Frontiers of Agriculture in China

ISSN 1673-7334

ISSN 1673-744X(Online)

CN 11-5729/S

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Research article
A comparative study on segregation analysis and QTL mapping of quantitative traits in plants—with a case in soybean
Junyi GAI,Yongjun WANG,Xiaolei WU,Shouyi CHEN
Front. Agric. China. 2007, 1 (1): 1-7.  
https://doi.org/10.1007/s11703-007-0001-3

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Two approaches of genetic analysis of quantitative traits were compared with a case study on soybean. One approach was the segregation analysis developed by Gai et al. (2003), which utilized information from individuals of one or multiple segregation populations as well as that from parents based on the principles of the major-gene plus polygene inheritance model, mixture distribution, joint maximum-likelihood function, IECM (Iterated Expectation and Conditional Maximization) algorithm, and Akaike’s information criterion and goodness of fit tests. Another approach was quantitative trait locus (QTL) mapping with molecular markers. A recombinant inbred line (RIL) population with 201 families derived from (Kefeng No.1x1138-2) F2:7:10 along with their parents were tested in a randomized block design experiment. The 171 RFLP, 60 SSR, and 79 AFLP molecular markers were used to mark the 201 families. The data of nine traits, i.e., number of days to flowering, number of days to maturity, plant height, number of nodes on main stem, number of pods per node, 100-seed weight, protein content, oil content, and plot yield, were analyzed with the segregation analysis procedure of RIL population with parents (Gai et al., 2003; Zhang and Gai, 2000; Zhang et al., 2001) to detect their genetic system, and those along with the molecular marker data were analyzed with WinQTL Cartographer (Basten et al., 1999; Zeng, 1993, 1994) to detect their QTL system. The results showed that both procedures could detect the main major genes or QTLs, and therefore, could be used as a mutual check and supplement. From the results that most of the traits were mainly controlled by three or four QTLs, it was impressed that the segregation analysis procedure of four major-gene plus polygene mixed inheritance model should be developed to fit the requirements. The results also showed that the QTLs of the involved traits concentrated on several linkage groups, such as C2, B1, F1, M, and N. Finally, the results showed that the experimental sample was not necessarily coincident with the theoretical population according to equality test, symmetry test, and representation test, and therefore, the sample should be checked, tested and then adjusted to fit the theoretical requirements through deleting the extra-biased families and markers.

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Modeling grain protein formation in relation to nitrogen uptake and remobilization in rice plant
Yan ZHU,Weiguo LI,Qi JING,Weixing CAO,Horie Takeshi
Front. Agric. China. 2007, 1 (1): 8-16.  
https://doi.org/10.1007/s11703-007-0002-2

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Protein concentration of grain is an important quality index of rice, and formation of grain protein largely depends on pre-anthesis nitrogen assimilation and post-anthesis nitrogen remobilization in the rice plant. The primary objective of this study was to develop a simplified process model for simulating nitrogen accumulation and remobilization in plant and protein formation in rice grains on the basis of an established rice growth model. Six field experiments, involving different years, eco-sites, varieties, nitrogen rates, and irrigation regimes, were conducted to obtain the necessary data for model building, genotypic parameter determination, and model validation. Using physiological development time (PDT) as general time scale of development progress and cultivar-specific grain protein concentration as genotypic parameter, the dynamic relationships of plant nitrogen accumulation and translocation to environmental and genetic factors were quantified and synthesized in the present model. The pre-anthesis nitrogen uptake rate by plant changed with the PDT in a negative exponential pattern, and post-anthesis nitrogen uptake rate changed with leaf area index (LAI) in an exponential equation. Post-anthesis nitrogen translocation rate depended on the plant nitrogen concentration and dry weight at anthesis as well as residue nitrogen concentration of plant at maturity. The nitrogen for protein synthesis in grains came from two sources: the nitrogen pre-stored in leaves, stem and sheath before anthesis and then remobilized after anthesis, and the nitrogen absorbed directly by plant after anthesis. Finally, the model was tested by using the data sets of different years, eco-sites, varieties, and N fertilization and irrigation conditions with the root mean square errors (RMSE) 0.22%-0.26%, indicating the general and reliable features of the model. It is hoped that by properly integrating with the existing rice growth models, the present model can be used for predicting grain protein concentration and grain protein yield of rice under various environments and genotypes.

