甘蓝型油菜湿害胁迫响应性状的全基因组关联分析及候选基因预测

湿害严重影响油菜的产量和品质,前人在耐湿机制和生理响应等方面已经做了许多研究,但涉及油菜耐湿相关基因的研究相对较少。本研究以248份甘蓝型油菜品种(系)为材料,进行湿害胁迫处理,调查了8个湿害响应的相关性状,基于60K Illumina Infinium SNP芯片基因型数据对各性状耐湿系数进行了全基因组关联分析和湿害响应候选基因预测。结果显示,湿害胁迫较正常灌溉油菜幼苗绿叶数减少,地上部干重和鲜重以及叶片可溶性蛋白含量降低,叶片POD酶活性和MDA含量略有升高。地下部干重和鲜重在多数材料中降低,而在有些材料中升高,变化幅度均较小。经全基因组关联分析共检测到与耐湿系数显著关联的SNP标记36个,可解释表型变异8.28%~12.95%,其中17个所关联的耐湿系数在基因型间具有显著(P<0.05)或极显著(P<0.01)差异,其所在的Blocks共覆盖了71个候选基因,包括Blast到同源拟南芥基因64个,主要编码转录因子(如Transcription initiation factor IIF、bZIP68、myb-like HTH transcriptional regulator family protein)、转运蛋白(如SUC2)、生长抑制子(如ING2)、蛋白磷酸酶(如Protein phosphatase 2C family protein)、DNA/RNA结合蛋白[如bHLH DNA-binding superfamily protein、RNA-binding(RRM/RBD/RNP motifs)family protein]、激素响应蛋白(如ARF8、ADC2、ERD6、NF-YC9)以及氧化胁迫、渗透胁迫、盐胁迫或水分剥夺响应蛋白(如ERD6、NP1、TIR-NBS-LRR、CRT1b)等。本研究可为揭示甘蓝型油菜耐湿机理和培育耐湿新品种奠定基础。

基于植物功能性状的土壤侵蚀退化修复框架

当前,我国水土保持林草措施正在积极向提升生态功能为目标转变。为实现这一目标,管理者和工程师需要明确的生态学理论和方法作为指导。通过综述植物功能性状对侵蚀胁迫的响应和对土壤功能的影响机制,验证基于性状响应-影响的生态修复框架在土壤侵蚀治理中的2个关键理论:1)植物性状的变异体现植物对侵蚀退化环境的适应性;2)植物性状显著影响土壤生态过程。进而提出基于植物性状响应—影响的侵蚀退化修复框架。该框架将植物性状对环境变化响应纳入性状对生态系统影响的分析,根据恢复的水土保持服务目标,选择具有影响上述功能的特定植物性状,选择不受侵蚀(或物种间相互作用)胁迫或具有抗逆性的性状进行植物配置。该框架能扩宽当前土壤侵蚀植被治理的研究思路和实践领域,对提升我国的水土保持林草措施具有重要参考意义。

黄土高原典型小流域草地群落功能性状对土壤水分的响应

植物功能性状可以响应生境的变化并决定生态系统的功能,探究植物功能性状间的关系及其随土壤有效水分梯度的变化规律,对认识不同水分条件下植被在群落水平碳水代谢关系和维持水分平衡的生理生态学机制具有重要意义。以甘肃定西典型半干旱黄土小流域草地群落为研究对象,采用排序分析和回归拟合方法,分析了30个代表性草地样地中7个植物功能性状加权均值对土壤有效水分的响应以及响应性状间的相关关系。结果显示:(1)7个性状中,除叶宽与土壤有效水分无明显相关外,叶长、株高、叶面积、比叶面积、叶厚和叶干物质含量均与土壤有效水分显著性相关,可识别为草地在群落水平对土壤水分的响应性状。(2)草地群落通过降低株高,减小叶长、叶面积和比叶面积,增加叶厚和叶干物质含量以适应土壤有效水分减少;其中叶干物质含量的解释度最大,是土壤水分的最优响应性状。(3)除叶厚与叶长无显著相关外,其余功能性状均存在显著相关,说明草地群落的功能性状在土壤水分梯度上已基本形成了一个相互权衡或协同变化的功能性状组合。

RITSD Analysis of the Agronomic Traits of Somaclonal in Rice

[Objective]The aim was to study the sensitive response characteristics of the main agronomic traits of somaclonal and the variation of sensitive response of the lines of somaclonal to sowing date. [Method]The RITSD changing of agronomic traits was studied by using 24 rice somaclonal and its donor parent under two sowing dates. [Result]The average values of RITSD were higher （over one） for the traits of pant height （PH）,density of spikelets （DS）,filled spikelets per panicle （FSP）,spikelets per panicle （SP） and grain weight per plant （GWP）,but lower for days of sowing to heading （DSH）,effective panicles （EP）,panicle length （PL）,seed setting rate （SS） and 1 000-grain weight （1 000-GW）. These showed that PH,DS,FSP,SP and GWP were easily affected by sowing date and tended to higher with the later sowing; the RITSD of somaclonal changed with the agronomic traits. The frequency of RITSD＇ variation of DSH and PH was higher than that of PL. The RITSD＇ value of EP,PL,DS,FSP,SP and SS became higher,and higher or lower for DSH and GWP in different somaclonal; compared with the donor,20 of 24 was significantly different,and the frequency of RITSD variation was over 83. 3%,however,RITSD of the most lines （75%） changed only for 1-2 characters; cluster analysis showed that the RITSD of agronomic traits belonged to different combinations of somaclonal in rice. [Conclusion]the study had provided a theoretical basis for the screening and using of the somaclonal.

