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    Crop Genetics · Breeding · Germplasm Resources
    Defective callose walls and cell plates during abnormal meiosis cause male-sterility in the oat mutant zbs1
    SHI Xiao, WU Jin-xia, ZHOU Hai-tao, YANG Xiao-hong, LI Tian-liang, ZHANG Xin-jun, YANG Cai, HAN Xiao
    2016, 15(2): 241-248.  DOI: 10.1016/S2095-3119(15)61086-3
    Abstract ( )   PDF in ScienceDirect  
    During meiosis in flowering plants, degradation of the callose wall in tetrads releases newly produced microspores, which develop into mature pollen grains. In this study, we identified zbs1, a male-sterile mutant of naked oat (Avena nuda L.) that displayed complete spikelet sterility due to inviable mature pollen. The abnormal pollen grains originated from microspores with a defective callose wall and cell plate during meiosis. The defective callose wall and cell plate of the zbs1 mutant were detected by the labeling of cell wall epitopes (β-1,3-glucan) with immunogold during meiosis, and an abnormal chromosome configuration was observed by propidium iodide staining. The mature pollen grains of the zbs1 mutant were irregular in shape, and abnormal germination was observed by scanning electron microscopy. Together, our results indicate that the cause of male sterility in zbs1 is abnormal meiosis.
    Identification and characterization of the GH3 gene family in maize
    ZHANG Dong-feng, ZHANG Nan, ZHONG Tao, WANG Chao, XU Ming-liang, YE Jian-rong
    2016, 15(2): 249-261.  DOI: 10.1016/S2095-3119(15)61076-0
    Abstract ( )   PDF in ScienceDirect  
    The phytohormone auxin plays a central role in coordinating plant growth and development. GH3 is one of the three gene families that respond rapidly during auxin stimulation. Here, we report the identification and characterization of the GH3 gene family in maize. A total of 12 GH3 genes were identified, which are not evenly distributed over the 10 maize chromosomes. Maize GH3 protein sequences share a conserved domain which occupies nearly the entire protein. Diversified cis-elements were found in promoters of maize GH3 genes. In this study, the 12 maize GH3 proteins were primarily classified into two phylogenetic groups, similar to the 13 rice GH3 proteins, while 9 of the 19 Arabidopsis GH3 proteins were observed in the third phylogenetic group. Microarray analysis showed that expression of maize GH3 genes is temporally and spatially modulated. Additionally, maize GH3 genes displayed variable changes at transcript level upon pathogen infection. Results presented here provide insight into the diversification and evolution of GH3 proteins, and lay a foundation for the functional characterization of these GH3 genes in future, especially for elucidating the mechanisms of GH3-mediated pathogenesis.
    The identification of presence/absence variants associated with the apparent differences of growth period structures between cultivated and wild soybeans
    LI Yan-fei, HONG Hui-long, LI Ying-hui, MA Yan-song, CHANG Ru-zhen, QIU Li-juan
    2016, 15(2): 262-270.  DOI: 10.1016/S2095-3119(15)61048-6
    Abstract ( )   PDF in ScienceDirect  
    The cultivated soybean (Glycine max (L.) Merr.) was distinguished from its wild progenitor Glycine soja Sieb. & Zucc. in growth period structure, by a shorter vegetative phase (V), a prolonged reproductive phase (R) and hence a larger R/V ratio. However, the genetic basis of the domestication of soybean from wild materials is unclear. Here, a panel of 123 cultivated and 97 wild accessions were genotyped using a set of 24 presence/absence variants (PAVs) while at the same time the materials were phenotyped with respect to flowering and maturity times at two trial sites located at very different latitudes. The major result of this study showed that variation at PAVs is informative for assessing patterns of genetic diversity in Glycine spp. The genotyping was largely consistent with the taxonomic status, although a few accessions were intermediate between the two major clades identified. Allelic diversity was much higher in the wild germplasm than in the cultivated materials. A significant domestication signal was detected at 11 of the PAVs at 0.01 level. In particular, this study has provided information for revealing the genetic basis of photoperiodism which was a prominent feature for the domestication of soybean. A significant marker-trait association with R/V ratio was detected at 14 of the PAVs, but stripping out population structure reduced this to three. These results will provide markers information for further finding of R/V related genes that can help to understand the domestication process and introgress novel genes in wild soybean to broaden the genetic base of modern soybean cultivars.
    Overexpression of IbMIPS1 gene enhances salt tolerance in transgenic sweetpotato
    WANG Fei-bing, ZHAI Hong, AN Yan-yan, SI Zeng-zhi, HE Shao-zhen, LIU Qing-chang
    2016, 15(2): 271-281.  DOI: 10.1016/S2095-3119(14)60973-4
    Abstract ( )   PDF in ScienceDirect  
    Myo-inositol-1-phosphate synthase (MIPS) is a key rate limiting enzyme in the de novo biosynthesis of myo-inositol in plants. In the present study, the IbMIPS1 gene was introduced into sweetpotato cultivar Xushu 18 and the transgenic plants exhibited significantly enhanced salt tolerance compared with the wild-type (WT). Overexpression of IbMIPS1 up-regulated the salt stress responsive genes, including myo-inositol monophosphatase (MIPP), pyrroline-5-carboxylate synthase (P5CS), pyrroline-5-carboxylate reductase (P5CR), psbA, phosphoribulokinase (PRK), and superoxide dismutase (SOD) genes, under salt stress. Inositol and proline content, SOD and photosynthesis activities were significantly increased, whereas malonaldehyde (MDA) and H2O2 contents were significantly decreased in the transgenic plants. These findings suggest that the IbMIPS1 gene may enhance salt tolerance of sweetpotato by regulating the expression of salt stress responsive genes, increasing the content of inositol and proline and enhancing the activity of photosynthesis.
