The quaternion approach to solve the coupled nonlinear Schrodinger equations (CNSEs) in fibers is proposed, converting the CNSEs to a single variable equation by using a conception of eigen-quaternion of coupled qua...The quaternion approach to solve the coupled nonlinear Schrodinger equations (CNSEs) in fibers is proposed, converting the CNSEs to a single variable equation by using a conception of eigen-quaternion of coupled quater- nion. The crosstalk of quarter-phase-shift-key signals caused by fiber nonlinearity in polarization multiplexing systems with 100 Cbps bit-rate is investigated and simulated. The results demonstrate that the crosstalk is like a rotated ghosting of input constellation. For the 50 km conventional fiber link, when the total power is less than 4roW, the crosstalk effect can be neglected; when the power is larger than 20roW, the crosstalk is very obvious. In addition, the crosstalk can not be detected according to the output eye diagram and state of polarization in Poincare sphere in the trunk fiber, making it difficult for the monitoring of optical trunk link.展开更多
Based on the asymptotic spectral distribution of Wigner matrices, a new normality test method is proposed via reforming the white noise sequence. In this work, the asymptotic cumulative distribution function (CDF) o...Based on the asymptotic spectral distribution of Wigner matrices, a new normality test method is proposed via reforming the white noise sequence. In this work, the asymptotic cumulative distribution function (CDF) of eigenvalues of the Wigner matrix is deduced. A numerical Kullback-Leibler divergence of the empiric-d spectral CDF based on test samples from the deduced asymptotic CDF is established, which is treated as the test statistic. For validating the superiority of our proposed normality test, we apply the method to weak SIPSK signal detection in the single-input single-output (SISO) system and the single-input multiple-output (SIMO) system. By comparing with other common normality tests and the existing signal detection methods, simulation results show that the proposed method is superior and robust.展开更多
The rapid developing of the fourth generation(4G)wireless communications has aroused tremendous demands for high speed data transmission due to the dissemination of various types of the intelligent user terminals as w...The rapid developing of the fourth generation(4G)wireless communications has aroused tremendous demands for high speed data transmission due to the dissemination of various types of the intelligent user terminals as well as the wireless multi-media services.It is predicted that the network throughput will increase展开更多
The complexity of signal controlled traffic largely stems from the various driving behaviors developed in response to the traffic signal. However, the existing models take a few driving behaviors into account and cons...The complexity of signal controlled traffic largely stems from the various driving behaviors developed in response to the traffic signal. However, the existing models take a few driving behaviors into account and consequently the traffic dynamics has not been completely explored. Therefore, a new cellular automaton model, which incorporates the driving behaviors typically manifesting during the different stages when the vehicles are moving toward a traffic light, is proposed in this paper. Numerical simulations have demonstrated that the proposed model can produce the spontaneous traffic breakdown and the dissolution of the over-saturated traffic phenomena. Furthermore, the simulation results indicate that the slow-to-start behavior and the inch-forward behavior can foster the traffic breakdown. Particularly, it has been discovered that the over-saturated traffic can be revised to be an under-saturated state when the slow-down behavior is activated after the spontaneous breakdown. Finally, the contributions of the driving behaviors on the traffic breakdown have been examined.展开更多
Parasitic plants and their hosts communicate through haustorial connections.Nutrient deficiency is a common stress for plants,yet little is known about whether and how host plants and parasites communicate during adap...Parasitic plants and their hosts communicate through haustorial connections.Nutrient deficiency is a common stress for plants,yet little is known about whether and how host plants and parasites communicate during adaptation to such nutrient stresses.In this study,we used transcriptomics and proteomics to analyze how soybean(Glycine max)and its parasitizing dodder(Cuscuta australis)respond to nitrate and phosphate deficiency(-N and-P).After-N and-P treatment,the soybean and dodder plants exhibited substantial changes of transcriptome and proteome,although soybean plants showed very few transcriptional responses to-P and dodder did not show any transcriptional changes to either-N or-P.Importantly,large-scale interplant transport of mRNAs and proteins was detected.Although the mobile mRNAs only comprised at most 0.2%of the transcriptomes,the foreign mobile proteins could reach 6.8%of the total proteins,suggesting that proteins may be the major forms of interplant communications.Furthermore,the interplant mobility of macromolecules was specifically affected by the nutrient regimes and the transport of these macromolecules was very likely independently regulated.This study provides new insight into the communication between host plants and parasites under stress conditions.展开更多
