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    Crop Genetics · Breeding · Germplasm Resources
    Improvement of Yield and Its Related Traits for Backbone Hybrid Rice Parent Minghui 86 Using Advanced Backcross Breeding Strategies
    ZHANG Hong-jun, WANG Hui, YE Guo-you, QIAN Yi-liang, SHI Ying-yao, XIA Jia-fa, LI Ze-fu, ZHU Ling-hua, GAO Yong-ming, LI Zhi-kang
    2013, 12(4): 561-570.  DOI: 10.1016/S2095-3119(13)60273-7
    Abstract ( )   PDF in ScienceDirect  
    How to overcome yield stagnation is a big challenge to rice breeders. An effective method for quickly developing new cultivars is to further improve an outstanding cultivar. In this study, three advanced backcross populations under yield selection that consist of 123 BC2F2:4 introgression lines (ILs) were developed by crossing Minghui 86 (recurrent parent, RP) with three high-yielding varieties (donors), namely, ZDZ057, Fuhui 838, and Teqing, respectively. The progeny testing allowed the identification of 12 promising ILs that had significantly higher mean grain yields than Minghui 86 in two environments. A total of 55 QTLs that affect grain yield and its related traits were identified, which included 50 QTLs that were detected using the likelihood ratio test based on stepwise regression (RSTEP-LRT) method, and eight grain yield per plant (GY) QTLs were detected using chi-squared (c2) test. Among these QTLs, five QTLs were simultaneously detected in different populations and 22 QTLs were detected in both environments. The beneficial donor alleles for increased GY and its related traits were identified in 63.6% (35 out of 55) of the QTLs. These promising ILs and QTLs identified will provide the elite breeding materials and genetic information for further improvement of the grain yield for Minghui 86 through pyramiding breeding.
    Characterization of Ethylene Receptors and Their Interactions with GmTPRA Novel Tetratricopeptide Repeat Protein (TPR) in Soybean (Glycine max L.)
    NIU Yan-yan, CHEN Ming, XU Zhao-shi, LI Lian-cheng, CHEN Xue-ping , MA You-zhi
    2013, 12(4): 571-581.  DOI: 10.1016/S2095-3119(13)60274-9
    Abstract ( )   PDF in ScienceDirect  
    Ethylene receptors play important roles not only in regulation of growth and development but also in response to environmental stimuli of plants. However, there are few reports on ethylene receptors in soybean. In this article, putative ethylene receptors of soybean were searched from soybean genomic database (http://www.phytozome.net/search.php) and analyzed. The ethylene receptor gene family in soybean comprising eight members, designated as GmERS1-1, GmERS1-2, GmETR1-1, GmETR1-2, GmETR2-1, GmETR2-2, GmEIN4-1, and GmEIN4-2 corresponding with their homologous genes in Arabidopsis, were isolated and analyzed. Phylogenetic analysis indicated that the eight soybean ethylene receptors (SERs) were in two subfamilies and further divided into four groups, viz., groups I (GmERS1-1 and GmERS1-2), II (GmETR1-1 and GmETR1-2), VI (GmETR2-1 and GmETR2-2), and VII (GmEIN4-1 and GmEIN4-2). Protein structure of the members in groups I and II from subfamily I were more conserved than the members in other two groups from subfamily II. Expression patterns of the SERs were compared with the homologous genes in Arabidopsis. The results demonstrated that expression patterns of the SERs differed from Arabidopsis members in the same group, suggesting that SERs are involved in different signal pathways compared to ethylene receptors in Arabidopsis. Promoter analysis showed that the sequences of the members in each group were different from each other, and some specific binding elements of transcription factors detected in promoter sequences might explain the differences between the members in the same group. A novel soybean TPR protein (tetratricopeptide repeat protein), GmTPR, was identified to interact with GmETR1-1, apparently an important ethylene receptor in ethylene signaling pathway in soybean. This suggested that GmTPR might be a novel downstream component of the ethylene signaling pathway.
    Molecular Cloning and Characterization of Three Novel Genes Related to Fatty Acid Degradation and Their Responses to Abiotic Stresses in Gossypium hirsutum L.
