Screening and Verification of Low Nitrogen Tolerant and Nitrogen Sensitive Cotton Germplasm

[Objective] The aim of this study is to evaluate nitrogen efficient cotton germplasms and improve nitrogen use efficiency. [Method] Eighty cotton germplasms were selected and evaluated in the hydroponic experiment under low (0.25 mmol·L^－1) and high (5 mmol·L^－1) nitrogen concentration. Different traits for screening were identified and nitrogen use efficiency types were classified. Field experiments were also performed for comparison and confirmation of the identified germplasms. [Result] The results showed that there were significant differences in the total plant dry matter, shoot nitrogen accumulation and nitrogen absorption efficiency in cotton germplasms at the two nitrogen levels. Based on coefficient of variation, principal component analysis and correlation, six traits including total plant dry matter, shoot dry matter, root dry matter, total nitrogen accumulation, shoot nitrogen accumulation and nitrogen absorption efficiency were used as screening indicators. According to the Heatmap clustering analysis and the nitrogen efficiency comprehensive index, two germplasms (Lu05R59 and CCRI 69) were identified as low nitrogen tolerant and nitrogen efficient, and two germplasms (Coker 201 and Xinluzhong 30) as low nitrogen sensitive and nitrogen inefficient. The results of field experiment were consistent with the results of the hydroponic culture at the seedling stage. [Conclusion] It was finally determined that Lu05R59 and CCRI 69 were the low nitrogen tolerant and nitrogen efficient germplasms, and Coker 201 and Xinluzhong 30 were low nitrogen sensitive and nitrogen inefficient germplasms. The results of these studies provide the possibility for screening and rapid identification of nitrogen use efficiency in cotton at the seedling stage, and provide the ideal materials and theoretical basis for further study of cotton nitrogen efficient.     

粪肠球菌生长曲线的测定及其对小鼠脑组织的影响

为测定致羔羊脑炎粪肠球菌（Enterococcus faecalis）的生长曲线，寻求一种快速而准确的方法测定不同生长时期粪肠球菌数量，并客观评价其毒性强弱及其对小鼠脑组织的影响，试验采用平板菌落计数法和OD-Monitor振荡比浊法（D_λ值法）测定粪肠球菌的生长曲线，探究该菌在合适时间段内的吸光值（D_{600 nm}）与平板菌落计数法测定的活菌数（CFU）的关系。用粪肠球菌感染小鼠，观察记录小鼠的死亡情况，最后采用Karber法计算粪肠球菌感染小鼠的半数致死量（LD₅₀）。用LD₅₀的剂量感染小鼠，及时采集死亡小鼠脑组织，未死亡的小鼠72 h后全部剖杀取脑组织，一部分做涂片染色，制作病理切片，观察病理变化；一部分进行培养，用于PCR方法进行细菌的回收鉴定。结果显示，用两种方法测定此株粪肠球菌的生长曲线基本一致，在2~8 h生长迅速，为对数生长期，8~14 h生长缓慢，为稳定期，14 h之后死亡数增加，进入衰亡期；对12 h粪肠球菌D_{600 nm}与CFU的关系进行探讨，成功建立回归方程：y=20.769x-1.3422，R²=0.997；其感染小鼠的LD₅₀为7.77×10¹¹个活菌。以此剂量感染小鼠，脑组织涂片染色和培养染色，均能看到革兰氏阳性球菌；PCR结果显示，均出现了大小为112 bp的条带。对脑组织进行病理学观察发现该菌可导致脑组织充血、出血、形成微血栓，脑膜充血。通过生长曲线和其D_{600 nm}与CFU关系的建立，可实时监测粪肠球菌数量，为后期更深入研究粪肠球菌穿越血脑屏障的机制奠定重要的理论基础。     

基于“一带一路”倡议的中泰渔业协作发展探索

在渔业方面，贯彻落实“一带一路”倡议，实施渔业“走出去，引进来”战略，促进我国水产养殖业和周边国家地区的交流合作，共同推动区域传统渔业向现代渔业转型升级，是现代渔业发展的必然方向。泰国作为“一带一路”之东盟国家，从泰国的渔业资源现状、渔业产业发展、渔业现阶段存在的优势和不足以及中泰渔业协作发展探索等多个方面进行阐述，通过研究泰国渔业现状及探索中泰渔业协作发展之路，提出技术支撑、资源引进、取长补短、共同进步等相对应的策略与建议，为中国-东盟国家在基于“一带一路”倡议的渔业层面战略发展提供样本。      

群井开采对毛乌素沙地地下水位的影响——以榆林市榆阳区昌汗敖包村土地开发项目为例

为探究毛乌素沙地大规模现代化高标准农田地下水开采对地下水位的影响，以榆林市榆阳区昌汗敖包村土地开发项目地下水监测网覆盖区作为研究区，选取分布于研究区的8眼机井进行了为期1年的地下水位埋深动态特征监测。结果表明:在灌溉期间，地下水位埋深呈先减小后增大的趋势；灌溉结束至进入下个灌溉周期之前，地下水位埋深逐渐增大至正常值。因此群井开采并未对项目区地下水位造成实质影响。      