Microbial consortia are ubiquitous in nature,in which multiple microbial species cooperate to complete some important tasks such as lignocellulose degradation.Because of the advantages such as reduced metabolic burden...Microbial consortia are ubiquitous in nature,in which multiple microbial species cooperate to complete some important tasks such as lignocellulose degradation.Because of the advantages such as reduced metabolic burden and robustness to environment disturbances,developing a microbial consortium is a promising approach for valuable product synthesis,lignocellulose utilization,human health care,bioremediation and sustainable energy,etc.Despite the benefits,however,most artificial microbial consortia confront the problems of instability and low efficiency due to growth competition and metabolite incompatibility.To overcome these challenges,multiple strategies to design efficient synthetic microbial consortia have been reported.In this review,the interactions that determine the stability and performance of microbial consortia were described.Progress of artificial microbial consortia research was summarized,and the key strategies i.e.,spatial or temporal segregation,separated utilization of nutrients,nutrient cross-feeding and division of labor,that will be of great importance for achieving a stable and efficient microbial consortium were highlighted.Two novel advanced tools,signaling molecule systems and computational models,were also introduced and discussed.We believed that combining the universal cell–cell signaling molecule systems with computational models will be promising for synthetic microbial consortia construction in the future.展开更多
The relation between the phase shift and the mean optical power (MOP) output from a delay-line inter- ferometer (DLI) port applied for phase-shift keying (PSK) signal demodulation is proven of a cosine law irrel...The relation between the phase shift and the mean optical power (MOP) output from a delay-line inter- ferometer (DLI) port applied for phase-shift keying (PSK) signal demodulation is proven of a cosine law irrelevant to signal modulation condition. The variation amplitude of the MOP is proportional to the transition duration of the modulation pulses. This phenomenon is interpreted as the result of the sta- tistical and waveform characteristics of the PSK. The conclusions verified by simulation and experiment are generalized to other modulation formats and then applied to phase detuning monitoring, delay time judgment of DLI, and independence of modulation data assessment.展开更多
As an essential plant macronutrient, the low availability of phosphorus (P) in most soils imposes serious limitation on crop production. Plants have evolved complex responsive and adaptive mechanisms for acquisition...As an essential plant macronutrient, the low availability of phosphorus (P) in most soils imposes serious limitation on crop production. Plants have evolved complex responsive and adaptive mechanisms for acquisition, remobilization and recycling of phosphate (Pi) to maintain P homeostasis. Spatio-temporal molecular, physiological, and biochemical Pi deficiency responses developed by plants are the consequence of local and systemic sensing and signaling pathways. Pi deficiency is sensed locally by the root system where hormones serve as important signaling components in terms of developmental reprogramming, leading to changes in root system architecture. Root-to-shoot and shoot-to-root signals, delivered through the xylem and phloem, respectively, involving Pi itself, hormones, miRNAs, mRNAs, and sucrose, serve to coordinate Pi deficiency responses at the whole-plant level. A combination of chromatin remodeling, transcriptional and posttranslational events contribute to globally regulating a wide range of Pi deficiency responses. In this review, recent advances are evaluated in terms of progress toward developing a comprehen- sive understanding of the molecular events underlying control over P homeostasis. Application of this knowledge, in terms of developing crop plants having enhanced attributes for P use efficiency, is discussed from the perspective of agricultural sustainability in the face of diminishing global P supplies.展开更多
