Frontiers of Agriculture in China

ISSN 1673-7334

ISSN 1673-744X(Online)

CN 11-5729/S

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Identification, inheritance and QTL mapping of root traits related to tolerance to rhizo-spheric stresses in soybean (G. max (L.) Merr.)
GAI Junyi, LIU Ying, LV Huineng, XING Han, ZHAO Tuanjie, YU Deyue, CHEN Shouyi
Front. Agric. China. 2007, 1 (2): 119-128.  
https://doi.org/10.1007/s11703-007-0022-y

Abstract   PDF (414KB)
A sample of soybean accessions (Glycine max (L.) Merr.) from Huanghe Huaihe Haihe and Middle Lower Changjiang Valleys in China was used to identify their tolerance to rhizo-spheric stresses, including drought, aluminum toxin and low phosphorus. A total of 15 accessions highly tolerant to at least one of the abiotic stresses were screened out. The correlation between drought tolerance and the relative values of total root length, root volume and dry root weight (relative to dry plant weight) were all significant at 0.01 level, respectively. So did for the correlation between aluminum toxin tolerance and the stress to non-stress ratios of the number of lateral roots, tap root length, total root length, root volume and dry root weight. The inheritance study on the above three root traits related to drought tolerance under segregation analysis indicated that between the two parents of the recombinant inbred line (RIL) population of (Kefeng 1?Nannong 1138-2), the relative values of dry root weight, total root length and root volume were controlled by two major genes plus polygenes with their major gene heritability values 62.26% 91.81% and polygene heritability values 2.99% 24.75%, respectively, and for the latter two traits, the two major genes linked together with recombination value 4.30% and 1.93%, respectively. The inheritance study on the five root traits related to aluminum toxin tolerance revealed that between the two parents of the recombinant inbred line RIL) population of (Bogao?NG94-156), the stress to non-stress ratios of lateral root number, tap root length, total root length and dry root weight were controlled by three major genes plus polygenes with their major gene heritability values 80.22% 91.81% and polygene heritability values 3.52% 11.39%, while the stress to non-stress ratio of root volume was controlled by three major genes with their major gene heritability value 93.44%. The (Kefeng 1?Nannong 1138-2) RIL population was also used for mapping QTLs of relative dry root weight, total root length and root volume related to drought tolerance. Five, three and five QTLs located on Linkage group N6-C2, N8-D1b+W, N11-E and N18-K for each of the three traits, respectively, were identified. Each of the traits appeared to have one locus (Dw1, Rl1, Rv1) with relatively large effect in comparison with their other loci, and the three loci in above parentheses were located in the same region STAS8_3T-STAS8_6T on N6-C2 with a same distance to the flanking markers. Thus, Dw1, Rl1, and Rv1 even might be a same locus and performed as pleiotropic of a same gene. The results between segregation analysis and QTL mapping appeared relatively consistent, therefore could be used for verification each other.
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Assessment of genetic diversity among Chinese upland cottons with Fusarium and/or Verticillium wilts resistance by AFLP and SSR markers
WANG Xingfen, MA Jun, YANG Shuo, ZHANG Guiyin, MA Zhiying
Front. Agric. China. 2007, 1 (2): 129-135.  
https://doi.org/10.1007/s11703-007-0023-x

Abstract   PDF (304KB)
Genetic diversity among 95 Chinese upland cottons with Fusarium and/or Verticillium wilts resistance was estimated using Amplified Fragment Length Polymorphism (AFLP) and Simple Sequence Repeat (SSR) markers. Twenty EcoRI-MseI AFLP and 19 SSR primers with polymorphism were selected to perform the fingerprinting. The results showed that 20 AFLP primer pairs produced a total of 1 480 major bands among 95 genotypes, and 214 were polymorphic bands. The number of total bands per primer pair ranged from 47 to 109, with an average of 74.0. The polymorphism information content (PIC) values for the 20 primer pairs varied from 0.01 (E-ACT/M-CAT) to 0.24 (E-ACA/M-CTA), and the average value was 0.09. Nineteen SSR primers generated 89 DNA bands, of which 61 were polymorphic. The total number of alleles per locus varied from 3 to 8, with an average of 4.7. The average PIC value for the SSR amplification products was 0.69. Genetic similarity estimates for the entire data set ranged from 0.978 to 0.998 based on AFLP and SSR bands. It was proved that the close genetic relationship and narrow genetic diversity existed in the tested cultivars. The clustering patterns could not be correlated to the geographic origin, the pedigree and common parentage of the cultivars.
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Relationship between potassium chloride suppression of corn stalk rot and soil microorganism characteristics
LIU Xiaoyan, JIN Jiyun, HE Ping, LIU Hailong, LI Wenjuan
Front. Agric. China. 2007, 1 (2): 136-141.  
https://doi.org/10.1007/s11703-007-0024-9

