Screening of Broad-spectrum Resistance Resources against Rice Bacterial Leaf Streak

[ Objectives] Rice materials with broad-spectrum resistance against several pathogenic strains of Xanthomans oryzae pv. Oryzicola （Xooc） at multiple growth stages were screened, in order to provide reliable resistance sources for variety breeding against rice bacterial leaf streak. [ Methods] A total of 1 100 rice lines with rich genetic background were offered as selective objects, and highly susceptible cultivar Jingang 30 was used as the control. Inoculation was carried out with five strong pathogenic strains of Xooc through acupuncture method at various growth stages for resistance identification. [ Results] Fourteen disease-resistant materials were obtained through preliminary screening, accounting for 1.27% of the total materials. Nine materials moderately resistant to bacterial leaf streak were obtained via secondary screening, accounting for 0.82% of the total materials. Besides, three of them （ RL6, RL9 and RLL4） were resistant to a number of pathogenic strains of Xooc at three growth stages. In particular, RL16 presented broad-spectrum resistance to multi-strains with high resistance levels. Six of them （ RI2, RIA, RIS, RL8, RL11 and RL12） were resistant to single strain at single growth stage. [ Conclusions] The obtained three materials have broad-spectrum resistance to bacterial leaf streak at multiple growth stages, which can be served as an important source to cultivate disease-resistant rice varieties. RL6 maintains high broad-spectrum resistance at all growth stages, which can be used as a prior resistance source for rice variety breeding. Six materials obtained with resistance against bacterial leaf streak at particular growth stages can be used as candidate resistance sources.

In vitro Screening of Fusarium Wilt-resistant Germplasm Resources of Red Edible Seed Watermelon( Citrullus lanatus ssp. vulgaris var. megalaspermus Lin et Chao)

[ Objective] This study aimed to establish an appropriate technology system for in vitro screening of Fuzarium wilt-resistant germplasm resources of red edible seed watermelon and obtain variants resistant to fusaric acid, thus providing resistant materials for breeding Fusarium wilt-resistant red edible seed watermel- on. [ Method] Using Zhongxin No. 1 red edible seed watermelon advemitious buds as screening materials and fusaric acid （FA） as a stress agent, in vitro screen- ing of Fusarium wilt-resistant red edible seed watermelon clonal variants and identification of Fusarium wilt-resistance of the germplasm resources of red edible seed watermelon were performed. [ Result] The results showed that the appropriate FA for in vitro screening of Fusarium wilt-resistant red edible seed watermelon vari- ants was 15 mg/L. In vitro screening system for Fusarium wilt-resistant red edible seed watermelon variants was established preliminarily and FA-resistant regenera- ted plants were obtained. Among the 36 germplasm resources of red edible seed watermelon, there were 2 highly resistant materials, 6 moderately resistant materi- als, 11 slightly resistant materials and 17 highly susceptible materials. [ Conclusion] This study confirmed preliminarily that in vitro screening method is effective for obtaining resistant materials of red edible seed watermelon.

Evaluation and Genetic Classification of Rice Germplasm Resources Resistant to Rice Blast

[ Objective] This study aimed to explore rice germplasm resources resistant to rice blast and provide theoretical basis for the modification of rice blast- resistant germplasm resources. [ Method] The resistance of 120 rice materials to rice blast was identified at three experimental areas. [ Result] The resistance of 120 experimental materials was at grade 0 -9 to panicle blast in Hainan Province, at grade 0 -9 to seedling blast in Fujian Province and at grade 3 -9 topanicle blast in Guangxi Zhuang Autonomous Region. Analysis of correlations between agronomic traits and rice blast resistance indicated that the resistance of experimental materials could not be simply determined based on agronomic traits. Furthermore, 61 published SSR makers closely linked to rice blast were selected and synthe- sized for genotypic analysis of 120 experimental materials. The results of cluster analysis preliminarily divided 120 germplasms into resistant varieties and susceptible varieties. [ Conclusion] These rice germplasm resources are of important value for breeding new materials resistant to rice blast.

Screening of Tomato Resources Resistant to Tomato Gray Mold

This study was conducted to screen tomato resources resistant to gray mold for the first time by in-vitro stem inoculation method.The results showed that Solanum habrochaites T2-07-316 was highly resistant to gray mold,and had the relative stem infection rate and relative stem rot expansion rate of 0 on the 6^(th) day after inoculation.There were also other seven transgenic common tomato materials which showed higher resistance to gray mold,with a relative stem infection rate in the range of 15.00%-38.33% and a relative stem rot expansion rate in the range of 10.22%-23.57%.Among them,T2-07-337 had the best resistance.