Plants adjust their development in relation to the availability of nutrient sources. This necessitates signal- ing between root and shoot. Aside from the well-known systemic signaling processes mediated by auxin, cyto...Plants adjust their development in relation to the availability of nutrient sources. This necessitates signal- ing between root and shoot. Aside from the well-known systemic signaling processes mediated by auxin, cytokinin, and sugars, new pathways involving carotenoid-derived hormones have recently been identified. The auxin-responsive MAX pathway controls shoot branching through the biosynthesis of strigolactone in the roots. The BYPASSI gene affects the production of an as-yet unknown carotenoid-derived substance in roots that promotes shoot development. Novel local and systemic mechanisms that control adaptive root development in response to nitrogen and phosphorus starvation were recently discovered. Notably, the ability of the NITRATE TRANSPORTER 1.1 to transport auxin drew for the first time a functional link between auxin, root development, and nitrate availability in soil. The study of plant response to phos- phorus starvation allowed the identification of a systemic mobile miRNA. Deciphering and integrating these signaling pathways at the whole-plant level provide a new perspective for understanding how plants regulate their development in response to environmental cues.展开更多
An optical signal-to-noise ratio (OSNR) aware lightpath provisioning mechanism (OSNR-LPM) is proposed for distributed optical networks. This OSNR-LPM takes the OSNR value of the lightwave along the lightpath into ...An optical signal-to-noise ratio (OSNR) aware lightpath provisioning mechanism (OSNR-LPM) is proposed for distributed optical networks. This OSNR-LPM takes the OSNR value of the lightwave along the lightpath into consideration when establishing the lightpath for the connection request using resource reservation protocol-traffic engineering (RSVP-TE). Moreover, the OSNR-LPM makes full advantages of the OSNR monitoring function in each node and assigns the lightwave by judging the OSNR value carried by the signaling message in order to guarantee the reliable establishment of the lightpath in the data plane. The simulation results show that the OSNR-LPM outperforms other lightpath assignment mechanisms in terms of real blocking probability in the data plane.展开更多
A domain-level gradient-based routing (DLR) algorithm for heterogeneous optical networks with syn- chronous digital hierarchy and optical transport network domains is proposed and experimentally vali- dated. This al...A domain-level gradient-based routing (DLR) algorithm for heterogeneous optical networks with syn- chronous digital hierarchy and optical transport network domains is proposed and experimentally vali- dated. This algorithm classifies domains into groups with incremental levels on the basis of domain-level partitioning, and guides paths level by level along a gradient on the basis of interdomain routing tree evolution. The proposed algorithm is implemented in the hierarchical path computation element-based control architecture for connection provisioning. Testbeds with commercial and emulated nodes are es- tablished to verify the feasibility and performance of the algorithm. Experimental and emulation results show that DLR effectively performs in terms of network blocking probability, real time characteristics, and scalability.展开更多
The emergence of the tracheophyte-based vascular system of land plants had major impacts on the evolution of terrestrial biology, in general, through its role in facilitating the development of plants with increased s...The emergence of the tracheophyte-based vascular system of land plants had major impacts on the evolution of terrestrial biology, in general, through its role in facilitating the development of plants with increased stature, photosynthetic output, and ability to colonize a greatly expanded range of environmental habitats. Recently, considerable progress has been made in terms of our understanding of the developmental and physiological programs involved in the formation and function of the plant vascular system. In this review, we first examine the evolutionary events that gave rise to the tracheophytes, followed by analysis of the genetic and hormonal networks that cooperate to orchestrate vascular development in the gymnosperms and angiosperms. The two essentialfunctions performed by the vascular system, namely the delivery of resources (water, essential mineral nutrients, sugars and amino acids) to the various plant organs and provision of mechanical support are next discussed. Here, we focus on critical questions relating to structural and physiological properties controlling the delivery of material through the xylem and phloem. Recent discoveries into the role of the vascular system as an effective long-distance communication system are next assessed in terms of the coordination of developmental, physiological and defense-related processes, at the whole-plant level. A concerted effort has been made to integrate all these new findings into a comprehensive picture of the state-of-the-art in the area of plant vascular biology. Finally, areas important for future research are highlighted in terms of their likely contribution both to basic knowledge and applications to primary industry.展开更多
