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2019 Vol. 18 No. 1 Previous Issue    Next Issue

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Crop Science

Crop Science
Horticulture
Plant Protection
Animal Science · Veterinary Medicine
Agro-ecosystem & Environment
Food Science
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Somatic embryogenesis (SE) plays a vital role in genetic transformation and massive propagation of important agronomicaland economical crops. In this study, we conducted a systematic assessment of the morphological, cytochemical, and cytogenetical characteristics of six culture strains with various embryogenic/regenerative potential during SE process in cotton. Results indicated that the six cell culture strains had stable ploidy levels, and did not reveal any relationship between the cytogenetic state and their morphogenetic potential. Moreover, the six culture strains were compared via double staining with Evans blue and Acetocarmine to efficiently distinguish embryogenic and nonembryogenic cells and determine the embryogenic nature of the calli. In addition, the kind of auxins added in medium affected not only growth property, color, size of cell clumps but also ploidy level and regeneration ability. By combining analysis of morphological, cytochemical, and cytogenetical characteristics of the cell cultures, we are able to obtain and maintain homogeneous cell population with high morphogenic and regeneration ability and establish efficient somatic embryogenesis and regeneration system from short-term cell cultures in upland cotton, which highlight the application of biotechnological approaches in crop breeding, and above all, to better understand totipotency of cells in higher plants. The photo here shows high-regenerative somatic embryos under light microscope, provided by Prof. Zeng Fanchang from the State Key Laboratory of Crop Biology, Ministry of Science and Technology/College of Agronomy, Shandong Agricultural University, China. See pages 1–8 by Guo et al. in details.


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Crop Science

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Identification and characterization of cell cultures with various embryogenic/regenerative potential in cotton based on morphological, cytochemical, and cytogenetical assessment GUO Hui-hui, WU Jian-fei, CHEN Cui-xia, WANG Hong-mei, ZHAO Yun-lei, ZHANG Chao-jun, JIA Yin-hua, LIU Fang, NING Tang-yuan, CHU Zhao-hui, ZENG Fan-chang 2019, 18(1): 1-8.  DOI: 10.1016/S2095-3119(17)61876-8 Abstract ( )   PDF (10560KB) ( )   Somatic embryogenesis (SE) plays a vital role in genetic transformation and massive propagation of important agronomical and economical crops.  Here, we conducted a systematic assessment of the morphological, cytochemical, and cytogenetical characteristics of six culture strains with various embryogenic/regenerative potential during SE process in cotton.  Results indicated that the six cell culture strains had stable ploidy levels, and did not reveal any relationship between the cytogenetic state and their morphogenetic potential.  Moreover, the six culture strains were compared via double staining with Evans blue and Acetocarmine to efficiently distinguish embryogenic and non-embryogenic cells and determine the embryogenic nature of the calli.  In addition, the kind of auxins added in medium affected not only growth property, color, size of cell clumps but also ploidy level and regeneration ability.  By combining analysis of morphological, cytochemical, and cytogenetical characteristics of the cell cultures, we are able to obtain and maintain homogeneous cell population with high morphogenic and regeneration ability and establish efficient somatic embryogenesis and regeneration system from short-term cell cultures in upland cotton, which highlight the application of biotechnological approaches in crop breeding, and above all, to better understand totipotency of cells in higher plants.

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Transcriptome profiling reveals insights into the molecular mechanism of drought tolerance in sweetpotato ZHU Hong, ZHOU Yuan-yuan, ZHAI Hong, HE Shao-zhen, ZHAO Ning, LIU Qing-chang 2019, 18(1): 9-24.  DOI: 10.1016/S2095-3119(18)61934-3 Abstract ( )   PDF in ScienceDirect   Sweetpotato, Ipomoea batatas (L.) Lam., is a globally important food crop and usually grown on arid- and semi-arid lands.  Therefore, investigating the molecular mechanism of drought tolerance will provide important information for the improvement of drought tolerance in this crop.  In this study, transcriptome analysis of the drought-tolerant sweetpotato line Xushu 55-2 was conducted on Illumina HiSeq 2500 platform.  A total of 86.69 Gb clean data were generated and assembled into 2 671 693 contigs, 222 073 transcripts, and 73 636 unigenes.  In total, 11 359 differentially expressed genes (DEGs) were identified after PEG6000 treatment, in which 7 666 were up-regulated and 3 693 were down-regulated.  Of the 11 359 DEGs, 10 192 DEGs were annotated in at least one database, and the remaining 1 167 DEGs were unknown.  Abscisic acid (ABA), ethylene (ETH), and jasmonic acid (JA) signalling pathways play a major role in drought tolerance of sweetpotato.  Drought-inducible transcription factors were identified, some of which have been reported to be associated with drought tolerance and others are unknown in plants.  In addition, 7 643 SSRs were detected.  This study not only reveals insights into the molecular mechanism of drought tolerance in sweetpotato but also provides the candidate genes involved in drought tolerance of this crop.

