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2013 Vol. 12 No. 11 Previous Issue    Next Issue

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Special Focus: Meat Quality and Meat Products Characteristics
Section 1: Animal Welfare and Meat Quality
Special Focus: Meat Quality and Meat Products Characteristics
Section 2: Meat Products
Crop Genetics · Breeding · Germplasm Resources
Physiology & Biochentry · Tillage · Cultivation
Plant Protection
Soil & Fertilization · Irrigation · Agro-Ecology & Environment




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Special Focus: Meat Quality and Meat Products Characteristics

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MEAT AND MEAT PRODUCTS José M Lorenzo 2013, 12(11): 1916-1918.  DOI: 10.1016/S2095-3119(13)60642-5 Abstract ( )   PDF in ScienceDirect

Section 1: Animal Welfare and Meat Quality

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Key Factors Involved in Lamb Quality from Farm to Fork in Europe Carlos Sa?udo, Erica Muela , María del Mar Campo 2013, 12(11): 1919-1930.  DOI: 10.1016/S2095-3119(13)60629-2 Abstract ( )   PDF in ScienceDirect   World lamb consumption is approximately 2 kg per capita with large variations between continents, e.g., 17 kg in Oceania vs. 0.7 kg in North America. With less than one million tonnes, the international trade of sheep meat contributes to a small percentage of the total meat exchanged between countries. On the other hand, lamb represents the highest rate of species trading in relation to the total sheep meat produced. It is therefore likely to find a wide variability of different lamb products in the same market, and that the conservation procedures (such as refrigeration, packaging or freezing), chemical composition, especially the fat due to its implication in human health, flavour development and juiciness perception (affected, i.e., by the feeding or the age or slaughter weight of the animal) and acceptability (based on culinary background) could be considered important indicators of this advantageous situation. In this paper some studies related to the aforementioned indicators are discussed.

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Impact of Adrenaline or Cortisol Injection on Meat Quality Development of Merino Hoggets Dario G Pighin, Sebastian A Cunzolo, Maria Zimerman, Adriana A Pazos, Ernesto Domingo, Anibal J Pordomingo , Gabriela Grigioni 2013, 12(11): 1931-1936.  DOI: 10.1016/S2095-3119(13)60630-9 Abstract ( )   PDF in ScienceDirect   Increased levels of stress hormones in the muscle could lead to post mortem metabolic/structural modifications that could be reflected on meat quality. The present study investigated the metabolic effect of either adrenaline or cortisol injected into lambs in order to obtain an animal model of acute stress. Results showed that adrenaline or cortisol injection lead to glucose metabolism and muscle temperature increase. Muscle pH immediately post mortem was affected by adrenaline treatment. Water holding capacity (WHC) of fresh muscle, final muscle pH and temperature registered at 24 h post mortem were not affected by injected hormones. Hardness and adhesiveness of LD muscle evaluated 3 d post mortem tended to increase as a result of adrenaline or cortisol injection. Results demonstrated that injected hormones were able to affect the post mortem muscle biochemistry and the pH/T curve independently of final muscle pH.

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Dietary Supplementation of Oregano and Sage Dried Leaves on Performances and Meat Quality of Rabbits Luca Rotolo, Francesco Gai, Silvana Nicola, Ivo Zoccarato, Alberto Brugiapaglia , Laura Gasco 2013, 12(11): 1937-1945.  DOI: 10.1016/S2095-3119(13)60631-0 Abstract ( )   PDF in ScienceDirect   The aim of this research was to evaluate the dietary supplementation 1% (w/w) of oregano and sage dried leaves on performances and meat quality of broiler rabbits. A feeding trial, which lasted 48 d, was carried out on 105 male Bianca Italiana rabbits randomly divided in seven groups and fed ad libitum. At the end of the trial ten animals per group were slaughtered and samples of dorsal muscle were taken in order to perform laboratory analysis. Mortality rate did not statistically differ between groups. Growth performances of animals fed diets supplemented with aromatic plants were higher (P<0.05) than those of animals of control group, whereas carcass parameters were not affected by treatments excepting for the slaughter weight that showed the same trend as growth performances. Meat quality traits, oxidative lipid stability and fatty acid profile were not influenced by aromatic plant supplementation. In conclusion, oregano and sage in form of dried leaves can be used in rabbit without adverse effects on performance, carcass characteristics and meat quality traits.

