烟草青枯病研究进展

青枯病是烟草上的一种主要病害,由细菌引起。近两年由于气候的原因,在局部地区发生流行,导致烟叶产量大幅下降,质量降低。因此,加强烤烟青枯病综合防治,对烤烟的可持续发展至关重要。该文详细介绍了烟草青枯病的病害症状、病原菌、侵染循环、发病条件、发病机制,目前对烟草青枯病的防治办法及防治展望,旨在为研究此病提供参考     

北京大兴春棚瓜类多食性害虫种类及动态调查

了解北京大兴地区春棚瓜类作物之一西瓜害虫主要种类及发生规律,为及时提供害虫预测预报和防治依据。通过田间调查和黄板诱虫对大兴春棚西瓜害虫种类及种群动态进行连续2年调查。结果发现,春棚作物西瓜主要害虫种类都是多食性害虫红蜘蛛、蓟马和蚜虫。黄板诱虫量最高为蓟马,其次为蚜虫,为优势害虫,其他害虫占比都低于0.5%。田间发生较多为红蜘蛛和无翅蚜,连续2年占比分别都在58.07%和6.35%以上,为优势种。无翅蚜高峰期(5月上中旬)早于有翅蚜(5月下旬),6月中旬后减轻。黄板诱到的蓟马6月达高峰,并持续到拉秧。瓜棚花内蓟马6月中旬达高峰,7月因花量减少而有所降低。红蜘蛛2014年6月上旬达到高峰,其后持续降低。2015年有所加重,发生期也有所提前,5月即可轻微发生,6月数量急剧增加,中旬达高峰并持续到拉秧。5—6月重点防治蚜虫,6—7月重点防治蓟马和红蜘蛛。     

陕北马铃薯晚疫病发生趋势预报

正近日根据陕西各地植保部门调查,结合天气预报、栽培品种及菌源量综合分析,陕西省植物保护工作总站预计陕北马铃薯晚疫病中等发生,局部低洼、湿度大的田块重发生,发生面积100万亩。预报依据:1.气象条件。7月中下旬,陕北连续出现降雨,正值马铃薯易感病的花期,对晚疫病侵染十分有利。据陕北各地晚疫病监测预警系统点监测,目前监测点大部已进入侵染2代以上,一旦再次出现降雨,即达防治指标。天气预报陕北7~8月份气     

矮化密植栽培条件下夏玉米大小斑病发生消长规律的研究

近年来,江苏省大力推广夏玉米矮化密植栽培,即栽培密度由常规的4000株/亩左右增加到6000—6500株/亩,同时于植株抽雄前5—7天喷施玉米健壮素,使叶形直立、短而宽、叶片增厚、叶色加深、株形矮健节间短、根系发达气生根多、抗倒伏,充分发挥了大群体优势,增产效果明显。但大、小斑病发生规律也发生了变化,故研究夏玉米矮化密植栽培条件下的大、小斑病发生情况及流行规律,对夏玉米大、小斑病的防治有很重要的意义。 1 材料和方法 1.1 夏玉米大、小斑病发生情况调查于发病盛期(8月中旬)选择有代表性的田块,5点取样,每块田不少于200株,分别     

正确识别保护地黄瓜的两种病害

保护地黄瓜产量高,效益好,近年由于连续种植、环境因素控制不良及栽培管理不当等影响,极易发生霜霉病和细菌性角斑病。二者苗期至成株期均可混合发生,且症状比较接近。发病时生产者常因误诊或防治不彻底等原因造成多次重复侵染,引起植株生长不良,产量和品质下降,特别是冬春温室大棚,损失更加严重。为解决这一问题,我们对保护地黄瓜霜霉病和细菌性角斑病     

遵义县番茄晚疫病发生规律及防治技术

近年来,遵义县番茄种植面积不断增加,播种期提早和推迟,都会使番茄晚疫病发病提早,为害加重。为了有效控制该病的为害,自2002年以来对番茄晚疫病的发生规律和防治技术进行了调查研究。1发生规律番茄晚疫病在遵义县一年有两个流行高峰。平坝地区5月25~30日始发,6月上旬—7月上旬     

农药使用与植保技术问与答

<正>问:水稻刚开始破口,现在在下小雨,能否等几天雨停了再用三环唑防治穗颈瘟?答:江苏省水稻主栽品种总体对穗颈瘟的抗性不佳,一旦气候条件适宜,尤其是破口扬花期遇到持续低温阴雨天气,有大流行的潜在威胁。气温20～30℃,连续阴雨,田间湿度大,稻株表面长时间有水膜,平均相对湿度在90%以上,稻瘟病往往大发生。穗颈瘟重在破口期用药防治,发病后再用药效果很差。水稻破口期遇持续阴雨天气,应抓住雨停间隙施药防治穗颈     