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Isolation and sequencing analysis on the seed-specific promoter from soybean
Qinggele CAIYIN,Mingchun LI,Dongsheng WEI,Yi CAI,Laijun XING
Front. Agric. China. 2007, 1 (1): 17-23.  
https://doi.org/10.1007/s11703-007-0003-1

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Physiological analysis on pre-harvest sprouting in recombinant inbred rice lines
Longxing TAO,Xi WANG,Huijuan TAN,Haisheng CHEN,Changdeng YANG,Jieyun ZHUANG,Kangle ZHENG
Front. Agric. China. 2007, 1 (1): 24-29.  
https://doi.org/10.1007/s11703-007-0004-0

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Effects of nitrogen fertilizer on nitrogen use efficiency and yield of rice under different soil conditions
Quanbao YE,Hongcheng ZHANG,Haiyan WEI,Ying ZHANG,Benfu WANG,Ke XIA,Zhongyang HUO,Qigen DAI,Ke XU
Front. Agric. China. 2007, 1 (1): 30-36.  
https://doi.org/10.1007/s11703-007-0005-z

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Four rice cultivars were used to study the effects of nitrogen fertilizer on nitrogen use efficiency, yield and characteristics of nitrogen uptake under two soil conditions (sandy and clay soil) in soil culture pool. The results were as follows. First, yield of rice in sandy and clay soil was increased by nitrogen application, and that in clay soil was higher than that in sandy soil, but the effect of nitrogen on yield increment was greater in sandy soil than in clay soil. Second, nitrogen utilization of rice was different under different soil conditions. Nitrogen harvest index (NHI) and physiological Nitrogen use efficiency (PNUE) were higher in sandy soil than in clay soil. Apparent Nitrogen recovery efficiency (ANRE), partial factor productivity for applied Nitrogen (PFP), and soil Nitrogen dependent rate (SNDR) were higher in clay soil than in sandy soil. Agronomic Nitrogen use efficiency (ANUE) was varied in different cultivars under different soil conditions. Third, N harvest index, agronomic N use efficiency, physiological N use efficiency, partial factor productivity for applied N, and soil N dependent rate were decreased significantly with the increment of the amount of nitrogen applied under two soil conditions. In sandy soil, ANRE was increased with the increasing nitrogen application and reached the highest value at high nitrogen level. However, in clay soil, ANRE was increased with the increasing of nitrogen application at first, and reached the highest value at medium nitrogen level, then decreased dramatically at high nitrogen level. Fourth, N uptake rate for rice straw and for rice grain and total N uptake rate for rice were higher in sandy clay soil than in sandy soil, but the difference between them was relatively small. Fifth, under different soil conditions, there were significant genotypic differences in the effects of applying nitrogen fertilizer on nitrogen use efficiency, yield, and characteristics of nitrogen uptake.

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Effects of nitrogen application and maize growth on N2O emission from soil
Lanfang YANG,Zucong CAI
Front. Agric. China. 2007, 1 (1): 37-42.  
https://doi.org/10.1007/s11703-007-0006-y

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Using the pot experiment and closed static chamber-gas chromatography (GC) technique, this paper studied the effects of nitrogen application (150 and 300 mg/kg soil) and maize growth on N2O emission from soil. In maize-planted soil, the N2O emission rate increased with increasing N application rate, its peak appeared at the seedling stage, and there was no significant correlation between N2O emission rate and air temperature. Contrarily, in exposed soil, the peak of N2O emission rate occurred at the later stages of the experiment, and there was a significant exponential correlation between soil N2O emission rate and air temperature, in which Q10 (the value of soil N2O emission rate responding to temperature) was 4.4 and 3.2 in high and low N applications. The total amount of N2O emission increased remarkably with increased N application rate in both planted and un-planted soils. N2O emission inventory from exposed and maize-planted soils in high N application was 2.5 and 1.6 times as high as that in low N application, respectively. In the same N application rate, N2O emission inventory in high and low N application from exposed soil was 12 and 7.5 times as high as that from maize-planted soil, respectively. As compared with exposed soil, maize growth reduced N2O emission by 92%and 87%, respectively, at high and low N application rates. In summary, maize growth and nitrogen application not only affected the seasonal variation and magnitude of N2O emission from soil, but also altered the relationship between air temperature and soil N2O emission.