    Cloning, localization and expression analysis of two fw2.2-like genes in small- and large-fruited pear species
    TIAN Jia, ZENG Bin, LUO Shu-ping, LI Xiu-gen, WU Bin, LI Jiang
    2016, 15(2): 282-294.  DOI: 10.1016/S2095-3119(15)61075-9
    Abstract ( )   PDF in ScienceDirect  
    Fruit size is one of the most important agronomic characters, which is mainly determined by cell number and cell size. However, our current knowledge about pear is largely unknown. Through counting of pear mesocarp cells at different stages, we found that the cell number, rather than the cell size, is responsible for the differences between small- and large-fruited cultivars. Fruit weight-2.2 (fw2.2) is an important quantitative trait locus (QTL) affecting fruit weight in tomato and functions as a negative regulator in carpel cell division. To get more insights into this QTL in pear fruit development, we isolated two putative homologous fw2.2 genes, which were designated as fw2.2-like (PbFWL) genes. PbFWLs encode Cys-rich proteins with the CCXXXXCPC motif and belong to the PLAC8 superfamily. In addition, results from the subcellular localization indicated that PbFWLs were localized in the plasma membrane. The expression profile of the PbFWL genes by qRT-PCR showed they expressed higher in small-sized fruit cultivar than that in large-sized fruit cultivar during the cell division period. In summary, our data suggest that these two PbFWLs might be negatively related to the cell division in pear fruit.
    Effects of chilling tolerance induced by spermidine pretreatment on antioxidative activity, endogenous hormones and ultrastructure of indica-japonica hybrid rice seedlings
    ZENG Yan-hua, ZAHNG Yu-ping, XIANG Jing, WU Hui, CHEN Hui-zhe, ZHANG Yi-kai, ZHU De-feng
    2016, 15(2): 295-308.  DOI: 10.1016/S2095-3119(15)61051-6
    Abstract ( )   PDF in ScienceDirect  
    Spermidine (Spd) is known to be involved in the regulation of plant responses to chilling stress and counteract the adverse effect of stress conditions. Antioxidant activities, endogenous hormones and ultrastructure change under chilling stress were investigated in indica-japonica hybrid rice seedlings. 12-d-old seedlings were subjected to exogenous Spd (1 mmol L–1) and then a chilling stress (6°C, 4 d) was induced, followed by a subsequent recovery (25°C, 4 d). Results showed that malondialdehyde (MDA) and proline content were enhanced significantly, whereas shoot fresh and dry weights decreased during chilling stress and after recovery; chlorophyll content of chilling-stressed seedlings increased slightly but declined after recovery; additionally, total soluble sugar, sucrose, fructose and starch contents increased significantly during chilling stress, and only soluble sugar and fructose contents were observed in increase after recovery; chilling stress-induced increases in superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) activities, but declined after recovery, and the level of ascorbate peroxidase was lower during chilling stress and after recovery; however, endogenous indole-3-acetic acid (IAA), zeatin riboside (ZR), gibberellic acid (GA3), and abscisic acid (ABA) levels were induced decreased compared with Spd pretreatment. The microscopic analysis revealed that chilling stress-induced destruction of the chloroplast envelope during chilling stress and increased the number of plastoglobuli along with aberrations in thylakoid membranes after recovery. In contrast, exogenous Spd protected rice seedlings from chilling-induced injuries in terms of lower malondialdehyde, proline and carbohydrates accumulation coupled with increased endogenous hormones metabolism. After recovery, Spd pretreatment chilling-exposed seedlings showed higher activities of antioxidant enzymes and normal physiological function of chloroplasts. These results suggest that Spd could promote effectively chilling tolerance which might be largely attributable to the integrity of cell structure and normal metabolism of endogenous hormones in indica-japonica hybrid rice seedlings.
    Effects of high temperature during grain filling on physicochemical properties of waxy maize starch
    LU Da-lei, YANG Huan, SHEN Xin, LU Wei-ping
    2016, 15(2): 309-316.  DOI: 10.1016/S2095-3119(15)61095-4
    Abstract ( )   PDF in ScienceDirect  
    Understanding the waxy maize starch physicochemical properties response to heat stress during grain filling could improve starch quality. The effects of heat stress during early (1–15 days after pollination, DAP) and late (16–30 DAP) grain filling stages on the starch physicochemical properties of four waxy maize varieties were evaluated. Crystallinity only increased in Suyunuo 5 after exposure to high temperature at late grain filling stage. The effects of heat stress on digestibility and swelling power were dependent on varieties and stages. Generally, swelling power was increased by heat stress at early grain development stage and digestibility was increased by high temperature at late grain filling stage, respectively. The results of correlation analysis indicated the starch with large granule size could swell well and easy digest. Peak, trough, final, and breakdown viscosities in response to heat stress were dependent on stages and varieties. In general, peak, trough and final viscosities were decreased and increased by heat stress at early grain formation and late grain filling stages, respectively; whereas the breakdown and setback viscosities were similar among the three treatments. Heat stress increased the gelatinization temperatures and retrogradation percentage. Gelatinization range decreased under heat stress at 1–15 DAP but remained constant under heat stress at 16–30 DAP in all varieties. The starch exposed to high temperature at 16–30 DAP presented higher digestibility and peak viscosity and lower retrogradation percentage than those at 1–15 DAP. Therefore, heat stress at early grain formation stage severely affects the physicochemical properties of starch.