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No-tillage effects on grain yield and nitrogen requirements in hybrid rice transplanted with single seedlings: Results of a long-term experiment HUANG Min, CHEN Jia-na, CAO Fang-bo, ZOU Ying-bin, Norman Uphoff 2019, 18(1): 24-32.  DOI: 10.1016/S2095-3119(17)61873-2 Abstract ( )   PDF in ScienceDirect   This study was conducted to determine whether, and if so how, the grain yield and nitrogen (N) requirements of hybrid rice transplanted as single seedlings are affected by no-tillage (NT) practices.  A fixed field experiment was done at the Experimental Farm of Hunan Agricultural University in Changsha, Hunan Province, China, from 2004 to 2014.  Grain yield and yield attributes (panicle number per m2, spikelet number per panicle, spikelet filling percentage, grain weight, total biomass, and harvest index) were evaluated as well as the N-use characteristics (total N uptake, internal N-use efficiency, and N requirements) of hybrid rice transplanted as single seedlings comparing NT with conventional tillage (CT).  A significant finding was that there were no significant differences in grain yield, yield attributes, and N-use characteristics between CT and NT.  Averaged across the 11 years, grain yield and N requirements were 9.51 t ha−1 and 20.2 kg t−1 under CT and 9.33 t ha−1 and 20.0 kg t−1 under NT, respectively.  There were significant yearly variations in grain yield, yield attributes, and N-use characteristics observed under both CT and NT.  The yearly variation in grain yield was related to simultaneous changes in spikelet number per panicle, grain weight, total biomass, and harvest index.  Also, it was found that grain yield was positively correlated with internal N-use efficiency but negatively correlated with N requirements.  It is concluded that grain yield and N requirements in hybrid rice when transplanted as single seedlings are not affected adversely by NT.  The results of this study suggest that (1) compatible relationships among yield attributes can be established in hybrid rice that is transplanted as single seedlings, and (2) higher grain yield and higher N-use efficiency can be concurrently achieved in hybrid rice transplanted as single seedlings.

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No-tillage effects on grain yield and nitrogen requirements in hybrid rice transplanted with single seedlings: Results of a long-term experiment REN Ai-xia, SUN Min, WANG Pei-ru, XUE Ling-zhu, LEI Miao-miao, XUE Jian-fu, GAO Zhi-qiang, YANG Zhen-ping 2019, 18(1): 33-42.  DOI: 10.1016/S2095-3119(18)61980-X Abstract ( )   PDF in ScienceDirect   Sowing date and seeding rate are critical for productivity of winter wheat (Triticum aestivum L.).  A three-year field experiment was conducted with three sowing dates (20 September (SD1), 1 October (SD2), and 10 October (SD3)) and three seeding rates (SR67.5, SR90, and SR112.5) to determine suitable sowing date and seeding rate for high wheat yield.  A large seasonal variation in accumulated temperature from sowing to winter dormancy was observed among three growing seasons.  Suitable sowing dates for strong seedlings before winter varied with the seasons, that was SD2 in 2012–2013, SD3 in 2013–2014, and SD2 as well as SD1 in 2014–2015.  Seasonal variation in precipitation during summer fallow also had substantial effects on soil water storage, and consequently influenced grain yield through soil water consumption from winter dormancy to maturity stages.  Lower consumption of soil water from winter dormancy to booting stages could make more water available for productive growth from anthesis to maturity stages, leading to higher grain yield.  SD2 combined with SR90 had the lowest soil water consumption from winter dormancy to booting stages in 2012–2013 and 2014–2015; while in 2013–2014, it was close to that with SR67.5 or SR112.5.  For productive growth from anthesis to maturity stages, SD2 with SR90 had the highest soil water consumption in all three seasons.  The highest water consumption in the productive growth period resulted in the best grain yield in both low and high rainfall years.  Ear number largely contributed to the seasonal variation in grain yield, while grain number per ear and 1 000-grain weight also contributed to grain yield, especially when soil water storage was high.  Our results indicate that sowing date and seeding rate affect grain yield through seedling development before winter and also affect soil water consumption in different growth periods.  By selecting the suitable sowing date (1 October) in combination with the proper seeding rate of 90 kg ha–1, the best yield was achieved.  Based on these results, we recommend that the current sowing date be delayed from 22 or 23 September to 1 October.

Crop Science

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Shade stress decreases stem strength of soybean through restraining lignin biosynthesis LIU Wei-guo, Sajad Hussain, LIU Ting, ZOU Jun-lin, REN Meng-lu, ZHOU Tao, LIU Jiang, YANG Feng, YANG Wen-yu 2019, 18(1): 43-53.  DOI: 10.1016/S2095-3119(18)61905-7 Abstract ( )   PDF in ScienceDirect   Lodging is the most important constraint for soybean growth at seedling stage in maize-soybean relay strip intercropping system.  In the field experiments, three soybean cultivars Nandou 032-4 (shade susceptible cultivar; B1), Jiuyuehuang (moderately shade tolerant cultivar; B2), and Nandou 12 (shade tolerant cultivar; B3) were used to evaluate the relationship between stem stress and lignin metabolism in the stem of soybean.  Results showed that the intercropped soybean was in variable light condition throughout the day time and co-growth stage with maize.  The xylem area and cross section ratio played a main role to form the stem stress.  The B3 both in intercropping and monocropping expressed a high stem stress with higher xylem area, lignin content, and activity of enzymes (phenylalanine ammonia-lyase (PAL), 4-coumarate: CoA ligase (4CL), cinnamyl alcohol dehydrogenase (CAD), and peroxidase (POD)) than those of B1 and B2.  Among the soybean cultivars and planting pattern, lignin content was positively correlated with stem stress.  However, a negative correlation was found between lignin content and actual rate of lodging.  In conclusion, the shade tolerant soybean cultivar had larger xylem area, higher lignin content and activities of CAD, 4CL, PAL, and POD than other soybean cultivars in intercropping.  The lodging in maize-soybean intercropping can be minimized by planting shade tolerant and lodging resistant cultivar of soybean.  The lignin content in stem could be a useful indicator for the evaluation of lodging resistance of soybean in intercropping and activities of enzymes were the key factors that influence the lignin biosynthesis.

