不同种植密度下丛枝菌根真菌对玉米磷吸收的影响

【目的】利用土著丛枝菌根真菌(arbuscular mycorrhizal fungi,AM真菌)与作物形成互惠互利的共生关系提高作物对土壤磷的利用效率是解决农业生产中磷供需矛盾的主要途径之一,本研究在大田玉米不同种植密度条件下,研究AM真菌对玉米根系的侵染及磷吸收作用,为揭示集约化玉米高效获取磷的机理提供理论依据。【方法】以大田作物玉米的两种种植密度(5104 plants/hm2和9104 plants/hm2)体系为研究对象,在田间原位埋设PVC管装置,通过测定菌丝生长室中的菌丝密度和有效磷耗竭来确定不同种植密度体系条件下AM真菌对玉米磷吸收的作用。【结果】相对于低密度种植群体,高密度群体显著降低了玉米拔节期土壤有效磷的耗竭量,同时增加了玉米地上部的磷含量,即磷吸收效率,增幅达20%; 在玉米拔节期,增加种植密度使根际的根外菌丝生物量(菌丝密度)降低了4%,而非根际土壤中的根外菌丝生物量(菌丝密度)增加了37%; 高密度玉米种植密度群体中AM真菌的根外菌丝对土壤有效磷耗竭的贡献增加了22%。【结论】集约化玉米生产中土著AM真菌依然帮助植株从土壤中吸收有效磷; 高密度体系下玉米对磷的吸收更加依赖于AM真菌。高密度种植增加AM真菌对玉米的侵染、 根外菌丝量和对土壤有效磷的吸收。     

Prion-induced amyloid heart disease with high blood infectivity in transgenic mice

We investigated extraneural manifestations in scrapie-infected transgenic mice expressing prion protein lacking the glycophosphatydylinositol membrane anchor. In the brain, blood, and heart, both abnormal protease-resistant prion protein (PrPres) and prion infectivity were readily detected by immunoblot and by inoculation into nontransgenic recipients. The titer of infectious scrapie in blood plasma exceeded 10(7) 50% infectious doses per milliliter. The hearts of these transgenic mice contained PrPres-positive amyloid deposits that led to myocardial stiffness and cardiac disease.     

A SCAR marker linked to the N gene for resistance to root knot nematodes (Meloidogyne spp.) in pepper (Capsicum annuum L.)

The root-knot nematodes (Meloidogyne spp.) are important nematode pests and cause serious diseases in pepper in the world. No molecular markers linked to the nematodes resistance N gene have been reported. In this paper, ‘Carolina Wonder’ (Capsicum annuum L.), a sweet pepper line resistant to root-knot nematode with N gene, ‘20080-5-29’ (C. annuum L.), an inbred line susceptible to root-knot nematode with good horticultural characteristics, and their F₂ progeny with 320 individuals were used as materials. Evaluation of resistance and susceptibility of parental lines, F₁ and F₂ progeny inoculated with root-knot nematodes (Meloidogyne incognita) were carried out. ‘Bulked segregant analysis’ method was used to search for polymorphic markers from 512 pairs of AFLP primers. Based on the assessment of resistance and susceptibility and polymorphism of the AFLP marker in F₂ population, the genetic linkage distance between the AFLP marker and the N gene was estimated. One AFLP marker E39/M41-339 was obtained and transferred to a SCAR marker amplifying a 315 bp DNA fragment linked to the N resistant allele and a 331 bp fragment linked to the N⁺ susceptible allele. The distance between the molecular marker and the nematodes resistance N gene is 6.3 cM. This research delivered a valuable tool for the marker assisted selection of nematodes resistance in pepper.     

利用亚麻屑纤维素制备高吸水保水树脂的性能

通过碱蒸煮的方法,从亚麻屑中分离出纤维素.以水溶液聚合法,将亚麻屑纤维素与丙烯酸接枝共聚合成高吸水保水树脂.通过FTIR、SEM分析和表征了所合成树脂的结构和形貌,并测试了吸水速率、保水速率、重复使用性能和分别吸收0.1%的N、P、K肥水的性能.结果表明:合成的树脂是亚麻屑纤维素与丙烯酸的接枝共聚物,具有多孔结构,吸水速率较快.在30℃和60℃下干燥15h,合成的高吸水、保水树脂的保水率分别为66.53%和30.46%;在二次蒸馏水中重复第3次的吸水倍率能够达到1472.81g/g;在0.1%的KCl、尿素和过磷酸钙溶液中的吸水倍率分别为603.56、1844.63、10.91g/g.     