    The effects of grain texture and phenotypic traits on the thin-layer drying rate in maize (Zea mays L.) inbred lines
    SUN Le-xiu, LIU Shuang-xi, WANG Jin-xing, WU Cheng-lai, LI Yan, ZHANG Chun-qing
    2016, 15(2): 317-325.  DOI: 10.1016/S2095-3119(15)61052-8
    Abstract ( )   PDF in ScienceDirect  
    To explore the relation of maize grain texture and phenotypic traits with grain thin-layer drying rate, we observed the ultra- structure of maize grain, and tested three traits about the maize grain texture and four phenotypic traits. The vitreous part percentage was different (P<0.05) among different maize inbred lines. There was a significant relationship between the drying rate with grain texture and phenotypic traits. Main factors that influenced the drying rate were different during different drying stages. New results observed that empirical constants (k and N) in drying equation were different for seed of the 30 inbred lines of maize. The k of simplified diffusion equation and N of page equation were significantly influenced by both grain texture and phenotypic traits. These results could be used as guideline parameters for drying maize seeds having different grain characteristics during different drying stages.
    Effects of abiotic stress and hormones on the expressions of five 13-CmLOXs and enzyme activity in oriental melon (Cucumis melo var. makuwa Makino)
    LIU Jie-ying, ZHANG Chong, SHAO Qi, TANG Yu-fan, CAO Song-xiao, GUO Xiao-ou, JIN Ya-zhong, QI Hong-yan
    2016, 15(2): 326-338.  DOI: 10.1016/S2095-3119(15)61135-2
    Abstract ( )   PDF in ScienceDirect  
    Lipoxygenases (LOXs) are a group of non-heme, iron-containing enzymes and extensively involved in plant growth and development, ripening and senescence, stress responses, biosynthesis of regulatory molecules and defense reaction. In our previous study, 18 LOXs in melon genome were screened and identified, and five 13-LOX genes (CmLOX08, CmLOX10, CmLOX12, CmLOX13 and CmLOX18) were predicted to locate in chloroplast. Phylogenetic analysis result showed that the five genes have high homology with jasmonic acid (JA) biosynthesis-related LOXs from other plants. In addition, promoter analysis revealed that motifs of the five genes participate in gene expression regulated by hormones and stresses. Therefore, we analyzed the expressions of the five genes and LOX activity in leaves of four-leaf stage seedlings of oriental melon cultivar Yumeiren under abiotic stress: wounding, cold, high temperature and hydrogen peroxide (H2O2), and signal molecule treatments: methyl jasmonate (MeJA), abscisic acid (ABA) and salicylic acid (SA). Real time qPCR revealed that wounding and H2O2 induced the expressions of all the five genes. Only CmLOX08 was induced by cold while only CmLOX13 was suppressed by high temperature. ABA induced the expressions of CmLOX10 and CmLOX12 while inhibited CmLOX13 and CmLOX18. MeJA increased the 3 genes expressions except CmLOX08 and CmLOX13, whereas SA decreased the effect, apart from CmLOX12. All the abiotic stresses and signal molecules treatments increased the LOX activity in leaves of oriental melon. In summary, the results suggest that the five genes have diverse functions in abiotic stress and hormone responses, and might participate in defense response. The data generated in this study will be helpful in subcellular localization and transgenic experiment to understand their precise roles in plant defense response.
    Identification of the nitrogen-fixing Pseudomonas stutzeri major flagellar gene regulator FleQ and its role in biofilm formation and root colonization
    MA Yao, ZHANG Qiu-lei, YANG Zhi-min, LI Yun, YAN Yong-liang, PING Shu-zhen, ZHANG Li-wen, LIN Min, LU Wei
    2016, 15(2): 339-348.  DOI: 10.1016/S2095-3119(15)61132-7
    Abstract ( )   PDF in ScienceDirect  
    Flagellar biosynthesis and motility are subject to a four-tiered transcriptional regulatory circuit in Pseudomonas, and the master regulator FleQ appears to be the highest-level regulator in this hierarchical regulatory cascade. Pseudomonas stutzeri A1501 is motile by a polar flagellum; however, the motility and regulatory mechanisms involved in this process are unknown. Here, we searched the A1501 genome for flagella and motility genes and found that approximately 50 genes, which were distributed in three non-contiguous chromosomal regions, contribute to the formation, regulation and function of the flagella. The non-polar mutation of fleQ impaired flagellar biosynthesis, motility and root colonization but enhanced biofilm formation. FleQ positively regulates the expression of flagellar class II–IV genes, suggesting a regulatory cascade that is coordinated similar to that of the well-known P. aeruginosa. Based on our results, we propose that flagellar genes in P. stutzeri A1501 are regulated in a cascade regulated by FleQ and that flagellum-driven motility properties may be necessary for competitive rhizosphere colonization.