Nitrate is the main source of nitrogen for plants but often distributed heterogeneously in soil.Plants have evolved sophisticated strategies to achieve adequate nitrate by modulating the root system architecture. The ...Nitrate is the main source of nitrogen for plants but often distributed heterogeneously in soil.Plants have evolved sophisticated strategies to achieve adequate nitrate by modulating the root system architecture. The nitrate acquisition system is triggered by the short mobile peptides C-TERMINALLY ENCODED PEPTIDES(CEPs)that are synthesized on the nitrate-starved roots,but induce the expression of nitrate transporters on the other nitrate-rich roots through an unclear signal transduction pathway. Here,we demonstrate that the transcription factors HBI1 and TCP20 play important roles in plant growth and development in response to fluctuating nitrate supply. HBI1 physically interacts with TCP20, and this interaction was enhanced by the nitrate starvation. HBI1 and TCP20 directly bind to the promoters of CEPs and cooperatively induce their expression. Mutation in HBIs and/or TCP20 resulted in impaired systemic nitrate acquisition response. Our solid genetic and molecular evidence strongly indicate that the HBI1-TCP20 module positively regulates the CEPs-mediated systemic nitrate acquisition.展开更多
Iron(Fe) is an essential micronutrient required by all fruit trees. To elucidate the regulatory mechanism of auxin to the long-distance transport of Fe, a gene encoding a putative CS protein was isolated from Pyrus be...Iron(Fe) is an essential micronutrient required by all fruit trees. To elucidate the regulatory mechanism of auxin to the long-distance transport of Fe, a gene encoding a putative CS protein was isolated from Pyrus betulifolia. This gene was designated as Pb CS1 containing 1 422 bp in length with an open reading frame encoding a protein of 473 amino acids with a predicted molecular mass of 52.69 ku and a theoretical isoelectric point of 6.91. The deduced Pb CS1 protein contained a conserved CS domain and WPNVDAHS sequence existing in the PWPN-box. Based on its conserved domain and phylogenetic status, the Pb CS1 should be grouped into type-Ⅰ subfamily of plant CS. Quantitative real-time PCR results indicated that the Pb CS1 expression was enriched in leaves, roots and phloem, but relatively weak in xylem. Using split root systems, Fe deficiency in one portion of the root system could induce dramatic up-regulation of the Pb CS1 expression in the Fe-sufficient part, suggesting that the Pb CS1 expression was activated by systemic signals. In addition, supplying with NAA and exogenous auxin to the de-topped shoots could recover the Fe deficiency-induced up-regulation of the Pb CS1 expression in the Fe-sufficient part of the root system. In contrast, NPA(an auxin transport inhibitor) application to the shoot tips arrested up-regulation of the Pb CS1 expression in the untreated portion. The results suggested that Fe-deficiency-induced alterations of the Pb CS1 expression were mediated by auxin.展开更多
基金Supported by the National Natural Science Foundation of China under Grant No 61275075the Beijing Natural Science Foundation under Grant Nos 4132035 and 4144080
文摘The quaternion approach to solve the coupled nonlinear Schrodinger equations (CNSEs) in fibers is proposed, converting the CNSEs to a single variable equation by using a conception of eigen-quaternion of coupled quater- nion. The crosstalk of quarter-phase-shift-key signals caused by fiber nonlinearity in polarization multiplexing systems with 100 Cbps bit-rate is investigated and simulated. The results demonstrate that the crosstalk is like a rotated ghosting of input constellation. For the 50 km conventional fiber link, when the total power is less than 4roW, the crosstalk effect can be neglected; when the power is larger than 20roW, the crosstalk is very obvious. In addition, the crosstalk can not be detected according to the output eye diagram and state of polarization in Poincare sphere in the trunk fiber, making it difficult for the monitoring of optical trunk link.
