Casuarina equisetifolia L., a key pioneer species in tropical and subtropical coastal shelterbelts, suffers from ecological decline owing to recurrent infestations by Lymantria xylina Swinhoe. To address this, we deciphered the molecular defence mechanisms and identified reliable biomarker metabolites for resistance breeding. Phenotypic analyses suggesting that the resistance to L. xylina was jointly mediated by antixenosis and antibiosis, and three resistant half-sib families (e.g., 3-52, 5-80 and 5-218) were preliminarily identified. Integrated transcriptomic and metabolomic profiling of L. xylina herbivory demonstrated significant enrichment of differentially expressed genes in the circadian rhythm-plant, jasmonic acid signaling and phenylpropanoid biosynthesis pathways-which may mediate the optimization of defence responses. In parallel, differential accumulation metabolites were predominantly enriched in α-linolenic acid metabolism. In particular, the content of α-linolenic acid strongly correlated with resistance, while flavonoids and tannins also exhibited significant positive correlations, confirming their roles in the defence response. These results suggest that the α-linolenic acid to phenylpropanoid cascade may function as a core defence axis in C. equisetifolia against L. xylina. Collectively, α-linolenic acid, flavonoids and tannins serve as candidate biomarkers for breeding insect-resistant C. equisetifolia genotypes.

[目的]探讨南亚热带4种典型桫椤群落特征及生物多样性与土壤因子之间的耦合关系,为我国桫椤种群的科学保护和合理开发提供理论参考资料和依据.[方法]在福建省闽侯南屿国有林场选取4种典型的桫椤群落设置12块样地,分乔、灌、草和层间层进行群落学调查,分析4种群落各层物种组成、生物多样性,再运用CCA排序法分析4种桫椤群落样地及其物种重要值与土壤理化性质的关系.[结果]所调查的12块样地总共记录维管植物72种,隶属于43科66属,其中乔木13种,灌木32种,草本12种,层间植物21种;枇杷叶紫珠+杉木+桫椤群落乔木层Shannon-Wiener指数、Simpson指数、Pielou(1)指数和Pielou(2)指数与其他3种群落存在显著差异(P<0.05),柳杉+桫椤群落层间层的Margalef指数、Shannon-Wiener指数、Simpson指数、Pielou(1)指数和Pielou(2)指数总体上高于其他3种群落,其群落结构与其他3种群落存在较大差异;4种群落的桫椤种群在草本层稀少;4种群落的桫椤种群与土壤理化性质相关关系均不明显.[结论]试验地林下桫椤幼苗稀少将导致桫椤种群趋向退化,在管护过程中应加强桫椤自然更新的研究,减少人为干扰,促进桫椤种群的稳定和发展.

为探讨地役权管理对毛竹林群落结构和林下植物多样性的影响,以武夷山国家公园非地役权和地役权管理的毛竹林为研究对象,对毛竹林分结构和林下植物多样性进行全面调查.结果表明:非地役权和地役权管理毛竹林的总体密度差异显著(P＜0.05),其中1度竹密度差异不显著,而2度及以上活立竹差异显著(P＜0.05),表明二者之间密度的差异主要源于2度及以上活立竹数量的不同.地役权管理的毛竹林胸径略低于非地役权,但两者差异不显著(P＞0.05).排名前15的林下灌木中,在非地役权和地役权管理毛竹林中共同出现的有7种,其优势灌木分别为黄绒润楠和过路惊;而排名前15的林下草本植物中共同出现的有11种,其优势草本植物分别为淡竹叶和华里白.非地役权和地役权管理林下灌木和草本的多样性均无显著差异,这可能与地役权管理开展年限较短有关.