    Plant Protection
    Occurrence and molecular characterization of Potato spindle tuber viroid (PSTVd) isolates from potato plants in North China
    QIU Cai-ling, ZHANG Zhi-xiang, LI Shi-fang, BAI Yan-ju, LIU Shang-wu, FAN Guo-quan, GAO Yan-ling, ZHANG Wei, ZHANG Shu, Lü Wen-he, Lü Dian-qiu
    2016, 15(2): 349-363.  DOI: 10.1016/S2095-3119(15)61175-3
    Abstract ( )   PDF in ScienceDirect  
    China is the largest potato producing country worldwide, with this crop representing the fourth largest staple food crop in China. However, the steady presence of Potato spindle tuber viroid (PSTVd) over the past five decades has a significant economic impact on potato production. To determine why PSTVd control measures have been ineffective in China, more than 1 000 seed potatoes collected between 2009 and 2014 were subjected to PSTVd detection at the Supervision and Testing Center for Virus-free Seed Potatoes Quality, Ministry of Agriculture, China. A high PSTVd infection rate (6.5%) was detected among these commercial seed potatoes. Some breeding lines of potato collected from 2012 to 2015 were also tested for PSTVd infection, revealing a high rate of PSTVd contamination in these potato propagation materials. Furthermore, comparison of the full-length sequences of 71 different Chinese PSTVd isolates revealed a total of 74 predominant PSTVd variants, which represented 42 different sequence variants of PSTVd. Comparative sequence analysis revealed 30 novel PSTVd sequence variants specific to China. Comprehensive phylogenetic analysis uncovered a close relationship between the Chinese PSTVd sequence variants and those isolated from Russia. It is worth noting that three intermediate strains and six mild strains were identified among these variants. These results have important implications for explaining the ineffective control of PSTVd in China and thus could serve as a basic reference for designing more effective measures to eliminate PSTVd from China in the future.
    Chinese leek (Allium tuberosum Rottler ex Sprengel) reduced disease symptom caused by root-knot nematode
    HUANG Yong-hong, MAO Zhen-chuan, XIE Bing-yan
    2016, 15(2): 364-372.  DOI: 10.1016/S2095-3119(15)61032-2
    Abstract ( )   PDF in ScienceDirect  
    Root-knot nematodes (RKNs, Meloidogyne spp.) are obligate biotrophic parasites that settle close to the vascular tissues in plant roots. The diseases resulting from RKN infections cause serious damage to agricultural production worldwide. In the present paper, the resistance of Chinese leek (Allium tuberosum Rottler ex Sprengel) against RKNs, its suppressive effect on nematode disease, its nematicidal activity and its component profile were studied to identify an efficient disease control method. In soil heavily infected by nematodes, Chinese leek showed strong resistance to RKNs. Additionally, the gall indexes of cucumber plants rotated with Chinese leek and of tomato plants intercropped with Chinese leek were reduced by 70.2 and 41.1%, respectively. In a pot experiment, the gall indexes of Chinese leek extract-treated tomato and cucumber plants were reduced by 88.9 and 75.9%, respectively. In an in vitro experiment, the mortality rate of a RKN (Meloidogyne incognita J2) treated with Chinese leek extract was significantly higher than that of the control. The gas chromatography- mass spectrometry (GC-MS) analysis revealed that glycosides, carboxylic acids, ketones and organic sulfides are the main components in the Chinese leek extract. This study revealed that Chinese leek possesses a high resistance to RKNs, has strong nematicidal activity against M. incognita and can significantly reduce the incidence of disease caused by nematodes.
    Weed and insect control affected by mixing insecticides with glyphosate in cotton
    MA Xiao-yan, WU Han-wen, JIANG Wei-li, MA Ya-jie, MA Yan
    2016, 15(2): 373-380.  DOI: 10.1016/S2095-3119(15)61188-1
    Abstract ( )   PDF in ScienceDirect  
    Field studies were conducted in 2012 and 2013 to evaluate weed and insect control efficacy with glyphosate at 1 230 g ai (active ingredient) ha–1 and the insecticides acephate (728 g ai ha–1), carbosulfan (135 g ai ha–1), endosulfan (683 g ai ha–1), imidacloprid (32 g ai ha–1), or lambda-cyhalothrin (23 g ai ha–1), as well as glyphosate tank-mixed with these insecticides. Four of the most common weeds in cotton, common purslane, false daisy, goosegrass, and lambsquarters, were manually sown in the cotton field and treated with glyphosate alone or in combination with insecticides. Glyphosate efficacy, based on visual estimates of control and weed fresh weight at 21 d after treatment (DAT), was unaffected by the addition of insecticides. Four weeds were controlled by 93–97% and 86–100% (visual rating) and reduced weed fresh biomass by 98–99% and 96–100% with glyphosate alone and its combination with insecticides, respectively. Addition of glyphosate to acephate improved cotton aphid control compared with acephate alone. However, addition of glyphosate to carbosulfan, endosulfan, imidacloprid, or lambda-cyhalothrin did not affect the aphid control when compared with the insecticide alone treatments. These results indicate that cotton producers could potentially integrate weed and insect management strategies by choosing suitable insecticide mixing partners with glyphosate, thereby reducing the application costs without sacrificing the efficacy of the glyphosate or the insecticides.
