摘要：
Grain filling in rice, a staple cereal crop worldwide, is a critical determinant of grain yield and quality. However, there is little available information on the relationship between grain filling and grain photosynthetic capacity in rice. This study evaluated the genetic diversity among six rice cultivars for their grain filling rate (GR(0)) and the relationships with the grain chlorophyll contents and grain net photosynthetic rate (P-N). Significant variations in GR(0), P-N, and the chlorophyll contents (a, b, and total) in the grains of the cultivars were observed. Approximately 90 % of the variation in GR(0) was explained by the grain P-N. General linear model regression revealed significant positive correlations between P-N/GR(0) and the chlorophyll contents (a, b, and total) in the grains. There was also a significant positive correlation between P-N and GR(0). These positive correlations suggest a direct positive relationship between the grain filling rate and grain chlorophyll contents, which is indicative of the high photosynthetic capacity of the grains during the early grain filling period. These results suggest that the grain chlorophyll contents could be used as a molecular marker in marker-assisted breeding programs for rice cultivars with high grain net photosynthetic capacity during the early period of grain filling to improve grain yield.
作者机构：
[Zhang, Haiqing; Liu, Yang] Hunan Agr Univ, Southern Reg Collaborat Innovat Ctr Grain & Oil C, Changsha 410128, Peoples R China.;[He, Xiaoe; Liu, Yang] Hunan Acad Agr Sci, Hunan Rice Res Inst, Changsha 410125, Peoples R China.;[Zhang, Yuzhu; Chang, Shuoqi] Hunan Acad Agr Sci, Hunan Hybrid Rice Res Ctr, State Key Lab Hybrid Rice, Changsha 410125, Peoples R China.;[Zhu, Xinguang; Chang, Tiangen] Chinese Acad Sci, Shanghai Inst Plant Physiol & Ecol, CAS Ctr Excellence Mol Plant Sci, Natl Key Lab Plant Mol Genet, Shanghai 200031, Peoples R China.;[Li, Chao] Hunan Acad Agr Sci, Hunan Soil & Fertilizer Res Inst, Changsha 410125, Peoples R China.
通讯机构：
[Zhang, Haiqing; Zhang, Yuzhu] H;Hunan Agr Univ, Southern Reg Collaborat Innovat Ctr Grain & Oil C, Changsha 410128, Peoples R China.;Hunan Acad Agr Sci, Hunan Hybrid Rice Res Ctr, State Key Lab Hybrid Rice, Changsha 410125, Peoples R China.
摘要：
Topdressing at panicle differentiation (PF) according to soil fertility and regularity of rice nutrient absorption is an important agronomic practice used in cultivation of rice cultivars with a long growth duration. We studied the impacts of timing of nitrogen fertilizer application during PF on photosynthesis and yield-related agronomic traits in ‘Y-Liang-You 900’ and ‘Y-Liang-You 6’, which are representative rice cultivars with a long growth duration. Data for two years showed that timing of topdressing application during PF affected panicles per unit area, percentage grain set, spikelets per panicle, and leaf photosynthetic traits during the grain-filling period. Topdressing at the initial stage of flag-leaf extension resulted in higher grain yield (typically by 10.55–19.95%) than in plants without topdressing. Grain yield was significantly correlated with flag leaf photosynthetic rate and leaf SPAD value (r = 0.5640 and r = 0.5589, respectively; p < 0.01) at an advanced grain-filling stage (30 days after heading). Surprisingly, grain yield was not correlated with carbohydrate remobilization from the stem and sheath.For rice cultivars with a long growth duration, nitrogen-fertilizer topdressing must be applied at the initial stage of flag-leaf extension to delay leaf senescence during the grain-filling stage and realize the enhanced yield potential.
通讯机构：
[Hou, Bing-Kai] S;Shandong Univ, Sch Life Sci, Minist Educ, Key Lab Plant Dev & Environm Adaptat Biol, Qingdao 266237, Peoples R China.