基金Supported by the National Natural Science Foundation of China under Grant No 61371170the Fundamental Research Funds for the Central Universities under Grant Nos NP2015404 and NS2016038+1 种基金the Aeronautical Science Foundation of China under Grant No 20152052028the Funding of Jiangsu Innovation Program for Graduate Education under Grant No KYLX15_0282
文摘Based on the asymptotic spectral distribution of Wigner matrices, a new normality test method is proposed via reforming the white noise sequence. In this work, the asymptotic cumulative distribution function (CDF) of eigenvalues of the Wigner matrix is deduced. A numerical Kullback-Leibler divergence of the empiric-d spectral CDF based on test samples from the deduced asymptotic CDF is established, which is treated as the test statistic. For validating the superiority of our proposed normality test, we apply the method to weak SIPSK signal detection in the single-input single-output (SISO) system and the single-input multiple-output (SIMO) system. By comparing with other common normality tests and the existing signal detection methods, simulation results show that the proposed method is superior and robust.
文摘The rapid developing of the fourth generation(4G)wireless communications has aroused tremendous demands for high speed data transmission due to the dissemination of various types of the intelligent user terminals as well as the wireless multi-media services.It is predicted that the network throughput will increase
基金supported by the National Basic Research Program of China(Grand No.2012CB723303)the Beijing Committee of Science and Technology,China(Grand No.Z1211000003120100)
文摘The complexity of signal controlled traffic largely stems from the various driving behaviors developed in response to the traffic signal. However, the existing models take a few driving behaviors into account and consequently the traffic dynamics has not been completely explored. Therefore, a new cellular automaton model, which incorporates the driving behaviors typically manifesting during the different stages when the vehicles are moving toward a traffic light, is proposed in this paper. Numerical simulations have demonstrated that the proposed model can produce the spontaneous traffic breakdown and the dissolution of the over-saturated traffic phenomena. Furthermore, the simulation results indicate that the slow-to-start behavior and the inch-forward behavior can foster the traffic breakdown. Particularly, it has been discovered that the over-saturated traffic can be revised to be an under-saturated state when the slow-down behavior is activated after the spontaneous breakdown. Finally, the contributions of the driving behaviors on the traffic breakdown have been examined.
基金supported by the National Natural Science Foundation of China (31970274 (J.W.), 32170272 (X.W.), 32100251 (J.Z.), 32000179 (Y.X.))the Special Research Assistant of Chinese Academy of Sciences (J.Z. and Y.X.), China Postdoctoral Science Foundation (2022M713224 (J.Z.))+6 种基金the Strategic Priority Research Program of Chinese Academy of Sciences (XDPB16 (J.W.))the Yunnan Innovation Team Project (202105AE160013 (J.W.))CAS “Light of West China” Program (G.S.)Yunnan Revitalization Talent Support Program “Young Talents” Project (XDYC-QNRC-2022-0301 (J.Z.), XDYC-QNRC-2022-0001 (G.S.))the General and Key Project of the Applied Basic Research Program of Yunnan (202001AS070021(J.W.))Yunnan Fundamental Research Projects-General Project (202101AT070457 (S.L.))Yunnan Fundamental Research Projects-Youth Talent Project (202101AU070021(S.L.))
文摘Parasitic plants and their hosts communicate through haustorial connections.Nutrient deficiency is a common stress for plants,yet little is known about whether and how host plants and parasites communicate during adaptation to such nutrient stresses.In this study,we used transcriptomics and proteomics to analyze how soybean(Glycine max)and its parasitizing dodder(Cuscuta australis)respond to nitrate and phosphate deficiency(-N and-P).After-N and-P treatment,the soybean and dodder plants exhibited substantial changes of transcriptome and proteome,although soybean plants showed very few transcriptional responses to-P and dodder did not show any transcriptional changes to either-N or-P.Importantly,large-scale interplant transport of mRNAs and proteins was detected.Although the mobile mRNAs only comprised at most 0.2%of the transcriptomes,the foreign mobile proteins could reach 6.8%of the total proteins,suggesting that proteins may be the major forms of interplant communications.Furthermore,the interplant mobility of macromolecules was specifically affected by the nutrient regimes and the transport of these macromolecules was very likely independently regulated.This study provides new insight into the communication between host plants and parasites under stress conditions.