Abstract   PDF (341KB)
Observations from a site-fixed field trial of 12 years in Jilin Province show that potassium chloride (KCl) application has a significant positive influence on corn stalk rot incidence. Incubation experiments were conducted to study the effects of KCl and soil extracts on the growth of Fusarium graminearum, the most common stalk rot fungi in this area, and the population changes in rhizosphere fungi, bacteria and actinomyces at different growth stages of corn. The results show that KCl addition to the potato dextrose agar (PDA) medium could not directly suppress Fusarium graminearum development. Soil extracts from soil samples taken from the field plots with and without KCl application affected Fusarium graminearum development, with soil extracts with KCl treatments suppressing Fusarium graminearum development more significantly, compared with that from the KCl-free treatment. These results indicate that soil extracts play a role in the interaction between corn and Fusarium graminearum. Long-term KCl application may increase the populations of rhizosphere fungi and actinomyces in the early growth stages, while there is no significant difference in the number of bacteria in rhizosphere among the treatments. Also, the populations of rhizosphere fungi are negatively correlated with the incidence of stalk rot in the early growth stages of corn. The sensitive infection stages of pathogen to corn consist of the stages when there is significant difference in the populations of rhizosphere fungi and actinomyces. The change of microorganism populations (especially fungi) in soil may be associated with the incidence decrease and is one of the mechanisms of KCl suppressing corn stalk rot.
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Effects of nitrogen rate and ratio of base fertilizer and topdressing on uptake, translocation of nitrogen and yield in wheat
SHI Yu, YU Zhenwen, WANG Dong, LI Yanqi, WANG Xue
Front. Agric. China. 2007, 1 (2): 142-148.  
https://doi.org/10.1007/s11703-007-0025-8

Abstract   PDF (298KB)
Application of nitrogen (N) fertilizer is one of the most important measures to increase grain yield and protein content in winter wheat (Triticum aestivum L.) production. However, misuse of N fertilizer will not only affect grain yield and quality, but also cause the decline of economic benefits and related negative environmental effects. It is essential to study reasonable N application regimes for profitable yields, efficient N utilization and reduction in possible environmental pollution. The objective of this study was to determine the N uptake and translocation in wheat plants by using 15N isotope tracers in PVC cylinders (2.05 m long, &Phi 0.2 m, without bottom) in seven treatments: without N fertilizer application (N0); N application rate of 168 kg/hm2 (0.527 g/pot), with ratios of base fertilizer to topdressing of 1:1 (N1), 1:2 (N2) and 0:1 (N3); N application rate of 240 kg/hm2 (0.753 g/pot), with ratios of base fertilizer to topdressing of 1:1 (N4), 1:2 (N5) and 0:1 (N6). The 15N tracer experiment showed that the main basal N absorbed by plant from sowing to jointing stage accounted for 78.04% 89.67%; fertilizer N use efficiency (FNUE, N fertilizer accumulation in plant/N supplied) of topdressing was significantly higher than that of basal N; reducing basal N amount and increasing topdressing N amount could appropriately promote the plant s absorption of more N fertilizer and enhance FNUE, of which treatment N2 had the highest values. Under the high-yield condition, when N fertilizer rate was increased from 168 to 240 kg/hm2, there were no significant differences in the amount of N accumulation in plants and in grains between treatments with the same ratio of base fertilizer to topdressing; by reducing basal N amount and increasing topdressing N amount accordingly, the translocation efficiency (TE, accumulation amount from vegetative organs to grain/N accumulation in vegetative organs during anthesis) increased, and the amount of N assimilation to grains after anthesis and its contribution proportion (the amount of N assimilation to grains after anthesis/N accumulation in grain) also increased. In other words, grain N accumulation amount increased with increasing amount of topdressing N at the same N fertilizer rate. There were no significant differences among treatments N2, N3, N5 and N6 in grain N accumulation. Appropriate N fertilizer rate with a reduction in basal N amount and an increase in topdressing N amount such as in N2, N5 and N6 increased grain yield and protein content. In conclusion, under conditions used in this experiment, as far as grain yield, protein content and FNUE are concerned, the recommended appropriate N fertilizer application regime is treatment N2, with a N fertilizer rate of 168 kg/hm2 and a ratio of base fertilizer to topdressing of 1:2.
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Carbon storage and spatial distribution patterns of paddy soils in China
WANG Hongjie, YU Dongsheng, ZHAO Yongcun, SUN Weixia, LIU Qinghua, SHI Xuezheng, Jeremy Landon Darilek
Front. Agric. China. 2007, 1 (2): 149-154.  
https://doi.org/10.1007/s11703-007-0026-7