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Evaluation of Physicochemical, Microbiological and Sensory Stability of Frozen Stored Vacuum-Packed Lamb Meat Rafaella de Paula Paseto Fern, es , Maria Teresa de Alvarenga Freire, Celso da Costa Carrer 2013, 12(11): 1946-1952.  DOI: 10.1016/S2095-3119(13)60632-2 Abstract ( )   PDF in ScienceDirect   Nowadays, lamb meat represents only 7% of all meat produced in the world. In recent years the demand for standardized lamb meat cuts has been considered of great importance and the marketing occurs predominantly in the form of frozen cuts. Herewith, the main of this work was to evaluate the stability and safety of lamb meat during frozen storage. Meats were vacuum packed in high barrier multilayer plastic films and stored during 12 mon at (-18±1)ºC. The meat stability was assessed by physical and chemical (lipid oxidation, objective color, pH value, cooking losses and instrumental texture), microbiological (total count of psychrotrophic, coliform count at 45°C, coagulase-positive staphylococci and the presence of Salmonella) and sensory analysis (acceptance test and visual evaluation). The vacuum packed lamb meat remained stable as to most physical and chemical indexes. Microbiological indexes showed good stability throughout the storage period according to Brazilian legislation standards to pathogenic microorganisms. Although a significant reduction in tenderness (shear force increase from 3 to 8 kg), it showed a good sensorial acceptance for all attributes tested, including texture, with scores of around 7 (like moderately) during the 12 mon of storage. Therefore, it can be concluded that, under the conditions applied in this study, lamb meat presents a shelf life of at least 12 mon when stored at -18°C.

Special Focus: Meat Quality and Meat Products Characteristics

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Composition and Physico-Chemical Properties of Meat from Capons Fed Cereals Olga Díaz, Luisana Rodríguez, Alex , r Torres , ángel Cobos 2013, 12(11): 1953-1960.  DOI: 10.1016/S2095-3119(13)60633-4 Abstract ( )   PDF in ScienceDirect   Chemical composition, physico-chemical properties and fatty acid composition of breast and drumstick meat from capons (castrated male cockerels) fed cereals were studied. Three groups of capons were reared. One group was fed ad libitum the same commercial diet until the 4th mon of life. The last month of its life, the capons of this group were fed corn. The second and third group of capons were fed the same diet from caponization. The second group was fed mixture of corn (50%) and wheat (50%). The third group of capons was fed 2/3 corn and 1/3 mixture of corn (50%) and barley (50%). Capons were reared under free-range conditions and slaughtered at 150 d of age. Caponization was performed at 48 d. No significant effects of feeding in chemical composition, pH, water holding capacity, drip and cooking losses and texture of the meat were observed. The meat of the third group (capons fed 83% corn) was more yellow and showed higher content of C18:2 than that of the other capons.

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Pork Meat Quality of Preto Alentejano and Commercial Largewhite Landrace Cross Alfredo Teixeira , S , ra Rodrigues 2013, 12(11): 1961-1971.  DOI: 10.1016/S2095-3119(13)60634-6 Abstract ( )   PDF in ScienceDirect   This work aimed to evaluate the physical-chemical characteristics of pork from a local breed (Portuguese black pork called Preto Alentejano) and a commercial breed. Sixteen animals were used, 4 females and 4 males from each breed. Animals had 80-100 kg of live weight. The longissimus muscle between the 5th thoracic vertebra and the 10th lumbar vertebra was used in the analysis. Samples were analysed for protein, fat, pigments, ashes, dry mater, water-holding capacity, and texture. Results of fat and pigments contents indicate significant (P<0.05 and P<0.01) differences for all treatments. For protein, ashes, dry mater, water-holding capacity and texture, no significant differences were found for sex. In the analysis of fatty acids composition, ten were detected, being the main ones C16:0, C18:0, C16:1, C18:1, C18:2. There was a predominance of monounsaturated fatty acids (MUFA), followed by saturated (SFA) and polyunsaturated (PUFA). Differences were significant for sex (P<0.01) and breed (P<0.01). Preto Alentejano breed and females presented the higher percentages of SFA (P<0.01) and MUFA (P<0.001) fatty acids. Differences between breeds might be due to breed production system and feed differences.