基金This work was supported by the National Key R&D Program of China(2018YFA0902200)National Natural Science Foundation of China(No.21776157No.22078173).
文摘Microbial consortia are ubiquitous in nature,in which multiple microbial species cooperate to complete some important tasks such as lignocellulose degradation.Because of the advantages such as reduced metabolic burden and robustness to environment disturbances,developing a microbial consortium is a promising approach for valuable product synthesis,lignocellulose utilization,human health care,bioremediation and sustainable energy,etc.Despite the benefits,however,most artificial microbial consortia confront the problems of instability and low efficiency due to growth competition and metabolite incompatibility.To overcome these challenges,multiple strategies to design efficient synthetic microbial consortia have been reported.In this review,the interactions that determine the stability and performance of microbial consortia were described.Progress of artificial microbial consortia research was summarized,and the key strategies i.e.,spatial or temporal segregation,separated utilization of nutrients,nutrient cross-feeding and division of labor,that will be of great importance for achieving a stable and efficient microbial consortium were highlighted.Two novel advanced tools,signaling molecule systems and computational models,were also introduced and discussed.We believed that combining the universal cell–cell signaling molecule systems with computational models will be promising for synthetic microbial consortia construction in the future.
基金supported in part by the National Natural Science Foundation of China(Nos. 61007045,61025004 and 61032005)the National "863" Program of China(Nos.2009AA01Z223 and 2009AA01Z253)
文摘The relation between the phase shift and the mean optical power (MOP) output from a delay-line inter- ferometer (DLI) port applied for phase-shift keying (PSK) signal demodulation is proven of a cosine law irrelevant to signal modulation condition. The variation amplitude of the MOP is proportional to the transition duration of the modulation pulses. This phenomenon is interpreted as the result of the sta- tistical and waveform characteristics of the PSK. The conclusions verified by simulation and experiment are generalized to other modulation formats and then applied to phase detuning monitoring, delay time judgment of DLI, and independence of modulation data assessment.
基金supported by grants from the United States Department of AgricultureNational Institute of Food and Agriculture (NIFA 201015479+2 种基金 W.J.L.)the National Natural Science Foundation of China (31025022 H.L.)
文摘As an essential plant macronutrient, the low availability of phosphorus (P) in most soils imposes serious limitation on crop production. Plants have evolved complex responsive and adaptive mechanisms for acquisition, remobilization and recycling of phosphate (Pi) to maintain P homeostasis. Spatio-temporal molecular, physiological, and biochemical Pi deficiency responses developed by plants are the consequence of local and systemic sensing and signaling pathways. Pi deficiency is sensed locally by the root system where hormones serve as important signaling components in terms of developmental reprogramming, leading to changes in root system architecture. Root-to-shoot and shoot-to-root signals, delivered through the xylem and phloem, respectively, involving Pi itself, hormones, miRNAs, mRNAs, and sucrose, serve to coordinate Pi deficiency responses at the whole-plant level. A combination of chromatin remodeling, transcriptional and posttranslational events contribute to globally regulating a wide range of Pi deficiency responses. In this review, recent advances are evaluated in terms of progress toward developing a comprehen- sive understanding of the molecular events underlying control over P homeostasis. Application of this knowledge, in terms of developing crop plants having enhanced attributes for P use efficiency, is discussed from the perspective of agricultural sustainability in the face of diminishing global P supplies.