夏季养猪企业关切的繁殖问题调查

当前养猪业进入困难时期，企业运营成本高企。炎热的夏季，种猪繁殖问题较为突出，再加上非洲猪瘟直接或者间接的原因，行业内母猪整体繁殖水平低下。团队近期对53家不同区域、不同规模、不同生产模式的养猪企业进行了调研，发现公猪问题、后备猪问题和哺乳期管理是当前猪场最为关心的3个问题。     

Differential regulation on C5 expression in goose versus mammals by glucose/palmitate provides a potential protection for goose fatty liver

Goose fatty liver is a specific type of nonalcoholic fatty liver that is protected from harmful effects associated with severe steatosis. Our previous findings suggest that suppression of the complement C5 may be relevant, but the mechanism is unclear. Therefore, in this study, we first verified the expression pattern of complement genes (including C5) during goose fatty liver formation and then determined the liver fat content and fatty acid composition by high-performance liquid chromatography (HPLC), followed by selecting the differential metabolites to treat HepG2, goose and mouse primary hepatocytes, aiming to explore the mechanism of C5 and inflammation suppression in goose fatty liver. The data confirmed the suppression of complement genes (including C5) in goose fatty livers. Moreover, fat content was significantly higher in fatty liver versus normal ones, with oleic acid and palmitic acid dominantly accounting for the difference. In line with this, high concentration of palmitate led to down regulation of C5 expression in goose primary hepatocytes whereas upregulation in mouse primary hepatocytes and HepG2 cells. In conclusion, regulation on C5 expression by fatty liver related factors including high level of palmitic acid may contribute to the protection of goose liver from severe hepatic steatosis.     

16份四川小麦生产品种在甘肃陇南抗条锈性表现

小麦条锈病我国小麦生产上的最主要的病害,种植抗病品种是防治该病最经济有效环保的措施。2014—2017年,先后对16份四川省小麦生产品种在甘肃陇南不同生态区的甘谷试验站和汪川良种场两地进行自然诱发鉴定,评价其抗病性。结果发现,所有供试品种均表现感病,川农10号等5份材料具有慢条锈性。     

番茄褪绿病毒在湖南省首次发生

2016年7月在湖南省蔬菜病害调查中发现,4种茄科蔬菜表现出叶脉间褪绿、叶片黄化等症状,疑似被番茄褪绿病毒(Tomato chlorosis virus,To CV)感染,同时叶片背面聚集了大量烟粉虱。采用To CV热激蛋白(heat shock protein 70,HSP70)序列的特异性引物对采集的番茄、茄子、辣椒、马铃薯样品和烟粉虱样品进行RT-PCR检测,均扩增出目标条带,且扩增序列与北京番茄To CV分离物(KC887999.1)部分序列相似度为99.0%,确认采集样品被To CV感染。4种茄科蔬菜To CV的感染率达70%~100%;发病叶片上烟粉虱的带毒率为66.7%~87.5%;鉴定出烟粉虱的生物类型为MED烟粉虱。这是湖南省首次确认该病毒,需要引起关注和加强防范。     

不同贮藏年限老芒麦种胚线粒体抗氧化功能的变化规律

种子在自然贮藏过程中常常伴随着内部生理机能的恶化，线粒体作为种子内活性氧（reactive oxide species，ROS）产生的主要位点是最先遭到破坏的细胞器。为探讨不同贮藏年限对老芒麦种胚线粒体抗氧化功能的影响，本试验以室温贮藏0～4年的老芒麦种子为材料，分析比较其老化规律及种胚线粒体抗氧化特性的变化规律。结果表明：随着贮藏年限的延长，老芒麦种子发芽势、发芽率和种苗鲜重逐渐下降，死种子逐渐增多，种胚线粒体苹果酸脱氢酶（mitochondria malate dehydrogenase，MDH）、谷胱甘肽还原酶（glutathione reductase，GR）、单脱氢抗坏血酸还原酶（monodehydroascorbate reductase，MDHAR）活性逐渐下降，但在死种子中超氧化物歧化酶（superoxide dismutase，SOD）活性显著升高。此外，在贮藏过程中老芒麦种胚线粒体O₂^·-产生速率不断上升，而H₂O₂含量则呈现逐渐降低的趋势，表明线粒体中O₂^·-的积累与细胞氧化损伤密切相关。     

围场县马铃薯中典型药物污染特征及健康风险评价

为掌握典型药物在农作物中的污染特征及健康风险,保障农产品质量安全,利用超声萃取-固相萃取-高效液相色谱/串联质谱(LC-MS/MS)技术,对围场县全县马铃薯中5大类(磺胺类、四环素类、氟喹诺酮类、大环内酯类及其他类)25种药物污染水平及富集效果进行了调查,并对健康风险进行了评价。结果表明,有20种目标物被检出,不同目标物检出率差异显著,检出含量范围为0.13～3.67μg·kg-1,单种污染物最高检出含量为17.0μg·kg-1。马铃薯对目标污染物的富集系数范围在0.01～39.6之间,最大富集系数为61.8。畜禽粪便是马铃薯中药物残留的主要来源,尽管整体检出水平和健康风险相对较低,但长期摄入与协同作用引发的潜在健康风险不容忽视。因此,仍需严控污染源头,推进畜禽粪便安全资源化利用,确保农田环境质量及农产品安全品质。