    DONG Jia, WEI Li-bin, HU Yan , GUO Wang-zhen
    2013, 12(4): 582-588.  DOI: 10.1016/S2095-3119(13)60275-0
    Abstract ( )   PDF in ScienceDirect  
    Fatty acid metabolism is responsible not only for oilseed metabolism but also for plant responses to abiotic stresses. In this study, three novel genes related to fatty acid degradation designated GhACX, Gh4CL, and GhMFP, respectively, were isolated from Gossypium hirsutum acc. TM-1. The phylogenetic analysis revealed that amino acid sequences of GhACX and GhMFP have the highest homology with those from Vitis vinifera, and Gh4CL has a closer genetic relationship with that from Camellia sinensis. Tissue- and organ-specific analysis showed that the three genes expressed widely in all the tested tissues, including ovules and fiber at different developing stages, with expressed preferentially in some organs. Among them, GhACX showed the most abundant transcripts in seeds at 25 d post anthesis (DPA), however, GhMFP and Gh4CL have the strongest expression level in ovules on the day of anthesis. Based on real-time quantitative RT-PCR, the three genes were differentially regulated when induced under wounding, methyl jasmonate (MeJA), cold, and abscisic acid (ABA) treatments. The characterization and expression pattern of three novel fatty acid degradation related genes will aid both to understand the roles of fatty acid degradation related genes as precursor in stress stimuli and to elucidate the physiological function in cotton oilseed metabolism.
    Identification of Differentially Expressed Genes in Sweetpotato Storage Roots Between Kokei No. 14 and Its Mutant Nongdafu 14 Using PCR-Based cDNA Subtraction
    CHEN Wei, ZHAI Hong, YANG Yuan-jun, HE Shao-zhen, LIU De-gao , LIU Qing-chang
    2013, 12(4): 589-595.  DOI: 10.1016/S2095-3119(13)60276-2
    Abstract ( )   PDF in ScienceDirect  
    The contents of carotenoids in the storage root of sweetpotato, Ipomoea batatas (L.) Lam. vary dramatically among different cultivars. However, so far little is known about the regulation of carotenoids synthesis in sweetpotato. In our laboratory, we identified a novel sweetpotato mutant, Nongdafu 14, which is a homogenous mutant derived from the wild type Kokei No. 14. The contents of carotenoids in the storage root of Nongdafu 14 were analyzed using high performance liquid chromatography (HPLC), and it was found that the amount of carotenoids, b-carotene, lutein and zeaxantion, three major types of carotenoids in sweetpotato storage roots, increased 2-26 folds in Nongdafu 14 compared to Kokei No. 14. Suppression subtractive hybridization (SSH) was used to identify genes that were differentially expressed in Nongdafu 14, and a differentially expressed cDNA library was constructed using the cDNA of Nongdafu 14 storage roots as tester and that of Kokei No. 14 storage roots as driver. Out of the 1 530 clones sequenced, we identified 292 nonredundant ESTs. GO and KEGG analyses of these differentially expressed ESTs indicated that diverse metabolism pathways were affected and candidate genes involved in regulation of carotenoids synthesis are suggested.
    A Co-Dominant Marker BoE332 Applied to Marker-Assisted Selection of Homozygous Male-Sterile Plants in Cabbage (Brassica oleracea var. capitata L.)
    CHEN Chen, ZHUANG Mu, FANG Zhi-yuan, WANG Qing-biao, ZHANG Yang-yong, LIU Yu-mei
    2013, 12(4): 596-602.  DOI: 10.1016/S2095-3119(13)60277-4
    Abstract ( )   PDF in ScienceDirect  
    The dominant genic male sterility (DGMS) gene CDMs399-3 derived from a spontaneous mutation in the line 79-399-3 of spring cabbage (Brassica oleracea var. capitata L.), has been successfully applied in hybrid seed production of several cabbage cultivars in China. During the development of dominant male sterility lines in cabbage, the conventional identification of homozygous male-sterile plants (CDMs399-3/CDMs399-3) is a laborious and time-consuming process. For marker-assisted selection (MAS) of the gene CDMs399-3 transferred into key spring cabbage line 397, expressed sequence tag-simple sequence repeats (EST-SSR) and SSR technology were used to identify markers that were linked to CDMs399-3 based on method of bulked segregant analysis (BSA). By screening a set of 978 EST-SSRs and 395 SSRs, a marker BoE332 linked to the CDMs399-3 at a distance of 3.6 cM in the genetic background of cabbage line 397 were identified. 7 homozygous male-sterile plants in population P1170 with 20 plants were obtained finally via MAS of BoE332. Thus, BoE332 will greatly facilitate the transferring of the gene CDMs399-3 into the key spring cabbage line 397 and improve the application of DGMS in cabbage hybrid breeding.