Thermo-responsive functionalized PNIPAM@Ag/Ag3PO4/CN-heterostructure photocatalyst with switchable photocatalytic activity

It is extremely important for photocatalysts to exhibit intelligent responsiveness to their environment. Herein, a poly N-isopropyl acrylamide(PNIPAM)-modified Ag/Ag3PO4-20/CN hybrid material with excellent convertible photocatalytic activity is prepared. PNIPAM has good hydrophilicity below the lower critical solution temperature(LCST);this increases the capacity of the photocatalyst for adsorbing tetracycline(TC) molecules. In addition, the PNIPAM-modified Ag/Ag3PO4-20/CN can prevent the loss of Ag3PO4. The dispersity is improved by loading g-C3N4 nanosheets(CN) for enhancing the efficiency of photocatalytic activity. Furthermore, a Z-scheme heterostructure is formed between CN and Ag3PO4, accelerating the separation efficiency of the holes and electrons. Ag nanoparticles can be used as electron-shuttle mediators, and electrons receiving more energy are transferred via the localized surface plasmon resonance(LSPR) effect. Furthermore, the PNIPAM@Ag/Ag3PO4-20/CN photocatalyst exhibits an excellent degradation rate for the degradation of TC when the temperature is lower than the LCST. The photoluminescence spectra and photocurrent curves prove that the carrier-separation efficiency of PNIPAM@Ag/Ag3PO4-20/CN is higher than those of Ag/Ag3PO4/CN and CN. The main active species of ·O2-and h+ are detected to reveal the plausible mechanism of the PNIPAM@Ag/Ag3PO4-20/CN hybrid material system. This work provides a way to develop intelligent materials for switchable photocatalytic applications.

Linear and nonlinear control of a robotic excavator

Various control systems for a robotic excavator named LUCIE (Lancaster University Computerized and Intelligent Excavator),were investigated. The excavator is being developed to dig trenches autonomously. One stumbling block is the achievement of adequate,accurate,quick and smooth movement under automatic control. Here,both classical and modern approaches are considered,including proportional-integral-derivative (PID) control tuned by conventional Zigler-Nichols rules,linear proportional-integral-plus (PIP) control,and a novel nonlinear PIP controller based on a state-dependent parameter (SDP) model structure,in which the parameters are functionally dependent on other variables in the system. Implementation results for the excavator joint arms control demonstrate that SDP-PIP controller provides the improved performance with fast,smooth and accurate response in comparison with both PID and linearized PIP control.

Predicting plant traits and functional types response to grazing in an alpine shrub meadow on the Qinghai-Tibet Plateau

The identification of easily measured plant functional types (PFTs) that consistently predict grazing response would be a major advance.The responses to grazing of individual traits and PFTs were analyzed along a grazing gradient in an alpine shrub meadow on the Qinghai-Tibet Plateau,China.Three response types were identified;grazing increaser (GI),grazing decreaser (GD),and neutral (NE) for both traits and PFTs.Seven traits were measured:plant height,economic group,cotyledon type,plant inclination,growth form,life cycle,and vegetative structure.The first five were significantly affected by grazing.Ordinal regressions for grazing response of the seven traits showed that the best single predictors of response were growth form (including the attributes "Scattered","Bunched" or "Closely Bunched"),and plant inclination ("Rosette","Prostrate",or "Erect"),followed by economic group ("Shrub","Grass","Sedge","Legume","Forb",or "Harmful") and plant height ("Tall","Medium",or "Small").Within the four optimal traits,the summed dominance ratio (SDR) of small plants,forbs,rosette and bunched plants,invariably increased,while that of tall plants,shrubs,grasses,and erect plants decreased,when grazing pressure was enhanced.Canonical correspondence analysis (CCA) identified eleven explanatory PFTs based on 195 defined PFTs,by combining the different attributes of the four optimal traits.Among explanatory PFTs,the most valuable in predicting the community response to grazing were Tall×Shrub×Erect×Scattered and Small×Forb×Rosette,as these have the closest connections with grazing disturbance and include fewer species.Species richness,diversity,and community evenness,did not differ among grazing treatments because turnover occurred in component species and their relative abundances along the grazing gradient.We have demonstrated that a minimum set of PFTs resulting from optimal individual traits can provide consistent prediction of community responses to grazing in this region.This approach provides a more accurate indicator of change within a changing environment than do univariate measures of species diversity.We hope to provide a link between management practices and vegetation structure,forming a basis for future,large scale,plant trait comparisons.

Coordinated motion of molecular motors on DNA chains with branch topology

To understand the macroscopic mechanical behaviors of responsive DNA hydrogels integrated with DNA motors,we constructed a state map for the translocation process of a single FtsKc on a single DNA chain at the molecular level and then investigated the movement of single or multiple FtsKc motors on DNA chains with varied branch topologies.Our studies indicate that multiple.FtsKc motors can have coordinated motion,which is mainly due to the force-responsive behavior of individual FtsKc motors.We further suggest the potential application of motors of FtsKc,together with DNA chains of specific branch topology,to serve as strain sensors in hydrogels.