2018 Vol. 17 No. 03 Previous Issue    Next Issue

    Crop Science
    Plant Protection
    Animal Science · Veterinary Medicine
    Agro-ecosystem & Environment
    Food Science
    Short Communication

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    Crop Science
    Characteristic analysis of tetra-resistant genetically modified rice
    HU Wen-bin, DENG Xiang-yang, DENG Xiao-xiang, DENG Li-hua, XIAO You-lun, HE Xing-jian, FU Xiqin, XIAO Guo-ying
    2018, 17(03): 493-506.  DOI: 10.1016/S2095-3119(17)61722-2
    Abstract ( )   PDF in ScienceDirect  
    In this study, the characteristic of three transformants named as B1C106-1, B1C106-2, and B1C106-3 were studied that carried three innate resistant genes Bph14, Bph15, and Xa23, and two enthetic resistant genes Cry1Ca# and Bar.  The five resistant genes were all verified by PCR and the two enthetic genes were identified in single copy insertion by Southern blot.  At tillering stage, the Cry1C and PAT (phosphinothricin acetyl transferase) protein contents in leaf, sheath, and stem of T2 generation were in the similar pattern: leaf>stem>sheath, and showed significant difference (P<0.01) among three organs. The average contents of Cry1C protein in plant of B1C106-1, B1C106-2, and B1C106-3 were 12.95, 6.57, and 11.30 μg g–1, respectively, and showed significant difference (P<0.01) among them.  However, the average contents of PAT in plant of B1C106-1, B1C106-2, and B1C106-3 were 28.54, 27.66, and 28.02 μg g–1, respectively, and there were no significant difference among three transformants.  The glufosinate tolerable concentration of three transformants of T3 generation reached at least 6 g L–1, and the mortality of rice leaf rollers were above 97.4% in 5 days after being fed with fresh transformants’ leaves.  The Cry1C protein toxicity was also assessed by silkworms, and the mortality of silkworms feeding mulberry leaves smeared with Cry1C protein extracts of leaves of B1C106-1, B1C106-2, and B1C106-3 were 90, 67.8, and 87.8%, respectively, that were positive correlation (r=0.993) with Cry1C protein contents in plant of three transformants.  The three transformants also maintained high resistance to brown planthopper and bacterial blight as the original version.  The above results indicate the tetra-resistant rice germplasm was well-developed by pyramiding innate and enthetic resistant genes in an elite line to provide with resistances of glufosinate, rice leaf roller, brown planthopper, and bacterial blight.  
    A wheat gene TaSAP17-D encoding an AN1/AN1 zinc finger protein improves salt stress tolerance in transgenic Arabidopsis
    XU Qiao-fang, MAO Xin-guo, WANG Yi-xue, WANG Jing-yi, XI Ya-jun, JING Rui-lian
    2018, 17(03): 507-516.  DOI: 10.1016/S2095-3119(17)61681-2
    Abstract ( )   PDF in ScienceDirect  
    The stress-associated protein (SAP) multigene family is conserved in both animals and plants.  Its function in some animals and plants are known, but it is yet to be deciphered in wheat (Triticum aestivum L.).  We identified the wheat gene TaSAP17-D, a member of the SAP gene family with an AN1/AN1 conserved domain.  Subcellular localization indicated that TaSAP17-D localized to the nucleus, cytoplasm, and cell membrane.  Expression pattern analyses revealed that TaSAP17-D was highly expressed in seedlings and was involved in NaCl response, polyethylene glycol (PEG), cold, and exogenous abscisic acid (ABA).  Constitutive expression of TaSAP17-D in transgenic Arabidopsis resulted in enhanced tolerance to salt stress, confirmed by improved multiple physiological indices and significantly upregulated marker genes related to salt stress response.  Our results suggest that TaSAP17-D is a candidate gene that can be used to protect crop plants from salt stress.  
    Characterization of GhSERK2 and its expression associated with somatic embryogenesis and hormones level in Upland cotton
    LIU Zheng-jie, ZHAO Yan-peng, ZENG Ling-he, ZHANG Yuan, WANG Yu-mei, HUA Jin-ping
    2018, 17(03): 517-529.  DOI: 10.1016/S2095-3119(17)61726-X
    Abstract ( )   PDF in ScienceDirect  
    Somatic embryogenesis (SE) is one of the most important steps during regeneration of cotton, but the molecular mechanism of SE remains unclear.  SOMATIC EMBRYOGENSIS RECEPTOR KINASE (SERK) gene is known to function in SE.  A homolog GhSERK2 (accession number: JF430801) was cloned from Upland cotton and characterized for its functions in SE.  GhSERK2 expressed in different tissues and showed higher expression level in floral organs than vegetative ones with the highest levels in ovule and anther.  GhSERK2 expressed during SE with a high level at globular embryos stage.  Upon treatment with indole-3-butytic acid (IBA), the transcription level of GhSERK2 was induced and promoted SE subsequently.  A 2-day treatment of 2,4-dichlorophenoxyacetic acid (2,4-D) induced the expression of GhSERK2, but treatments of 2,4-D for longer periods sharply inhibited the GhSERK2 transcription level of embryogenic callus (EC).  The levels of hormones, including 3-indoleacetic acid (IAA), abscisic acid (ABA), and brassinosteroid (BR), were increased in the initial calli induced from the over-expression of GhSERK2 cotton.  Our results indicated that GhSERK2 expression was associated with induction of SE and closely related to hormone levels during tissue culture in Upland cotton, and the gene might play an important role in regeneration of cotton.