Abstract   PDF (402KB)
Carbon storage in agricultural soils plays a key role in terrestrial ecosystem carbon cycles. Paddy soil is one of the major cultivated soil types in China and is of critical significance in studies on soil carbon sequestration. This paper estimated the organic and inorganic carbon density and storage in paddy soils, and analyzed the paddy soil stock spatial distribution patterns in China based on subgroups and regions using the newly compiled 1:1 000 000 digital soil map of China as well as data from 1 490 paddy soil profiles. Results showed that paddy soils in China cover an area of about 45.69 Mhm2, accounting for 4.92% of total soil area in China. Soil organic and inorganic carbon densities of paddy soils in China showed a great heterogeneity. Paddy soil organic carbon densities (SOCD) in soil profile ranged from 0.53 to 446.2 kg/m2 (0 to 100 cm) while the paddy soil inorganic carbon densities (SICD) ranged from 0.05 to 90.03 kg/m2. Soil organic carbon densities of paddy soils in surface layer ranged from 0.17 to 55.38 kg/m2 (0 to 20 cm), with SICD of paddy soils ranging from 0.01 to 21.85 kg/m2. Profile based and surface layer based paddy soil carbon storages (SCS) are 5.39 Pg and 1.79 Pg, respectively. Paddy soil organic carbon storage (SOCS) accounts for 95% of the total carbon storage. Profile based and surface layer based SOCS of paddy soils are 5.09 Pg and 1.72 Pg, respectively. Soil inorganic carbon storage (SICS) of paddy soils accounts for 5% of the total carbon storage in China. Profile based and surface layer based paddy SICS are 0.30 Pg and 0.07 Pg respectively. Among all the eight paddy soil subgroups, hydromorphic, submergenic and percogenic paddy soils account for 85.2% of the total paddy soil areas all over China. Consequently, profile based carbon storages of these three subgroups account for 78.1% of the total profile based paddy SCS in China. Most paddy soils in China are distributed in the East-China, South-China and South-west China regions, therefore, 92.6% of China s profile based paddy SCS focuses on these three regions. The estimates of soil carbon stocks in paddy soils will help to identify areas or soil subgroups which are of particular interest for soil carbon gains and losses.
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A simulation model-assisted study on water and nitrogen dynamics and their effects on crop performance in the wheat-maize system I: The model
LIANG Weili, LV Hongzhan, WANG Guiyan, D. J. Connor, G. M. Rimmington
Front. Agric. China. 2007, 1 (2): 155-165.  
https://doi.org/10.1007/s11703-007-0027-6