Section 2: Meat Products

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Application of Natural Antioxidants from Strawberry Tree (Arbutus unedo L.) and Dog Rose (Rosa canina L.) to Frankfurters Subjected to Refrigerated Storage Mónica Armenteros, David Morcuende, Sonia Ventanas , Mario Estévez 2013, 12(11): 1972-1981.  DOI: 10.1016/S2095-3119(13)60635-8 Abstract ( )   PDF in ScienceDirect   The effect of the addition of natural antioxidants from strawberry tree (Arbutus unedo L.; AU) and dog rose (Rosa canina L.; RC), in frankfurters elaborated with or without the addition of antioxidant additives (sodium ascorbate and nitrite) was studied. Six different types of experimental frankfurters were prepared depending on the addition of phenolic-rich extracts from RC and AU and the presence (P) or absence (C) of antioxidant additives. Thiobarbituric acid reactive substances (TBARS)-numbers significantly increased during chilled storage of C-frankfurters while additives and fruit phenolics inhibited lipid oxidation in P-frankfurters. The amount of protein carbonyls significantly increased in all treatments except in P-AU frankfurters. The discoloration process that occurred during the chilled storage was reduced by the addition of substances with proven antioxidant activity (P-frankfurters). Texture characteristics as hardness, springiness, cohesiveness and gumminess also suffered a significant deterioration in C-frankfurters. The use of phenolic fruit extracts in combination with traditional antioxidant additives is a successful strategy to enhance the oxidative stability of frankfurters without modifying their color and texture properties.

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Mediterranean Berries as Inhibitors of Lipid Oxidation in Porcine Burger Patties Subjected to Cooking and Chilled Storage Rui Ganh?o, Mario Estévez, Mónica Armenteros , David Morcuende 2013, 12(11): 1982-1992.  DOI: 10.1016/S2095-3119(13)60636-X Abstract ( )   PDF in ScienceDirect   The efficiency of extracts from Arbutus unedo L. (AU), Crataegus monogyna L. (CM), Rosa canina L. (RC), and Rubus ulmifolius Schott. (RU) to inhibit lipid oxidation in raw, cooked and cooked and chilled (2°C/12 d) porcine burger patties, was investigated. The modification of the fatty acid profile during processing treatments (cooking and chilling), the quantitative measurements of thiobarbituric acid reactive substances (TBA-RS), and lipid-derived volatiles, were used as indicators of lipid oxidation. Polyunsaturated fatty acids (PUFA) gradually decreased during cooking and the subsequent storage of cooked burger patties with this decrease being significantly greater (P<0.05) in control patties than in those with added berry extracts. In accordance, the control patties showed significantly higher TBA-RS numbers and counts of lipid-derived volatiles in all treatments when compared to the berry-added counterparts (P<0.05). Results from the present work show, for the first time, that extracts from A. unedo, C. monogyna, R. canina, and R. ulmifolius are promising antioxidants which could enhance the nutritional, safety and sensory properties of porcine burger patties.

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Changes of Intramuscular Fat Composition, Lipid Oxidation and Lipase Activity in Biceps femoris and Semimembranosus of Xuanwei Ham During Controlled Salting Stages WANG Zhen-yu, GAO Xiao-guang, ZHANG Ji-hong, ZHANG De-quan , MA Chang-wei 2013, 12(11): 1993-2001.  DOI: 10.1016/S2095-3119(13)60637-1 Abstract ( )   PDF in ScienceDirect   Fatty acid composition of neutral lipids (NLs), phospholipids (PLs) and free fatty acids (FFAs) from intramuscular fat (IMF), lipid oxidation and lipase activity in muscle Semimembranosus (SM) and msucle Biceps femoris (BF) of dry-cured Xuanwei ham during the 90-d salting stages were analysed. The salt content increased from 0.34 to 3.52% in BF and from 0.10 to 5.42% in SM during the 90 d salting stage, respectively. PLs of IMF in both BF and SM decreased 54.70% (P<0.001) and 34.64% (P<0.05), furthermore, the saturated fatty acids (SFA), monounsaturated fatty acids (MUFA) and polyunsaturated fatty acids (PUFA) of PLs in both muscles were hydrolysed almost isochronously. FFAs were increased from 0.46 g 100 g-1 lipids to 2.92 g 100 g-1 lipids in BF at the end of salting, which was lower than SM (from 1.29 g 100 g-1 lipids to 9.70 g 100 g-1 lipids). The activities of acid lipase, neutral lipase and acid phospholipase all remained active in the 90 d. The thiobarbituric acid reactive substances (TBARS) was slowly increased to 1.34 mg kg-1 muscle in BF and to 2.44 mg kg-1 muscle in SM during the salting stage. In conclusion, the controlled salting process prompted the hydrolysis of PLs of IMF notably and increased the lipid oxidation of muscles within some limits.