SUMMARYAustralian pine (Casuarina spp.) is extensively planted in tropical and subtropical regions for wood production, shelterbelts, environmental protection, and ecological restoration due to their superior biological characteristics, such as rapid growth, wind and salt tolerance, and nitrogen fixation. To analyze the genomic diversity of Casuarina, we sequenced the genomes and constructed de novo genome assemblies of the three most widely planted Casuarina species: C. equisetifolia, C. glauca, and C. cunninghamiana. We generated chromosome‐scale genome sequences using both Pacific Biosciences (PacBio) Sequel sequencing and chromosome conformation capture technology (Hi‐C). The total genome sizes for C. equisetifolia, C. glauca, and C. cunninghamiana are 268 942 579 bp, 296 631 783 bp, and 293 483 606 bp, respectively, of which 25.91, 27.15, and 27.74% were annotated as repetitive sequences. We annotated 23 162, 24 673, and 24 674 protein‐coding genes in C. equisetifolia, C. glauca, and C. cunninghamiana, respectively. We then collected branchlets from male and female individuals for whole‐genome bisulfite sequencing (BS‐seq) to explore the epigenetic regulation of sex determination in these three species. Transcriptome sequencing (RNA‐seq) revealed differential expression of phytohormone‐related genes between male and female plants. In summary, we generated three chromosome‐level genome assemblies and comprehensive DNA methylation and transcriptome datasets from both male and female material for three Casuarina species, providing a basis for the comprehensive investigation of genomic diversity and functional gene discovery of Casuarina in the future.

Numerous real-world systems can be naturally modeled as multilayer networks, providing an efficient tool to characterize these complex systems. Although recent progress in understanding the controlling of synthetic multiplex networks, how to control real multilayer systems remains poorly understood. Here, we explore the controllability and energy requirement of molecular multiplex networks coupled by transcriptional regulatory network (TRN) and protein-protein interaction (PPI) network from the perspective of network structural characteristics. Our findings reveal that the driver nodes tend to avoid essential or pathogen-related genes. However, imposing external inputs on these essential or pathogen-related genes can remarkably reduce the energy cost, implying their crucial role in network control. Moreover, we find that the minimal driver nodes, as well as the energy required, are associated with disassortative coupling between TRN and PPI networks. Our results provide a comprehensive understanding of the roles of genes in biology and network control across several species.

以武夷山米槠(Castanopsis carlesii(Hemsl.)Hay.)群落为研究对象,采用生态位测定与种间联结方法,分析了米槠种群乔木层25个优势种群生态位与种间联结.结果显示:米槠、树参(Dendropanax dentiger(Harms.)Merr.)、弯蒴杜鹃(Rhododendron henryi Hance.)和少叶黄杞(Engelhardtia fenzlii Merr.)的生态位较大.群落生态位相似性和重叠性平均分别为0.36和0.42.优势种群间生态位低度重叠占71％,而高度重叠仅9.67％.乔木层总体联结性呈不显著正联结.Pearson相关系数和Spearman秩相关系数检验结果均发现相关性显著的种群占比较低,不显著种群占绝大多数,负联结种对大于正联结.根据主成分分析排序和种间联结关系分析结果,本研究将25个优势物种划分为4个生态种组.总的来说,米槠群落总体呈相对稳定的阶段,多数种对呈不显著相关或无相关性,独立性相对较强.

The control of complex networks is affected by their structural characteristic. As a type of key nodes in a network structure, cut vertexes are essential for network connectivity because their removal will disconnect the network. Despite their fundamental importance, the influence of the cut vertexes on network control is still uncertain. Here, we reveal the relationship between the cut vertexes and the driver nodes, and find that the driver nodes tend to avoid the cut vertexes. However, driving cut vertexes reduce the energy required for controlling complex networks, since cut vertexes are located near the middle of the control chains. By employing three different node failure strategies, we investigate the impact of cut vertexes failure on the energy required. The results show that cut vertex failures markedly increase the control energy because the cut vertexes are larger-degree nodes. Our results deepen the understanding of the structural characteristic in network control.

Despite the significant advances in identifying the driver nodes and energy requiring in network control, a framework that incorporates more complicated dynamics remains challenging. Here, we consider the conformity behavior into network control, showing that the control of undirected networked systems with conformity will become easier as long as the number of external inputs beyond a critical point. We find that this critical point is fundamentally determined by the network connectivity. In particular, we investigate the nodal structural characteristic in network control and propose optimal control strategy to reduce the energy requiring in controlling networked systems with conformity behavior. We examine those findings in various synthetic and real networks, confirming that they are prevailing in describing the control energy of networked systems. Our results advance the understanding of network control in practical applications.