Abstract   PDF (397KB)
Based on data collected from field experiments, a comprehensive model was built on the Ithink (a registered trademark of iSee Systems) platform to simulate the dynamics of water and nitrogen, and crop performance in the winter wheat-summer maize double cropping system of the North China plain. The model, consisting of seven sub models, i.e. weather generator, phenology, biomass, dry matter partitioning, water balance, nitrogen balance, and nitrogen absorption and partitioning, well reflects water and nitrogen use and their relationship with crop yield under field conditions. A vertical water movement equation is employed in the water balance sub model to account for movement between layers. Crop transpiration and soil evaporation are simulated separately according to potential evaporation, crop cover and a soil water deficit coefficient. Soil evaporation is from the surface layer only while crop transpiration comprises the total amount of water absorbed by the root system from all soil layers. The model considers that nitrogen transformations, transfers and uptake are fulfilled by root systems. Transformation of nitrogen as mineralization, fixation and denitrification are responsive to soil moisture and temperature. Nitrogen movement is simulated with a convection-dispersion equation with nitrate as the soil solute. Nitrogen absorption and partitioning sub model includes the effects of water and nitrogen supply, crop nitrogen demand and nitrogen content in various crop organs. The model can be used to simulate crop yield, water- and nitrogen-use efficiencies and water-nitrogen leaching to specific soil layers in different water and nitrogen management practices.
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Growth and development characteristics of super-high-yielding mid-season japonica rice
YANG Jianchang, DU Yong, WU Changfu, LIU Lijun, WANG Zhiqin, ZHU Qingsen
Front. Agric. China. 2007, 1 (2): 166-174.  
https://doi.org/10.1007/s11703-007-0028-5

Abstract   PDF (522KB)
Rice is one of the most important food crops in China. The realization of the super-high-yielding (SHY) type has great significance in ensuring food security in this country. This study investigated the growth and development characteristics of the super-high-yielding rice (grain yield> 11 t/hm2). Four mid-season japonica rice cultivars (including lines): Lianjiajing 2, Huajing 5, 0026 and 9823, were grown in the paddy field. Growth analysis was performed during the growth period, and yield components were determined at maturity. Results showed that SHY rice had more sipkelets per panicle and higher filled-grain percentage than the high-yielding rice (CK, grain yield 8.98 9.16 t/hm2). There was no significant difference in the 1 000-grain weight between the super-high-yielding and the CK. Super-high-yield rice exhibited fewer tillers at the early growth stage (from transplanting to jointing), with a higher ratio of productive tillers to total tillers, when compared with the CK. The leaf area index (LAI), photosynthetic potential and dry matter accumulation were lower for the SHY rice than those for the CK at the early growth stage, and the differences were not significant between the two rice types at heading, but were greater in the former than the latter after heading. The root-shoot ratio at each growth stage, root bleedings from heading to maturity, grain-leaf ratio, translocation percentage of the matter from stems and sheaths and harvest index of super-high-yielding rice were greater than those of CK. The indexes for the growth and development of SHY mid-season rice population were suggested, i.e. total spikelets >4.5?104/m2, filled-grain percentage>90%, 1 000-grain weight>26 g; ratio of productive tillers>80%, leaf area index at heading 7.5 8.0, photosynthetic potential during the whole growth period >5?106 m2 " d/hm2, total dry matter weight at maturity >22 t/hm2, harvest index >0.51; grain-leaf ratio (number of spikelets per cm2 leaf area) >0.58; root-shoot ratio at heading >0.25 and amount of root exudates >5 g/m2 " h. The regulation approaches and key cultivation techniques for raising the super-high-yielding population were also discussed.
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Biological characteristics of strain F603 of Epicoccom sp., an antagonistic fungus for controlling Phytophthora infestans
LIU Xiaoyun, HU Tongle, CAO Keqiang
Front. Agric. China. 2007, 1 (2): 175-178.  
https://doi.org/10.1007/s11703-007-0029-4