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Simple model based on artificial neural network for early prediction and simulation winter rapeseed yield Gniewko Niedbała 2019, 18(1): 54-61.  DOI: 10.1016/S2095-3119(18)62110-0 Abstract ( )   PDF (1633KB) ( )   The aim of the research was to create a prediction model for winter rapeseed yield.  The constructed model enabled to perform simulation on 30 June, in the current year, immediately before harvesting.  An artificial neural network with multilayer perceptron (MLP) topology was used to build the predictive model.  The model was created on the basis of meteorological data (air temperature and atmospheric precipitation) and mineral fertilization data.  The data were collected in the period 2008–2017 from 291 productive fields located in Poland, in the southern part of the Opole region.  The assessment of the forecast quality created on the basis of the neural model has been verified by defining forecast errors using relative approximation error (RAE), root mean square error (RMS), mean absolute error (MAE), and mean absolute percentage error (MAPE) metrics.  An important feature of the created predictive model is the ability to forecast the current agrotechnical year based on current weather and fertilizing data.  The lowest value of the MAPE error was obtained for a neural network model based on the MLP network of 21:21-13-6-1:1 structure, which was 9.43%.  The performed sensitivity analysis of the network examined the factors that have the greatest impact on the yield of winter rape.  The highest rank 1 was obtained by an independent variable with the average air temperature from 1 January to 15 April of 2017 (designation by the T1-4_CY model).

Horticulture

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Overhead supplemental far-red light stimulates tomato growth under intra-canopy lighting with LEDs ZHANG Ya-ting, ZHANG Yu-qi, YANG Qi-chang, LI Tao 2019, 18(1): 62-69.  DOI: 10.1016/S2095-3119(18)62130-6 Abstract ( )   PDF (1023KB) ( )   Far-red (FR) light regulates phytochrome-mediated morphological and physiological plant responses.  This study aims to investigate how greenhouse tomato morphology and production response to different durations of FR light during daytime and at the end of day (EOD).  High-wire tomato plants were grown under intra-canopy lighting consisting of red (peak wavelength at 640 nm) and blue (peak wavelength at 450 nm) light-emitting diodes (LEDs) with photosynthetic photon flux density (PPFD) of 144 μmol m–2 s–1 at 10 cm away from the lamps, and combined with overhead supplemental FR light (peak wavelength at 735 nm) with PPFD of 43 μmol m–2 s–1 at 20 cm below the lamps.  Plants were exposed to three durations of FR supplemental lighting including: 06:00–18:00 (FR12), 18:00–19:30 (EOD-FR1.5), 18:00–18:30 (EOD-FR0.5), and control that without supplemental FR light.  The results showed that supplemental FR light significantly stimulated stem elongation thereby resulting in longer plants compared with the control.  Moreover, FR light altered leaf morphology toward higher leaf length/width ratio and larger leaf area.  The altered plant architecture in FR supplemented plants led to a more homogeneous light distribution inside the canopy.  Total plant biomass was increased by 9–16% under supplemental FR light in comparison with control, which led to 7–12% increase in ripe fruit yield.  Soluble sugar content of the ripe tomato fruit was slightly decreased by longer exposure of the plants to FR light.  Dry matter partitioning to different plant organs were not substantially affected by the FR light treatments.  No significant differences were observed among the three FR light treatments in plant morphology as well as yield and biomass production.  We conclude that under intra-canopy lighting, overhead supplemental FR light stimulates tomato growth and production.  And supplementary of EOD-FR0.5 is more favorable, as it consumes less electricity but induces similar effects on plant morphology and yield.

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Effects of different color paper bags on aroma development of Kyoho grape berries JI Xiao-hao, WANG Bao-liang, WANG Xiao-di, SHI Xiang-bin, LIU Pei-pei, LIU Feng-zhi, WANG Hai-bo 2019, 18(1): 70-82.  DOI: 10.1016/S2095-3119(18)62008-8 Abstract ( )   PDF in ScienceDirect   This study investigated the influence of red, green, blue, and white paper bags on the free volatile compound development of Kyoho grape berries from green to harvest.  Seven functional groups of volatiles were identified during the development of Kyoho grape berries including esters, aldehydes, alcohols, terpenes, ketones, acids, and hydrocarbons.  Esters and aldehydes were abundant in Kyoho grape berries, mainly represented by ethyl acetate, ethyl butyrate, and (E)-2-hexenal.  They accumulated quickly after veraison and slightly decreased toward maturation.  Red, green, blue, and white paper bags promoted the accumulation of esters and inhibited the accumulation of aldehydes, also inhibited the accumulation of alcohols, tepenes, ketones, and acids.  Their effect from strong to weak was green, blue, red, and white paper bags.  The expression profiles of genes in the lipoxygenase-hydroperoxide lyase (LOX-HPL) pathway were also analyzed and the results indicated that the regulation of red, green, blue, and white paper bags on aldehydes, alcohols, and esters volatile aromas was at transcriptional level.  The results expanded our comprehension in grape aroma biosynthesis and berry bagging technique in table grape cultivation.