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Screening for plant extracts to control potato late blight
Shutong WANG,Tongle HU,Fengqiao ZHANG,R. Forrer H.,Keqiang CAO
Front. Agric. China. 2007, 1 (1): 43-46.  
https://doi.org/10.1007/s11703-007-0007-x

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Six extracts from plant material (Galla chinensis, Potentilla erecta, Rheum rhabarbarum, Salviae officinalis, Sophora flavescens, and Terminalia chebula) were tested for controlling effects against the infection of Phytophthora infestans on detached potato leaves, seedlings, and tuber slices. On detached leaves, G. chinensis (2%), R. rhabarbarum (rhizome, 2%) and S. flavescens (2%) extracts showed a significant control effect, with a control efficacy of 96.67%, G. chinensis was the best. On seedlings R. rhabarbarum (rhizome, 2%) showed the best inhibiting effect, followed by S. flavescens (2%), T. chebula (1%), and G. chinensis (2%). The control efficacies were 91.67%, 75.00%, 70.24%, and 64.29%, respectively on the seventh day after inoculation. However, on potato slices, none of the plant extracts showed effective protection against infection and sporangia pro duction by P. infestans. The reason was analyzed and the potential for developing a natural fungicide based on these plant materials was discussed.

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Active oxygen metabolism in the floral buds and leaves of the new cytoplasm male sterile (CMS) line and its maintainer line of non-heading Chinese cabbage
Jianyu YUAN,Xilin HOU,Changwei ZHANG,Fan YE
Front. Agric. China. 2007, 1 (1): 47-51.  
https://doi.org/10.1007/s11703-007-0008-9

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The cytoplasm male sterile (CMS) line and its maintainer line of the newly-bred non-heading Chinese cabbage were taken as experimental materials. The production rate of superoxide anion radical (O2- ), contents of malondialdehyde (MDA) and hydrogen peroxide (H2O2), and the activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) as well as ascorbate peroxidase (APX) were determined in buds of different developmental stages and leaves during vegetative and florescence stages. As showed by the results, there were higher levels of MDA and H2O2 contents, higher O2- production rate and higher activities of SOD, POD, and CAT in the buds of the CMS lines than that in the buds of the fertile lines, while the APX activity was different from the other three enzymes above. There were differences in activities of protective enzymes in leaves but no significant differences in MDA contents and O2- production rate, which showed that the differences in metabolism of active oxygen between CMS and its maintainer were mainly apparent in reproductive organs.

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Cloning and functional analysis of the genes involved in signal transduction in tomato Cf-4-Avr4 pathosystem
Qing LIU,Dongxin FENG,Xiaowu WANG,Yongchen DU
Front. Agric. China. 2007, 1 (1): 52-57.  
https://doi.org/10.1007/s11703-007-0009-8

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Hypersensitive response (HR) is one of the most efficient and common resistance mechanisms in plants. Cloning signaling genes are very important to elucidate the resistance mechanisms. A gene in tomato homologous to several resistance proteins in plant was involved in HR and named as RGL (Resistance Gene Like). RGL protein was used as a bait to screen interacting protein(s) from tomato cDNA library through the yeast two-hybrid system. Two interacting proteins were found, which were called as RGLIP-1 and RGLIP2 (RGL Interacting Protein), respectively. RGLIP-1 is a protein of 291 amino acids with significant homology with thylakoid lumen protein. RGLIP-2 is a protein of 248 amino acids with significant homology with transducin protein. Virus-Induced Gene Silencing (VIGS) of the two genes results in a partial and complete suppression of Avr4induced HR, which indicates that both genes are involved in hypersensitive response.

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Effects of cinnamic acid on the physiological characteristics of cucumber seedlings under salt stress
Xuezheng WANG,Hua WANG,Fengzhi WU,Bo LIU
Front. Agric. China. 2007, 1 (1): 58-61.  
https://doi.org/10.1007/s11703-007-0010-2

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Effects of cinnamic acid on the physiolo gical characteristics of cucumber (Shandong Mici) seedlings under salt stress were studied, and the best concentration and treatment time were ascertained. The results showed that cinnamic acid relatively increased the leaf relative water content and the chlorophyll content, decreased plasma membrane permeability, mitigated membrane damage, inhibited the accumulation of malondialdehyde (product of membrane lipid peroxidation), and promoted the activity of membrane protective enzymes such as super oxide dismutase and peroxidase, therefore improving the adaptabilities of cucumber to salt stress. It is concluded that the best treatment time of cinnamic acid is in the two euphylla period, and the best treatment concentration of cinnamic acid is 50 μmol/L.