关键词：
Arabidopsis thaliana;auxin;glycosylation
摘要：
Auxin is a class of plant hormone that plays a crucial role in the life cycle of plants, particularly in the growth response of plants to ever-changing environments. Since the auxin responses are concentration-dependent and higher auxin concentrations might often be inhibitory, the optimal endogenous auxin level must be closely controlled. However, the underlying mechanism governing auxin homeostasis remains largely unknown. In this study, a UDP-glycosyltransferase (UGT76F1) was identified from Arabidopsis thaliana, which participates in the regulation of auxin homeostasis by glucosylation of indole-3-pyruvic acid (IPyA), a major precursor of the auxin indole-3-acetic acid (IAA) biosynthesis, in the formation of IPyA glucose conjugates (IPyA-Glc). In addition, UGT76F1 was found to mediate hypocotyl growth by modulating active auxin levels in a light- and temperature-dependent manner. Moreover, the transcription of UGT76F1 was demonstrated to be directly and negatively regulated by PIF4, which is a key integrator of both light and temperature signaling pathways. This study sheds a light on the trade-off between IAA biosynthesis and IPyA-Glc formation in controlling auxin levels and reveals a regulatory mechanism for plant growth adaptation to environmental changes through glucosylation of IPyA.
摘要：
Hemerocallis citrina Borani is an important crop and its flower buds are widely consumed in East Asian areas as a vegetable, as well as in traditional Chinese medicine, due to its health-promoting properties. Metabolites present in plant-derived foods or medicines are in part responsible for their desirable flavor profiles and health benefits. Nevertheless, detailed information about these compounds in H. citrina is scarce. Therefore, this study aimed to investigate the metabolites by high-performance liquid chromatography/quadrupole time-of-flight mass spectrometry (HPLC-Q-TOF-MS). In this study, a total of 144 compounds, including 14 amides, 25 polyphenols, 44 flavonols, 35 anthraquinones, 15 naphthols, and 11 other components, were detected by the established screening method and were identified by their precise m/z values, characteristic tandem mass spectrometry (MS/MS) data and fragmentation pathways of references, 111 of which were reported in this plant for the first time. The distribution of identified ingredients in different parts of H. citrina was determined. Interestingly, colchicine, which had been reported as a toxic compound in the fresh flower buds in previous studies and various news reports, was not found. This work marks the first comprehensive study of metabolites from commercial flower buds and different parts of H. citrina. (C) 2020 Elsevier B.V. All rights reserved.
摘要：
We present a solution-region based approach for the synthesis of straight-line linkages, which is based on the stationary curvature point on curve and higher order stationery point theory of infinite approximation geometry. The selection of the Ball-Burmester point and the distribution of the solution-regions are discussed in this work. Further, two alternative cases have been analyzed for finding the Ball-Burmester point positions of the crank-rocker straight-line mechanism, when one side-link is collinear with the frame. The distribution diagrams of the Ball-Burmester point positions are depicted to help the designers extract complete solutions. Infinite solutions for the mechanism can be expressed for each case on a diagram by employing the solution-region method. These diagrams will help the designers find the inherent mechanism intuitively and streamline the selection of results. The results indicate that the efficiency of design and reliability have been effectively improved owing to the implementation of these methods.
关键词：
Anti-Biofilm;Citrus medica L. var. sarcodactylis swingle;Essential oil;Fingered citron;Listeria monocytogenes
摘要：
Listeria monocytogenes is an important foodborne pathogen that could cause listeriosis and poses potential threats to human health. Citrus medica L. var. sarcodactylis Swingle, also known as Fingered Citron, is a citrus species widely cultivated in South China. The aim of this work was to investigate the anti-biofilm efficacy of essential oil from Fingered Citron (FCEO) against L. monocytogenes. The crystal violet assay showed that FCEO exhibited strong anti-biofilm activity on both inhibiting biofilm formation and eradicating preformed biofilm. XTT assay indicated that FCEO significantly increased the metabolic active cells in the biofilm. Confocal scanning laser microscopy images and COMSTAT assay revealed that FCEO destroyed the intact architecture of biofilm, reduced biofilm biomass, thickness and substratum coverage. The morphological changes of cells in the biofilm were observed by scanning electron microscopy, which showed that FCEO could cause the wrinkle, collapse, lysis and cytoplasmic content leakage of cells. Our results also indicated that FCEO displayed its anti-biofilm activity through both biofilm dispersal and cell killing. Our findings provide evidence that FCEO exhibits strong anti-biofilm activity and might be used as a potential agent to control L. monocytogenes biofilm.