    GmNAC15 overexpression in hairy roots enhances salt tolerance in soybean
    LI Ming, HU Zheng, JIANG Qi-yan, SUN Xian-jun, GUO Yuan, QI Jun-cang, ZHANG Hui
    2018, 17(03): 530-538.  DOI: 10.1016/S2095-3119(17)61721-0
    Abstract ( )   PDF in ScienceDirect  
    The NAC (NAM, ATAF1/2 and CUC2) transcription factor family plays a key role in plant development and responses to abiotic stress.  GmNAC15 (Glyma15g40510.1), a member of the NAC transcription factor family in soybean, was functionally characterized, especially with regard to its role in salt tolerance.  In the present study, qRT-PCR (quantitative reverse transcription PCR) analysis indicated that GmNAC15 was induced by salt, drought, low temperature stress, and ABA treatment in roots and leaves.  GmNAC15 overexpression in soybean (Glycine max) hairy roots enhanced salt tolerance.  Transgenic hairy roots improved the survival of wild leaves; however, overexpression of GmNAC15 in hairy root couldn’t influnce the expression level of GmNAC15 in leaf.  GmNAC15 regulates the expression levels of genes responsive to salt stress.  Altogether, these results provide experimental evidence of the positive effect of GmNAC15 on salt tolerance in soybean and the potential application of genetic manipulation to enhance the salt tolerance of important crops. 
    Molecular cloning and functional characterization of a soybean GmGMP1 gene reveals its involvement in ascorbic acid biosynthesis and multiple abiotic stress tolerance in transgenic plants
    XUE Chen-chen, XU Jin-yan, WANG Can, GUO Na, HOU Jin-feng, XUE Dong, ZHAO Jin-ming, XING Han
    2018, 17(03): 539-553.  DOI: 10.1016/S2095-3119(17)61727-1
    Abstract ( )   PDF in ScienceDirect  
    L-Ascorbic acid (AsA) plays an important role in plants and animals.  In plants, GDP-D-mannose pyrophosphorylase (GMP) is essential in the AsA biosynthetic pathway.  However, little is known about the genes encoding GMP in soybean and here we report genetic and functional analysis of the GmGMP1 (Glycine max GDP-D-mannose pyrophosphorylase 1) gene in this species.  GmGMP1 encoded a GDP-mannose pyrophosphorylase and exhibited higher transcript levels in the leaf than in the root, stem, flower, and seed.  Transcript of this gene was ubiquitous in the vegetative and reproductive organs, and was induced by abiotic stress and light.  Increasing expression of GmGMP1 in Arabidopsis and soybean through an overexpressing approach caused pronounced enhancement of AsA content, and was implicated in lowering the superoxide anion radical content and lipid peroxidation levels in Arabidopsis, and conferring tolerance to osmotic and high salt stresses during seed germination.  The present study represents the first systematic determination of soybean genes encoding GDP-mannose pyrophosphorylase and provides useful evidence for the functional involvement of GmGMP1 in control of AsA content and conferring tolerance to osmotic and salt stress.
    Responses of the antioxidant system to fluroxypyr in foxtail millet (Setaria italica L.) at the seedling stage
    GUO Mei-jun, WANG Yu-guo, YUAN Xiang-yang, DONG Shu-qi, WEN Yin-yuan, SONG Xi-e, GUO Ping-yi
    2018, 17(03): 554-565.  DOI: 10.1016/S2095-3119(17)61808-2
    Abstract ( )   PDF in ScienceDirect  
    Foxtail millet (Setaria italica L.) is an important food and fodder crop in semi-arid areas.  However, there are few herbicides suitable for use on weed control in field-grown foxtail millet during the post-emergence herbicides stage.  The present study was conducted using four concentrations (0.5, 1, 2, and 4 L ai ha–1) of foliar-applied fluroxypyr, and the effect of fluroxypyr on selected metabolic and stress-related parameters in foxtail millet were assessed after 15 days.  In this study, increasing concentrations decreased plant height and accumulation of chlorophylls.  Our results also showed that malondialdehyde (MDA) accumulated in response to fluroxypyr application, demonstrating increased lipid peroxidation due to excessive reactive oxygen species production.  In response to this oxidative stress, the activities of antioxidant enzymes were generally enhanced.  Non-enzymatic antioxidant defense systems, which function in concert with antioxidant enzymes, can also protect plant cells from oxidative damage by scavenging reactive oxygen species (ROS).  In conclusion, the hybrid variety (Zhangzagu) exhibited a greater tolerance to fluroxypyr than did the conventional variety Jingu 21, which might be associated with the antioxidant mechanisms of Zhangzagu hybrid millet.  