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Fertilization in Brassica campestris ssp. pekinensis and its duration of each stage
Jie PENG,Jiaheng SHEN
Front. Agric. China. 2007, 1 (1): 62-66.  
https://doi.org/10.1007/s11703-007-0011-1

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This paper reports the process of fertilization in Brassica campestris ssp. pekinensis and the duration of each stage. The results are as follows: (1) Pollen germinates on stigma 2-3 h after pollination. (2) 4-8 h after pollination, pollen tube grows in the style. (3) 8-14 h after pollination, pollen tube grows in the ovary and gets into the ovule via the micropyle. (4) 16 h after pollination, one sperm nucleus moves to the egg and enters it. (5) The sperm nucleus adheres to the nuclear membrane of the egg 18 h after pollination. (6) 20 h after pollination, it enters the egg nucleus and male chromatin gradually disperses and 24 h after pollination, a male nucleolus appears. A large female nucleolus and a small male nucleolus occur in the nucleus of the fertilized egg, and zygote formed. The dispersing of sperm chromatin in the egg nucleus takes about 4 h. (7) 32-34 h after pollination, the division of zygote begins. The dormancy stage of the zygote lasts for about 8-10 h. (8) The pair polar nuclei lie in the chalazal end of the egg before fertilization, which may fuse into a secondary nucleus or not. (9) 16-18 h after pollination, the sperm nucleus moves to the polar nuclei or the secondary nucleus. 18 h after pollination, the sperm nucleus adheres to the nuclear membrane of the polar nuclei or that of the secondary nucleus. (10) 20 h after pollination, the sperm nucleus enters one of the polar nuclei or the secondary nucleus and a triple fusion takes place. The process of fusion is similar to the karyogamy but faster. The dispersing of the sperm chromatin in the polar nucleus or secondary nucleus takes about 2 h. (11) 22 h after pollination, the primary endosperm nucleus formed. The female and male nucleoli cannot fuse with each other before mitotic division of the primary endosperm nucleus. (12) 24 h after pollination, the division of the primary endosperm nucleus actually takes place.

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Effect of microenvironments and exogenous substance application on 5’-nucleotidase activities in apple peel
Jianguang ZHANG,Bao DI,Yingli LI,Jianqiang ZHANG,Jianshe SUN,Yufang LIU
Front. Agric. China. 2007, 1 (1): 67-71.  
https://doi.org/10.1007/s11703-007-0012-0

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The present experiment was conducted to examine the effect of microenvironments and exogenous substance application on 5’-nucleotidase activity in apple peel tissue. By enclosing apple fruits in bags, treating them with exogenous active oxygen species and regulative agents or placing them under controlled conditions at different fruit temperatures or relative humidity, the 5’-nucleotidase activities were compared with the corresponding controls. The results indicated that, a considerable effect of the microenvironments was found on 5’-nucleotidase activities in fruit peel tissue. The highest enzymatic activity appeared in fruits on the southwest exposure of canopy, regardless of bagged or non-bagged fruits, significantly higher than those from any other exposures. Fruits with bags had a significantly higher 5’-nucleotid-ase activity than the exposed ones. A variation in enzymatic activities was observed in fruits enclosed with different types of bags, which were supposed to alter the microenvironments around them. Within a certain range, gradual or fluctuating rise of fruit temperatures could favor the increase of 5’nucleotidase activities as a result of heat adaptation, whereas the activity would be inhibited if the temperature-rising period was too short or temperature differential was too large. No matter what temperatures fruits were subjected to, high relative humidity was favorable for stimulating the 5’nucleotidase activities, which might partly explain why fruit sunburn would not happen in humid climates. Treatments with four kinds of exogenous active oxygen species could reduce the 5’-nucleotidase activities significantly but spraying with CaCl2 was able to enhance 5’-nucleotidase activities by 55.39%, reaching a 5% significant level.