Abstract   PDF (343KB)
Factors influencing vegetative growth and spore germination of strain F603 of Epicoccom sp., an antagonistic fungus for Phytophthora infestans (Mont) de Bary, were studied. Among the different growth media tested, Rye agar was the best medium for its vegetative growth. The range of temperature and pH value for mycelial growth was 5 35?C and 2 12, respectively, with the optimum 25?C and 6 9, respectively. The fungus grew better in Czapek medium with maltose and dextrose as carbon sources and peptone, KNO3, and NaNO3 as nitrogen sources. The range of temperature for spore germination of strain F603 was 5 35?C, the optimum was 20?C. The range of temperature for sporulation was 10 30?C, and the optimum was 15 18?C.
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Screening and identification of mutants of Magnaporthe grisea by REMI
XIONG Ruyi, LIU Juan, ZHOU Yijun, FAN Yongjian, ZHENG Xiaobo
Front. Agric. China. 2007, 1 (2): 179-182.  
https://doi.org/10.1007/s11703-007-0030-y

Abstract   PDF (358KB)
The plasmid pUCATPH was used to establish a transformation system in wild-type isolate M131 of Magnaporthe grisea. Six hundred and thirty-nine transformants were obtained by restriction enzyme-mediated integration (REMI) with hygromycin B (hyg B) resistance as a tag. Morphological analysis of two of the REMI mutants confirmed that they produced little melanin under black light and continued for three generations. Pathogenicity identification of six mutants screened proved that they made pathogenicity changes on three sets of differential varieties with different resistance genes. Rep-PCR analyses showed that two morphological mutants and two pathogenicity mutants differed from wild-type isolate M131 at the molecular level. RFLP analyses were performed to study the four mutants at the molecular level and the integration sites of the plasmid DNA. The results showed that the plasmid was inserted into all four mutants and that the insertion sites were random.
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Inhibitory efficacy of calcium cyanamide on the pathogens of replant diseases in strawberry
WANG Lijing, HU Tongle, JI Lijing, CAO Keqiang
Front. Agric. China. 2007, 1 (2): 183-187.  
https://doi.org/10.1007/s11703-007-0031-x

Abstract   PDF (262KB)
Replant diseases in strawberry caused by Rhizoctonia solani, Fusarium oxysporum and Verticillium dahliae are serious problems for its sustainable production under continuous cropping. This research studied the inhibitory effect of calcium cyanamide on pathogenic fungi in Petri dishes and on sterilized soil. Results indicated that calcium cyanamide had an obvious inhibitory effect on three pathogens on potato dextrose agar (PDA) plates. Among them, the inhibitory effect on Rhizoctonia solani was the highest. As the concentrations of calcium cyanamide was increased from 0.1 to 10 mg/mL, the inhibition rate on mycelial growth increased from 1.43% to 100%. Inhibitory effects on Fusarium oxysporum and Verticillium dahliae also existed on Petri dishes but to a lesser extent. Similar results were also observed in sterilized soil. When the concentration of calcium cyanamide in sterilized soil was 0.1%, the inhibitory effect on Fusarium oxysporum and Verticillium dahliae was 68.46% and 54.46%, respectively. The inhibitive effect of calcium cyanamide on Fusarium oxysporum and Verticillium dahliae increased quickly as the soil moisture changed from 10% to 40% for Verticillium dahliae and from 10% to 60% for Fusarium oxysporum. This indicated that the inhibitive effect of calcium cyanamide could be influenced greatly by the moisture content in the soil.
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Molecular cloning and characterization of nitrate reductase gene cDNA from non-heading Chinese cabbage
SUN Feifei, HOU Xilin, LI Ying, CUI Xiumin
Front. Agric. China. 2007, 1 (2): 188-192.  
https://doi.org/10.1007/s11703-007-0032-9