    Physiology & Biochentry · Tillage · Cultivation
    Influence of High Temperature Stress on Net Photosynthesis, Dry Matter Partitioning and Rice Grain Yield at Flowering and Grain Filling Stages
    Lü Guo-hua, WU Yong-feng, BAI Wen-bo, MA Bao, WANG Chun-yan , SONG Ji-qing
    2013, 12(4): 603-609.  DOI: 10.1016/S2095-3119(13)60278-6
    Abstract ( )   PDF in ScienceDirect  
    Climate change is recognized to increase the frequency and severity of extreme temperature events. At flowering and grain filling stages, risk of high temperature stress (HTS) on rice might increase, and lead to declining grain yields. A regulated cabinet experiment was carried out to investigate effects of high temperature stress on rice growth at flowering and grainfilling stages. Results showed that no obvious decrease pattern in net photosynthesis appeared along with the temperature rising, but the dry matter allocation in leaf, leaf sheath, culm, and panicle all changed. Dry weight of panicle decreased, and ratio of straw to total above ground crop dry weight increased 6-34% from CK, which might have great effects on carbon cycling and green house gas emission. Grain yield decreased significantly across all treatments on average from 15 to 73%. Occurrence of HTS at flowering stage showed more serious influence on grain yield than at grain filling stage. High temperature stress showed negative effects on harvest index. It might be helpful to provide valuable information for crop simulation models to capture the effects of high temperature stress on rice, and evaluate the high temperature risk.
    Effect of Cadmium Stress on the Growth, Antioxidative Enzymes and Lipid Peroxidation in Two Kenaf (Hibiscus cannabinus L.) Plant Seedlings
    LI Feng-tao, QI Jian-min, ZHANG Gao-yang, LIN Li-hui, FANG Ping-ping, TAO Ai-fen , XU Jian-tang
    2013, 12(4): 610-620.  DOI: 10.1016/S2095-3119(13)60279-8
    Abstract ( )   PDF in ScienceDirect  
    The effects of cadmium stress on the growth, antioxidative enzymes and lipid peroxidation in two kenaf plants, Fuhong 991 and ZM412, were analysed under control (0.5-strength Hoagland’s nutrient solution) or five levels of cadmium stress (0.5- strength Hoagland’s nutrient solution containing different concentrations of Cd2+). The leaves and roots of control and cadmium-stressed plants were harvested after 3 wk. At the same Cd concentration, the Cd tolerance index of Fuhong 991 was higher than that of ZM412, indicating that Fuhong 991 may be more tolerant to Cd than ZM412. The superoxide dismutase (SOD), catalase activity (CAT) and peroxidase (POD) activities fluctuated in the leaves of the Cd-stressed plants compared to the control, whereas the glutathione reductase activity (GR) was much larger than the control for Fuhong 991, ensuring that sufficient quantities of GSH were available to respond to the cadmium stress. In comparison to the control, the dynamic tendency of the SOD, CAT and POD activities in roots of the Cd-stressed plants all increased and then declined, but the POD activity of Fuhong 991 remained nearly unchanged at all of the stress levels. The increase in the enzyme activities demonstrated that Fuhong 991 was more tolerant to cadmium than ZM 412. The lipid peroxidation was enhanced only in the leaves of Cd-stressed ZM 412. These findings indicated that antioxidative activities may play important roles in Cd-stressed Fuhong 991 and ZM 412 and that the leaf and root cell membranes of Fuhong 991 have a greater stability than those of ZM 412. For pollution monitoring purposes, the GR activity in the roots and leaves may serve as a biomarker of Cd for Fuhong 991, whereas lipid peroxidation may serve as biomarker for ZM 412.
    Comparisons of Yield and Growth Behaviors of Hybrid Rice Under Different Nitrogen Management Methods in Tropical and Subtropical Environments
    Ibrahim Md, PENG Shao-bing, TANG Qi-yuan, HUANG Min, JIANG Peng , ZOU Ying-bin
    2013, 12(4): 621-629.  DOI: 10.1016/S2095-3119(13)60280-4
    Abstract ( )   PDF in ScienceDirect  
    To compare the grain yield and growth behaviors of hybrid rice, field experiments were conducted in a subtropical environment in Changsha, Hunan Province, China, and in two tropical environments in Gazipur and Habiganj in Bangladesh during 2009 to 2011. Three hybrid rice cultivars were grown under three nitrogen (N) management treatments in each experiment. The results showed that grain yield was significantly affected by locations, N treatments and their interaction but not by cultivars. Changsha produced 8-58% higher grain yields than Bangladesh locations. Sink size (spikelet number per unit land area) was responsible for these yield differences. Larger panicle size (spikelet number per panicle) contributed to greater sink size in Changsha. Aboveground total biomass was greater in Changsha than in Bangladesh locations, whereas harvest index was higher in Bangladesh locations than in Changsha. Crop growth rate (CGR) was greater at Changsha than Bangladesh locations during vegetative phase, while the difference was relatively small and not consistent during the later growth phases. Higher leaf area index and leaf area duration were partly responsible for the greater CGR in Changsha. Real-time N management (RTNM) produced lower grain yields than fixed-time N management in more than half of the experiments. Our study suggested that further improvement in rice yield in the tropical environments similar to those of Bangladesh will depend mainly on the ability to increase panicle size as well as CGR during vegetative phase, and the chlorophyll meter threshold value used in RTNM needs to be modified according to environmental conditions and cultivar characteristics to achieve a desirable grain yield.