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Acquirement of a new male sterile germplasm of Chinese jujube
Jiurui WANG,Ling LIU,Mengjun LIU,Junyi ZHOU
Front. Agric. China. 2007, 1 (1): 72-75.  
https://doi.org/10.1007/s11703-007-0013-z

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A male sterile germplasm of Chinese jujube (Ziziphus jujuba Mill.), named ‘male sterile No.1’ (JMS1), was firstly identified from a natural population through studies of pollen amount and vitality and its anatomy. Its microspores got massed and then disaggregated after the tetrad stage during pollen development. Then its anthers became empty, or only pollen vestiges remained in the yellow buds. The pollen became abortive after the tetrad stage. Hypertrophy and hyperplasia of tapetum at the tetrad stage were related to pollen abortion. In view of its moderate embryo fertility, big fruit-size and early maturing, ‘JMS1’ could be used as a worthwhile female parent in the cross breeding of Chinese jujube.

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Population dynamics of oriental fruit fly Bactrocera dorsalis (Diptera: Tephritidae) in Xishuangbanna, Yunnan Province, China
Hui YE,Jianhong LIU
Front. Agric. China. 2007, 1 (1): 76-80.  
https://doi.org/10.1007/s11703-007-0014-y

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Annual monitoring of the population dynamics of the oriental fruit fly Bactrocera dorsalis (Hendel) (Diptera: Tephritidae) in Xishuangbanna, southern Yunnan, was conducted by using methyl eugenol-baited traps in 1997, 2000, and 2003, and factors including temperature, rainfall, and host species with respect to the population fluctuation were analyzed systematically. The results showed that the fruit fly was present all year round in Xishuangbanna. Its population remained at a lower level from November to February, and increased from March until it reached a peak in June or July, depending on the rainfall that year. Afterward, the fly population declined remarkably until October. Temperature, rainfall, and host fruits were major factors comprehensively influencing the population fluctuation. The monthly mean temperature was in a range of temperatures suitable for development and reproduction of the fly. But the monthly mean minimum temperature from December to February was lower than the suitable temperature range, which was suggested a possible reason for the lower populations in winter months. Rainfall was another essential factor influencing the population fluctuations. The population was depressed when the monthly rainfall amount was lower than 50 mm, but increased when rainfall ranged from 100 mm to 200 mm. When the monthly rainfall amount was higher than 250 mm, the fruit fly population was reduced remarkably. The heavy rain in July and August explained the decreasing population. Mango, orange, pear, longan, and peach were found to be the main host species of the fly in Xishuangbanna. Among them, mango and longan were most preferred by the fly. Therefore, the planted areas, fruiting period, and production exerted essential effects on the fly population fluctuations, which were regarded as another major factor influencing the fly population in that area. Briefly, temperature, monthly rainfall, and the host species, through the way of their functions, the influence strength, as well as the period that they occurred comprehensively impacted the population fluctuations of the fruit fly in Xishuangbanna.

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Aromatic constituents in fresh leaves of Lingtou Dancong Tea induced by drought stress
Panrong CAO,Chunyan LIU,Kebin LIU
Front. Agric. China. 2007, 1 (1): 81-84.  
https://doi.org/10.1007/s11703-007-0015-x

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The effect of different degrees of drought stress on the aromatic constituents and their relative contents in fresh leaves of Lingtou Dancong tea plants was studied in this paper. The results showed that drought stress could evidently increase the kinds of aromatic components in the fresh leaves. The largest number of kinds (58) of the aromatic constituents was detected when soil relative water content was 53.90%among all the designed treatments, while the lowest number was found under a soil relative water content of 99.75%. The total amount of relative contents of 17 kinds of aromatic components such as linalool etc., increased with drought stress, whereas 12 kinds of aromatic components such as tetradecanoic acid etc., decreased with drought stress. Linalool, linalool oxide, tetradecane, 10-methylnonadecane, and dodecanal showed high contents under the soil relative water content of 53.90%; Cyclohexane, 1-hexadecene, and 1tricosanolonly were induced in the soil relative water content of 53.90% and 29.25%; while drought stress could inhibit the synthesis of constituents of 7 kinds such as nonanedioic acid monomethyl ester, etc. Different degrees of drought stress could induce various kinds of aromatic constituents, and the number of aromatic constituents induced in fresh leaves increased with the strengthening of drought stress.