    Light interception and radiation use efficiency response to tridimensional uniform sowing in winter wheat
    TAO Zhi-qiang, WANG De-mei, MA Shao-kang, YANG Yu-shuang, ZHAO Guang-cai, CHANG Xu-hong
    2018, 17(03): 566-578.  DOI: 10.1016/S2095-3119(17)61715-5
    Abstract ( )   PDF in ScienceDirect  
    Improving radiation use efficiency (RUE) of the canopy is necessary to increase wheat (Triticum aestivum) production.  Tridimensional uniform sowing (U) technology has previously been used to construct a uniformly distributed population structure that increases RUE.  In this study, we used tridimensional uniform sowing to create a wheat canopy within which light was spread evenly to increase RUE.  This study was done during 2014–2016 in the Shunyi District, Beijing, China.  The soil type was sandy loam.  Wheat was grown in two sowing patterns: (1) tridimensional uniform sowing (U); (2) conventional drilling (D).  Four planting densities were used: 1.8, 2.7, 3.6, and 4.5 million plants ha–1.  Several indices were measured to compare the wheat canopies: photosynthetic active radiation intercepted by the canopy (IPAR), leaf area index (LAI), leaf mass per unit area (LMA), canopy extinction coefficient (K), and RUE.  In two sowing patterns, the K values decreased with increasing planting density, but the K values of U were lower than that of D.  LMA and IPAR were higher for U than for D, whereas LAI was nearly the same for both sowing patterns.  IPAR and LAI increased with increasing density under the same sowing pattern.  However, the difference in IPAR and LAI between the 3.6 and 4.5 million plants ha–1 treatments was not significant for both sowing patterns.  Therefore, LAI within the same planting density was not affected by sowing pattern.  RUE was the largest for the U mode with a planting density of 3.6 million plants ha–1 treatment.  For the D sowing pattern, the lowest planting density (1.8 million plants ha–1) resulted in the highest yield.  Light radiation interception was minimal for the D mode with a planting density of 1.8 million plants ha–1 treatment, but the highest RUE and highest yield were observed under this condition.  For the U sowing pattern, IPAR increased with increasing planting density, but yield and RUE were the highest with a planting density of 3.6 million plants ha–1.  These results indicated that the optimal planting density for improving the canopy light environment differed between the sowing patterns.  The effect of sowing pattern×planting density interaction on grain yield, yield components, RUE, IPAR, and LMA was significant (P<0.05).  Correlation analysis indicated that there is a positive significant correlation between grain yield and RUE (r=0.880, P<0.01), LMA (r=0.613, P<0.05), and spike number (r=0.624, P<0.05).  These results demonstrated that the tridimensional uniform sowing technique, particularly at a planting density of 3.6 million plants ha–1, can effectively increase light interception and utilization and unit leaf area.  This leads to the production of more photosynthetic products that in turn lead to significantly increased spike number (P<0.05), kernel number, grain weight, and an overall increase in yield.
    5-Aminolevulinic acid alleviates herbicide-induced physiological and ultrastructural changes in Brassica napus
    XU Ling, Faisal Islam, ZHANG Wen-fang, Muhammad A Ghani, Basharat Ali
    2018, 17(03): 579-592.  DOI: 10.1016/S2095-3119(17)61676-9
    Abstract ( )   PDF in ScienceDirect  
    It is well known that application of 5-aminolevulinic acid (ALA) could promote the plant growth under abiotic stress in oilseed rape (Brassica napus L.).  However, the specifics of its physiological and ultrastructural regulation under herbicide stress conditions are poorly understood.  In the present study, alleviating role of ALA in B. napus was investigated under four levels of herbicide propyl 4-(2-(4,6-dimethoxypyrimidin-2-yloxy) benzylamino) benzoate (ZJ0273) (0, 100, 200 and
    500 mg L–1) with or without 1 mg L–1 ALA treated for 48 or 72 h.  Results showed that after 48 h of herbicide stress, the growth of rape seedlings was significantly inhibited with the successive increases of the ZJ0273 concentrations from 0 to 500 mg L–1, but this inhibition was obviously alleviated by exogenous application of ALA.  However, when treatment time prolonged to 72 h, the recovery effects of ALA could not be evaluated due to the death of plants treated with the highest concentration of ZJ0273 (500 mg L-1).  Further, the root oxidizability and activities of antioxidant enzymes (superoxide dismutase, peroxidase and ascorbate peroxidase) were dramatically enhanced by the application of 1 mg L–1 ALA under herbicide stress.  Therefore, plants treated with ALA dynamically modulated their antioxidant defenses to reduce reactive oxygen species (ROS) accumulation and malondialdehyde (MDA) content induced by herbicide stress.  Additionally, exogenously applied ALA improved the ultrastructure’s of chloroplast, mitochondria and nucleus, and induced the production of stress proteins.  Our results suggest that ALA could be considered as a potential plant growth regulator for the improvement of herbicide tolerance through alleviation of the physiological and ultrastructural changes induced by the herbicide in crop production.