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Effect of the Inclusion of Chestnut in the Finishing Diet on Volatile Compounds of Dry-Cured Ham from Celta Pig Breed José M Lorenzo, Javier Carballo , Daniel Franco 2013, 12(11): 2002-2012.  DOI: 10.1016/S2095-3119(13)60638-3 Abstract ( )   PDF in ScienceDirect   The effect of the inclusion of chestnut in pigs finishing diet on volatile compounds of dry-cured Celta ham was studied. Twelve hams of each type (from three different pigs finishing diets: concentrate (CO), mixed (MI) and chestnut (CH)) were used. Volatiles were extracted using a purge-and-trap method and analyzed by gas chromatography/mass spectrometry (GC/MS). Thirty-nine volatile compounds were identified in dry-cured Celta ham samples. Most abundant volatiles in ham samples were aldehydes, which represented respectively, 53% (CO), 51% (MI) and 46% (CH) of the total volatile composition. With the exception of 2-butenal, 2-methyl, all aldehydes were affected by feeding system. On the other hand, hydrocarbons n-alkanes were the second major group in the volatile profile of dry-cured Celta hams and represented 28.9, 35.7 and 32.4% of the total volatile composition for CO, MI and CH groups, respectively. Ham samples from chestnut group showed a higher content of alcohols and this result could be related with the inclusion of chestnut in the finishing diet of pigs. Principal component analysis showed a good separation among groups. The discriminant analysis selected eight variables (butanoic acid, hexanal, octanal, nonenal (E), decenal (E), tetradecane, decane trimethyl and pyridine 2-methyl) and calculated two discriminating functions to predict if chestnut has been included in the finishing diet. Thus, it was possible to discriminate between groups fed with finishing diets containing chestnuts in their composition (mixed and chestnut group).

Crop Genetics · Breeding · Germplasm Resources

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Unintended Changes in Genetically Modified Rice Expressing the Lysine-Rich Fusion Protein Gene Revealed by a Proteomics Approach ZHAO Xiang-xiang, TANG Tang, LIU Fu-xia, LU Chang-li, HU Xiao-lan, JI Li-lian , LIU Qiaoquan 2013, 12(11): 2013-2021.  DOI: 10.1016/S2095-3119(13)60539-0 Abstract ( )   PDF in ScienceDirect   Development of new technologies for evaluating genetically modified (GM) crops has revealed that there are unintended insertions and expression changes in GM crops. Profiling techniques are non-targeted approaches and are capable of detecting more unintended changes in GM crops. Here, we report the application of a comparative proteomic approach to investigate the protein profile differences between a GM rice line, which has a lysine-rich protein gene, and its non-transgenic parental line. Proteome analysis by two-dimensional gel electrophoresis (2-DE) and mass spectrum analysis of the seeds identified 22 differentially expressed protein spots. Apart from a number of glutelins that were detected as targeted proteins in the GM line, the majority of the other changed proteins were involved in carbohydrate metabolism, protein synthesis and stress responses. These results indicated that the altered proteins were not associated with plant allergens or toxicity.