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Effects of Cd and Pb pollution on soil enzymatic activities and soil microbiota
Shuqing LIU,Zhixin YANG,Xiaomin WANG,Xiaogui ZHANG,Rutai GAO,Xia LIU
Front. Agric. China. 2007, 1 (1): 85-89.  
https://doi.org/10.1007/s11703-007-0016-9

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Based on a representative sampling method and pot experiment with different concentrations of Cd and Pd, the enzymatic activities (urease, phosphatase, catalase, invertase), population of bacteria, fungus and actinomycete in the soil, the Cd and Pd pollution status of soil samples (from the wastewater-irrigated area of Baoding suburb) were appraised. Unitary linear and nonlinear curve-fitting optimization models were applied in the research, and the relationship between Pb and Cd causing pollution and enzymatic activities of the tested soils were discussed. The research may provide a theoretical basis for protecting the environment in the region of Baiyangdian Lake, Hebei province, prevent soil pollution, and ascertain biochemical indexes, which reflect soil heavy metal pollution levels.

The research results indicated that: (1) there was obvious accumulation of Pb and Cd in the wastewater-irrigated area, also the accumulation in wastewater-irrigated soil is more than that in fresh water-irrigated soil, and accumulation on surface layer was more than that in the lower layer. Pb and Cd contents in the tested soils exceeded the standards of soil background values for some major cities at home and abroad and the world soil Cd and Pb contents range. This means that the tested soil had reached a lightly polluted level; (2) there existed an obvious negative correlation between soil enzymatic activities and Pb and Cd contents in wastewater-irrigated soil, where the soil urease and catalase activities decreased obviously with the increase of Pb and Cd contents in soil. Therefore, the urease and catalase can be considered as biochemical indexes that reflect the degree of soil Pb and Cd pollution; (3) the pot experiments indicated that the influence of Cd on soil enzymatic activities was greater than that of Pb. Generally, the effect of Cd on soil phosphatase, urease, catalase is more obvious than that on invertase, while Pb has a more obvious effect on invertase than Cd; (4) pot experiments of triple cropping showed that, Cd and Pb had an obvious inhi biting effect on microbes. The influence sensitivity of Cd and Pb on different microbes was ordered as bacteria >actinomycete> fungus. Cd had a greater inhibiting effect on microbes than Pb, the influence of Cd and Pb on actinomycete and fungus was relatively smaller, therefore, bacteria can be chosen as an important index that reflects the effect of Cd and Pb on microbe sensitivity.

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Adjuvant effect of an extract from Cochinchina momordica seeds on the immune responses to ovalbumin in mice
Chenwen XIAO,Songhua HU,Zahid Iqbal Rajput
Front. Agric. China. 2007, 1 (1): 90-95.  
https://doi.org/10.1007/s11703-007-0017-8

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The seed of the Momordica cochinchinensis (Lour.) Spreng as a traditional Chinese medicine has been utilized in China for more than 1 200 years. It is traditionally used for the treatment of inflammatory swelling, scrofula, tinea, diarrhea as well as suppurative skin infections such as sore, carbuncles, furuncles and boils in both humans and animals. In this study, an extract from Cochinchina momordica seeds (ECMS) is evaluated for its adjuvant effect and safety. The results suggest that when co-administered with ECMS in Balb/c mice, ovalbumin (OVA, 10 μg) may induce significantly higher specific antibody production than OVA used alone (P<0.05). Analysis of antibody isotypes indicates that the ECMS can promote the production of both IgG1 and IgG2a, but favor the IgG2a. Splenocyte proliferative responses to concanavalin A, lipopolysaccharides or OVA are significantly higher in mice immunized with OVA mixed with ECMS than immunized with OVA alone or mixed with aluminum hydroxide (P<0.05). No local reactions and negative effects on the body weight gain occurred after the injection of OVA mixed with various amounts of ECMS in mice. Therefore, the ECMS is safe for injection and can be used as a potential vaccine adjuvant biasing the production of IgG2a in mice.

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Influence of Radix scutellariae on Th1/Th2 cytokine balance in RU486-induced abortion in mice
Xiuhui ZHONG,Wanyu SHI,Aituan MA,Xiaodan WANG,Jianlou ZHANG,Xuezhong LI
Front. Agric. China. 2007, 1 (1): 96-100.  
https://doi.org/10.1007/s11703-007-0018-7