Resistance Evaluation of Eggplant Resources to Verticillium wilt in Sichuan Province

[Objective] Aimed to lay a scientific foundation for eggplant resistant breeding, the resistant field identification of eggplant resources to Verticillium wilt was carried out. [Method] Test materials were 35 eggplant resources, which were collected from various places in Sichuan province since 2001. These eggplant resources were made resistance evaluation to Verticillium wilt by watering injured roots with Verticillium dahliae spore suspension. [Result] The eggplant resources had good resistance to Verticillium wilt. Among 35 evaluated resources, 10 resources like 242-9OP, 41-1,35-R5, etc. were resistant, while 23 resources like 68 ×47, Zizaoqie, 32-1, etc. were tolerant. Some resistant resources like 41-1,35-R5, 47-R1, etc. had been transferred into new resistant varieties like EF9910, etc. by breeding institutes. [Conclusion] The resistant level and future resistance breeding direction of eggplant resources in Sichuan were clarified by the resistance evaluation of eggplant resources so as to provide a technical guidance for eggplant resistance breeding.

Screening of Drought Stress Indicators and Analysis of Drought Resistance in Cultivated Rice Germplasm Resources in Guangxi

This study aimed to screen drought stress indicators and analyze the drought resistance in 105 cultivated rice germplasm resources in Guangxi Zhuang Autonomous Region under drought stress in the whole growth period based on D value of seven morphological traits including panicle neck thickness,effective panicle number per plant,1 000-grain weight,filled grain number per panicle,total grain number,seed setting rate and yield per plant.According to the results,under drought stress,yield per plant exhibited significant positive correlation with panicle neck thickness and exhibited extremely significant positive correlation with other five morphological traits.Based on the identification and evaluation of comprehensive drought-resistance index D value,seven highly drought-resistant cultivated rice varieties were screened,accounting for 6.67％.Upland rice germplasm resources in Guangxi Zhuang Autonomous Region possess strong drought-resistance capacity,which could be used to screen highly drought-resistant rice germplasm materials.This study provided material basis and theoretical reference for breeding drought resistant rice cultivars in Guangxi Zhuang Autonomous Region.

Herbivore and native plant diversity synergistically resist alien plant invasion regardless of nutrient conditions

Alien plant invasion success can be inhibited by two key biotic factors:native herbivores and plant diversity.However,few studies have experimentally tested whether these factors interact to synergistically resist invasion success,especially factoring in changing global environments(e.g.nutrient enrichment).Here we tested how the synergy between native herbivores and plant diversity affects alien plant invasion success in various nutrient conditions.For this purpose,we exposed alien plant species in potmesocosms to different levels of native plant diversity(4 vs.8 species),native generalist herbivores,and high and low soil nutrient levels.We found that generalist herbivores preferred alien plants to native plants,inhibiting invasion success in a native community.This inhibition was amplified by highly diverse native communities.Further,the amplified effect between herbivory and native plant diversity was independent of nutrient conditions.Our results suggest that a higher diversity of native communities can strengthen the resistance of native generalist herbivores to alien plant invasions by enhancing herbivory tolerance.The synergistic effect remains in force in nutrient-enriched habitats that are always invaded by alien plant species.Our results shed light on the effective control of plant invasions using multi-trophic means,even in the face of future global changes.

Preparation and performance evaluation of the slickwater using novel polymeric drag reducing agent with high temperature and shear resistance ability

Slickwater fracturing fluids are widely used in the development of unconventional oil and gas resources due to the advantages of low cost,low formation damage and high drag reduction performance.However,their performance is severely affected at high temperatures.Drag reducing agent is the key to determine the drag reducing performance of slickwater.In this work,in order to further improve the temperature resistance of slickwater,a temperature-resistant polymeric drag reducing agent(PDRA)was synthesized and used as the basis for preparing the temperature-resistant slickwater.The slickwater system was prepared with the compositions of 0.2 wt%PDRA,0.05 wt%drainage aid nonylphenol polyoxyethylene ether phosphate(NPEP)and 0.5 wt%anti-expansion agent polyepichlorohydrindimethylamine(PDM).The drag reduction ability,rheology properties,temperature and shear resistance ability,and core damage property of slickwater were systematically studied and evaluated.In contrast to on-site drag reducing agent(DRA)and HPAM,the temperature-resistant slickwater demonstrates enhanced drag reduction efficacy at 90℃,exhibiting superior temperature and shear resistance ability.Notably,the drag reduction retention rate for the slickwater achieved an impressive 90.52%after a 30-min shearing period.Additionally,the core damage is only 5.53%.We expect that this study can broaden the application of slickwater in high-temperature reservoirs and provide a theoretical basis for field applications.