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Proteomic Analysis of Cucumber Defense Rresponses Induced by Propamocarb WU Peng, QIN Zhi-wei, WU Tao, ZHOU Xiu-yan, XIN Ming , GUO Qian-qian 2013, 12(11): 2022-2035.  DOI: 10.1016/S2095-3119(13)60370-6 Abstract ( )   PDF in ScienceDirect   Propamocarb is an agricultural chemical that has been widely used to protect cucumber plants from downy mildew. To understand the mechanisms of cucumber defense responses to propamocarb, we investigated the physiological and proteomic responses of the cucumber line D0351 with propamocarb application. We found that after treatment with propamocarb, the activities of detoxifying enzymes (glutathione reductase, GR; glutathione S-tramsferase, GST) and soluble sugar content of cucumber fruit were significantly increased, but malonaldehyde (MDA) content was significantly reduced. To identify components of propamocarb responsive signaling, we compared the high resolution two-dimensional gel electrophoresis (2-DE) protein profiles of control and propamocarb-treated fruits, and identified 18 differentially expressed (13 up-regulated and 5 down-regulated) proteins induced by propamocarb which were determined by matrix-assisted laser desorption/ionization timeof- flight mass spectrometry (MALDI-TOF-MS). The majority of the proteins had functions related to detoxication, energy and transport, protein biosynthesis, regulating reactions and defending against stresses. A real-time quantitative reverse transcriptional-polymerase chain reaction (qRT-PCR) was used to compare transcript and protein accumulation patterns for 18 candidate proteins, and the expression of 14 was consistent at both transcript and protein levels. The responses of cucumber proteome to propamocarb seemed complex; the identified proteins may play an important role in regulating adaptation activities following exposure to propamocarb. Data presented herein may shed light on understanding cucumber fruit defense responses under propamocarb treatment.

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Identification of Zinc Deficiency-Responsive MicroRNAs in Brassica juncea Roots by Small RNA Sequencing SHI Dong-qing, ZHANG Yuan, MA Jin-hu, LI Yu-long , XU Jin 2013, 12(11): 2036-2044.  DOI: 10.1016/S2095-3119(13)60641-3 Abstract ( )   PDF in ScienceDirect   The importance of zinc (Zn) as a micronutrient essential for plant growth and development is becoming increasingly apparent. Much of the world’s soil is Zn-deficient, and soil-based Zn deficiency is often accompanied by Zn deficiency in human populations. MicroRNAs (miRNAs) play important roles in the regulation of plant gene expression at the level of translation. Many miRNAs involved in the modulation of heavy metal toxicity responses in plants have been identified; however, the role of miRNAs in the plant Zn deficiency response is almost completely unknown. Using high-throughput Solexa sequencing, we identified several miRNAs that respond to Zn deficiency in Brassica juncea roots. At least 21 conserved candidate miRNA families, and 101 individual members within those families, were identified in both the control and the Zn-deficient B. juncea roots. Among this, 15 miRNAs from 9 miRNA families were differentially expressed in the control and Zn-deficient plants. Of the 15 differentially expressed miRNAs, 13 were up-regulated in the Zn-deficient B. juncea roots, and only two, miR399b and miR845a, were down-regulated. Bioinformatics analysis indicated that these miRNAs were involved in modulating phytohormone response, plant growth and development, and abiotic stress responses in B. juncea roots. These data help to lay the foundation for further understanding of miRNA function in the regulation of the plant Zn deficiency response and its impact on plant growth and development.

Physiology & Biochentry · Tillage · Cultivation

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Biological Effects of Low Energy N+ Beams Implantation on Calluses of Autotetraploid Rice ZHAO Shuai-peng, HUANG Qun-ce, LIANG Qiu-xia, ZHANG Shu-gen, JIAO Zhen 2013, 12(11): 2045-2055.  DOI: 10.1016/S2095-3119(13)60331-7 Abstract ( )   PDF in ScienceDirect   Calluses of two autotetraploid rice (DPR (4) and Zijing (4)) were implanted with 30 KeV N+ beams at doses ranging from 1.0×1015 to 9.0×1015 ions cm-2. The differentiation rates of calluses, the concentration of malondialdehyde (MDA), the activities of superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD), and the change of esterase (EST) spectrum were measured and analyzed on the calluses stage. The results showed that differentiation rates of calluses under 3.0×1015 ions cm-2 ((46.12±2.01)%) were higher than the other treatment groups in DPR (4), and those of Zijing (4) were similar under the doses of 1.0×1015, 3.0×1015 and 5.0×1015 ions cm-2 ((40.55±2.74), (37.77±3.04) and (34.56±2.65)%) and were higher than that of 7.0×1015 and 9.0×1015 ions cm-2. When the doses were 3.0×1015 and 5.0×1015 ions cm-2, the activities of SOD, POD and CAT were notably enhanced, and the accumulation of MDA content was markedly alleviated in the implanted calluses of two materials, as well as the activity of EST was increased by the additional isforms DPR (4). Whereas the anti-oxidative systems and enzymes spectrum of EST were destroyed seriously, the accumulation of MDA was significantly aggravated, also the differentiation rate of calluses reduced sharply and almost closed to zero when the implantation doses were 7.0×1015 and 9.0×1015 ions cm-2. It suggested that the proper dose of ion implantation effectively maintained the normal membrane structure and metabolism, and it would be also a feasible approach for autotetraploid rice to improve its genetic characteristics at calluses stage. Additionally, the differences of the radiation resistance between DPR (4) and Zijing (4) could be related to the different genotypes.