摘要：
In this study, the complete mitochondrial genome sequence of the Qingyuan chicken (Gallus gallus) was reported for the first time by using the high-throughput sequencing technology. The complete mitogenome sequence of Qingyuan chicken exhibits a typical genetic structure of vertebrate double-strands circular genome, containing a D-loop region, 2 ribosomal RNA genes, 13 protein-coding genes and 22 transfer RNA genes. Our work provides a source of useful data for mitochondrial researches and chicken phylogenetic studies.
摘要：
This paper proposes a novel hybrid forecast model to forecast crude oil price on considering the long memory, asymmetric, heavy-tail distribution, nonlinear and non-stationary characteristics of crude oil price. First, we use a signal de-noising method to reduce excessive noise significantly in the crude oil price. Then we employ empirical mode decomposition to transform the de-noised price into different intrinsic mode functions (IMFs). Finally, some complex long memory GARCH-M models are used to forecast different IMFs and a residual. Empirical results show that the proposed hybrid forecasting model WPD-EMD-ARMA-FIGARCH-M achieves significant effect during periods of extreme incidents. The robustness test shows that this hybrid model is superior to traditional models. (C) 2020 Elsevier B.V. All rights reserved.
关键词：
Foundation parental lines;IBD segments;Maize (Zea mays L.);Suwan germplasm
摘要：
Suwan germplasm plays important roles in maize breeding in tropical/subtropical regions, especially in southern China. To analyze the genetic characteristics of Suwan maize germplasm, one panel of 73 lines derived from the Suwan population and temperate resources were collected and genotyped using 56,110 single-nucleotide polymorphism (SNP) markers. The results revealed four subgroups, namely, QR273, Ki32, HCL645, and PH4CV, with an average genetic distance of 0.304, varying from 0.001 to 0.370. In addition, many identical-by-descent (IBD) segments were found among Suwan germplasms and their descendants, of which 78 segments were detected only in the QR273 subgroup, 18 segments were detected only in the Ki32 subgroup, 53 and 11 segments were detected only in the PH4CV and the HCL645 subgroup, respectively. Pairwise comparisons showed that 13 segments were common between the QR273 and Ki32 subgroups, 5 segments were common between the QR273 and HCL645 subgroups, 26 segments were common between the QR273 and PH4CV subgroups. Five and 14 segments were common between the Ki32 versus HCL645 subgroups and Ki32 versus PH4CV subgroups. Three segments were commonly detected in the Ki32, QR273, and HCL645 subgroups. Candidate gene analysis showed that 132 genes were located in these segments, wherein seven new candidate genes were associated with flower time (FT)-related traits, which were located in the IBD segments of QR273 or HCL645. Zm00001d033130_T005 and Zm00001d013768_T001 were located in the IBD segments specific to the QR273 subgroup. These two genes function in cell differentiation and flower development and would be very important for the phenotypic variations of the given FP subgroups. These results provide new insights and scientific proof for dissecting the genetic basis of complex traits and the utilization of Suwan germplasm in future maize breeding.