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Growth and physiological responses of four kiwifruit genotypes to salt stress and resistance evaluation ZHONG Yun-peng, QI Xiu-juan, CHEN Jin-yong, LI Zhi, BAI Dan-feng, WEI Cui-guo, FANG Jin-bao 2019, 18(1): 83-95.  DOI: 10.1016/S2095-3119(18)62011-8 Abstract ( )   PDF in ScienceDirect   In this study, four genotypes (Acva-1, Acva-2, Acva-3 and ZM-2) of Actinidia germplasm resources were grown in different NaCl concentrations (0, 0.4, 0.8 and 1.2 g L–1).  The growth, physiological and biochemical indicators were measured, and a graded scale was developed as the salt damage index (SDI) according to different damage symptoms in leaves.  The results showed SDI increased gradually, and average number and length of new shoot decreased significantly.  Three antioxidant enzymes (superoxide dismutase, peroxidase and catalase) and two osmotic adjustment substances (soluble sugar and proline) showed different changes in old and new leaves of four genotypes.  SPAD values exhibited a decreased trend in the whole except in the new leaves of Acva-2.  Malonaldehyde contents increased and root activity decreased with the increasing salt concentrations.  Principal component analysis was used to assess the salt tolerance, and the results showed Acva-3, from Actinidia valvata Dunn., had the strongest tolerance to salt, and could be a potential resistant resource to the salt-tolerance dedicated rootstock breeding of kiwifruit.

Plant Protection

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Comparative analysis of protein kinases and associated domains between Ascomycota and Basidiomycota PEI Guo-liang, GUO Jun, WANG Qin-hu, KANG Zhen-sheng 2019, 18(1): 96-107.  DOI: 10.1016/S2095-3119(18)62022-2 Abstract ( )   PDF (1842KB) ( )   Protein kinases play an important role in every aspect of cellular life.  In this study, we systemically identified protein kinases from the predicted proteomes of 59 representative fungi from Ascomycota and Basidiomycota.  Comparative analysis revealed that fungi from Ascomycota and Basidiomycota differed in the number and variety of protein kinases.  Some groups of protein kinases, such as calmodulin/calcium regulated kinases (CMGC) and those with the highest group percentages are the most prevalent protein kinases among all fungal species tested.  In contrast, the STE group (homologs of the yeast STE7, STE11 and STE20 genes), was more abundant in Basidiomycetes than in Ascomycetes.  Importantly, the distribution of some protein kinase families appeared to be subphylum-specific.  The tyrosine kinase-like (TKL) group had a higher protein kinase density in Agaricomycotina fungi.  In addition, the distribution of accessory domains, which could have functional implications, demonstrated that usage bias varied between the two phyla.  Principal component analysis revealed a divergence between the main functional domains and associated domains in fungi.  This study provides novel insights into the variety and expansion of fungal protein kinases between Ascomycota and Basidiomycota.

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Molecular mapping of stripe rust resistance gene YrH9017 in wheat-Psathyrostachys huashanica introgression line H9017-14-16-5-3 MA Dong-fang, HOU Lu, SUN Cai, ZHANG Xing, YIN Jun-liang, GUO Qing-yun, ZHU Yong-xing 2019, 18(1): 108-114.  DOI: 10.1016/S2095-3119(18)62048-9 Abstract ( )   PDF in ScienceDirect   Several new stripe rust pathogen races emerged in the wheat growing regions of China in recent years.  These races were virulent to most of the designated wheat seedling resistance genes.  Thus, it is necessary and worthwhile to identify new valuable resistant materials for the sake of diversifying resistant sources, pyramiding different resistance genes and achieving durable resistance.  Here, we identified the resistance gene, temporarily designated as YrH9017, in wheat-Psathyrostachys huashanica introgression line H9017-14-16-5-3.  A total of 146 F2 plants and their derived F2:3 families in a cross of Mingxian 169 and H9017-14-16-5-3 were used to evaluate seedling stripe rust response and as a mapping population.  Finally, we constructed a genetic map including eight simple sequence repeat (SSR) markers and expressed sequence tag (EST) markers.  YrH9017 was located on the long arm of chromosome 2A and closely linked with two EST-sequence tagged site (EST-STS) markers BG604577 and BE471201 at 1.3 and 1.8 cM distance, respectively.  The two closest markers could be used for marker-assisted selection of YrH9017 in breeding.

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Effect of plant extracts on activity of some defense enzymes of apple fruit in interaction with Botrytis cinerea Jalal Gholamnezhad 2019, 18(1): 115-123.  DOI: 10.1016/S2095-3119(18)62104-5 Abstract ( )   PDF in ScienceDirect   The efficacy of seven plant extracts (neem, fennel, lavender, thyme, pennyroyal, salvia and asafetida) in controlling postharvest of apple (caused by Botrytis cinerea) was evaluated in vitro and in vivo.  In vitro, all plant extracts treatments inhibited spore germination.  Inhibitory rates of pore germination was 17.41 and 20.83% for neem extract treatment (methanolic and aqueous extracts, respectively) with significant difference compared to control (73.6 and 85.33%) for aqueous and methanol extracts.  In the storage conditions, the application of aqueous extract of neem (at concentration of 25%) resulted in 89.11% reduction of disease severity compared with the untreated control.  Results of enzymes activity showed the plant extracts can increase the activity of peroxidase, phenylalanine ammonia-lyase, β-1,3-glucanase and polyphenol oxidase in the presence of pathogens, in apple fruits.  However, the results of this research revealed that application of neem extracts was more effective than the application of other plant extracts.  According to this study, it could be concluded that plant extracts may be useful to control postharvest disease as a safe alternative option to chemical fungicides.