    Effects of insect-resistant transgenic cotton on ground-dwelling beetle assemblages (Coleoptera)
    ZHAO Cai-yun, YU Xiao-dong, LIU Yong-bo, LI Jun-sheng
    2016, 15(2): 381-390.  DOI: 10.1016/S2095-3119(15)61141-8
    Abstract ( )   PDF in ScienceDirect  
    We compared the ground-dwelling beetle assemblages under four scenarios in which transgenic Bt (Cry 1Ac) cotton (33B), transgenic Bt (Cry 1Ac)+CpTI cotton (SGK321), conventional cotton (33), conventional cotton (Shiyuan 321) in North China. During the survey in two years (2009–2010), 24 ground beetle species were captured with pitfall traps in 20 plots which included five replicates for each cotton type. No significant difference was observed in the number of ground beetle species captured, activity density, evenness and Shannon-Wiener diversity among the four cotton varieties. Chlaenius posticalis was less abundant in transgenic Bt+CpTI cotton (SGK321) fields than its conventional cotton (Shiyuan 321), but more abundant in transgenic Bt cotton (33B) fields compared with its conventional cotton (33). There was no significant difference for other abundant species between in transgenic cotton and in conventional cotton fields. Based on non-metric multidimensional scaling (NMDS) analysis, ground-dwelling beetle assemblages were similar in transgenic and conventional cotton over the two years, but the ground-dwelling beetle assemblages in transgenic cotton 33B significantly differed from that in the conventional cotton (strain 33) in 2010. No strong evidence that the transgenic cotton effect on ground-dwelling beetle assemblages was found in this study.
    Animal Science · Veterinary Science
    Effects of high ambient temperature on lipid metabolism in finishing pigs
    WU Xin, LI Ze-yang, JIA An-feng, SU Hong-guang, HU Chun-hong, ZHANG Min-hong, FENG Jing-hai
    2016, 15(2): 391-396.  DOI: 10.1016/S2095-3119(15)61061-9
    Abstract ( )   PDF in ScienceDirect  
    In this study, we investigated the effects of high ambient temperature on lipid metabolism in finishing pigs. Sixteen pigs ((79.6±1.2) kg) were randomly assigned to two groups: (1) ambient temperature of 30°C with ad libitum access to feed (HT; n=8) and (2) ambient temperature of 22°C and fed the average amount consumed by eight pigs in HT group on the previous day (PF; n=8). After 21 days of constant exposure to different environmental conditions, all the pigs were euthanized, and blood and tissue samples were obtained. High ambient temperature increased the proportion of backfat (P=0.04, +21.6%) and flare fat (P<0.01, +43.3%). Compared with pair-fed pigs, the activities of fatty acid synthase (FAS) and malic enzyme in backfat and flare fat were lower (P<0.05) in heat-stressed pigs, as were the amounts of acetyl-CoA-carboxylase and FAS in the longissimus muscle (LM), the amount of FAS in backfat (P<0.01), and FAS activity in the liver (P<0.01). Ambient temperature did not affect the amount of hormone-sensitive lipase in different tissues. The amount of lipoprotein lipase in flare fat tended to be higher (P=0.09, +28.3%), and the activities of β-hydroxyacyl coenzyme A dehydrogenase in front and back of LM were lower (P<0.01, –48.3 and –49.8%, respectively) at 30°C than at 22°C. The plasma concentration of high-density lipoprotein tended to be lower (P=0.08), but the plasma concentrations of very low-density lipoprotein (VLDL) (P=0.09, +50.0%) and nonestesterified fatty acid (NEFA) (P=0.04, +44.2%) were higher in heat-stressed pigs. We concluded that high ambient temperature depressed de novo fatty acid synthesis in both adipose tissues and the liver. However, β-oxidation of fatty acid in skeletal muscles was also inhibited in the high-temperature environment. As a result, more plasma NEFAs were used to synthesize VLDLs in the liver and were absorbed by adipose tissues. This may be one reason that high ambient temperature enhances the accumulation of backfat and flare fat in finishing pigs.
    Expression analysis for candidate genes associated with eggshell mechanical property
    SUN Cong-jiao, DUaN Zhong-yi, QU Lu-jiang, ZhENg Jiang-xia, YaNg Ning, XU gui-yun
    2016, 15(2): 397-402.  DOI: 10.1016/S2095-3119(14)60969-2
    Abstract ( )   PDF in ScienceDirect  
    Damaged eggshells result in losses of eggs. The genetic mechanism of variable eggshell strength is still unclear. The current study was conducted to verify whether the eggshell calcification related genes, CALB1, SPP1, DMP4, BMP2 and SLIT2, were associated with eggshell mechanical property. For this purpose quantitative PCR (q-PCR) analysis was performed to detect gene expression between two groups of hens laying strong and weak eggs. The hens were selected from 360 White Leghorn layers at 60 wk to ensure that the strong and weak eggs differed significantly in breaking strength but not in eggshell thickness and weight. Using this special strong/weak eggshell model, we found that the expression of CALB1 in the uterus of strong shell group was about 3-fold higher (P<0.05) than that in weak shell group. The DMP4 expression was significantly higher (2-fold, P<0.05) in the uterus of weak shell group than that in strong shell group. However, no difference was observed for genes of SPP1, SLIT2 and BMP2 between these two groups. The current study provides a new insight to investigate the association of candidate genes with eggshell mechanical property.