    Effects of ozone-treated domestic sludge on hydroponic lettuce growth and nutrition
    YANG Peng, GUO Yan-zhi, QIU Ling
    2018, 17(03): 593-602.  DOI: 10.1016/S2095-3119(17)61868-9
    Abstract ( )   PDF (775KB) ( )  
    Here, the ozone-treated domestic sludge was diluted up to four different multiples and utilized as a nutritional source for hydroponic lettuce growth.  Additionally, lettuce was cultured using the modified Hoagland nutrient solution as a control.  The effects of ozone-treated domestic sludge on lettuce growth and nutrition were studied.  Results showed that the lettuce treated with modified Hoagland inorganic nutrient solution had increased leaf number, plant height, fresh weight and dry weight compared to those treated with the ozone-treated domestic sludge dilution (P<0.05).  However, the lettuce cultivated with the 2-fold ozone-treated sludge dilution showed significantly higher (P<0.05) contents of chlorophyll, soluble sugar and ascorbic acid (Vc) compared to that treated with modified Hoagland nutrient solution.  And the nitrate concentration in the lettuce cultured with the 2-fold ozone-treated sludge dilution was 53.93% less than that cultured with the modified Hoagland nutrient solution, which was a significant improvement (P<0.05).  This study suggested that the 2-fold ozone-treated sludge dilution is optimal for lettuce hydroponic nutrient requirements.
    Physiological response of four wolfberry (Lycium Linn.) species under drought stress
    ZHAO Jian-hua, LI Hao-xia, ZHANG Cun-zhi, AN Wei, YIN Yue, WANG Ya-jun, CAO You-long
    2018, 17(03): 603-612.  DOI: 10.1016/S2095-3119(17)61754-4
    Abstract ( )   PDF in ScienceDirect  
    We studied gas-exchange, chlorophyll pigments, lipid peroxidation, antioxidant enzymes, and biomass partitioning responses in seedlings of four wolfberry species (Lycium chinense Mill. var. potaninii (Pojark.) A. M. Lu, Lycium chinense Mill., Lycium barbarum L., and Lycium yunnanense Kuang & A. M. Lu) under four water supply regimes.  In all four species, drought affected seedlings in terms of chlorophyll content, net photosynthesis rate (Pn), transpiration rate (E), and lipid peroxidation.  Drought also increased some antioxidant enzyme activities, such as peroxidase (POD), catalase (CAT), superoxide dismutase (SOD), and ascorbate peroxidase (APX).  Significant changes in dry biomass partitioning also occurred in response to water stress.  In particular, dry biomass of leaves and fruits decreased significantly.  L. chinense Mill. and L. barbarum L. possessed greater drought tolerance and exhibited superior antioxidant processing ability and other related physiological traits compared to the other two species. L. chinense Mill. was the most tolerant to all levels of drought.  In contrast, L. yunnanense Kuang & A. M. Lu was more affected by water supply and had the lowest resistance to drought stress.  These findings would provide some important information regarding genetic resources for future forest tree improvement in relation to drought tolerance. 
    Plant Protection
    Preparation of dry flowable formulations of Clonostachys rosea by spray drying and application for Sclerotinia sclerotiorum control
    WU Hong-qu, SUN Li-li, LIU Fang, Wang Zhi-ying, CAO Chuan-wang
    2018, 17(03): 613-620.  DOI: 10.1016/S2095-3119(17)61811-2
    Abstract ( )   PDF in ScienceDirect  
    A dry flowable formulation of Clonostachys rosea with fungicidal activity against Sclerotinia sclerotiorum was prepared by spray drying.  The formulation was optimized by a four-factor, three-level orthogonal experiment to screen inert ingredients and spray-drying conditions.  The optimal dry flowable formulation of C. rosea included 30% C. rosea (ratio of conidia powder and its fermentation broth is 1:3), 3% Morwet EFW, 4% k12, 10% Morwet D425, 9% sodium salt of polynaphthalene sulphonic acid (NNO), 5% croscarmellose sodium, 5% (NH4)2SO4, 0.5% carboxymethyl cellulose sodium (CMC-Na), 1% oxalic acid and palygorskite (carrier) up to 100%.  The formulation exhibited good physical characteristics, such as high dispersibility, viability and a long shelf life.  Plate antagonism tests and pot trials indicated that the dry flowable formulation was very effective against S. sclerotiorum, with control efficiency of up to 88.30%.  This dry flowable formulation of C. rosea is a new potential commercial fungicide for spray drying to control S. sclerotiorum.  