文摘Plants adjust their development in relation to the availability of nutrient sources. This necessitates signal- ing between root and shoot. Aside from the well-known systemic signaling processes mediated by auxin, cytokinin, and sugars, new pathways involving carotenoid-derived hormones have recently been identified. The auxin-responsive MAX pathway controls shoot branching through the biosynthesis of strigolactone in the roots. The BYPASSI gene affects the production of an as-yet unknown carotenoid-derived substance in roots that promotes shoot development. Novel local and systemic mechanisms that control adaptive root development in response to nitrogen and phosphorus starvation were recently discovered. Notably, the ability of the NITRATE TRANSPORTER 1.1 to transport auxin drew for the first time a functional link between auxin, root development, and nitrate availability in soil. The study of plant response to phos- phorus starvation allowed the identification of a systemic mobile miRNA. Deciphering and integrating these signaling pathways at the whole-plant level provide a new perspective for understanding how plants regulate their development in response to environmental cues.
基金supported in part by the National "863" Program of China (Nos. 2009AA01z255 and 2009AA01A345)the National "973" Program of China (No.2007CB310705)+1 种基金the National Natural Science Foundation of China (No. 60932004)the Specialized Research Fund for the Doctoral Program of Higher Education of China (No. 200800130001)
文摘An optical signal-to-noise ratio (OSNR) aware lightpath provisioning mechanism (OSNR-LPM) is proposed for distributed optical networks. This OSNR-LPM takes the OSNR value of the lightwave along the lightpath into consideration when establishing the lightpath for the connection request using resource reservation protocol-traffic engineering (RSVP-TE). Moreover, the OSNR-LPM makes full advantages of the OSNR monitoring function in each node and assigns the lightwave by judging the OSNR value carried by the signaling message in order to guarantee the reliable establishment of the lightpath in the data plane. The simulation results show that the OSNR-LPM outperforms other lightpath assignment mechanisms in terms of real blocking probability in the data plane.
基金supported by the"863"Project of China(Nos.2012AA011301 and 2009AA01Z254)the National"973"Program of China(Nos.2010CB328203 and 2010CB328205)the National Natural Science Foundation of China(No.61201188)
文摘A domain-level gradient-based routing (DLR) algorithm for heterogeneous optical networks with syn- chronous digital hierarchy and optical transport network domains is proposed and experimentally vali- dated. This algorithm classifies domains into groups with incremental levels on the basis of domain-level partitioning, and guides paths level by level along a gradient on the basis of interdomain routing tree evolution. The proposed algorithm is implemented in the hierarchical path computation element-based control architecture for connection provisioning. Testbeds with commercial and emulated nodes are es- tablished to verify the feasibility and performance of the algorithm. Experimental and emulation results show that DLR effectively performs in terms of network blocking probability, real time characteristics, and scalability.
基金supported in part by the National Science Foundation (grants IOS-0752997 and IOS-0918433 to WJL grants IOS#0749731, IOS#051909 to PK)+8 种基金the Department of Energy, Division of Energy Biosciences (grantsDE-FG02-94ER20134 to WJL)the US Department of Agriculture, Agricultural Research Service (under Agreement number58-6250-0-008 to MAG)the Spanish Ministry of Science andInnovation (MICINN) (grants AGL2007-61948 and AGL2009-09018 to AFLM)the Ministry of Education, Science, Sportsand Culture of Japan (grant 19060009 to HF)the JapanSociety for the Promotion of Science (JSPS grant 23227001to HF)the NC-CARP project (to HF)the NationalKey Basic Research Program of China (grant 2012CB114500to XH)the National Natural Science Foundation of China (grant31070156 to XH)the NSFC-JSPS cooperation project(grant 31011140070 to HF and XH)
文摘The emergence of the tracheophyte-based vascular system of land plants had major impacts on the evolution of terrestrial biology, in general, through its role in facilitating the development of plants with increased stature, photosynthetic output, and ability to colonize a greatly expanded range of environmental habitats. Recently, considerable progress has been made in terms of our understanding of the developmental and physiological programs involved in the formation and function of the plant vascular system. In this review, we first examine the evolutionary events that gave rise to the tracheophytes, followed by analysis of the genetic and hormonal networks that cooperate to orchestrate vascular development in the gymnosperms and angiosperms. The two essentialfunctions performed by the vascular system, namely the delivery of resources (water, essential mineral nutrients, sugars and amino acids) to the various plant organs and provision of mechanical support are next discussed. Here, we focus on critical questions relating to structural and physiological properties controlling the delivery of material through the xylem and phloem. Recent discoveries into the role of the vascular system as an effective long-distance communication system are next assessed in terms of the coordination of developmental, physiological and defense-related processes, at the whole-plant level. A concerted effort has been made to integrate all these new findings into a comprehensive picture of the state-of-the-art in the area of plant vascular biology. Finally, areas important for future research are highlighted in terms of their likely contribution both to basic knowledge and applications to primary industry.