    Myofiber development during embryonic to neonatal development in duck breeds differing in muscle growth rates
    LI Hui-fang, SHU Jing-ting, SHAN Yan-ju, CHEN Wen-feng, SONG Chi, XU Wen-juan
    2016, 15(2): 403-413.  DOI: 10.1016/S2095-3119(14)60949-7
    Abstract ( )   PDF in ScienceDirect  
    Little is known about the muscle developmental patterns during embryonic to neonatal development in ducks. We investigated the developmental patterns in the lateral gastrocnemius muscles of Gaoyou and Jinding ducks differing in their muscle growth rates during the final stages of egg incubation and the first week after hatching. Expression of the MyoD gene was quantified by quantitative real-time PCR (qRT-PCR). The average cross-sectional area and diameter of the fibers increased from embryonic day 21 (E21), peaking at E27, and then declining slightly 7 d after hatching. The density of the fibers decreased initially but increased after hatching in both breeds and sexes. The within-breed variation in muscle fiber-type composition was greater than the average variation between the breeds. Overall, the percentage of type I fibers increased and that of type IIb fibers decreased consistently. However, the percentage of type IIa fibers was almost constant as development proceeded in both duck breeds. The profiles of MyoD mRNA expression were similar in both breeds, and a significantly positive relationship was observed between the expression of MyoD and the percentage of type IIb fibers. This study firstly revealed the characteristics of duck muscle development and differences between the two breeds differing in growth rates. Moreover, type IIb fibers might convert to type I fibers in the lateral gastrocnemius, while MyoD may potentially function in controlling the muscle fiber phenotype during the secondary myogenesis of muscle development.
    Rumen methane output and fermentation characteristics of gramineous forage and leguminous forage at differing harvest dates determined using an in vitro gas production technique
    ZHONG Rong-zhen, FANG Yi, SUN Hai-xia, WANG Min, ZHOU Dao-wei
    2016, 15(2): 414-423.  DOI: 10.1016/S2095-3119(15)61036-X
    Abstract ( )   PDF in ScienceDirect  
    An in vitro rumen gas production technique was employed to determine the methane production and fermentation characteristics of Leymus chinensis and Medicago ruthenica at differing harvest dates (May 15, May 30, June 30, July 30, August 30 and September 30), which are sequential phases within a single continuous growth of two 10-year-old pastures. To quantify the rate of degradation and compare in vitro rumen fermentation characteristic, a logistic-exponential model, where initial gas volume was zero (LE0), was used to fit gas production and methane output results. Dried, milled forage samples were incubated in vitro for 72 h at 39°C and gas production was recorded intermittently throughout the incubation and gas samples were collected to measure methane production. Results showed that there were significant interactions between species and harvest for all chemical composition variables (P<0.001) and condensed tannin content (P<0.001). L. chinensis produced more total gas and methane than M. ruthenica (P<0.001). Both total gas and methane production decreased lineally (P<0.001) with advancing harvest date. The degradation rates of L. chinensis and M. ruthenica harvested on September 30 were lower than those on the other harvest dates (P<0.01). M. ruthenica fermented fluid had higher concentration of ammonia N (P<0.05) and molar proportions of isobutyrate (P<0.01), valerate (P<0.001) and isovalerate (P<0.01) in total volatile fatty acids than L. chinensis. Furthermore, concentration of isovalerate decreased cubically with advancing harvest date (P<0.05). In conclusion, M. ruthenica produced less methane than L. chinensis and the total gas and methane production decreased with advancing harvest date for both species, which may be due to the changes in contents of chemical compositions and condensed tannin in forages.
    The effects of the unsaturated degree of long-chain fatty acids on the rumen microbial protein content and the activities of transaminases and dehydrogenase in vitro
    GAO Jian, JING Yu-jia, WANG Meng-zhi, SHI Liang-feng, LIU Shi-min
    2016, 15(2): 424-431.  DOI: 10.1016/S2095-3119(15)61081-4
    Abstract ( )   PDF in ScienceDirect  
    This study investigated the effects of the degree of unsaturation (unsaturity) of long-chain fatty acids on microbial protein content and the activities of transaminases and dehydrogenase in vitro using goat rumen fluid as the cultural medium. Six types of fatty acids, stearic acid (C18:0, group A, control group), oleic acid (C18:1, n-9, group B), linoleic acid (C18:2, n-6, group C), α-linolenic acid (C18:3, n-3, group D), arachidonic acid (C20:4, n-6, group E), and eicosapentaenoic acid (C20:5, n-3, group F), were tested, and the inclusion ratio of each fatty acid was 3% (w/w) in total of culture substrate. Samples were taken at 0, 3, 6, 9, 12, 18 and 24 h, respectively, during culture for analyses. Compared with stearic acid, linoleic acid, α-linolenic acid, and arachidonic acid increased the bacterial protein content, while oleic acid and eicosapentaenoic acid had no significant effects; the protozoal protein content was reduced for all the unsaturated fatty acids, and the magnitude of the reduction appeared to be associated with the degree of unsaturity of fatty acids. The total microbial protein content was dominantly accounted by the protozoal protein content (about 4–9 folds of the bacterial protein), and only increased by linoleic acid, but reduced by oleic acid, arachidonic acid and eicosapentaenoic acid. There were no significant effects in the activities of both glutamic oxaloacetic transaminase (GOT) and glutamic-pyruvic transaminase (GPT) for all the other fatty acids, except for arachidonic acid which enhanced GOT activity and oleic acid which enhanced GPT activity. The total dehydrogenase activity was positively correlated with the degree of unsaturation of fatty acids. In conclusion, the inclusion of 3% of long-chain unsaturated fatty acids increased bacterial protein content, whereas reduced protozoal protein content and enhanced dehydrogenase activity. The fatty acids with more than three double bonds had detrimental effects on the microbial protein content. This work demonstrates for the first time the effect rule of the unsaturation degree of long-chain fatty acids on the rumen microbial protein in vitro.