    Maize Yield Gains in Northeast China in the Last Six Decades
    NIU Xing-kui, XIE Rui-zhi, LIU Xin, ZHANG Feng-lu, LI Shao-kun , GAO Shi-ju
    2013, 12(4): 630-637.  DOI: 10.1016/S2095-3119(13)60281-6
    Abstract ( )   PDF in ScienceDirect  
    In 2010, Chinese maize yields increased from 961.5 kg ha-1 in 1949 to 5 453.8 kg ha-1. This increase is the result of genetic improvements, an increase in nitrogen application, and refinement of planting densities. The objective of this study was to provide a theoretical basis for maize production research by analyzing the maize yield gain characteristics. Six varieties of maize were selected for the study; each selection is representative of a typical or commonly used maize variety from a specific decade, beginning from the 1950s and continuing through each decade into the 2000s. The selections and their corresponding decade were as follows: Baihe, 1950s; Jidan 101, 1960s; Zhongdan 2, 1970s; Yedan 13, 1980s; Zhengdan 958, 1990s; and Xianyu 335, 2000s. Each variety was planted under four different densities (37 500, 52 500, 67 500, and 82 500 plants ha-1) and four different nitrogen applications (0, 150, 225, and 300 kg ha-1) to study the effects on yield gain characteristics. The obtained results demonstrated that there was a maize yield increase of 123.19% between the 1950s variety and the 2000s variety. Modern Chinese maize varieties had a higher yield advantage. They also displayed the additional potential to acquire higher yield under increased planting densities and nitrogen applications. At the present cultivation levels (planting at 67 500 plants ha-1 with 225 kg ha-1 nitrogen application), the contribution types and corresponding yield increase percentages were as follows: genetic improvement, 45.37%; agronomic-management improvement, 30.94%; and genotype× agronomicmanagement interaction, 23.69%. At high-yielding cultivation levels (planting at 82 500 plants ha-1 with 300 kg ha-1 nitrogen application), the contribution types and corresponding yield increase percentages were as follows: genetic improvement, 31.30%; agronomic-management improvement, 36.23%; and genotype × agronomic-management interaction, 32.47%. The contribution of agronomic-management and genotype × agronomic-management interaction to yield increase would be larger with the corresponding management improvement. To further increase maize grain yield in China, researchers should further examine the effects of agronomic-management on maize yield and the adaptation of variety to agronomic-management.
    Plant Protection
    Genetic Analysis and Molecular Mapping of a Stripe Rust Resistance Gene YrH9014 in Wheat Line H9014-14-4-6-1
    MA Dong-fang, HOU Lu, TANG Ming-shuang, WANG Hai-ge, LI Qiang , JING Jin-xue
    2013, 12(4): 638-645.  DOI: 10.1016/S2095-3119(13)60271-3
    Abstract ( )   PDF in ScienceDirect  
    Stripe rust, caused by Puccinia striiformis f. sp. tritici (Pst), is one of the most widespread and destructive wheat diseases in many wheat-growing regions of the world. The winter wheat translocation line H9014-14-4-6-1 has all stage resistance. To identify stripe rust resistance genes, the segregating populations were developed from the cross between H9014-14-4-6-1 and Mingxian 169 (a wheat cultivar susceptible to all Pst races identified in China). The seedlings of the parents and F1 plants, F2, F3 and BC1 generations were tested with Pst races under controlled greenhouse conditions. Two genes for resistance to stripe rust were identified, one dominant gene conferred resistance to SUN11-4, temporarily designated YrH9014 and the other recessive gene conferred resistance to CYR33. The bulked segregant analysis and simple sequence repeat (SSR) markers were used to identify polymorphic markers associated with YrH9014. Seven polymorphic SSR markers were used to genotype the F2 population inoculated with SUN11-4. A linkage map was constructed according to the genotypes of seven SSR markers and resistance gene. The molecular map spanned 24.3 cM, and the genetic distance of the two closest markers Xbarc13 and Xbarc55 to gene locus was 1.4 and 3.6 cM, respectively. Based on the position of SSR marker, the resistance gene YrH9014 was located on chromosome arm 2BS. Amplification of a set of nulli-tetrasomic Chinese Spring lines with SSR marker Xbarc13 indicated that YrH9014 was located on chromosome 2B. Based on chromosomal location, the reaction patterns and pedigree analysis, YrH9014 should be a novel resistance gene to stripe rust. This new gene and flanking markers got from this study should be useful for marker-assisted selection (MAS) in breeding programs for stripe rust.