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Selectivity and sublethal effects of some frequently-used biopesticides on the predator Cyrtorhinus lividipennis Reuter (Hemiptera: Miridae) DAI Wei, LI Yao, ZHU Jun, GE Lin-quan, YANG Guo-qing, LIU Fang 2019, 18(1): 124-133.  DOI: 10.1016/S2095-3119(17)61845-8 Abstract ( )   PDF (783KB) ( )   The green miridbug, Cyrtorhinus lividipennis, is an important predator of the rice brown planthopper, Nilaparvata lugens.  In this study, the selective toxicity of seven commercial biopesticides for C. lividipennis was examined under laboratory conditions; abamectin was the most selective to C. lividipennis, followed by matrine and azadirachtin.  Veratridine, rotenone, Bacillus thuringiensis and Beauveria bassiana showed less selectivity for C. lividipennis.  Subsequently, matrine, abamectin and azadirachtin were selected for sublethal assessments with respect to C. lividipennis due to their high toxicities to N. lugens.  C. lividipennis treated with sublethal concentrations (LC10 and LC20) of the three biopesticides could distinguish volatiles released from healthy and N. lugens-infested plants indicating that the biopesticides tested did not affect the foraging ability of surviving miridbugs.  Azadirachtin decreased the consumption capability of C. lividipennis when the densities of N. lugens were 20, 30, 40 and 50 insects per vial.  Sublethal concentration treatment did not impact the pre-oviposition period or egg hatchability of C. lividipennis.  However, the fecundity of C. lividipennis exposed to azadirachtin and abamectin increased by 27–41% compared to the untreated individuals.  In summary, abamectin or matrine together with C. lividipennis could be considered an effective, sustainable pest management strategy for rice.

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Effects of lead stress on Vg expression in the beet armyworm over five successive generations SU Hong-hua, YANG Yong, QIAN Yuan-yuan, YE Zi-bo, CHEN Yu-qing, YANG Yi-zhong 2019, 18(1): 134-142.  DOI: 10.1016/S2095-3119(18)61931-8 Abstract ( )   PDF in ScienceDirect   Heavy metals have been found to be endocrine disruptors in invertebrates.  Lead is one of the most widespread elements of contamination, but there has been no research about the effects of lead stress on vitellogenin (Vg) gene expression in insects exposed to lead over multiple generations.  In this paper, the effects of different concentrations of lead (0, 0.3, 4.8 and 76.8 mg kg–1) on the expression of Vg in the beet armyworm over five successive generations were studied.  The results showed that lead stress had significant effects on Vg expression in a dose-dependent manner.  For females at the larval and adult stages, as lead concentration increased, Vg expression was significantly inhibited; for males at these two developmental stages, Vg expression was induced and increased as lead concentration increased.  In addition, with the increase over stressed generations, inhibited effects for females and induced effects for males at the larval and adult stages became increasingly more obvious.  However, at the pupal stage, Vg expression in the two genders was different from that at the larval and adult stages.  The results indicate that lead stress can upregulate Vg expression in males which should be a useful indicator for environmental risk assessment.

Animal Science · Veterinary Medicine

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Effect of dietary supplementation with mulberry (Morus alba L.) leaves on the growth performance, meat quality and antioxidative capacity of finishing pigs ZENG Zhu, JIANG Jun-jie, YU Jie, MAO Xiang-bing, YU Bing, CHEN Dai-wen 2019, 18(1): 143-151.  DOI: 10.1016/S2095-3119(18)62072-6 Abstract ( )   PDF in ScienceDirect   The present study was conducted to evaluate the effect of dietary mulberry (Morus alba L.) leaves powder (MLP) supplementation on meat quality of finishing pigs.  A total of 40 Duroc×Landrace×Yorkshire pigs (initial body weight of (40.5±0.63) kg) were randomly allotted into two treatments, fed either with control diet or 15% MLP diet for 85 d.  The results showed that MLP diet decreased (P≤0.05) average daily gain (ADG) and increased (P<0.05) feed/gain ratio (F/G) in the finishing and whole period.  MLP diet also decreased (P<0.05) carcass weight, dressing percentage, last rib and average backfat depth.  However, MLP diet increased (P<0.05) intramuscular fat (IMF) content, decreased (P<0.05) shear force, cooking loss and drip loss.  In addition, MLP diet increased (P<0.05) total antioxidative capacity, glutathione peroxidase and tended (P<0.10) to increase total superoxide dismutase in serum.  In longissimus thoracis, myosin heavy chain (MyHC) I and IIa mRNA levels were increased (P≤0.05) for MLP diet.  In conclusion, 15% MLP supplementation reduced the growth performance and carcass traits, but improved meat quality of finishing pigs possibly through the change of myofiber characteristics, enhancement of antioxidative capacity and increase of IMF.