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Characteristics of Photosystem II Behavior in Cotton (Gossypium hirsutum L.) Bract and Capsule Wall ZHANG Ya-li, LUO Hong-hai, HU Yuan-yuan, Reto J Strasser, ZHANG Wang-feng 2013, 12(11): 2056-2064.  DOI: 10.1016/S2095-3119(13)60343-3 Abstract ( )   PDF in ScienceDirect   Though bract and capsule wall of boll in cotton (Gossypium hirsutum L.) have different photosynthetic capacities, the features of photosystem II (PS II) in these organs are scarce. In this paper, chlorophyll a fl uorescence emission was measured to investigate the difference in the photosynthetic apparatus of dark-acclimated (JIP-test) and light-acclimated (light-saturation pulse method) bract and capsule wall. Compared with leaves, the oxygen evolving system of non-foliar organs had lower effi ciency. The pool size of PS II electron acceptor of non-foliar organs was small, and the photochemical activity of leaves was higher than that of the bract and capsule wall. In regard to the photosystem I (PS I) electron acceptor side, the pool size of end electron acceptors of leaves was larger, and the quantum yield of electron transport from QA (PS II primary plastoquinone acceptor) further than the PS I electron acceptors of leaves was higher than that of bract and capsule wall. In all green organs, the actual quantum yield of photochemistry decreased with light. The thermal dissipation fraction of light absorbed by the PS II antennae was the highest in bract and the lowest in capsule wall relative to leaves. Compared with leaves, capsule wall was characterized by less constitutive thermal dissipation and via dissipation as fl uorescence emission. These results suggested that lower PS II photochemical activity in non-foliar organs may be result from limitations at the donor side of PS II and the acceptor sides of both photosystems.

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Developmental Characteristics and Cinnamic Acid Resistance of Root Border Cells in Cucumber and Figleaf Gourd Seedlings QIAO Yong-xu, ZHANG Yong-ping, ZHANG Hong-xin, TIAN Yong-qiang , GAO Li-hong 2013, 12(11): 2065-2073.  DOI: 10.1016/S2095-3119(13)60368-8 Abstract ( )   PDF in ScienceDirect   Root border cells (RBCs) originate from the root tip epidermis and surround the root apices. In this study, we evaluated the developmental characteristics and the roles of RBCs in protection of root apices of cucumber and fi gleaf gourd seedlings from CA toxicity. The formation of RBCs and the emergence of the root tip occurred almost simultaneously in root apices of cucumber and fi gleaf gourd seedlings. CA ranging from 0 to 0.25 mol L-1 inhibited root elongation and decreased root cell viability in the root tip, moreover the inhibitory effects of CA were more signifi cant in the CA-sensitive cucumber than in the CA-tolerant fi gleaf gourd. Removal of RBCs from root tips led to more severe CA induced inhibition of root elongation and decline in root cell viability. Increasing CA levels and treatment time decreased the relative viability of attached and detached RBCs. CA also induced a thicker mucilage layer surrounding attached RBCs of both species. Additionally, a signifi cantly higher relative cell viability of attached RBCs and thicker mucilage layers were observed in fi gleaf gourd. These results suggest that RBCs play an important role in protecting root tips from CA toxicity.