    Response of Cytochrome P450 Expression to Maize Volatiles in Helicoverpa armigera (Hübner)
    WU Shao-ying, SHI Xue-yan, WANG Yi , GAO Xi-wu
    2013, 12(4): 646-652.  DOI: 10.1016/S2095-3119(13)60282-8
    Abstract ( )   PDF in ScienceDirect  
    The 7-ethoxycoumarin O-deethylase (ECOD) activities of cytochrome P450s and differential expression of six cytochrome P450 genes induced by the volatiles from both damaged and undamaged maize plants were investigated in the cotton bollworm, Helicoverpa armigera (Hübner). The ECOD activity changed with time of exposure to maize volatiles. At 36 h after cotton bollworm larvae exposure to maize volatiles, the ECOD activities in cotton bollworm damaged and artificially damaged groups were 2.36 and 4.53 times higher than the control group respectively. The relative expression levels of CYP4S1, CYP6B2 and CYP6B7 in the cotton bollworm were significantly increased in artificially damaged plant group, which was 2.93, 5.09 and 10.66 times higher than that in the control group, respectively. The expression levels of CYP6B2, CYP6B6, CYP9A12, and CYP9A14 were much lower in the larvae exposure to volatiles from both healthy and pest damaged maize seedlings than in the control group at 12 h after larvae exposure to maize volatiles. For the cotton bollworm damaged maize group, the expression of CYP4S1 and CYP9A14 increased.
    Emergence, Mating and Oviposition Behavior of the Chinese Population in Pink Bollworm, Pectinophora gossypiella (Lepidoptera: Gelechiidae)
    WU Huai-heng, HUANG Min-song, WAN Peng, Kris A G Wyckhuys , WU Kong-ming
    2013, 12(4): 653-662.  DOI: 10.1016/S2095-3119(13)60283-X
    Abstract ( )   PDF in ScienceDirect  
    The pink bollworm, Pectinophora gossypiella (Lepidoptera: Gelechiidae) is one of the most serious lepidopteran pests of cotton in the world. This pest invaded China at the onset of the 20th century, possibly through repeated introductions from several different locations worldwide. In this paper, we describe different behavioral parameters of this Hubei P. gossypiella strain under laboratory and field conditions. Using an infra-red video recorder, we observed (nocturnal) emergence, flight and mating activities, and oviposition patterns. Moth emergence started from 13:00 and continued up till 23:00. Under laboratory and field conditions, 2-7-d-old moths initiated flight around sunset, peaked 50 min later and gradually declined until 04:00. Although mating started immediately after darkness (i.e., 20:00), mating behavior was most intense from 23:00 to 03:40. Oviposition also showed distinct time-related patterns, with approx. 70% eggs laid between 20:00 and 22:00. In the studies of the relationship between flight and oviposition, the duration of flight had an effect on oviposition. The 1-d-old moths flown for 6 and 12 h began oviposition earlier than the unflown ones, and the 6-h flight had no effect on the egg production. However, the longevity of the flown moths was shortened after flight. In addition, the peaks of oviposition for the flown moths were advanced 2-3 d. The age when the moths flied affected the oviposition of adult moths. The earlier the moths started to fly after emergence, the greater the fecundity they had. The average egg production of moths flown for 24 h was less than that of non-flown moths which were of the same age. Both flight and delay in mating could advance the oviposition peak. Our study provides detailed insights in nocturnal activities and the reproductive biology of local P. gossypiella populations, which could be employed to fine-tune current pest management programs in China.