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Effect of relative humidity at either acute or chronic moderate temperature on growth performance and droppings’ corticosterone metabolites of broilers ZHOU ying, LI Xiu-mei, ZHANG Min-hong, FENG Jing-hai 2019, 18(1): 152-159.  DOI: 10.1016/S2095-3119(18)62049-0 Abstract ( )   PDF in ScienceDirect   The present study aimed to investigate the effect of relative humidity (RH) at either acute or chronic moderate ambient temperature (Ta) on growth performance and droppings’ corticosterone metabolites of broilers.  Two experiments were conducted: effect of RH (35, 60 or 85%) on average daily feed intake (ADFI) and droppings’ corticosterone metabolites at acute (1 d: 20–26 or 31–20°C, 26 or 31°C for 6 h d–1 at 10:00–16:00) moderate Ta (experiment 1) and effect of RH (35, 60 or 85%) on growth performance and droppings’ corticosterone metabolites at chronic (step-wisely increasing temperature by 3°C every 3 d from 20 to 32°C within 15 d: 20–23–26–29–32°C) moderate Ta (experiment 2).  Droppings were collected at the 2, 4, 6, 8, and 22 h after Ta-RH controlled in experiment 1 and at the 2, 4, 6, and 22 h after Ta controlled to 32°C in experiment 2.  The results showed that: 1) In experiment 1, 85% RH increased (P<0.05) the droppings’ corticosterone metabolites at the 2, 6, 8, and 22 h and 35% RH increased (P<0.05) it at the 2 and 22 h compared to the 60% RH.  Moreover, 85% RH further increased (P<0.05) it compared to the 35% RH, however, no difference (P>0.05) was found in ADFI among the three RH groups at acute moderate 26°C; 35 and 85% RH increased (P<0.05) droppings’ corticosterone metabolites at the 2, 6, 8 and 22 h and decreased (P<0.05) ADFI compared to the 60% RH, moreover, 85% RH further increased (P<0.05) droppings’ corticosterone metabolites and further decreased (P<0.05) ADFI compared to the 35% RH at acute moderate 31°C; and the average of droppings’ corticosterone metabolites in the whole period had a negative correlation (P<0.02) with the ADFI.  2) In experiment 2, 85% RH increased (P<0.01) droppings’ corticosterone metabolites only at the 2 h and decreased (P<0.02) ADFI and average daily gain (ADG) compared to the 60% RH, no difference (P>0.05) in droppings’ corticosterone metabolites was found between the 35 and 60% RH, however, 35% RH decreased (P<0.01) ADG compared to the 60% RH, and the average of droppings’ corticosterone metabolites in the whole period also had a negative correlation (P<0.02) with ADFI and ADG.  In conclusion, droppings’ corticosterone metabolites could be used as a RH stress index and low and high RH, especially high RH, reduced growth performance possibly through inducing RH stress at moderate temperature.

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Mycoplasma leachii causes bovine mastitis: Evidence from clinical symptoms, histopathology and immunohistochemistry CHANG Ji-tao, YU De-bin, LIANG Jian-bin, CHEN Jia, WANG Jian-fa, WANG Fang, JIANG Zhi-gang, HE Xi-jun, WU Rui, YU Li 2019, 18(1): 160-168.  DOI: 10.1016/S2095-3119(18)62051-9 Abstract ( )   PDF (8004KB) ( )   Twelve quarters of six lactating cows were inoculated with Mycoplasma leachii strain GN407 through intramammary ductal infusion; another 12 quarters were inoculated with heat-inactivated M. leachii culture medium as negative controls.  Multidisciplinary procedures, including clinical assessment, etiology assessment, pathology and immunohistochemistry (IHC), were used to elucidate the pathogenicity of M. leachii in bovine mastitis.  From post-inoculation days (PIDs) 3 to 9, 12 inoculated quarters developed mild to severe clinical mastitis and mammary tissue histopathological changes, including inflammatory cell infiltration and architectural destruction of mammary gland ducts.  The M. leachii antigen was also detected by IHC in the mammary gland epithelial cells of the inoculated quarters as a weak signal on PID 6 and as a strong signal on PID 9.  The control quarters also developed mild mastitis and histopathological changes on PID 9, and M. leachii was also detected by IHC.  Throughout the experimental period, the quarters of the negative control cow were clinically and pathologically normal, and the M. leachii antigen was not detected.  In conclusion, direct histological and immunohistochemical evidence confirmed that M. leachii causes clinical bovine mastitis through histopathological lesions induced by invasion of the pathogen into mammary gland cells and through inflammatory cell infiltration.