Casuarina equisetifolia plantations of eight areas in the five provinces in different southeast coastal latitudes（Hainan, Guangdong, Guangxi, Fujian and Zhejiang） were taken as the research subjects.This paper studied the distribution pattern of biomass and productivity of middle-aged forests and mature forests with latitude, and analyzed the correlation between productivity and main environmental factors of Casuarina equisetifolia plantation.The results of the study were as follows: the height and biomass of middle-aged forests decreased with the increase of latitude and the DBH in low latitude areas was higher than that in high latitude areas; biomass of middle-aged forests and mature forests in Casuarina equisetifolia plantation did not change regularly on latitude gradient; the biomass distribution of middle-aged forests and mature forests in Casuarina equisetifolia plantation showed as trunk＞root＞branch＞leaf, except for the middle-aged forests in Casuarina equisetifolia plantation in Dianbai of Guangdong province; the productivity of Casuarina equisetifolia plantation decreased with the increase in the age of forests, and the productivity of middle-aged forests in Casuarina equisetifolia plantation on higher latitude in Wenzhou of Zhejiang province was significantly lower than that in other research areas; the productivity of mature forests in Casuarina equisetifolia was of no significant difference among each study area; the productivity of middle-aged forests in Casuarina equisetifolia plantation was significantly correlated with annual average temperature, annual average precipitation and actual evapotranspiration, while that of mature forests was not significantly correlated.

Casuarina equisetifolia (L.) is an indispensable tree species in the construction of the backbone of the shelterbelt system in subtropical coastal regions, as it can resist wind, sand, drought, and salt. Under global warming and water shortage, it is important to clarify the mechanisms through which C. equisetifolia adapts to drought stress and to breed drought-resistant varieties in order to enhance the ecological protection provided by coastal shelterbelts. Here, we aimed to explore the response characteristics of C. equisetifolia to drought stress and investigate the associations of NAC genes with drought resistance. Seedlings of 16 half-sib C. equisetifolia families were subjected to drought treatment. Seedling growth, morphology, physiological and biochemical indices, and drought resistance were comprehensively evaluated. The drought-resistant families designated 4-383, 3-80, 3-265, 3-224, and 1-195 were selected using multiple indices and methods. Correlation and structural equation model analyses revealed that CCG007578 might regulate growth and osmoprotection in C. equisetifolia while CCG028838 and CCG004029 may scavenge reactive oxygen species. The correlation and structural equation model analyses of seedling height growth (ΔH), survival rate (S), malondialdehyde (MDA), superoxide dismutase (SOD), and CCG007578 expression were used to identify drought resistance in C. equisetifolia. The aforementioned drought-resistant families provide basic materials for future research on genes encoding drought-resistance proteins and the molecular breeding of drought-resistant C. equisetifolia.

闽南沙岸木麻黄防护林带更新采用水黄皮造林试验,包括木麻黄基干林带更新采取林内套种水黄皮试验和海岸后侧木麻黄林带采伐迹地采用木麻黄与水黄皮带状混交试验.结果表明:木麻黄基干林带内水黄皮的保存率、树高和胸径随林带郁闭度的增加而降低,不同郁闭度林带内水黄皮的保存率、树高和胸径差异达到显著水平;林带内套种水黄皮对土壤肥力起到改善作用;木麻黄与水黄皮带状混交能提高木麻黄的生长量、林分防风效能和土壤肥力.

为评价锥栗园生草法相比传统清耕法和施用化学除草剂法,果园土壤质量的绿肥恢复效益,本研究以福建典型的红壤丘陵山区锥栗园为研究对象,采用随机区组设计,将供试样地均分为面积0.3～0.5 hm2的若干试验小区,全园清除自然杂草后,设置撒播鼠茅草(Mode1)、黑麦草(Mode2)、光叶紫花苕(Mode3)3种生草处理,并以施用草甘膦(CK1)和清耕(CK2)处理为对照,每种处理3个重复,2年后,分析3种冷季型绿肥、清耕及施用草甘膦对锥栗园土壤理化性质、酶活性、微生物群落等指标的影响.结果表明:1)相较于清耕处理和喷施草甘膦处理,3种生草处理土壤碱解氮、有效磷、速效钾含量有明显提升,其中鼠茅草处理最高,分别为74.14、156.87和234.76 mg·kg-1;黑麦草处理土壤孔隙度最高,为56.03％;鼠茅草和黑麦草处理土壤蔗糖酶活性提升明显,分别为32.29和26.87 U·g-1.2)5种处理土壤共有优势细菌类群主要为放线菌门、变形菌门、绿弯菌门和酸杆菌门,相对丰度分别为24.9％～28.9％、20.9％～28.8％、13.7％～18.6％和10.8％～12.9％,共有优势真菌类群主要为子囊菌门和担子菌门,相对丰度分别为37.4％～73.7％和15.3％～54.4％.3)相较于清耕处理,3种生草处理细菌群落Chao1指数和Shannon指数均有所提升,真菌群落有所下降.4)相较于清耕处理和喷施草甘膦处理,3种生草处理土壤变形菌门、拟杆菌门和厚壁菌门细菌相对丰度均有所下降,绿弯菌门和浮酶菌门细菌则有所增加,生草促使锥栗园土壤细菌群落由快速生长型向缓慢生长型转变.5)5种处理细菌群落和真菌群落非计量多维尺度转换排序(NMDS)表明,土壤真菌群落分异程度高于细菌群落.6)相关分析(CA)和冗余分析(RDA)表明,生草处理通过改变土壤蔗糖酶、过氧化氢酶活性和碱解氮含量,喷施草甘膦处理通过改变土壤碳氮比,清耕处理通过限制土壤自然含水率改变真菌相关优势类群.综上,锥栗园短期人工生草对土壤理化性质和酶活性有一定程度的改善作用,生草处理与清耕处理和喷施草甘膦处理均会形成特异土壤真菌群落.