    Relationships Between Icariin and Anti-Apoptotic miRNA-21 in Mouse Blastocyst Development In vitro
    SHI Ya-ran, WANG Zhan-he, CAO Yong-chun, LU Yan, TIAN Jin-ling, ZhANG Chao, JIA Zi-ye, CHEN Wu
    2013, 12(4): 663-669.  DOI: 10.1016/S2095-3119(13)60284-1
    Abstract ( )   PDF in ScienceDirect  
    In this study, the effect of icariin, a flavonoid from the Chinese traditional medicine epimedium, on miRNA-21 of mouse developmental blastocysts in vitro and the development of preimplantation embryos were studied. The possible effective targets of icariin promoting preimplantation embryo development in vitro and anti-apoptosis were determined. The embryos were cultured in modified CZB medium (mCZB) as control group. The experimental group (Ica group) was supplemented with 0.6 μg mL-1 icariin. Mouse pronuclear embryos were cultured in vitro until blastocysts. The development rates of preimplantation embryos were observed. The total cell number, apoptotic cell number and the rate of apoptotic cells in blastocysts were analysed by the staining of Hoechst33342 and labeling of TUNEL and detected under a laser confocal scanning microscope. The miRNA-21 expression, the mRNA levels of pro-apoptotic Caspase3, and the target genes of miRNA-21: pro-apoptotic PTEN, anti-apoptotic Bcl-2 were detected by real-time RT-PCR. The results showed that percentages of morulaes and blastocysts in Ica group were both extremely higher than control group ((85.14±6.57)% vs. (72.04±11.58)%; (82.50±7.11)% vs. (66.80±11.70)%, respectively, P<0.01). The total cell number of blastocysts had extreme difference between Ica group and control group ((61.40±9.64) vs. (46.23±4.50), P<0.01). The apoptotic cell number and rate of apoptotic cells of blastocysts were both reduced in Ica group ((1.47±0.51) vs. (2.94±0.66); (2.40±0.27)% vs. (6.25±0.62)%, respectively, P<0.01). Compared to control group, addition of icariin into mCZB extremely increased the expression of anti-apoptotic miRNA-21 (P<0.01), down-regulated pro-apoptotic Caspase3 (P<0.05) and PTEN (P<0.01), up-regulated anti-apoptotic Bcl-2 (P<0.01). In conclusion, icariin could reduce the apoptosis, promote the embryo development in vitro by enhancing miRNA-21 expression to up-regulated anti-apoptotic genes and down-regulated proapoptotic genes. These apoptosis-related genes were regulated by miRNA-21.
    Animal Science · Veterinary Science
    Energy Requirements for Maintenance and Growth of German Mutton Merino Crossbred Lambs
    DENG Kai-dong, DIAO Qi-yu, JIANG Cheng-gang, TU Yan, ZHANG Nai-feng, LIU Jie, MA Tao
    2013, 12(4): 670-677.  DOI: 10.1016/S1671-2927(00)8823
    Abstract ( )   PDF in ScienceDirect  
    A comparative slaughter trial and a metabolism trial were conducted to determine the requirement of net energy (NE) and metabolizable energy (ME) by the crossbreed of German Mutton Merino×Inner Mongolia Merino for fattening from 35 to 50 kg of body weight (BW). 49 crossbred female lambs ((33.9±2.3) (SD) kg BW) of German Mutton Merino×Inner Mongolia Merino were used. 34 lambs were randomly chosen for comparative slaughter, which were offered an identical mixture diet (concentrate:roughage=55:45) at 100, 75 or 55% of ad libitum intake, whereas the remainders were used in the metabolism trial to evaluate the ME of the diet after methane production was measured by open-circuit respirometry. As feed intake decreased from 100 to 75 and 55% of ad libitum intake, the apparent digestibility of dry matter (DM) linearly increased (P=0.010) from 60.8 to 63.6 and 66.9%, respectively, and methane production decreased from 52.1 to 44.3 and 39.9 L d-1, respectively, but the ratio of methane energy to gross energy intake increased linearly (P=0.010) from 8.20 to 8.96 and 10.97%, respectively. Consequently, the ME values of the diet increased from 9.35 to 9.64 and 9.85 MJ kg-1 DM, respectively. The NE requirement for maintenance (NEm) was 255 kJ kg-1 BW0.75, and the ME requirement for maintenance (MEm) was 352 kJ kg-1 BW0.75, with a partial energy efficiency for maintenance (km) of 0.72. The NE requirement for growth (NEg) ranged from 1.26 to 4.66 MJ d-1 as average daily gains increased from 100 to 300 g d-1, with a partial energy efficiency for growth (kg) of 0.45. These results indicated that the NEg required by crossbred female lambs of German Mutton Merino×Inner Mongolia Merino was lower than the recommendation of the American or British nutritional system.
    Conophylline Promotes the Proliferation of Immortalized Mesenchymal Stem Cells Derived from Fetal Porcine Pancreas (iPMSCs)
    ZHANG Hui-ru, LI Dan, CAO Hui, Lü Xiao, CHU Yuan-kui, BAI Yao-fu, JIN Ya-ping, PENG
    2013, 12(4): 678-686.  DOI: 10.1016/S2095-3119(13)60286-5
    Abstract ( )   PDF in ScienceDirect  
    Conophylline, is a bis (indole) alkaloid consisting of two pentacyclic aspidosperma skeletons, isolated from Tabernaemontana divaricata, which has been found to induce b-cell differentiation in rat pancreatic acinar carcinoma cells and in cultured rat pancreatic tissue. However, the precise role of conophylline in the growth and survival of immortalized pancreatic mesenchymal stem cells (iPMSCs) derived from fetal porcine pancreas were not understood at present. To determine whether this molecule is involved in controlling the proliferation of iPMSCs, we examined the effects of conophylline on iPMSCs. We found that conophylline can robustly stimulate iPMSCs proliferation, even promote their potential differentiation into islet-like clusters analyzed by cell counting, morphology, RT-PCR and real-time PCR, Western blotting, glucose-stimulated insulin release and insulin content analysis. The effects of conophylline were inhibited by LY294002, which is the inhibitor of the PI3K pathway. These results suggest that conophylline plays a key role in the regulation of cell mass proliferation, maintenance of the undifferentiated state of iPMSCs and also promotes iPMSCs differentiated into insulin-producing cells.