    Soil & Fertilization﹒Irrigation﹒Plant Nutrition﹒ Agro-Ecology & Environment
    Determining N supplied sources and N use efficiency for peanut under applications of four forms of N fertilizers labeled by isotope 15N
    WANG Cai-bin, ZHENG Yong-mei, SHEN Pu, ZHENG Ya-ping, WU Zheng-feng, SUN Xue-wu, YU Tian-yi, FENG Hao
    2016, 15(2): 432-439.  DOI: 10.1016/S2095-3119(15)61079-6
    Abstract ( )   PDF in ScienceDirect  
    Rational application of different forms of nitrogen (N) fertilizer for peanut (Arachis hypogaea L.) requires tracking the N supplied sources which are commonly not available in the differences among the three sources: root nodule, soil and fertilizer. In this study, two kinds of peanut plants (nodulated variety (Huayu 22) and non-nodulated variety (NN-1)) were choosed and four kinds of N fertilizers: urea-N (CONH2-N), ammonium-N (NH4 +-N), nitrate-N (NO3 –-N) and NH4 ++NO3 –-N labeled by 15N isotope were applied in the field barrel experiment in Chengyang Experimental Station, Shandong Province, China, to determine the N supplied sources and N use efficiency over peanut growing stages. The results showed that intensities and amounts of N supply from the three sources were all higher at middle growing stages (pegging phase and podding phase). The accumulated amounts of N supply from root nodule, soil and fertilizer over the growing stages were 8.3, 5.3 and 3.8 g m–2 in CONH2-N treatment, which are all significantly higher than in the other three treatments. At seedling phase, soil supplied the most N for peanut growth, then root nodule controlled the N supply at pegging phase and podding phase, but soil mainly provided N again at the last stage (pod filling phase). For the whole growing stages, root nodule supplied the most N (47.8 and 43.0%) in CONH2-N and NH4 +-N treatments, whereas soil supplied the most N (41.7 and 40.9%) in NH4 ++ NO3 –-N and NO3 –-N treatments. The N use efficiency was higher at pegging phase and podding phase, while accumulated N use efficiency over the growing stages was higher in CONH2-N treatment (42.2%) than in other three treatments (30.4% in NH4 +-N treatment, 29.4% in NO3 –-N treatment, 29.4% in NH4 ++NO3 –-N treatment). In peanut growing field, application of CONH2-N is a better way to increase the supply of N from root nodule and improve the N use efficiency.
    The effects of nitrogen fertilizer application on methane and nitrous oxide emission/uptake in Chinese croplands
    SUN Bin-feng, ZHAO Hong, Lü Yi-zhong, LU Fei, WANG Xiao-ke
    2016, 15(2): 440-450.  DOI: 10.1016/S2095-3119(15)61063-2
    Abstract ( )   PDF in ScienceDirect  
    The application of nitrogen (N) fertilizer to increase crop yields has a significant influence on soil methane (CH4) and nitrous oxide (N2O) emission/uptake. A meta-analysis was carried out on the effect of N application on (i) CH4 emissions in rice paddies, (ii) CH4 uptake in upland fields and (iii) N2O emissions. The responses of CH4 emissions to N application in rice paddies were highly variable and overall no effects were found. CH4 emissions were stimulated at low N application rates (<100 kg N ha–1) but inhibited at high N rates (>200 kg N ha–1) as compared to no N fertilizer (control). The response of CH4 uptake to N application in upland fields was 15% lower than control, with a mean CH4 uptake factor of –0.001 kg CH4-C kg–1 N. The mean N2O emission factors were 1.00 and 0.94% for maize (Zea mays) and wheat (Triticum aestivum), respectively, but significantly lower for the rice (Oryza sativa) (0.51%). Compared with controls, N addition overall increased global warming potential of CH4 and N2O emissions by 78%. Our result revealed that response of CH4 emission to N input might depend on the CH4 concentration in rice paddy. The critical factors that affected CH4 uptake and N2O emission were N fertilizer application rate and the controls of CH4 uptake and N2O emission. The influences of application times, cropping systems and measurement frequency should all be considered when assessing CH4 and N2O emissions/uptake induced by N fertilizer.