    Evaluation of Chinese rice varieties resistant to the root-knot nematode Meloidogyne graminicola
    Zhan Li-ping, Ding Zhong, Peng De-liang, Peng Huan, Kong Ling-an, Liu Shi-ming, Liu Ying, Li Zhong-cai, HUANG Wen-kun
    2018, 17(03): 621-630.  DOI: 10.1016/S2095-3119(17)61802-1
    Abstract ( )   PDF in ScienceDirect  
    The root-knot nematode Meloidogyne graminicola, which is distributed worldwide, is considered a major constraint on rice production in Asia.  The present study used the root gall index and number of nematodes inside the roots to evaluate resistance/susceptibility to M. graminicola in different subpopulations of Oryza sativa (aus, hybrid aus, indica, hybrid indica, temperate japonica, tropical japonica).  Nematode development in highly resistant varieties was also evaluated.  Analyses of randomly selected 35 varieties showed the number of M. graminicola nematodes inside the roots correlated very strongly (r=0.87, P≤0.05) with the nematode gall index, and the results from pot and field experiments revealed similar rankings of the varieties for resistance/susceptibility.  Among the 136 tested varieties, temperate japonica displayed the highest gall index, followed by tropical japonica, indica, hybrid indica, aus, and hybrid aus. Zhonghua 11 (aus), Shenliangyou 1 (hybrid aus) and Cliangyou 4418 (hybrid indica) were highly resistant to M. graminicola under both pot and field conditions.  Further examination of nematode development suggested that compared to susceptible rice, M. graminicola penetrated less often into highly resistant varieties and more frequently failed to develop into females.  The promising varieties found in the present research might be useful for the breeding of hybrid rice in China and for the further development of practical nematode management measures.   
    The damage risk evaluation of Aphis gossypii on wheat by host shift and fitness comparison in wheat and cotton
    FAN Yin-jun, LI Fen, Abd Allah A. H. Mohammed, YI Xiao-qin, ZHANG Min, Nicolas Desneux, GAO Xi-wu
    2018, 17(03): 631-639.  DOI: 10.1016/S2095-3119(17)61784-2
    Abstract ( )   PDF in ScienceDirect  
    Aphids are considered as one of the key pests for wheat production worldwide.  Major aphid species that infest wheat in China include Sitobion avenae, Rhopalosiphum padi, Schizaphis graminum and Metopolophium dirhodum.  However, during our wheat field survey in Wenshang County of Shangdong Province, China, we observed that Aphis gossypii can feed on wheat.  The damage risk of A. gossypii on wheat was assessed using host shift method.  A population of A. gossypii collected from a wheat field in 2015 and another population reared on cotton under laboratory conditions for a decade without exposure to insecticides were used in the study.  The results of host shift demonstrated that the A. gossypii colony from wheat has not yet developed wheat specialization.  Moreover, the assessment of A. gossypii fitness on wheat and cotton showed that fecundity and net reproductive rate of A. gossypii population fed on wheat was significantly higher comparing to the population fed on cotton, whether the initial host of A. gossypii population was wheat or cotton.  This study raises a warning that the cotton aphid has potential to establish well on wheat and it may cause significant effects under specific circumstances.  Therefore, future studies are required to evaluate the effects of A. gossypii on wheat production.  
    Release performance and sustained-release efficacy of emamectin benzoate-loaded polylactic acid microspheres
    YIN Ming-ming, ZHU Xin-yan, CHEN Fu-liang
    2018, 17(03): 640-647.  DOI: 10.1016/S2095-3119(17)61763-5
    Abstract ( )   PDF in ScienceDirect  
    High-performance liquid chromatography (HPLC) was employed to determine drug release rates based on emamectin benzoate concentrations in the medium.  Release kinetics equations were used to fit the drug release behavior.  The effects of particle size and release medium pH on the release rate were also investigated.  The indoor toxicity of emamectin benzoate-loaded polylactic acid microspheres on the diamondback moth larva (Plutella xylostella) was studied to explore drug sustained-release performance.  In acidic and neutral media, the drug release behavior of the microspheres was in accord with the first-order kinetics equation.  Increasing the spray dosage of emamectin benzoate-loaded polylactic acid microspheres initially resulted in an equivalent insecticidal efficacy with the conventional emamectin benzoate microemulsion.  However, the drug persistence period was four-fold longer than that observed using the conventional formulation.  The developed emamectin benzoate-loaded polylactic acid microspheres showed dramatic sustained-release performance.  A treatment threshold of greater than 35 mg mL–1 was established for an efficient accumulated release concentration of emamectin benzoate-loaded microspheres.