Abstract   PDF (458KB)
Four non-heading Chinese cabbage (Brassica campestris ssp. chinensis Makino) cultivars, Suzhouqing, Xuekeqing, Huangxinwu, Aijiaohuang, were planted to investigate the activity of nitrate reductase (NRA) in leaves. After being induced by KNO3 at 50 mmol/L for different hours, the NRAs of the four cultivars were determined in vivo. The results showed that the NRAs changing trends of these four cultivars were similar. The highest NRAs in leaves reached their maximum at the 4th, 4th, 6th, and the 6th hour of induction, respectively. According to these results, the level of NR mRNA in plants could be enhanced by nitrate inducement. Then, the total RNA was isolated from the leaves of Suzhouqing that was induced by KNO3 at 50 mmol/L for four hours, and two fragments of NR cDNA were obtained through RT-PCR using specific primers. The products of PCR were cloned and sequenced. They are 1 125 and 438 base pairs, which were named nr1125 and nr438, encoding 374 and 135 amino acids, respectively. Finally, nr1125 was accepted and released by GenBank (accession number DQ001901).
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Threshold criteria for heavy metals in the soils of hazard-free dry fruit production regions of China
ZHANG Jianguang, LIU Yufang, ZHOU Junyi, GUO Suping, LI Baoguo, WANG Wenjiang
Front. Agric. China. 2007, 1 (2): 193-196.  
https://doi.org/10.1007/s11703-007-0033-8

Abstract   PDF (239KB)
Determination of proper threshold criteria for heavy metals in soils is an important basis for hazard-free dry fruit production in China. Based on the detection of heavy metal contents in soils in this study, it is initially concluded that the soils for dry fruit production in China are suitable for hazard-free growing. Moreover, the soil safety qualification for dry fruit production is much better than that in some developed countries or regions, which might help our production have a competitive advantage on the international market. However, soil Cr contents in the country are slightly higher, so that it is necessary to take steps to control any contamination during the whole chain of production. The following threshold criteria for heavy metals in soils is suggested according to physical, ecological and economical considerations: Hg 0.15 mg/kg; As 20 mg/kg; Pb 50 mg/kg; Cd 0.30 mg/kg and Gr 200 mg/kg.
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Formation causes and recovery of the “Black Soil Type” degraded alpine grassland in Qinghai-Tibetan Plateau
SHANG Zhanhuan, LONG Ruijun
Front. Agric. China. 2007, 1 (2): 197-202.  
https://doi.org/10.1007/s11703-007-0034-7

Abstract   PDF (272KB)
The formation causes and ecological rebuilding of the Black Soil Type  degraded alpine grassland are summarized. The formation of the Black Soil Type  degraded grassland was caused mainly by climate warming, decreasing glaciers, overgrazing, and damage by rats. The ecological restoration of the Black Soil Type  degraded alpine grassland relies not only on grassland building, but also on reasonable management and planning of grassland resources. Guaranty measures for developing the alpine grassland animal husbandry in a healthy way include intensifying the educational investment in pasture regions, practicing long-term contracts for grassland, and strengthening the grassland legislation. The authors believe that the Qinghai-Tibetan Plateau ecosystem has a special characteristic inertia or inert gases , which weaken the self-renewing capability of the ecosystem and makes its structure frail. The inertia characteristic may be the important reason that makes ecological rebuilding so difficult; in addition, other problems need to be studied deeply to provide scientific bases for the ecological building in the Qinghai-Tibetan Plateau.
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Nutrient elements and heavy metals in the sediment of Baiyangdian and Taihu Lakes: A comparative analysis of pollution trends
YANG Zhuo, LI Bowen, WANG Wei, LI Guibao
Front. Agric. China. 2007, 1 (2): 203-209.  
https://doi.org/10.1007/s11703-007-0035-6