Natural Products and Antiviral Resistance

Viral diseases are minacious with the potential for causing pandemics and treatment is complicated because of their inherent ability to mutate and become resistant to drugs. Antiviral drug resistance is a persistent problem that needs continuous attention by scientists, medical professionals, and government agencies. To solve the problem, an in-depth understanding of the intricate interplay between causes of antiviral drug resistance and potential new drugs specifically natural products is imperative in the interest and safety of public health. This review delves into natural product as reservoir for antiviral agents with the peculiar potentials for addressing the complexities associated with multi-drug resistant and emerging viral strains. An evaluation of the mechanisms underlying antiviral drug activity, antiviral drug resistance is addressed, with emphasis on production of broad-spectrum antiviral agents from natural sources. There is a need for continued natural product-based research, identification of new species and novel compounds.

An Analysis on the Heat Resistance of Rice Germplasm Resources during Flowering Period

56 Chinese rice core germplasm resources,18 foreign rice germplasm resources and 6 restorer lines are subjected to high temperature stress during flowering period. Based on relative spikelet fertility rate,rice heat resistance is evaluated. The results show that different resistance to high temperature exists in different varieties,and 6 new rice varieties present high heat resistance.

Report on Screening Test of Dazhou Superior Ramie Germplasm Resources

[Objectives]To promote the development of the ramie industry in Dazhou City of Sichuan Province and provide a material basis for the breeding of new ramie varieties.[Methods]The Institute of Bast Fiber Crops of Dazhou Academy of Agricultural Sciences performed a screening test of excellent ramie germplasm resources from 2017 to 2019 to compare the growth,resistance,raw fiber yield and fiber fineness of the experimental materials.[Results]All the experimental materials showed strong growth potential,drought resistance and disease resistance.There were 8 kinds of resources with a fiber fineness greater than 2000 m/g,of which 3 kinds of resource materials had a fiber fineness greater than 2300 m/g;12 kinds of resources has the raw fiber yield exceeding the control and 10 kinds of resources had the raw fiber yield≥2000 kg/ha;3 kinds of resources met the requirements of the high-yield and high-quality indicators(fiber fineness exceeding 2000 m/g and raw fiber yield≥2000 kg/ha),they were BD0718,BD1614 and BYL2.[Conclusions]These high-quality ramie resources can provide a rich resource base for the breeding of new ramie varieties.

High corrosion resistance 21%Cr-0.4%Cu ferritic stainless steel contributing to resource conservation

With prices for metal resources such as nickel and molybdenum soaring,there is a heightened sense of crisis concerning resource scarcity.While Type304,the most common stainless steel,offers excellent corrosion resistance,its price is affected significantly by the cost of nickel because of its 8%nickel content.The stainless steel that has the same corrosion resistance as that of Type304 and does not contain nickel and molybdenum has been required.JFE Steel Corporation has developed a new 21%Cr-0.4%Cu stainless steel,the world's first ferritic stainless steel,which offers equivalent corrosion resistance to Type304 while containing absolutely no nickel or molybdenum,two rare metals.The newly developed steel contains 21%chromium with the addition of 0.4% copper.The development of the steel is based on a new discovery that the passive films of stainless steels could be strengthened by the synergy effect of high chromium content and copper addition.Copper addition enriches the chromium content in passive films after field exposure.Newly developed 21%Cr-0.4%Cu stainless steel is adopted for many applications as a substitution for Type304,including commercial kitchenware,building materials and industrial machinery.The steel is expected to be a new standard of a ferritic stainless steel as a substitution for Type304.