Agro-ecosystem & Environment

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Closing the nitrogen use efficiency gap and reducing the environmental impact of wheat-maize cropping on smallholder farms in the Guanzhong Plain, Northwest China LÜ Feng-lian, HOU Miao-miao, ZHANG Hong-tao, Asif Khan, Muhammad Ayaz, QIANGJIU Ciren, HU Chang-lu, YANG Xue-yun, SUN Ben-hua, ZHANG Shu-lan 2019, 18(1): 169-178.  DOI: 10.1016/S2095-3119(18)61948-3 Abstract ( )   PDF in ScienceDirect   A high crop yield with the minimum possible cost to the environment is generally desirable.  However, the complicated relationships among crop production, nitrogen (N) use efficiency and environmental impacts must be clearly assessed.  We conducted a series of on-farm N application rate experiments to establish the linkage between crop yield and N2O emissions in the Guanzhong Plain in Northwest China.  We also examined crop yield, partial factor productivity of applied N (PFPN) and reactive N (Nr) losses through a survey of 1 529 and 1 497 smallholder farms that grow wheat and maize, respectively, in the region.  The optimum N rates were 175 and 214 kg ha−1 for winter wheat and summer maize, respectively, thereby achieving the yields of 6 799 and 7 518 kg ha−1, correspondingly, with low N2O emissions based on on-farm N rate experiments.  Among the smallholder farms, the average N application rates were 215 and 294 kg ha−1 season−1, thus producing 6 490 and 6 220 kg ha−1 of wheat and maize, respectively.  The corresponding PFPN values for the two crops were 36.8 and 21.2 kg N kg−1, and the total N2O emissions were 1.50 and 3.88 kg ha−1, respectively.  High N balance, large Nr losses and elevated N2O emissions could be explained by the overdoses of N application and low grain yields under the current farming practice.  The crop yields, N application rates, PFPN and total N2O for wheat and maize were 18 and 24% higher, 42 and 37% less, 75 and 116% higher, and 42 and 47% less, correspondingly, in the high-yield and high-PFPN group than in the average smallholder farms.  In conclusion, closing the PFPN gap between the current average and the value for the high-yield and high-PFPN group would increase crop production and reduce Nr losses or the total N2O emissions for the investigated cropping system in Northwest China.

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Derivation of soil Pb/Cd/As thresholds for safety of vegetable planting: A case study for pakchoi in Guangdong Province, China LI Fu-rong, WEN Dian, WANG Fu-hua, SUN Fang-fang, WANG Xu, DU Ying-qiong, LIU Xiang-xiang, WAN Kai 2019, 18(1): 179-189.  DOI: 10.1016/S2095-3119(18)61975-6 Abstract ( )   PDF in ScienceDirect   Regional guidelines for soil heavy metals, in conjunction with specific crops, are proposed to better assess soil environmental quality.  In this study, large amounts of soils with different levels of Pb/Cd/As pollution were collected in Guangdong Province, China, to carry out a pot experiment, which was closer to the actual situation and properties of the heavy metal contaminated soils.  Taking the widely planted vegetable pakchoi as the research object, we analyzed the correlations between the Pb/Cd/As concentrations in pakchoi and the total or available soil Pb/Cd/As concentrations and established their optimal regression equations.  And then, the total and available soil Pb/Cd/As thresholds for pakchoi were calculated according to the allowable Pb/Cd/As limits in pakchoi and were compared with the current soil assessment standards.  Furthermore, a lot of paired vegetable-soil samples in field were collected and their pollution situations were assessed by both the current limit thresholds and the calculated thresholds.  Obviously, it was more consistent to assess the Cd and As pollution situation of the vegetable and soil samples with the calculated soil thresholds than the current soil assessment thresholds.  It further proved that it was necessary to explore the soil heavy metal thresholds for safety of vegetable in specific regions, which would be more scientific and practical to guide safety production of local agricultural products and effective utilization of soil resources.

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A major pathway for carbon and nitrogen losses- Gas emissions during storage of solid pig manure in China SHAN Nan, LI Hu, LI Jian-zheng, Ee Ling Ng, MA Yan, WANG Li-gang, CHEN Qing 2019, 18(1): 190-200.  DOI: 10.1016/S2095-3119(17)61902-6 Abstract ( )   PDF (1246KB) ( )   This study investigated the carbon (C) and nitrogen (N) gas emissions (N2O, NH3, CO2 and CH4) from solid pig manure management in China.  Gas emissions were quantified from static piles over 60 days during summer in China’s Yangtze River Basin, using Drager-Tube and static chamber-gas chromatography techniques.  High emissions of NH3 and N2O were observed at the early stage of storage, but high emission of CH4 occured later during storage.  Overall, 62% of the total C in the original pile was lost; CO2 and CH4 emissions accounted for 57 and 0.2% of C lost respectively.  Over the same time, 41% of the total N in the original pile was lost; NH3 and N2O emissions accounted for 15 and 0.3% of N lost respectively.  The volatilization of NH3 during storage in summer was 4.56 g NH3 per kg dry weight.  The total greenhouse gas (GHG) emissions during storage accounted for 67.93 g CO2 equivalent per kg dry weight; N2O and CH4 contributed to 46 and 55% of total GHG emissions respectively.  Given China’s major role in pig production, further attention should given to pig manure management to mitigate its contribution to atmospheric pollution.

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Removal of Cd and Pb with biochar made from dairy manure at low temperature CHEN Zhi-liang, ZHANG Jian-qiang, HUANG Ling, YUAN Zhi-hui, LI Zhao-jun, LIU Min-chao 2019, 18(1): 201-210.  DOI: 10.1016/S2095-3119(18)61987-2 Abstract ( )   PDF in ScienceDirect   Biochar (BC) derived from waste products is a cost-effective sorbent for remediation of metal-contaminated soils.  We studied the kinetics and adsorption mechanisms for removal of metal ions, such as lead (Pb2+) and cadmium (Cd2+) with biochar.  The adsorption capacities of BC for Pb2+ and Cd2+ increased after alkaline treatment.  The highest sorption capacities were 175.53 and 68.08 mg g–1, for Pb and Cd, respectively.  The Langmuir adsorption isotherm and pseudo second kinetic equation could well fit the adsorption processes, revealing that the sorption mechanisms of Pb2+ and Cd2+ by BC are complex and predominantly controlled by chemisorption.  BC has a higher affinity for Pb than Cd, due to easy hydrolysis of Pb at low pH.  Furthermore, precipitation as carbonate minerals (2PbCO3·Pb(OH)2 and CdCO3) and complexation with functional groups (carboxyl and hydroxyl) were also important for adsorption of Pb and Cd by BC.