以平潭岛幸福洋6 a生木麻黄基干林为研究对象,选用6种典型的冠幅—胸径关系模型,采用决定系数(R2)、平均绝对误差(MAE)、剩余均方根误差(RMSE)和变异系数(CV)等检验指标,筛选最优模型,并利用Matlab GUI回调函数对模型进行程序设计,模拟预测基干林冠幅和胸径生长动态.结果表明:(1)木麻黄基干林最优冠幅—胸径关系模型为CW =-2.558+2.037 In DBH;(2)经过计算机模拟抚育预测,林分株数密度分别为＞3 000株·hm-2、2 000～3 000株·hm-2和＜2 000株·hm-2的6 a生木麻黄基干林,最有利于木麻黄径向生长的模拟抚育间伐年限分别为6 a、4 a和5 a,平均胸径分别可以增加16.73％、24.03％和19.08％,平均冠幅可增长31.65％、11.89％和13.95％.

We measured the annual net biomass growth, carbon content of each component and soil heterotrophic respiration in four low-efficiency interplanting patterns, i.e., Pinus massoniana stands interplanting Myrica rubra, Sapindus mukurossi, Camellia oleifera and Gardenia jasminoides in Changting County, Fujian Province, with the aim to analyze the effects of interplanting patterns on carbon storage pattern and carbon balance of low-efficiency P. massoniana stand. The ranges of carbon content in different organs of M. rubra, S. mukurossi, C. oleifera, G. jasminoides and P. massoniana were 41.1%-50.1%, 42.2%-50.6%, 45.1%-48.9%, 44.7%-49.6% and 46.1%-51.9%, respectively. Carbon content of the same organ significantly differed among tree species. The pattern of P. massoniana interplanting M. rubra and S. mukurossi had the highest carbon stock and annual net carbon increase reserves, with values of 67.62-68.42 t·hm-2 and 9.21-9.45 t·hm-2·a-1, respectively. Followed by the lower pattern of C. oleifera, G. jasminoides, with values of 31.96-36.24 t·hm-2 and 4.09-4.16 t·hm-2·a-1, respectively. The P. massoniana pure forest was the lowest, with values of 17.01 t·hm-2 and 2.00 t·hm-2·a-1, respectively. Annual flux of soil heterotrophic respiration was following the order of P. massoniana interplanting M. rubra pattern (7.41 t·hm-2·a-1) > P. massoniana interplanting C. oleifera pattern (5.89 t·hm-2·a-1)> P. massoniana interplanting S. mukurossi pattern (5.86 t·hm-2·a-1) > P. massoniana interplanting G. jasminoides pattern (4.95 t·hm-2·a-1) > P. massoniana pure forest (2.45 t·hm-2·a-1). Annual net ecosystem carbon balance of P. massoniana interplanting M. rubra and S. mukurossi patterns were 2.04 and 3.27 t C·hm-2·a-1, showing a "carbon sink" pattern. The net carbon balance in the patterns of P. massoniana interplanting C. oleifera and G. jasminoides along with P. massoniana pure forest were -1.80, -0.80 and -0.45 t C·hm-2·a-1, which expressed a "carbon source" pattern. In the short-term, interplanting with M. rubra or S. mukurossi could improve the carbon income of the low-efficiency P. massoniana stand ecosystem.