基金This work was funded by the National Natural Science Foundation of China(Grant Nos.31970306,31600199,and 31670284)by China Postdoctoral Science Foundation(Grant Nos.2017M612259,2018T110684,and 2020M672047)+2 种基金by Shandong Province Natural Science Foundation(Grant Nos.ZR2019ZD16,JQ201708,and ZR2018ZC0334)by the Shandong Province Postdoctoral Science Foundation(Grant No.11200078311023 to J.W.)by Shandong Province Agricultural Variety Improvement Project(Grant No.2019LZGC-015)。
文摘Nitrate is the main source of nitrogen for plants but often distributed heterogeneously in soil.Plants have evolved sophisticated strategies to achieve adequate nitrate by modulating the root system architecture. The nitrate acquisition system is triggered by the short mobile peptides C-TERMINALLY ENCODED PEPTIDES(CEPs)that are synthesized on the nitrate-starved roots,but induce the expression of nitrate transporters on the other nitrate-rich roots through an unclear signal transduction pathway. Here,we demonstrate that the transcription factors HBI1 and TCP20 play important roles in plant growth and development in response to fluctuating nitrate supply. HBI1 physically interacts with TCP20, and this interaction was enhanced by the nitrate starvation. HBI1 and TCP20 directly bind to the promoters of CEPs and cooperatively induce their expression. Mutation in HBIs and/or TCP20 resulted in impaired systemic nitrate acquisition response. Our solid genetic and molecular evidence strongly indicate that the HBI1-TCP20 module positively regulates the CEPs-mediated systemic nitrate acquisition.
基金financial support from China Agriculture Research System (CARS-29-13)
文摘Iron(Fe) is an essential micronutrient required by all fruit trees. To elucidate the regulatory mechanism of auxin to the long-distance transport of Fe, a gene encoding a putative CS protein was isolated from Pyrus betulifolia. This gene was designated as Pb CS1 containing 1 422 bp in length with an open reading frame encoding a protein of 473 amino acids with a predicted molecular mass of 52.69 ku and a theoretical isoelectric point of 6.91. The deduced Pb CS1 protein contained a conserved CS domain and WPNVDAHS sequence existing in the PWPN-box. Based on its conserved domain and phylogenetic status, the Pb CS1 should be grouped into type-Ⅰ subfamily of plant CS. Quantitative real-time PCR results indicated that the Pb CS1 expression was enriched in leaves, roots and phloem, but relatively weak in xylem. Using split root systems, Fe deficiency in one portion of the root system could induce dramatic up-regulation of the Pb CS1 expression in the Fe-sufficient part, suggesting that the Pb CS1 expression was activated by systemic signals. In addition, supplying with NAA and exogenous auxin to the de-topped shoots could recover the Fe deficiency-induced up-regulation of the Pb CS1 expression in the Fe-sufficient part of the root system. In contrast, NPA(an auxin transport inhibitor) application to the shoot tips arrested up-regulation of the Pb CS1 expression in the untreated portion. The results suggested that Fe-deficiency-induced alterations of the Pb CS1 expression were mediated by auxin.