Abstract   PDF (462KB)
Based on the sample data on the concentrations of nutrient elements and heavy metals in the sediment collected from Baiyangdian Lake (BL) in June 2004, the pollution level and the distribution of N, P, organic matter (OM), and the heavy metals Cu, Zn, Cd and Pb in water body sediment were analyzed. The pollution trends and current loads between BL and Taihu Lake (TL) were compared using relevant data from BL obtained in 1982 and 1994 and from TL in 1988 and 2000. The findings showed an ever-increasing trend of pollution year by year both in the sediment of BL and TL, although N and P pollution was somehow controlled at the end of the 1990s. The pollution situation in the BL area indicated that the downriver regions were more seriously polluted than the upriver regions, and the most heavily polluted sites were the outlet of the Fuhe River, the original wastewater reservoir of Tanghe River, and the densely populated Chunshui and Wangjiazhai villages. For the TL, the northern lakeside regions were found to be more seriously polluted than the southern regions, although the center of the lake was still relatively pollution free. The most heavily polluted spots were Wuli Lake, Meiliang Bay near Changzhou, Wuxi and other neighboring cities. While the Cd pollution in BL was greater than that in TL, there were not many differences in the average loads of Cu, Zn and Pb. This paper discusses the alternative measures to deal with the different pollution levels in these two lakes.
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The effect of immune stress on ideal amino acid pattern for piglets
LI Jianwen, CHEN Daiwen, ZHANG Keying, LONG Dingbiao
Front. Agric. China. 2007, 1 (2): 210-213.  
https://doi.org/10.1007/s11703-007-0036-5

Abstract   PDF (259KB)
Two nitrogen-balance experiments were conducted to determine the optimum balance pattern among four amino acids (lysine, methionine, tryptophan and threonine) on a digestible basis in the diet of piglets (10 kg) treated with lipopolysaccharide or saline as control. The method of amino acid deletion was adopted. All pigs were of a single genetic background and geographical origin. In each group, fifteen Landrance ? Rongchang castrated piglets were allotted randomly to one of five groups of dietary amino acid regimens. The positive control group was supplemented with four amino acids. One of the four amino acids was reduced by about 25% in the respective treatment groups. After finishing the nitrogen-balance experiments, the slaughter technique was used to determine the ideal amino acid digestibility of the positive control by using chromium oxide (3 g/kg) as the indicator. The results showed that the ideal amino acid pattern of lysine/methionine/threonine/tryptopham on the digestible basis was 100:27:29:59 for 10 kg pigs under immune stress, and 100:30:21:61 for piglets under normal conditions.
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Effect of mating combination and environmental factors on hatchability of chicken eggs in Tibet
MO Delin, LI Kui, ZHU Mengjin, XU Rifu, FAN Bin, LIU Bang, QIANGBA Yangzong, TANG Xiaohui
Front. Agric. China. 2007, 1 (2): 214-219.  
https://doi.org/10.1007/s11703-007-0037-4

Abstract   PDF (313KB)
To improve the hatchability of introduced highyield chickens in Tibet, and ameliorate the egg yield and reproduction traits of the local Tibetan chickens, four mating combinations between the Recessive White and Tibetan chicken were employed to investigate the effect of the mating combination and environmental factors on hatchability in this study. The results showed that the fertility of the eggs with Tibetan chicken as female parent was significantly lower than that with Recessive White as female parent (P<0.05), while hatchability was the reverse (P<0.05). The embryonic mortality of Recessive White was significantly higher by 7.95% than the Tibetan chickens, particularly during the last stage of incubation. The hatchability of combination III, whose female parent was Tibetan chicken, was higher by 20.44% than combination II, whose female parent was Recessive White. This provided a theoretical basis for a cross using the Tibetan chicken as female parent. Binary logistic regression analysis results also showed that the mating combination and environmental temperature were of importance to egg hatchability.
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Effects of ascites syndrome in broilers on their growth performances and the availability of energy and nutrients
SUN Bin, ZHANG Keying, ZENG Qiufeng, WANG Cairong
Front. Agric. China. 2007, 1 (2): 220-223.  
https://doi.org/10.1007/s11703-007-0038-3

Abstract   PDF (262KB)
An experiment was carried out to investigate the effects of ascites syndrome (AS) on the growth performance and availability of dietary energy and nutrients in broilers. One hundred and twenty one-day-old avian broilers were randomly allotted into two groups (control group and test group) with six replications of ten birds. In the test group, the addition of 3, 3, 5-triiodothyronine (T3, 1.5 mg/kg diet) and low ambient temperature (LAT) were used to induce AS. Results showed that T3 and LAT could successfully induce AS in broilers with an incidence rate of 66.7% and a mortality rate of 23.3%. Compared with the control, the bird growth performance of the test group was decreased (P<0.05) and heart index was increased (P<0.05). For the test group, the availability of dietary energy (P<0.01), crude fat (P<0.01), crude protein (P<0.05), and most amino acids in the second week were lower compared with the control group. Results showed that the low availability of energy and nutrients and the poor growth resulted from the high AS incidence rate.
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Effects of Shenpang acupoint-stimulation on estrogen receptor immunoreactive neurons in thalamus of rabbits
LUO Qihui, CHEN Zhengli, ZHU Chunmei, HUANG Yidan, FAN Guangli
Front. Agric. China. 2007, 1 (2): 224-228.  
https://doi.org/10.1007/s11703-007-0039-2