    Animal Science · Veterinary Medicine
    Effect of in ovo zinc injection on the embryonic development, tissue zinc contents, antioxidation, and related gene expressions of broiler breeder eggs
    SUN Xiao-ming, LIAO Xiu-dong, LU Lin, ZHANG Li-yang, MA Qiu-gang, XI Lin, LUO Xu-gang
    2018, 17(03): 648-656.  DOI: 10.1016/S2095-3119(17)61704-0
    Abstract ( )   PDF in ScienceDirect  
    Two experiments were conducted to investigate the effect of in ovo zinc (Zn) injection on the embryonic development, tissue Zn contents, antioxidation and related gene expressions of fertilized eggs of Arbor Acres broiler breeders.  Experiment 1 was conducted to determine an optimal embryonic age for early in ovo injection.  A total of 720 fertilized eggs with similar weights were randomly allotted to 4 treatments with 6 replicates per treatment and 30 eggs per replicate in a completely randomized design.  The eggs were injected with 0.1 mL sterilized water at 3, 6 and 9 embryonic days of incubation (E3, E6 and E9) or non-injection (the control), respectively.  The results from experiment 1 showed that E3 and E6 injections increased (P<0.05) the embryonic mortalities, and decreased (P<0.05) hatchabilities compared to the non-injected control, but no differences (P>0.05) between E9 injection and the non-injected control were observed in either embryonic mortality or hatchability.  The findings suggest that the E9 is the optimal embryonic age for early in ovo injection.  In experiment 2, a total of 672 fertilized eggs with similar weights were randomly allocated to 7 treatments with 6 replicates per treatment and 16 eggs per replicate in a completely randomized design.  The eggs were injected with 0 (the negative control), 50, 100, 150, 200, or 250 μg Zn/egg as reagent grade ZnSO4·7H2O in a 0.1-mL solution, or non-injection (the positive control), respectively at E9–10.  The results from the experiment 2 demonstrated that no differences (P>0.05) among 50 and 100 μg Zn/egg groups and the negative control were observed in the embryonic mortality and hatchability, however, the injection of 200 μg Zn/egg increased (P<0.05) the embryonic mortality, and injections of 150 and 200 μg Zn/egg decreased (P<0.05) hatchabilities compared with the controls.  The embryonic tibia Zn contents at E20 were increased (P<0.05) by injections of 150, 200 and 250 μg Zn/egg.  Zinc injection did not affect (P>0.05) malonaldehyde (MDA) contents, copper- and Zn-containing superoxide dismutase (CuZnSOD) activities and mRNA expression levels in the liver and heart of chick embryos at E15 and E20.  Compared with the negative control, injections of 50, 150 and 200 μg Zn/egg up-regulated (P<0.05) the metallothionein (MT) mRNA expression levels in the embryonic liver at E20.  These results indicated that in ovo Zn injections increased Zn contents in the embryonic tibia and MT mRNA expression levels in the embryonic liver at E20, however, injections of 150–200 µg Zn/egg were harmful to the embryonic development.
    Effects of Bupleurum extract on blood metabolism, antioxidant status and immune function in heat-stressed dairy cows
    CHENG Jian-bo, FAN Cai-yun, SUN Xian-zhi, WANG Jia-qi, ZHENG Nan, ZHANG Xing-kai, QIN Junjie, WANG Xiu-min
    2018, 17(03): 657-663.  DOI: 10.1016/S2095-3119(17)61801-X
    Abstract ( )   PDF in ScienceDirect  
    This experiment was conducted to evaluate the effects of Bupleurum extract (BE) on blood metabolites, antioxidant status, and immune function in dairy cows under heat stress.  Forty lactating Holstein cows were randomly assigned to 1 of 4 treatments.  The treatments consisted of 0, 0.25, 0.5, and 1.0 g of BE kg–1 dry matter.  Supplementation with BE decreased (P<0.05) blood urea nitrogen (BUN) contents and increased blood total protein (TP) and albumin (ALB) levels compared with control cows, but it had no effects (P>0.05) on blood glucose (GLU), nonesterified fatty acid (NEFA), total triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), and high density lipoprotein cholesterol (HDL-C).  Compared with control cows, cows fed BE had higher (P<0.05) superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activity.  However, supplementation with BE had no effect (P>0.05) on total antioxidant capacity (T-AOC) or malondialdehyde (MDA) levels.  The immunoglobulin (Ig) A and G contents increased (P<0.05) in cows fed 0.25 or 0.5 g of BE kg–1.  Interleukin (IL)-2 and IL-4 levels were higher (P<0.05) in cows fed 0.5 and 1.0 g of BE kg–1, and IL-6 was significantly elevated (P<0.05) in cows fed 0.5 g of BE kg–1.  There were no treatment effects (P>0.05) on the CD4+ and CD8+ T lymphocyte ratios, CD4+/CD8+ ratio, or tumor necrosis factor-α (TNF-α) level among the groups.  These findings suggest that BE supplementation may improve protein metabolism, in addition to enhancing antioxidant activity and immune function in heat-stressed dairy cows.  