Research Progress in Molecular Mechanism of Broad-spectrum Disease Resistance in Rice

Yield loss caused by crop diseases seriously restricts global food security.Breeding disease-resistant varieties with resistance(R)genes is acknowledged as the most economical and effective way to control diseases.Therefore,exploring broad-spectrum resistance(BSR)genes to pathogens and clarifying the underlying mechanism are the basis for effective utilization of BSR resources and finding new approaches for disease control.In the past 20 years,significant progress has also been made in plant immune mechanism and remarkable achievements have been made in researches on broad-spectrum disease resistance of major grain crops,and the potential molecular mechanisms of some BSR have been revealed.Here,the advances of broad-spectrum disease resistance in rice(including the representative cloned BSR genes and their molecular mechanisms)were reviewed.In addition,the problems,opportunities and challenges encountered by BSR were analyzed,and the development of BSR research and its application in rice production were prospected.

甘薯抗茎腐病鉴定技术的建立及种质资源抗性分析

为优化甘薯种质抗茎腐病鉴定技术,通过分析不同的接种方法和菌液浓度对甘薯种质抗性的影响,建立甘薯抗茎腐病鉴定标准,为甘薯抗病育种奠定基础。利用组培瓶蛭石薯苗擦伤接菌法和最佳接种菌液浓度(1.1×10^(7)CFU·mL^(-1)),对最具代表性的6个甘薯品种进行接种鉴定,并与田间抗性品种比较进行验证,室内接种抗性鉴定结果与田间抗性表现基本一致,表明新抗性鉴定技术的鉴定结果具有准确性、可靠性。进一步对65个甘薯材料进行抗病鉴定,发现绝大部分材料表现为感病或中感,7份种质(YD7002、DY7082-1、浙紫薯1号、TF1118、DY7032、南薯88和浙紫薯4号)对甘薯茎腐病具有稳定抗性。文章建立了甘薯抗茎腐病的新鉴定技术,鉴定和筛选出对甘薯茎腐病表现稳定抗性的种质,为甘薯抗茎腐病育种提供重要的种质资源,对于甘薯病害防控具有重要意义。

36份马棘种质资源抗旱性评价

【目的】分析不同程度的干旱胁迫处理对马棘生理指标的影响,探索其抗旱生理响应特征,为马棘抗旱种质筛选和遗传改良提供参考依据。【方法】以重庆地区广泛收集的36份野生马棘种质资源为试验材料,采用盆栽培养的方式待马棘幼苗生长至第90天时开始干旱处理,分别在胁迫0 d(对照组CK,土壤相对含水量为田间持水量的80%~85%)、胁迫7 d(中度干旱,土壤含水量为田间持水量的40%~50%)和胁迫14 d(重度干旱,土壤相对含水量为田间持水量的20%~25%)时测定各处理下马棘叶片的渗透调节物质含量、相对含水量和抗氧化酶活性,利用抗旱系数结合隶属函数和聚类分析法对马棘的抗旱性进行综合评价。【结果】在干旱胁迫下,36份马棘种质的生理响应变异丰富,不同种质的抗旱能力差异显著。通过对同一指标的均值比较分析发现,与对照相比,渗透调节物质丙二醛(MDA)、可溶性蛋白(SP)和脯氨酸(Pro)含量随着干旱程度增加而上升;超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)活性随着干旱程度增加而呈“凸”字形变化;相对含水量(RWC)随着干旱程度增加而降低。7个检测指标中,POD活性的变异系数最大,而RWC的变异系数最小。通过隶属函数、综合D值和聚类分析可将36份马棘种质的抗旱能力分为抗旱型(8份种质)和敏感型(28份种质)两类。通过对两种类型种质的生理指标分析发现,抗旱型种质的抗氧化酶活性和渗透调节物质Pro含量高于敏感型种质。【结论】干旱胁迫下36份马棘种质资源的生理响应具有丰富的多样性和变异,通过综合评价分析初步筛选出8份抗旱型马棘种质。

132份葡萄种质资源叶片对灰霉病的抗性鉴定

为明确不同葡萄种质对灰霉病的抗性差异,以132份葡萄种质叶片为试材,采用人工接种病原菌的方法鉴定其对灰霉病的抗性。结果表明,不同葡萄种质对灰霉病的抗性差异明显。对灰霉病表现高抗(highly resistant,HR)的种质2份,占鉴定资源总数的1.51%;表现抗(resistant,R)的种质14份,占总数的10.61%;表现中抗(middle resistant,MR)的种质89份,占总数的67.42%;表现感病(susceptible,S)的种质22份,占比16.67%;表现高感(highly susceptible,HS)的种质5份,占比3.79%。未发现对灰霉病完全免疫的葡萄种质,其中圆叶葡萄较抗病;其次为美洲种、欧美杂种;欧亚种易感病。此外,地方种质资源郧西葡萄对灰霉病表现良好的抗性。研究结果为抗灰霉病葡萄新品种选育及相关理论研究提供了优异的种质资源。