Abstract   PDF (365KB)
To investigate the effects of Shenpang acupoint-stimulation in reproductive endocrinology, the changes in estrogen receptor immunoreactive (ER-IR) neurons after Shenpang acupoint-stimulation were studied by using immunohistochemistry. ER-IR positive reactions were detected in most nuclei of the thalamus. In the acupuncture-treated group, a great number of ER-IR positive neurons with clear dendrites existed in the nucleus, paraventricular nucleus, ventrolateral nucleus, ventromedial nucleus, ventroprincipal nucleus, centromedian nucleus, reticular nucleus, and periventricular nucleus of thalamus, and they were strongly stained. In addition, the ER-IR positive neurons were mainly located in the cytoplasm, nucleus and neutrite, and some also existed in the cytoplasmic membrane. In contrast, a few neurons existed in the above-mentioned nuclei in the control group, but they were slightly stained. It is concluded that Shenpang acupoint-stimulation can promote the expression of estrogen receptors in the above nuclei.
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Effects of photoperiod and melatonin on nitrogen partitioning and production performance of Inner Mongolia White Cashmere Goats
WANG Linfeng, YANG Gaiqing, FANG Liyun, LU Dexun, SUN Haizhou, ZHAO Xiuying, SHAN Dan
Front. Agric. China. 2007, 1 (2): 229-236.  
https://doi.org/10.1007/s11703-007-0040-9

Abstract   PDF (465KB)
This study investigated the effect of photoperiod and melatonin (MT) on nitrogen partitioning in Inner Mongolia White Cashmere goats in telogen in order to regulate nitrogen partitioning between the body and the fur, and promote cashmere production. Thirty-six castrated mature goats, with live weights ranging from 23 to 25 kg, were randomly allocated into three groups then exposed to different photoperiods (long daily photoperiod, LDPP; short daily photoperiod, SDPP; natural daily photoperiod, NDPP). In each group, half of the goats were implanted with MT. Total nitrogen sediment (ΔN) was tested with a general digestive and metabolism method. Body nitrogen sediment (NB) was measured by isotope dilution technique of tritiated water at the beginning and at the end of the experiment (NB = BNend-BNbeg) and fur nitrogen deposited (NF) was calculated using the formula NF = ΔN-NB. Results showed that: (1) there was a significant difference in NB and NF partitioning in different treatments of photo period and MT. The NF partitioning was increased with the shortening of photoperiod and it was higher in the implanted groups than in the non-implanted groups. The minimum and maximum percentages in LDPP and SDPP+MT were (23.6±0.46)% and (36.1±0.79)% respectively. There was a strong interaction between SDPP and implantation of MT; while BN partitioning showed the reverse for photoperiod and implantation of MT; (2) there is an additional cashmere production of (338.83±72) g in SDPP and implanted groups with an average increase of 73.86%. The traits of the newly grown cashmere were all in the range of the textile standard; (3) hormones related to nitrogen partitioning and body composition varied with different treatments: the levels of MT and insulin (INS) increased with the shortening of photoperiod and were higher in the implanted groups than in the non-implanted groups, and there was a strong interaction between SDPP and MT implantation; prolactin, insulin like growth factor I and leptin showed the opposite results to MT and INS. This study provides evidence that MT and photoperiod can be used to regulate nitrogen partitioning, modulate cashmere goat body composition and improve cashmere production in practice. The technique can be extended to Inner Mongolia and other cashmere goat raising areas in China.
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