摘要：
The demand for clean and renewable energy has promoted the rapid development of state-of-the-art energy storage electrochemical systems. Vanadium redox flow batteries attract much more attentions due to low cost and high security, unfortunately the low catalytic activity of electrodes for vanadium ion redox process is the main barrier to achieve a high efficiency. This work proposes a novel composite electrode derived from Bacillus mycoides to overcome the dilemma between high degree of graphitization and uniform heteroatom doping. Consequently, this composite electrode simultaneously achieves rapid charge migration and high electrocatalytic activity and enhances the vanadium ion redox reaction on porous lamellar carbon (PLC) materials. Compared with the pristine electrode, the potential polarization for V(IV)//(V) and V(II)/V(III) redox couples on PLC electrode decrease by 254 mV and 278 mV, respectively. Moreover, a high stability for cycling continuously for over 1000 cycles at a high current density of 200 mA cm(-2) and a high energy efficiency can be realized based on PLC electrode. This work not only paves the way to achieve high energy efficiency of vanadium redox flow batteries, but also provides a feasible and novel way to design carbon materials with high catalytic activity and high electronic conductivity.
摘要：
Biochar-based controlled release nitrogen fertilizers (BCRNFs) have received increasing attention due to their ability to improve nitrogen-use efficiency (NUE) and increase crop yields. We previously developed a novel BCRNF, but its effects on soil microbes, NUE, and crop yields have not been reported. Therefore, we designed a pot experiment with five randomised treatments: CK (without urea and biochar), B (addition biochar without urea), B + U (biochar mixed urea), Urea (addition urea without biochar), and BCRNF (addition BCRNF), to investigate the effects of BCRNF on nitrifiers and denitrifiers, and how these impact nitrogen supply and NUE. Results of high-throughput sequencing revealed bacterial community groups with higher nutrient metabolic cycling ability under BCRNF treatment during harvest stage. Compared to Urea treatment, BCRNF treatment stimulated nitrification by increasing the copy number of the bacterial amoA gene and reducing nitrous oxide emission by limiting the abundance of nirS and nirK. Eventually, BCRNF successfully enhanced the yield (~ 16.6%) and NUE (~ 58.79%) of rape by slowly releasing N and modulating the abundance of functional microbes through increased soil nitrification and reduced denitrification, as compared with Urea treatment. BCRNF significantly improved soil NO(3)(-), leading to an increase in N uptake by rape and NUE, thereby promoting rape growth and increasing grain yield.
关键词：
Mining and manufacturing;Rock weathering;Fertilizer and pesticide use;Principal component analysis;Mixed metal pollution;Surface water pollution
摘要：
This study collected past sampling data on total concentrations of 12 heavy metals (Cd, Pb, Cr, Hg, Zn, Cu, Ni, Al, Fe, Mn, As, and Co) in surface water bodies, i.e., 168 rivers and 71 lakes, from 1972 to 2017. The intent was to investigate the levels and sources of heavy metal pollution across five decades and five continents. Mean heavy metal concentrations in global river and lake water, and the number of heavy metals with concentrations greater than the published threshold limits as per the standards of both the World Health Organization (WHO) and the United States Environmental Protection Agency (USEPA) were generally lower in the 1970s and 1980s than in the 1990s, 2000s, and 2010s. Over time, heavy metal pollution in surface water has changed from single metal pollution to mixed metal pollution. Heavy metal concentrations in water, and the number of heavy metals with concentrations above the threshold limits for both WHO and USEPA standards were lower in the developed countries of Europe and North America, and higher in the developing countries of Africa, Asia, and South America. Over time, the main sources of metal pollution have changed from mining and manufacturing to rock weathering and waste discharge. The main metal sources differed across the five continents, with fertilizer and pesticide use, along with rock weathering, being dominant in Africa. Mining and manufacturing, along with rock weathering, were dominant in Asia and Europe. Mining and manufacturing, along with fertilizer and pesticide use, were dominant sources in North America, while four sources (mining and manufacturing, fertilizer and pesticide use, rock weathering, and waste discharge) were responsible for the majority of heavy metal pollution in the river and lake water bodies of South America. Additionally, implementing rigorous standards on metal emissions and recycling metals from wastewater are effective for controlling heavy metal source pollution. (C) 2020 The Authors. Published by Elsevier B.V.