Plant Protection

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Hydrolysis and Photolysis of Herbicide Clomazone in Aqueous Solutions and Natural Water Under Abiotic Conditions CAO Jia, DIAO Xiao-ping , HU Ji-ye 2013, 12(11): 2074-2082.  DOI: 10.1016/S2095-3119(13)60506-7 Abstract ( )   PDF in ScienceDirect   The hydrolysis and photolysis of clomazone in aqueous solutions and natural water were assessed under natural and controlled conditions. Kinetics of hydrolysis and photolysis of clomazone were determined by HPLC-DAD. Photoproducts were identifi ed by HPLC-MS. No noticeable hydrolysis occurred in aqueous buffer solutions ((25±2)°C, pH (4.5±0.1), pH (7.4±0.1), pH (9.0±0.1); (50±2)°C, pH (4.5±0.1), pH (7.4±0.1)) or in natural water up to 90 d. At pH (9.0±0.1) and (50±2)°C the half-life of clomazone was 50.2 d. Clomazone photodecomposition rate in aqueous solutions under UV radiation and natural sunlight followed fi rst-order kinetics. Degradation rates were faster under UV light (half-life of 51-59 min) compared to sunlight (halflife of 87-136 d). Under UV light, four major photoproducts were detected and tentatively identifi ed according to HPLC-MS spectral information such as 2-chlorobenzamide, N-hydroxy-(2-benzyl)-2-methylpropan-amide, 2-[2-phenol]-4,4-dimethyl- 3-isoxazolidinone and 2-[(4,6-dihydroxyl-2-chlorine phenol)]-4,4-dimethyl-3-isoxazolidinone. These results suggested that clomazone photodegradation proceeds via several reaction pathways: 1) dehalogenation; 2) substitution of chlorine group by hydroxyl; 3) cleavage of the side chain. Photosensitizers, such as H2O2 and ribofl avin, could enhance photolysis of clomazone in natural sunlight. In summary, we found that photoreaction is an important dissipation pathway of clomazone in natural water systems.

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Nicotinic Acetylcholine Receptor Gene Family of the Pea Aphid, Acyrthosiphon pisum LIU Yi-peng, LIN Ke-jian, LIU Yang, GUI Fu-rong , WANG Gui-rong 2013, 12(11): 2083-2091.  DOI: 10.1016/S2095-3119(13)60505-5 Abstract ( )   PDF in ScienceDirect   The nicotinic acetylcholine receptors (nAchRs) are cholinergic receptors that form ligand-gated ion channels by five subunits in insect and vertebrate nervous systems. The insect nAChR is the molecular target of a class of insecticides, neonicotinoids. Here, we identified and cloned 11 candidate nAChR subunit genes in Acyrthosiphon pisum using genome-based bioinformatics combined modern molecular techniques. Most A. pisum nAChRs including α1, α2, α3, α4, α6, α8, and β1 show highly sequence identities with the counterparts of other insects examined. Expression profiles analysis showed that all subunit genes were expressed in adult head. At least two subunits have alternative splicing that obviously increase A. pisum nicotinic receptor diversity. This study will be invaluable for exploring the molecular mechanisms of neonicotinoid-like insecticides in sucking pests, and for ultimately establishing the screening platform of novel insecticides.

Soil & Fertilization · Irrigation · Agro-Ecology & Environment

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Soil pH Dynamics and Nitrogen Transformations Under Long-Term Chemical Fertilization in Four Typical Chinese Croplands MENG Hong-qi, XU Ming-gang, Lü Jia-long, HE Xin-hua, LI Jian-wei, SHI Xiao-jun, PENG 2013, 12(11): 2092-2102.  DOI: 10.1016/S2095-3119(13)60398-6 Abstract ( )   PDF in ScienceDirect   Long-term fertilization experiment provides the platform for understanding the proton budgets in nitrogen transformations of agricultural ecosystems. We analyzed the historical (1990-2005) observations on four agricultural long-term experiments in China (Changping, Chongqing, Gongzhuling and Qiyang) under four different fertilizations, i.e., no-fertilizer (control), sole chemical nitrogen fertilizer (FN), sole chemical phosphorous and potassium fertilizers (FPK) and chemical nitrogen, phosphorous and potassium fertilizers (FNPK). The significant decline in topsoil pH was caused not only by chemical N fertilization (0.29 and 0.89 ΔpH at Gongzhuling and Qiyang, respectively) but also by chemical PK fertilization (0.59 ΔpH at Gongzhuling). The enhancement of available nutrients in the topsoil due to long-term direct nutrients supply with chemical fertilizers was in the descending order of available P (168-599%)>available K (16-189%)>available N (9-33%). The relative rate of soil pH decline was lower under long-term judicious chemical fertilization (-0.036-0.034 ΔpH yr-1) than that under long-term sole N or PK fertilization (0.016-0.086 ΔpH yr-1). Long-term judicious chemical fertilization with N, P and K elements decreases the nutritional limitation to normal crop growth, under which more N output was distributed in biomass removal rather than the loss via nitrate leaching. We concluded that the N distribution percentage of nitrate leaching to biomass removal might be a suitable indicator to the sensitivity of agricultural ecosystems to acid inputs.