    An Evaluation of the Infection Status and Source of Subgroup J Avian Leukosis Virus in Cloned Free-Range Layers
    ZHANG Pei-pei, LIU Shao-qiong, WANG Jian, WANG Bo, ZHAO Cheng-di, ZHANG Yong-guang
    2013, 12(4): 687-693.  DOI: 10.1016/S2095-3119(13)60287-7
    Abstract ( )   PDF in ScienceDirect  
    In recent years, subgroup J avian leukosis virus (ALV-J) has been found to frequently infect layers in China. This virus is responsible for economic losses due to both mortality and decreased performance in chickens. In this study, 45-d-old cloned free-range layers were suspected to be infected with ALV and other immunosuppressive diseases because their feathers were unkempt and their growth rate was impaired. To estimate the infection status and determine the source of ALV-J in the flock, 30 cloacal swabs were randomly collected to measure the p27 antigen level by enzyme-linked immunosorbent assay (ELISA). Among the birds that were tested, 87% (26/30) were positive. In addition, 6 anticoagulant blood samples were aseptically collected at random from the flock when the layers were 60 d old. These samples were centrifuged to obtain the leukocytes, which were then used to inoculate chicken embryo fibroblast (CEF) cells for the identification of ALV-J by indirect immunofluorescence (IFA). Of the samples tested, 100% (6/6) were positive. The flock’s production performance was also investigated, and 10 layers were necropsied to evaluate pathological changes at 115 d of age. The flock never laid eggs even though they reached the age of the first laying (110 d). Furthermore, there were pathological changes present, including atrophy of the thymus and bursa of Fabricius, undeveloped ovaries, glandular stomach haemorrhage, and hepatosplenomegaly. Paraffin-embedded sections of intumescent liver and spleen were prepared for antigen localisation using IFA. Positive signals were prevalent in paraffin-embedded sections of the intumescent liver and spleen. Furthermore, provirus DNA was extracted from 4 cloned free-range layers, and 2 paternal parents (HR native cocks), and the gp85 gene of ALV-J was amplified by PCR to analyse the genetic variation. The results of the autogenous variation analysis showed that the 6 strains were 98.5-99.7% homologous. This study indicated that there was persistent infection with ALV-J by dynamic inspection, which seriously reduced the production performance of the flock. In addition, the genetic variation analysis showed that ALV-J in the flock was more likely to have originated from the paternal parent, the HR native cock.
    Soil & Fertilization · Irrigation · Agro-Ecology & Environment
    Long-Term Effect of Fertilizer and Rice Straw on Mineral Composition and Potassium Adsorption in a Reddish Paddy Soil
    LIAO Yu-lin, ZHENG Sheng-xian, NIE Jun, XIE Jian, LU Yan-hong , QIN Xiao-bo
    2013, 12(4): 694-710.  DOI: 10.1016/S2095-3119(13)60288-9
    Abstract ( )   PDF in ScienceDirect  
    Increasing K+ adsorption can be an effective alternative in building an available K pool in soils to optimize crop recovery and minimize losses into the environment. We hypothesized that long-term fertilization might change K+ adsorption because of changes in the chemical and mineralogical properties of a rice (Oryza sativa L.). The aims of this study were (i) to determine clay minerals in paddy soil clay size fractions using X-ray diffraction methods and a numerical diagramdecomposition method; (ii) to measure K+ adsorption isotherms before and after H2O2 oxidation of organic matter, and (iii) to investigate whether K+ adsorption is correlated with changes in soil chemical and mineral properties. The 30-yr longterm fertilization treatments caused little change in soil organic C (SOC) but a large variation in soil mineral composition. The whole-clay fraction (<5 μm) corresponded more to the fertilization treatment than the fine-clay fraction (<1 μm) in terms of percentage of illite peak area. The total percentage of vermiculite-chlorite peak area was significantly negatively correlated with the total percentage of illite peak area in the <5 μm soil particles (R=-0.946, P<0.0006). Different fertilization treatments gave significantly different results in K+ adsorption. The SOC oxidation test showed positive effects of SOC on K+ adsorption at lower K+ concentration ( 120 mg L-1) and negative effects at higher K+ concentration (240 mg L-1). The K+ adsorption by soil clay minerals after SOC oxidization accounted for 60-158% of that by unoxidized soils, suggesting a more important role of soil minerals than SOC on K+ adsorption. The K+ adsorption potential was significantly correlated to the amount of poorly crystallized illite present (R=0.879, P=0.012). The availability of adsorbed K+ for plant growth needs further study.