    Agro-ecosystem & Environment
    Optimized nitrogen application methods to improve nitrogen use efficiency and nodule nitrogen fixation in a maize-soybean relay intercropping system
    YONG Tai-wen, CHEN Ping, DONG Qian, DU Qing, YANG Feng, WANG Xiao-chun, LIU Wei-guo, YANG Wen-yu
    2018, 17(03): 664-676.  DOI: 10.1016/S2095-3119(17)61836-7
    Abstract ( )   PDF in ScienceDirect  
    In China, the abuse of chemical nitrogen (N) fertilizer results in decreasing N use efficiency (NUE), wasting resources and causing serious environmental problems.  Cereal-legume intercropping is widely used to enhance crop yield and improve resource use efficiency, especially in Southwest China.  To optimize N utilization and increase grain yield, we conducted a two-year field experiment with single-factor randomized block designs of a maize-soybean intercropping system (IMS).  Three N rates, NN (no nitrogen application), LN (lower N application: 270 kg N ha–1), and CN (conventional N application: 330 kg N ha–1), and three topdressing distances of LN (LND), e.g., 15 cm (LND1), 30 cm (LND2) and 45 cm (LND3) from maize rows were evaluated.  At the beginning seed stage (R5), the leghemoglobin content and nitrogenase activity of LND3 were 1.86 mg plant–1 and 0.14 mL h–1 plant–1, and those of LND1 and LND2 were increased by 31.4 and 24.5%, 6.4 and 32.9% compared with LND3, respectively.  The ureide content and N accumulation of soybean organs in LND1 and LND2 were higher than those of LND3.  The N uptake, NUE and N agronomy efficiency (NAE) of IMS under CN were 308.3 kg ha–1, 28.5%, and 5.7 kg grain kg–1 N, respectively; however, those of LN were significantly increased by 12.4, 72.5, and 51.6% compared with CN, respectively.  The total yield in LND1 and LND2 was increased by 12.3 and 8.3% compared with CN, respectively.  Those results suggested that LN with distances of 15–30 cm from the topdressing strip to the maize row was optimal in maize-soybean intercropping.  Lower N input with an optimized fertilization location for IMS increased N fixation and N use efficiency without decreasing grain yield.
    Estimation of irrigation requirements for drip-irrigated maize in a subhumid climate
    LIU Yang, YANG Hai-shun, LI Jiu-sheng, LI Yan-feng, YAN Hai-jun
    2018, 17(03): 677-692.  DOI: 10.1016/S2095-3119(17)61833-1
    Abstract ( )   PDF in ScienceDirect  
    Drip-irrigation is increasingly applied in maize (Zea mays L.) production in sub-humid region.  It is critical to quantify irrigation requirements during different growth stages under diverse climatic conditions.  In this study, the Hybrid-Maize model was calibrated and applied in a sub-humid Heilongjiang Province in Northeast China to estimate irrigation requirements for drip-irrigated maize during different crop physiological development stages and under diverse agro-climatic conditions.  Using dimensionless scales, the whole growing season of maize was divided into diverse development stages from planting to maturity.  Drip-irrigation dates and irrigation amounts in each irrigation event were simulated and summarized in 30-year simulation from 1981 to 2010.  The maize harvest area of Heilongjiang Province was divided into 10 agro-climatic zones  based on growing degree days, arid index, and temperature seasonality.  The simulated results indicated that seasonal irrigation requirements and water stress during different growth stages were highly related to initial soil water content and distribution of seasonal precipitation.  In the experimental site, the average irrigation amounts and times ranged from 48 to 150 mm with initial soil water content decreasing from 100 to 20% of the maximum soil available water.  Additionally, the earliest drip-irrigation event might occur during 3- to 8-leaf stage.  The water stress could occur at any growth stages of maize, even in wet years with abundant total seasonal rainfall but poor distribution.  And over 50% of grain yield loss could be caused by extended water stress during the kernel setting window and grain filling period.  It is estimated that more than 94% of the maize harvested area in Heilongjiang Province needs to be irrigated although the yield increase varied (0 to 109%) in diverse agro-climatic zones.  Consequently, at least 14% of more maize production could be achieved through drip-irrigation systems in Heilongjiang Province compared to rainfed conditions.
    Food Science
    Optimal storage temperature and 1-MCP treatment combinations for different marketing times of Korla Xiang pears
    JIA Xiao-hui, WANG Wen-hui, DU Yan-min, TONG Wei, WANG Zhi-hua, Hera Gul
    2018, 17(03): 693-703.  DOI: 10.1016/S2095-3119(17)61872-0
    Abstract ( )   PDF in ScienceDirect  
    Maintenance of green color is the primary indicator of quality in the market evaluation of Korla Xiang pears at present and can generally be achieved through early harvesting and decreasing the storage temperature, but the fruit quality was reduced by early harvesting, and the decreasing storage temperature increased the risk of chilling injury.  The objectives of this study were to determine the optimal storage parameters for different storage times and to find ways to preserve the green skin color of pears.  Specifically, we analyzed the effects of the ethylene inhibitor, 1-methylcyclopropene (1-MCP), combined with low temperature on quality and maintenance of the green color of Korla Xiang pears during storage.  We found that 1-MCP and/or low temperature reduced the loss of green color at 20°C after being removed from cold storage.  In addition, 1-MCP significantly inhibited the decline of titratable acid and ascorbic acid but had no significant effect on fruit firmness and total soluble solids.  Low temperature with or without 1-MCP inhibited the release of ethylene, inhibited the decline in the stalk preservation index, inhibited the increase in decay rate and weight loss rate during storage, and inhibited the increase in the core browning index after 225 days of storage.  Different storage temperatures had different effects on the quality of Korla Xiang pears.  Despite inhibiting ethylene release, a storage temperature of –1.5°C increased the respiration rate.  Storage at –1.5°C caused core browning early during storage due to chilling injury, whereas at 2°C core browning occurred late during storage due to senescence.  In late storage, 1-MCP had no significant effect on the maintenance of Korla Xiang pear quality at 2°C.  Based on these results, we determined the optimal combinations of low temperature and 1-MCP treatment to maintain pear quality while avoiding chilling injury.  For different marketing times, the optimal conditions for storage until New Year’s Day (a storage duration of 90 days) are 2°C or 1-MCP combined with 2°C.  For storage until the Spring Festival (a storage duration of 150 days), the optimal conditions are 0°C or 1-MCP combined with 0°C, and for storage until May (a storage duration of 225 days), the best conditions are 1-MCP combined with –1.5°C.   