为了探讨不同树种对养分贫瘠环境的适应策略,以中国亚热带海岸沙地上5种主要树种(木麻黄Casuarina equisetifolia、厚荚相思Acacia crassicarpa、湿地松Pinus elliottii、尾巨桉Euca-lyptus grandis x E.urophylla和潺槁木姜子Litsea glutinosa)为研究对象,测定成熟叶片和凋落叶中的钾(K)、钙(Ca)、钠(Na)、镁(Mg)、铝(Al)、铁(Fe)、锰(Mn)、铜(Cu)、锌(Zn)9种元素含量,研究相同立地条件下不同树种对不同元素的重吸收率.结果表明:不同树种叶片中K和Na的重吸收率均为正值,木麻黄小枝K和Na重吸收率最高,是典型的"营养保存型"树种.5个树种叶片中Ca、Fe、Mn、Al均为富集,潺槁木姜子叶片中Zn表现为重吸收,尾巨桉叶片中Mg为重吸收率,在其他树种叶片中Mg和Zn均为富集;Cu在非固氮树种中为重吸收,在固氮树种中为富集.5个树种对不同营养元素的吸收具有均衡性,立地条件和树种生物学特性共同影响了不同树种叶片的金属元素含量和重吸收效率.

本研究以福建典型的红壤丘陵山区锥栗(Castanea henryi)园为研究对象,采用随机区组设计,将供试样地分为面积0.3～0.5 hm2的若干试验小区,全园清除自然杂草后,设置撒播鼠茅草(Vulpia myuros,VM)籽、光叶紫花苕(Vicia villosa,VV)籽、黑麦草(Lolium perenne,LP)籽、紫云英(Astragalus simicus,AS)籽和园叶决明(Chamaecrista rotundifolia,CR)籽5种生草栽培,以及清耕(CT)和喷施草甘膦(GS),共7种不同处理,分析7种处理对锥果园土壤理化性质、微生物生物量碳氮和栗果农艺性状等指标的影响.结果 表明:1)各生草栽培处理的土壤总体质量显著高于CT和GS处理(P＜0.05);其中,在0-10cm和10-20 cm两个土层,VM处理的土壤水解性氮含量最高,分别为74.14和54.87 mg·kg-1,微生物生物量碳(MBC)含量也最高,分别为1.42和1.15 g·kg1;LP处理的土壤交换性钙含量最高,分别达到128和93.39 mg·kg-1,镁含量也最高,分别为114.95和66.28 mg·kg-1;VV处理的微生物生物量氮(MBN)含量最高,分别为47.68和30.89 mg·kg-1.(2)生草栽培显著改善了锥栗果实农艺性状,相比CT和GS处理,各生草栽培处理均不同程度地提高了果实中淀粉、可溶性糖、蛋白质、脂肪及磷钾钙镁营养元素的含量;VM处理的锥栗果实横纵径分别达到26.6和33.1 mm,单果质量13.549,果实个头明显增大,且VM处理的锥栗单位面积产量较CT和GS处理分别提高了59.44％、111.25％.(3) Mantel Test检验和随机森林分析表明,MBN、土壤水解性氮和交换性镁既是影响栗果总体农艺性状的关键因子,也是影响锥栗产量的最主要因子.综上,生草栽培可以提高锥果园土壤质量,改善锥栗果实农艺性状,提高锥栗产量,增加栗农收益;其中以VM处理表现最佳,可作为我国南方锥栗园地面管理的优先选择.