Food Science

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Role of flavonoids in plant interactions with the environment and against human pathogens - A review Muhammad Khalid, Saeed-ur-Rahman, Muhammad Bilal, HUANG Dan-feng 2019, 18(1): 211-230.  DOI: 10.1016/S2095-3119(19)62555-4 Abstract ( )   PDF (13402KB) ( )   Flavonoids are widely-distributed polyphenolic secondary metabolites with diverse biological activities in plants and benefit human health as protective dietary agents.  They participate in plants’ responses to harsh environmental conditions and effectively regulate the cell differentiation and growth.  In plants, the majority of their functions are attributed to their strong antioxidative properties.  Similarly, dietary flavonoids protect the human body against free radicals which are associated with the development of cancer and atherosclerosis.  Plants rich in polyphenols have been used to cure various diseases because of their antibacterial, antiviral, antifungal and anticancer properties.  This review summarizes the up-to-date research trends and development on flavonoids and its derivatives, working mechanisms and potential functions and applications particularly in relation to plant protection and human health.  Towards the end, notable concluding remarks with a close-up look at the future research directions have also been presented briefly.

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Nutritional evaluation of different cultivars of potatoes (Solanum tuberosum L.) from China by grey relational analysis (GRA) and its application in potato steamed bread making ZHOU Liang, MU Tai-hua, MA Meng-mei, ZHANG Ruo-fang, SUN Qing-hua, XU Yan-wen 2019, 18(1): 231-245.  DOI: 10.1016/S2095-3119(18)62137-9 Abstract ( )   PDF in ScienceDirect   Chemical composition (moisture, protein, starch, ash, fiber, fat), vitamins (vitamin C, vitamin B1, vitamin B2), total polyphenol content, antioxidant capacity, minerals, and amino acid of 14 potato cultivars in China were evaluated.  The results indicated that all parameters varied significantly among different potato cultivars.  The total starch, crude protein and fat content ranged between 57.42–67.83%, 10.88–14.10% and 0.10–0.73% dry weight (DW), respectively.  Moreover, the consumption of potato increased remarkably the dietary intake of vitamins, K, Mn and Cu.  In addition, the chemical score of amino acid varied considerably between different cultivars, which ranged from 54 (Neida 3 and Neida 41) to 71 (Neida 34).  Grey relational analysis (GRA) indicated that Neida 26 exhibited the most comprehensive nutritional values among potato cultivars, followed by Neida 42.  Different potato flours had a significant effect on the quality parameters of potato steamed bread (PSB), Neida 26 and Neida 34 were more suitable for making PSB.

Letter

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Developmental status and problems of rice ratooning LIN Wen-xiong 2019, 18(1): 246-247.  DOI: 10.1016/S2095-3119(19)62568-2 Abstract ( )   PDF in ScienceDirect   Rice ratooning cultivation is an imperative breakthrough technology for promoting supply-side structural reform of agriculture, implementing the national plan to reduce the area of double-cropping rice in the Yangtze River basin, China.  While, at the same time, it also contributes to ensure the absolute safety of grain ration and optimize grain production structure in China.  Rice ratooning is a cropping system in which we take advantage of the regeneration characteristics of the rice plant.  For instance, the axillary buds grow rapidly into seedlings and then proceed to the stage of tillering, heading, grain filling and ripening through adopting different planting measures after the main crop (the first cropping rice) is harvested.  Ratoon rice has a long history dating back 1 700 years in China.  Presently, two models are commonly employed for harvesting of ratoon rice, which are manual harvesting and mechanized harvesting of ratoon rice.  However, with the migration of Chinese rural labor forces, mechanized technology for ratoon rice has now become the main planting and harvesting mode.  Moreover, this is also the recommended cultivation technique with promising high grain yields and better economic efficiency and more importantly it has become increasingly popular due to its beneficial aspects with the ongoing efforts of scientific research.  The grain yield for both the main crop and ratooning crop is usually 15 t ha–1 yr–1 with a significant improvement on the economic benefits compared to the middle season and double season rice, respectively.  Upon comparison with the middle season rice, rice ratooning method was able to obtain the additional harvests by 4 500–6 000 kg grain yield ha–1, which was further increased by 11 000–15 000 CNY output ha–1 and 7 500–11 000 CNY net income ha–1.  We further recorded a higher rice quality with multiple saving benefits such as of seed, labor and water resources coupled with a 30–50% reduction in fertilizer use and a 40% decrease in pesticide application.  Eventually, the grain yields of ratoon rice were almost the same or slightly lower than that of the double season rice in a year.  Ultimately, all these beneficial aspects can lead to reduced costs, increased efficiency, and consequently can help in the enhancement of net income by 4 500 to 8 000 CNY ha–1.  Therefore, the development and extension of rice ratooning technology to suitable planting areas in China carries a positive significance to ensure a steady increase in grain output, and the higher economic efficiency of growing food crops for enhancement of the farmer’s income.  However, there is existence of some problems which need to be addressed. ...