    Assessment of Soil Water Content in Field with Antecedent Precipitation Index and Groundwater Depth in the Yangtze River Estuary
    XIE Wen-ping , YANG Jing-song
    2013, 12(4): 711-722.  DOI: 10.1016/S2095-3119(13)60289-0
    Abstract ( )   PDF in ScienceDirect  
    To better understand soil moisture dynamics in the Yangtze River Estuary (YRE) and predict its variation in a simple way, a field monitoring experiment was carried out along the north branch of the Yangtze River, where seawater intrusion was strong and salt-water variation is one of the limiting factors of local agriculture. In present paper, relation between antecedent precipitation index (API) and soil water content is studied, and effects of groundwater depth on soil water content was analyzed. A relatively accurate prediction result of soil water content was reached using a neural network model. The impact analysis result showed that the variation of the API was consistent with soil water content and it displayed significant correlations with soil water content in both 20 and 50 cm soil layer, and higher correlation was observed in the layer of 20 cm. Groundwater impact analysis suggested that soil moisture was affected by the depth of groundwater, and was affected more greatly by groundwater at depth of 50 cm than that at 20 cm layer. By introducing API, groundwater depth and temperature together, a BP artificial network model was established to predict soil water content and an acceptable agreement was achieved. The model can be used for supplementing monitoring data of soil water content and predicting soil water content in shallow groundwater areas, and can provide favorable support for the research of water and salt transport in estuary area.
    Integrating Remote Sensing and Proximal Sensors for the Detection of Soil Moisture and Salinity Variability in Coastal Areas
    GUO Yan, SHI Zhou, ZHOU Lian-qing, JIN Xi, TIAN Yan-feng , TENG Hong-fen
    2013, 12(4): 723-731.  DOI: 10.1016/S2095-3119(13)60290-7
    Abstract ( )   PDF in ScienceDirect  
    Soil moisture and salinity are two crucial coastal saline soil variables, which influence the soil quality and agricultural productivity in the reclaimed coastal region. Accurately characterizing the spatial variability of these soil parameters is critical for the rational development and utilization of tideland resources. In the present study, the spatial variability of soil moisture and salinity in the reclaimed area of Hangzhou gulf, Shangyu City, Zhejiang Province, China, was detected using the data acquired from radar image and the proximal sensor EM38. Soil moisture closely correlates radar scattering coefficient, and a simplified inversion model was built based on a backscattering coefficient extracted from multi-polarization data of ALOS/PALSAR and in situ soil moisture measured by a time domain reflectometer to detect soil moisture variations. The result indicated a higher accuracy of soil moisture inversion by the HH polarization mode than those by the HV mode. Soil salinity is reflected by soil apparent electrical conductivity (ECa). Further, ECa can be rapidly detected by EM38 equipment in situ linked with GPS for characterizing the spatial variability of soil salinity. Based on the strong spatial variability and interactions of soil moisture and salinity, a cokriging interpolation method with auxiliary variable of backscattering coefficient was adopted to map the spatial variability of ECa. When compared with a map of ECa interpolated by the ordinary kriging method, detail was revealed and the accuracy was increased by 15.3%. The results conclude that the integrating active remote sensing and proximal sensors EM38 are effective and acceptable approaches for rapidly and accurately detecting soil moisture and salinity variability in coastal areas, especially in the subtropical coastal zones of China with frequent heavy cloud cover.
    Short Communication
    An Experimental Method to Quantify Extractable Amino Acids in Soils from Southeast China
    CHEN Xian-you, WU Liang-huan, CAO Xiao-chuang, Sarkar Animesh, , ZHU Yuan-hong
    2013, 12(4): 732-736.  DOI: 10.1016/S2095-3119(13)60291-9
    Abstract ( )   PDF in ScienceDirect  
    The extraction and comparison of soil amino acids using different extractants (deionized water, K2SO4, Na2SO4, NaCl, KCl) were reported. Results showed that 0.5 mol L-1 K2SO4 with a 5 times extraction was a better method to assess the concentration of extractable amino acids in soils. The total amino acids extracted from soil planted for tea were similar to the total inorganic nitrogen. While they extracted from vegetable soil and paddy soil were much lower than the total inorganic nitrogen.