稻虾生态种养和机插密度对优良食味粳稻产量与品质的影响

为了解稻虾生态种养对太湖区域优良食味粳稻产量与品质的影响,以期为稻虾复合种养模式提供决策参考.选用5个优良食味粳稻品种(系),进行稻虾复合种养和宽窄行两种栽插密度处理,分析水稻产量与品质形成特点.与常规大田栽培比较,稻虾种养显著改善土壤理化性状,有效穗数显著增加,但茎蘖成穗率、穗粒数、结实率、千粒重和产量显著降低;稻虾...     

THE INTRODUCTION OF CORNUS STOLONIFERA AND ITS PROPAGATION TECHNIQUES

INTRODUCTIONCornusstoIonderaisoneofthespeciesofthegenusCornusLinnwhichbelongstothefamilycornaceae,originallydistributedintheareasfromNevadaMountaintoSisjiu,Texlenede,NewMexicoandAlaskaofU.S.AandtoNewfoundlandofCanada.Itisoftenfoundinconiferousforest-cov-eredmountainareaswithanelevationoflessthan27oom,alongthebanksofriversandgulliesandintheopenmoistplaces.Altboughthisspecieshasawiderangeofdistribution,itshabitatisrelativelynarrow.Selectingamoistplantingsiteisthekeytothesuceessfulintr…     

中国龙眼产业发展概况

龙眼果实营养价值高,是著名的食药兼用的热带特色果树.中国龙眼种植历史悠久,是世界龙眼的主要生产国.自中国-东盟自由贸易区建设的正式启动和"早期收获计划"签订后,中国的龙眼产业受到了来自其它生产国的严重冲击.该文介绍了世界龙眼生产概况、中国龙眼产业发展现状,分析了中国龙眼产业发展趋势,并提出了展望.     

比利时牧羊犬

<正>我国的养犬爱好者,对比利时牧羊犬(Belgian Shepherd Dog)的认识多半是来自比利时马里努阿犬(Belgian Malinois)。因为自20世纪末期开始,我国逐年进口马里努阿犬,尤其公安、军队、武警、海关等行业,     

热应激对鸡免疫性能的影响

以绵羊红细胞(SRBC)作为抗原,根据鸡对其产生抗体水平的高低,分为高抗体(HA)组和低抗体(LA)组鸡,然后以高温作为激源,研究其对两组鸡免疫性能的影响。结果表明:1)在未受应激时,HA组和LA组鸡的淋巴细胞转化率无差异;LA组鸡白细胞总数明显比HA组鸡高(P<0.01);LA组鸡异嗜性细胞与淋巴细胞的比值(H/L)显著高于HA组鸡(P<0.05)。2)急性热应激使HA组鸡淋巴细胞的转化受到抑制,但对LA组鸡无影响;慢性热应激使两组鸡的淋巴细胞转化率都下降,但对LA组鸡影响更明显。3)慢性热应激对HA组鸡白细胞总数无影响,但使其H/L值明显升高;慢性热应激对LA组鸡的H/L值无明显影响,但却使其白细胞总数明显下降。     

大豆转化系数的研究：Ⅱ,大豆杂交后代表观收获指数和粒茎比的遗传研究

用表观收获指数和粒茎比不同的12个亲本配制11个组合,对其后代表观收获指数和粒茎比进行了研究。结果表明,大豆F_1代表观收获指数和粒茎比存在一定的杂种优势,其优势程度因组合而异。表观收获指数和粒茎比在F_2代均呈广泛分离,多数组合表现出超亲现象,其遗传属于数量性状遗传,无母体效应。F_2、F_3代,表观收获指数和粒茎比与中亲值相关显著。F_2代表观收获指数和粒茎比的广义遗传力分别平均为46.19％和37.47％。可将表观收获指数和粒茎比(?)入高产育种、高光效育种和株型育种的选择指标。