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Effect of Different Vegetation Types on the Rhizosphere Soil Microbial Community Structure in the Loess Plateau of China ZHANG Chao, LIU Guo-bin, XUE Sha , XIAO Lie 2013, 12(11): 2103-2113.  DOI: 10.1016/S2095-3119(13)60396-2 Abstract ( )   PDF in ScienceDirect   The Loess Plateau in China is one of the most eroded areas in the world. Accordingly, vegetation restoration has been implemented in this area over the past two decades to remedy the soil degradation problem. Understanding the microbial community structure is essential for the sustainability of ecosystems and for the reclamation of degraded arable land. This study aimed to determine the effect of different vegetation types on microbial processes and community structure in rhizosphere soils in the Loess Plateau. The six vegetation types were as follows: two natural grassland (Artemisia capillaries and Heteropappus altaicus), two artificial grassland (Astragalus adsurgens and Panicum virgatum), and two artificial shrubland (Caragana korshinskii and Hippophae rhamnoides) species. The microbial community structure and functional diversity were examined by analyzing the phospholipid fatty acids (PLFAs) and community-level physiological profiles. The results showed that rhizosphere soil sampled from the H. altaicus and A. capillaries plots had the highest values of microbial biomass C, average well color development of carbon resources, Gram-negative (G-) bacterial PLFA, bacterial PLFA, total PLFA, Shannon richness, and Shannon evenness, as well as the lowest metabolic quotient. Soil sampled from the H. rhamnoides plots had the highest metabolic quotient and Gram-positive (G+) bacterial PLFA, and soil sampled from the A. adsurgens and A. capillaries plots had the highest fungal PLFA and fungal:bacterial PLFA ratio. Correlation analysis indicated a significant positive relationship among the microbial biomass C, G- bacterial PLFA, bacterial PLFA, and total PLFA. In conclusion, plant species under arid climatic conditions significantly affected the microbial community structure in rhizosphere soil. Among the studied plants, natural grassland species generated the most favorable microbial conditions.

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Soil Aggregate Stability and Aggregate-Associated Carbon Under Different Tillage Systems in the North China Plain DU Zhang-liu, REN Tu-sheng, HU Chun-sheng, ZHANG Qing-zhong , Humberto Blanco-Canqui 2013, 12(11): 2114-2123.  DOI: 10.1016/S2095-3119(13)60428-1 Abstract ( )   PDF in ScienceDirect   The influences of tillage systems on soil carbon (C) stocks have been studied extensively, but the distribution of soil C within aggregate fractions is not well understood. The objective of this study was to determine the influences of various tillage systems on soil aggregation and aggregate-associated C under wheat (Triticum aestivum L.) and corn (Zea mays L.) double cropping systems in the North China Plain. The experiment was established in 2001, including four treatments: moldboard plow (MP) with residue (MP+R) and without residue (MP-R), rotary tillage with residue (RT), and no-till with residue (NT). In 2007 soil samples were collected from the 0-5, 5-10, and 10-20 cm depths, and were separated into four aggregate-size classes (>2 000, 250-2 000, 53-250, and <53 μm) by wet-sieving method. Aggregate-associated C was determined, and the relationships between total soil C concentration and aggregation-size fractions were examined. The results showed that NT and RT treatments significantly increased the proportion of macroaggregate fractions (>2 000 and 250-2 000 μm) compared with the MP-R and MP+R treatments. Averaged across all depths, mean weight diameters of aggregates (MWD) in NT and RT were 47 and 20% higher than that in MP+R. The concentration of bulk soil organic C was positively correlated with MWD (r=0.98; P=0.024) and macroaggregate fraction (r=0.96; P=0.036) in the 0-5 cm depth. In the 0-20 cm depth, comparing with MP+R, total C occluded in the >2 000 μm fraction was increased by 9 and 6% under NT and RT, respectively. We conclude that adoption of conservation tillage system, especially no-till, can increase soil macro-aggregation and total C accumulation in macroaggregates, which may improve soil C sequestration in the intensive agricultural region of the North China Plain.