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The aim of this study is to investigate the significance of Th1/Th2 cytokine balance in the uterus in the early embryo loss (or resorption), and to elucidate immunological modulation at the maternal-fetal interface with Chinese herbal medicine Radix scutellariae (Huang Qin) and its constituents (Baicalin and Baicalein). Mifepristone (RU486) was given via subcutaneous injection in the scapular area to induce abortion in mice at day 7 of gestation. The levels of uterine Th1 cytokines (IFN-γ, IL-2) and Th2 cytokines (IL-4, IL-10) were analyzed by enzyme-linked immunosorbent assay (ELISA), respectively. The mean values of Th1 cytokines in the uterus of RU486-treated abortion mice were significantly higher (P<0.05) than that of the control mice, but no significant difference was observed regarding to the contents of Th2 cytokines of different groups (P>0.05). However, when the Radix scutellariae and its constituents were used to prevent RU486-induced abortion, the levels of IFN-γ and IL-2 decreased while that of IL-4 and IL-10 increased. The embryo loss induced by RU486 was closely related to the Th1/Th2 immune balance at the maternal-fetal interface. Radix scutellariae and its constituents have an anti-abortive effect through restoring the Th1/Th2 balance at the maternal-fetal interface.

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Cloning and expression of Mycobacterium bovis secreted protein MPB51 in Escherichia coli
Xiuyun JIANG,Chunfeng WANG,Chunfang WANG,Zhaoyang HE
Front. Agric. China. 2007, 1 (1): 101-104.  
https://doi.org/10.1007/s11703-007-0019-6

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The purpose of this study is to clone, identify, and express the mature secreted protein MPB51 from Mycobacterium bovis and to lay a good foundation for the diagnosis of M. bovis, for applying M. bovis vaccine into clinical practice, and for detection of immunity effectiveness. The gene encoding MPB51 was amplified from M. bovis Vallee111 chromosomal DNA by using PCR technique, PCR product was approximately 800 bp DNA segment. Clone vector pGEM-T-51 was successfully constructed by the PCR product that was cloned into pGEM-T vector by using T-A clone technique. pGEM-T-51 and pET28a(+) were digested by BamH I and EcoR I double enzymes. The prokaryotic expression vector pET28a-51 was constructed by using the purified MPB51 gene that was subcloned into the expression vector pET28a(+). Plasmid containing pET28a-51 was transformed into competence E. coli BL21 (DE3). The bacterium was induced by IPTG and its lysates were loaded directly onto SDS-PAGE. An approximately 30 kDa exogenous protein was observed on the SDS-PAGE. The protein was analyzed by using Western-blotting and it had the antigenic activity of M. bovis. These results could serve as a basis for further studies on the usefulness of the gene and its expression product in the development of subunit vaccine and DNA vaccine against bovine tuberculosis.

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Cellular immune responses of BALB/c mice induced by intramuscular injection of PRRSV-ORF5 DNA vaccine with different doses
Anchun CHENG,Mingshu WANG,Xiwen CHEN,Nigen XINI,Wenbo DOU,Xuemei LI,Wumei LIU,Gang WANG,Pingying ZHANG
Front. Agric. China. 2007, 1 (1): 105-110.  
https://doi.org/10.1007/s11703-007-0020-0

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BALB/c mice were immunized with 50 µg, 100 µg, 200 µg of pcDNA-PRRSV-ORF5 DNA vaccine respectively by intramuscular injection, with PBS and pcDNA3.1(+) as controls. Fluorescence activated cell Sorter (FACS) was used to detect the number of CD+4 and CD+8 T-lymphocytes. T-lymphocyte proliferation test was used to detect proliferation of the T-lymphocyte cells in peripheral blood lymphocytes of mice vaccinated with pcDNA-PRRSV-ORF5 DNA vaccine. The results showed that the difference in ConA response to T-lymphocytes in blood was highly significant between all experimental groups and the control group (P<0.01). The number of CD4+ T-lymphocytes in experimental groups was significantly higher than that of the control group 7 d after vaccination. The number of CD8+ T-lymphocytes in the experimental groups was higher than that of the control group 28 d after vaccination. Mice immunized with a higher dose (200 µg) of DNA vaccine demonstrated higher cellular immune response than those immunized with a lower dose (100 µg, 50 µg) of DNA vaccine. The results demonstrated that pcDNA-PRRSV-ORF5 DNA vaccine could induce a good cellular immune response which may be dose-dependent.

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Review
A review on studies in forage in China
Wenxing LONG,Xiaobo YANG,Meiying QI
Front. Agric. China. 2007, 1 (1): 111-117.  
https://doi.org/10.1007/s11703-007-0021-z

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A review is made of the achievements in the collection, conservation, and genetic diversity of forage germplasm resources; methods and goals for forage breeding; and development and utilization of forage in China. The current problems based on the researches in forage are analyzed, and some suggestions are put forward.

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