基于生态安全格局的资源枯竭型城市生态保护修复关键区识别:以徐州市贾汪区为例

科学构建生态安全格局、识别生态保护修复关键区是系统推进生态修复目标,实现资源枯竭型城市绿色转型发展和生态安全的基本保障与重要途径。本文以东部典型资源枯竭型城市徐州市贾汪区为例,通过定量评估土壤保持、碳存储、生境质量、产水量和固碳释氧五种生态系统服务功能变化,分析了绿色转型中的贾汪区生态修复治理成效。在此基础上,基于热点分析、最小累计阻力模型和电路理论等方法,识别了生态源地、生态廊道、生态“夹点”、障碍区等生态安全格局要素,分析了2000—2020年生态安全格局及其动态变化,并识别生态保护修复关键区域。研究结果表明:①2000—2020年贾汪区生态系统服务总体呈增加趋势,生态环境逐步得到改善,生态源地斑块数量逐渐减少但总面积持续增加,廊道分布由“西多东少”转变为“较为均衡”的格局。②确定生态保护修复关键区包括重要生态源地10处,重要生态廊道39处,障碍修复关键区5.53 km^(2),廊道保护关键区1.70 km^(2),多位于主城区西南部和潘安湖南部生态流动强度高且廊道狭窄处,应加强重点修复和保护。③根据生态保护修复关键区覆被类型,建议重要生态源地树立红线观念、加强生态用地和非生态用地有效连接、拓宽生态廊道范围、增加廊道沿线植被恢复等保护修复策略。研究结果可为资源枯竭型城市的生态修复规划确定优先修复事项提供有效技术支撑。

计及生态阻力成本的新能源基地风光电站容量规划与布局优化方法

由于沙漠、戈壁、荒漠新能源基地海拔高以及生态环境恶劣,生态阻力作用影响风光电站容量规划与布局。以新能源基地为研究对象,提出一种计及生态阻力成本的风光电站容量规划与布局优化方法。基于新能源基地广域气象数据和广域地理信息数据,建立资源时空特性表征模型,并选取3种关键生态阻力因子建立生态阻力评价体系,在此基础上构建综合生态阻力成本模型;基于资源时空特性表征模型及综合生态阻力成本模型,建立综合成本最低的风光电站容量规划与布局优化模型,并给出模型的求解流程。基于西北某新能源基地实际数据的算例仿真结果表明,所提方法能有效解决新能源基地自然资源开发与生态阻力之间的矛盾,在保障系统可靠运行的前提下提升系统经济性。

小麦种质资源耐盐性鉴定

盐碱胁迫严重影响农作物的生长发育,制约农作物产能的提升。本试验以国内外引进的40份小麦品种(系)和新疆2个主栽品种为材料,在0、300、600、900 mmol·L^(-1)NaCl浓度下模拟盐胁迫环境,研究不同浓度NaCl对小麦芽期农艺表现的影响,以期筛选出耐盐小麦品种。结果表明,测定的8项生长指标在42份种质资源之间存在显著差异。通过相关性分析、主成分分析、相对耐盐系数以及综合耐盐系数分析,鉴定出1份极耐盐品种(宁春45),1份耐盐品种(新冬39),2份较耐盐品种(濮兴5号和济麦21),这4份种质材料可用于南疆盐碱地小麦耐盐品种选育。

国家记忆工程背景下抗美援朝档案资源体系构建研究

国家记忆工程是收集、保存和传播中华民族重要事件和人物记忆资源的文化工程。抗美援朝运动及战争时期形成了大量珍贵的档案资料和实物遗存,但无论是内容还是载体都呈现出收集多元化和整理紧迫性的复杂现状。通过对抗美援朝档案资源范围和特点的解析,基于专业理论和原则从国家记忆工程、数字人文、口述资料建档、国际交流等路径系统性地构建抗美援朝档案资源体系。这一体系的建设推进了“十四五”期间档案事业的繁荣与发展、国家红色记忆工程的建设与完成以及抗美援朝精神的传承。