[目的]充分发挥海岸带木麻黄林地的生产潜力,为福建木麻黄人工林林分质量精准提升提供理论基础.[方法]基于福建省平潭岛海岸带木麻黄林样地调查和土壤分析,通过文献查阅,结合相关性分析筛选出影响木麻黄树高的主要养分因子,利用主成分分析方法对各样地多种土壤养分指标进行降维综合评价,并用聚类分析对所选样地土壤进行分级,最后结合立地因子的类别划分,运用数量化理论Ⅰ方法对木麻黄林立地条件进行立地质量评价和类型划分.[结果]海岸沙地木麻黄平均木树高与土壤有效磷呈极显著正相关(P<0.01);影响木麻黄生长的5个立地因子依贡献度大小分别为坡度(0.4602)>风向(0.4093)>土壤养分(0.2921)>海拔(0.2861)>土壤厚度(0.2856),其中坡度和风向与优势木高偏相关系数达极显著水平(P<0.01),海拔、土壤厚度和土壤养分皆达到显著水平(P<0.05);平潭岛海岸沙地木麻黄林立地评价结果可分为5个等级,其中Ⅱ级(较适宜)占比最大,为43.1％,其后依次为Ⅳ级(勉强适宜)、Ⅲ级(适宜)、Ⅴ级(不适宜)和Ⅰ级(最适宜),适宜、较适宜和最适宜等级总占比66.7％.[结论]通过立地评价与类型划分,认为平潭岛海岸沙地大部分立地条件较适合木麻黄生长,营造木麻黄林应选择坡度<15°、海拔高度10～100 m的立地条件,但海岸沙地土壤养分较为贫瘠,以低、贫养分为主,沿海沙地木麻黄林的生长主要受磷限制,在造林和抚育中应注意磷肥的补充.

为筛选有效提升红壤侵蚀区低效马尾松生态林水土保持功能的补植套种阔叶树种,采用布设标准径流小区的方法,定位观测福建长汀红壤侵蚀区4种典型的低效马尾松改造林分,分析不同补植套种林分模式对马尾松林地坡面产流产沙及其养分流失的影响.结果 表明:1)在降雨量和降雨次数较多的5-10月,马尾松林补植套种杨梅、无患子、油茶和黄栀子模式的产流量分别比马尾松纯林对照降低24.96％ ～ 42.19％、13.93％ ～53.68％、4.55％ ～ 26.45％和8.59％ ～32.98％;产沙量分别降低60.19％ ～ 84.86％、55.07％ ～ 87.14％、20.91％ ～ 67.06％和27.22％ ～72.66％;2)马尾松林补植套种杨梅和无患子模式的径流全氮、铵态氮、硝态氮流失量和侵蚀泥沙总碳流失量较接近,分别比马尾松纯林对照增加48.33％ ～ 48.79％、103.66％ ～ 139.05％、39.75％ ～ 42.29％和63.14％ ～66.57％;马尾松林补植套种油茶和黄栀子模式则分别增加19.96％ ～ 22.52％、74.89％ ～ 92.62％、15.44％ ～16.42％和25.24％ ～ 28.14％.其他养分流失量总体上与产流产沙的变化规律相似,表现为补植套种模式低于马尾松纯林对照;3)主成分分析表明,马尾松补植套种杨梅或无患子模式林分在降雨径流的作用下,较易引起土壤碳、氮的流失,而马尾松补植套种油茶或黄栀子模式林分则较易引起土壤磷、钾的流失.总体上看,补植套种杨梅或无患子在较短时间内改善低效马尾松林水土流失状况的效果较好.

为了解武夷山森林凋落物量和养分归还特征,对武夷山3个海拔典型森林的凋落物量和养分动态开展连续3年的监测.结果表明,常绿阔叶林(645 m)、针阔混交林(1028 m)和针叶林(1442 m)的凋落物总量分别为471.25、453.77和409.84 g/m2,森林凋落物总量随海拔升高呈减少的趋势.武夷山3种典型森林的凋落物总量具有明显的季节变化,均呈双峰型,但常绿阔叶林与针阔混交林和针叶林的凋落物总量峰值和次峰值出现时间近似相反.3种典型森林凋落物中落叶占绝对优势(78.1％～87.6％),落枝和其他组分较少.武夷山3种典型森林凋落物的养分年归还量均表现为C>N>K>P,且养分归还总量随海拔升高而减少.常绿阔叶林的凋落物量和养分归还量较高,可能与环境条件和植被特征相关.这为中亚热带森林生态系统养分循环和森林碳循环机理研究提供了理论依据.

Feedback is one of the most powerful influences in dynamical systems, performing a fundamental function in self-regulating processes. However, it is not known whether the underlying control of networked systems is associated with feedback. Here, we analyze structural feedback, defined by adding directed links from controlled nodes to driver nodes, to determine the control energy requirement of networked systems. We show that feedback systems with positive links require less energy than feedback systems with negative links, and the control energies of positive and negative perturbed feedback systems with the same amplitudes display a universal symmetry for regular graphs. Then, we describe an algorithm to construct a structural feedback system enabling the control of both synthetic and empirical networks. Our results improve the understanding of feedback in determining the control energy of dynamical systems, thus providing a potential way to devise new feedback control schemes.