    The characterization of acid and pepsin soluble collagen from ovine bones (Ujumuqin sheep)
    GAO Ling-ling, WANG Zhen-yu, LI Zheng, ZHANG Cai-xia, ZHANG De-quan
    2018, 17(03): 704-711.  DOI: 10.1016/S2095-3119(17)61751-9
    Abstract ( )   PDF in ScienceDirect  
    Ovine bones are the major by-products after slaughtered.  The present study was conducted to extract and characterize acid soluble collagens (ASC) and pepsin soluble collagens (PSC) from ovine bones (Ujumuqin sheep).  Ovine bones collagen were identified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) as type I collagen.  The results of Fourier transform infrared (FTIR) spectra analysis testified the existence of triple superhelical structure in both ASC and PSC, showing pepsin did not disrupt the triple helical structure of ovine bones collagen.  Glycine, accounting for one-third of total amino acids, was the major amino acid for ovine bones collagen.  Higher imino acid content was responsible for higher thermal denaturation temperature of ovine bones collagen compared to fish collagens.  The isoelectric point of ASC was lower than PSC due to the higher content of acidic amino acids.  Therefore, this study provides the potential reference for collagen extraction and application of ovine bones by-procduct.
    Short Communication
    Complete genome sequences of four isolates of Citrus leaf blotch virus from citrus in China
    LI Ping, LI Min, ZHANG Song, WANG Jun, YANG Fang-yun, CAO Meng-ji, LI Zhong-an
    2018, 17(03): 712-715.  DOI: 10.1016/S2095-3119(17)61860-4
    Abstract ( )   PDF in ScienceDirect  
    Citrus leaf blotch virus (CLBV) is a member of the genus Citrivirus, in the family Betaflexiviridae.  It has been reported CLBV could infect kiwi, citrus and sweet cherry in China.  Of 289 citrus samples from six regions of China, 15 were detected to be infected with CLBV in this study.  The complete genome of four isolates of CLBV was obtained from Reikou in Sichuan (CLBV-LH), Yura Wase in Zhejiang (CLBV-YL), Bingtangcheng in Hunan (CLBV-BT), Fengjie 72-1 in Chongqing (CLBV-FJ), respectively.  While they all represented 8 747 nucleotides in monopartite size, excluding the poly(A) tail, each of the isolates coded three open reading frames (ORFs).  Identity of the four isolates ranged from 98.9 to 99.8% to each other and from 96.8 to 98.1% to the citrus references in GenBank by multiple alignment of genomes.  A phylogenetic tree based on the genome sequences of available CLBV isolates indicated that the four isolates were clustered together, suggesting that CLBV isolates from citrus in China did not have obvious variation.  This is the first report of the complete nucleotide sequences of CLBV isolates infecting citrus in China.
    Detection of illegal dyes in foods using a polyethersulfone/multi-walled carbon nanotubes composite membrane as a cleanup method
    HE Ya-hui, WANG Jing
    2018, 17(03): 716-722.  DOI: 10.1016/S2095-3119(17)61694-0
    Abstract ( )   PDF in ScienceDirect  
    In this paper, a polyethersulfone (PES)/multi-walled carbon nanotubes (MWCNTs) composite membrane was prepared using phase inversion.  The surface morphology and internal structure of the membrane were observed by scanning electron microscopy (SEM).  The effects of MWCNTs content on various aspects of membrane performance such as porosity, water flux, and antifouling characteristics were investigated.  Results showed that proper addition of MWCNTs would improve the properties of the membrane.  MWCNTs had a strong adsorption capacity for industrial dyes and the composite membrane could be used as an effective method to identify and clean up illegal dyes in foods.  In addition, this new method for identifying dyes is rapid: the cleanup procedure in the determination of illegal dyes in foods by the composite membrane was shortened to 30 min or less compared to 6–8 h for traditional methods.