by conventional method, neutral detergent fiber and acid detergent fiber were measured by filter-bag method, the nutrition value of amino acid was evaluated by essential amino-acid scoring and chemistry scoring. The results indicated that: (1) the contents of CP, Ca, NDF and ADF were significantly different, the content of CP of water hyacinth was the highest, and CP contents in two kinds of leguminous forages grasses were significantly higher than that in gramineous forage grasses, while ADF contents in leguminous forages grasses were significantly lower than that in gramineous forage grasses; (2) there were amino acids of full range in the forages grasses, the contents of total amino acids and essential amino- acids were rich, methionine was the limiting amino acid in forages grasses. The conclusion showed that (1) CP content in water hyacinth, alfalfa and kudzu were higher, which could be used as feedstuff; (2) Italian rye and hybrid wolftail could be developed as coarse fodder; (3) methionine or methioninerich raw material should be added when producing complete formula feed for animals with the five kinds of forage grasses.

  Yield-increasing Mechanism of Biodegradable Mulch Cover Potato 2018, 34 (17):  140-144.  DOI: 10.11924/j.issn.1000-6850.casb17090117 Abstract + ( 695 )   To study the yield- increasing mechanism of winter potato with biodegradable mulch film in Guangdong, four treatments including biodegradable film, biodegradable herbicidal film, plastic film and bare land are set. The effects of different treatments on soil temperature, nutrients, potato yield and quality are studied by field experiments. The results show that soil temperature of different mulch films has no significant difference and has significant difference compared with that of bare land treatment, the 10 cm soil temperature of biodegradable herbicidal mulch film, biodegradable mulch film and plastic film increase by 2.17, 2.57 and 2.29℃ compared with that of bare land. The soil nutrients content of biodegradable herbicidal mulch film and biodegradable mulch film are the lowest, and that of bare land is the highest. The tuber yield of biodegradable herbicidal mulch film and biodegradable mulch film increase by 2335.5 and 2056.5 kg/hm2 compared with that of plastic film, increase by 5947.5 and 5668.5 kg/hm2 compared with that of bare land. Biodegradable mulch film could not only solve the white pollution problem, but also improve the marketable tuber yield of potato, it is very important to promote the potato industry in Guangdong.

  Construction and Purification Effect of Pond Recirculating Aquaculture System: Research Progress 2018, 34 (17):  145-152.  DOI: 10.11924/j.issn.1000-6850.casb17060016 Abstract + ( 541 )   The traditional aquaculture pattern can easily cause water pollution and waste of water resources. In order to reach the goal of healthy aquaculture, pond recirculating aquaculture system (PRAS) takes measures to purify water by using power flow purification and bioremediation techniques under the guidance of circular economy, such as establishing artificial wetland to form a sustainable development model. In this study, we summarized the construction of the three main models of PRAS and their effects on water purification, and analyzed the main problems in the operation of the system. The existing studies showed that the average removal rates of TN, TP, NH4+-N, CODMn, and NO2--N were basically maintained at 60%. Besides, we analyzed the factors such as the ratio of purification area to pond area as well as the effects of the substrate, plant, pH and temperature in the purification unit. This study can provide a reference for further in-depth research on PRAS.

  Farmers'' Homestead Transfer Intention and Its Influence Factors of Heilongjiang Province 2018, 34 (17):  153-157.  DOI: 10.11924/j.issn.1000-6850.casb17070047 Abstract + ( 571 )   Farmers" homestead as the most important reset provides the basic housing security and living security for the farmers, farmers" homestead transfer intention affects farmers’ land transfer behavior, the study has important significance to protect farmers’ rights and interests. The paper takes Maoershan of Heilongjiang province as the research area, takes farmers" homestead transfer intention as the research object, develop 237 questionnaire investigations from the four aspects such as family characteristics, professional characteristics, cultural characteristics and other aspects, and use the Logistic model to analysis the research result, find out the main factors, at last, according to the research result provide the suggestions to regulate rural residential land transfer.

  Rural Homestead Circulation in Heilongjiang Province Based on Household Survey: A Case Study of Maoershan Town, Heilongjiang Province 2018, 34 (17):  158-164.  DOI: 10.11924/j.issn.1000-6850.casb17100089 Abstract + ( 524 )   The purpose of this study is to study the problems and countermeasures of rural housing land transfer in Heilongjiang Province on the basis of the investigation of farmers, to activate the stock of rural housing land and improve the conservation and utilization of rural residential land. Based on the investigation of the current situation of the resettlement of rural homestead in the town of Maoer Township, this paper makes a preliminary discussion on the transfer of rural homestead from the perspective of farmers, and analyzes the rural areas of Maoer Township The current situation of the distribution of homesteads, revealing the problems existing in the rural homesteads in Maoer Township, drawing on the successful experiences and methods in literature, and put forward corresponding suggestions and countermeasures to institutionalize and standardize the rural homesteads in Maoer Town, Legal basis.