    Effects of plastic film mulching on soil greenhouse gases (CO2, CH4 and N2O) concentration within soil profiles in maize fields on the Loess Plateau, China
    NAN Wei-ge, YUE Shan-chao, HUANG Hai-zhou, LI Shi-qing, SHEN Yu-fang
    2016, 15(2): 451-464.  DOI: 10.1016/S2095-3119(15)61106-6
    Abstract ( )   PDF in ScienceDirect  
    To better understand the effects of plastic film mulching on soil greenhouse gases (GHGs) emissions, we compared seasonal and vertical variations of GHG concentrations at seven soil depths in maize (Zea mays L.) fields at Changwu station in Shaanxi, a semi-humid region, between 2012 and 2013. Gas samples were taken simultaneously every one week from non-mulched (BP) and plastic film-mulched (FM) field plots. The results showed that the concentration of GHGs varied distinctly at the soil-atmosphere interface and in the soil profile during the maize growing season (MS). Both carbon dioxide (CO2) and nitrous oxide (N2O) concentrations increased with increasement of soil depth, while the methane (CH4) concentrations decreased with increasement of soil depth. A strong seasonal variation pattern was found for CO2 and N2O concentrations, as compared to an inconspicuous seasonal variation of CH4 concentrations. The mean CO2 and N2O concentrations were higher, but the mean CH4 concentration in the soil profiles was lower in the FM plots than in the BP plots. The results of this study suggested that plastic film mulching significantly increased the potential emissions of CO2 and N2O from the soil, and promoted CH4 absorption by the soil, particularly during the MS.
    Spatial distribution prediction and benefits assessment of green manure in the Pinggu District, Beijing, based on the CLUE-S model
    ZHANG Li-ping, ZHANG Shi-wen, ZHOU Zhi-ming, HOU Sen, HUANG Yuan-fang, CAO Wei-dong
    2016, 15(2): 465-474.  DOI: 10.1016/S2095-3119(15)61064-4
    Abstract ( )   PDF in ScienceDirect  
    Green manure use in China has declined rapidly since the 1980s with the extensive use of chemical fertilizers. The deterioration of field environments and the demand for green agricultural products have resulted in more attention to green manure. Human intervention and policy-oriented behaviors likely have large impacts on promoting green manure planting. However, little information is available regarding on where, at what rates, and in which ways (i.e., intercropping green manure in orchards or rotating green manure in cropland) to develop green manure and what benefits could be gained by incorporating green manure in fields at the county scale. This paper presents the conversion of land use and its effects at small region extent (CLUE-S) model, which is specifically developed for the simulation of land use changes originally, to predict spatial distribution of green manure in cropland and orchards in 2020 in Pinggu District located in Beijing, China. Four types of land use for planting or not planting green manure were classified and the future land use dynamics (mainly croplands and orchards) were considered in the prediction. Two scenarios were used to predict the spatial distribution of green manure based on data from 2011: The promotion of green manure planting in orchards (scenario 1) and the promotion of simultaneous green manure planting in orchards and croplands (scenario 2). The predictions were generally accurate based on the receiver operating characteristic (ROC) and Kappa indices, which validated the effectiveness of the CLUE-S model in the prediction. In addition, the spatial distribution of the green manure was acquired, which indicated that green manure mainly located in the orchards of the middle and southern regions of Dahuashan, the western and southern regions of Wangxinzhuang, the middle region of Shandongzhuang, the eastern region of Pinggu and the middle region of Xiagezhuang under scenario 1. Green manure planting under scenario 2 occurred in orchards in the middle region of Wangxinzhuang, and croplands in most regions of Daxingzhuang, southern Pinggu, northern Xiagezhuang and most of Mafang. The spatially explicit results allowed for the assessment of the benefits of these changes based on different economic and ecological indicators. The economic and ecological gains of scenarios 1 and 2 were 175 691 900 and 143 000 300 CNY, respectively, which indicated that the first scenario was more beneficial for promoting the same area of green manure. These results can facilitate policies of promoting green manure and guide the extensive use of green manure in local agricultural production in suitable ways.
    Estimating the crop leaf area index using hyperspectral remote sensing
    LIU Ke, ZHOU Qing-bo, WU Wen-bin, XIA Tian, TANG Hua-jun
    2016, 15(2): 475-491.  DOI: 10.1016/S2095-3119(15)61073-5
    Abstract ( )   PDF in ScienceDirect  
    The leaf area index (LAI) is an important vegetation parameter, which is used widely in many applications. Remote sensing techniques are known to be effective but inexpensive methods for estimating the LAI of crop canopies. During the last two decades, hyperspectral remote sensing has been employed increasingly for crop LAI estimation, which requires unique technical procedures compared with conventional multispectral data, such as denoising and dimension reduction. Thus, we provide a comprehensive and intensive overview of crop LAI estimation based on hyperspectral remote sensing techniques. First, we compare hyperspectral data and multispectral data by highlighting their potential and limitations in LAI estimation. Second, we categorize the approaches used for crop LAI estimation based on hyperspectral data into three types: approaches based on statistical models, physical models (i.e., canopy reflectance models), and hybrid inversions. We summarize and evaluate the theoretical basis and different methods employed by these approaches (e.g., the characteristic parameters of LAI, regression methods for constructing statistical predictive models, commonly applied physical models, and inversion strategies for physical models). Thus, numerous models and inversion strategies are organized in a clear conceptual framework. Moreover, we highlight the technical difficulties that may hinder crop LAI estimation, such as the “curse of dimensionality” and the ill-posed problem. Finally, we discuss the prospects for future research based on the previous studies described in this review.