唐山地区独本菊病虫害防治

菊花在栽培过程中,尤其要注意防治病虫害。观察本地区病虫害发生规律,可掌握最佳防治时期。唐山地区常见的菊花病害有褐斑病、白粉病等,虫害有菊虎、蚜虫、飞虱、红蜘蛛等。病害褐斑病发病初期茎基部叶片上出现黄色斑点,后逐渐扩大为褐色斑块,病叶干枯、脱落。可借助雨、水传播。唐山地区6月开始发病,7、8月高温多雨季节发病率最高。防治方法:菊花栽培基地要求通风     

稻曲病科学防控策略

<正>稻曲病是典型的气侯型病害,水稻破口抽穗期的天气条件可以直接影响其发生程度,是造成近几年稻曲病年度间差异和地区间差异的重要影响因子之一。以长江中下游稻区为例,单季稻或晚稻破口期一般在8月中旬至9月上旬,此时段的气候条件年度间差异较大,若此时出现适温、高湿、寡照的天气条件.则稻曲病大发生。如阴雨天气造成农户无法施药或施药后防效不佳,会加剧稻曲病的局部流行。监测预警是预防稻曲病流行的前     

杨梅褐斑病发病流行规律与防治技术研究

为了研究探讨杨梅褐斑病发生流行规律与监测防控技术,笔者在浙江黄岩等杨梅主产区,采用系统监测与试验推广相结合的方法进行调查研究。结果表明：杨梅褐斑病在浙江杨梅主产区周年均有发生,全年出现3 个明显发病高峰期,以杨梅春梢、夏梢和秋梢萌发侵染发病重,为病害防控关键时期。初步探明了杨梅褐斑病的发病流行规律,以及栽培品种、田间管理、气候条件与病害发生的关系,制定了杨梅褐斑病的预测预报方法,确立了调查项目与方法,提出了发生流行趋势的预测方法。药剂试验结果表明,33.5%喹啉铜悬浮剂1000倍、1500倍和2000倍液对杨梅褐斑病的相对防效分别为78.83%、76.79%和74.05%,在杨梅果实内残留消解的半衰期为3.6~13.6 天,使用安全,已在杨梅上取得农业部农药登记证,可大面积应用生产。研究提出了病害防治策略和农业防治与药剂防治相结合的方法,综合控制病害的发生流行。     

Location of a high-lysine gene and the DDT-resistance gene on barley chromosome 7

Summary The high-lysine gene in Risø mutant 1508 conditions an increased lysine content in the endosperm via a changed protein composition, a decreased seed size, and several other characters of the seed. The designation lys3a, lys3b, and lys3c, is proposed for the allelic high-lysine genes in three Risø mutants, nos 1508, 18, and 19. Linkage studies with translocations locate the lys3 locus in the centromere region of chromosome 7. A linkage study involving the loci lys3 and ddt (resistance to DDT) together with the marker loci fs (fragile stem), s (short rachilla hairs), and r (smooth awn) show that the order of the five loci on chromosome 7 from the long to the short chromosome arm is r, s, fs, lys3, ddt. The distance from locus r to locus ddt is about 100 centimorgans.     

Simultaneous Determination of Four Phenolic Acids in Radix Salviae Miltiorrhizae Formula Granules by QAMS

[Objectives]This study aimed to establish a QAMS(quantitative analysis of multi-components by single-marker)method for simultaneous determination of four phenol...     

Pollen and pollination experiments. III. The viability of apple and pear pollen as affected by irradiation and storage

Summary Apple and pear pollen was irradiated with doses of 0, 50, 100, 250 and 500 krad (gamma rays) and stored at 4°C and 0–10% r.h. From the in-vitro germination percentages an average LD 50 dose of about 220 krad was estimated. For both irradiated and untreated pollen a close and corresponding lineair relationship existed between germination percentage and pollen tube growth.Irradiated pollen was much more sensitive to dry storage conditions than untreated pollen, resulting in less germination and more bursting. Apparently, irradiation caused the pollen cell membrane to lose its flexibility faster than normal. Rehydration of dry-stored, irradiated pollen in water-saturated air restored germination percentages up to their initial levels. The importance of this procedure in germination trials is stressed.     

Evolution under domestication involving disturbance of genic balance

Summary An hypothesis is developed that the rapid change from wild plants into domesticated crops principally involves the selection of alleles with non-functional gene products which leads to reduced control of the highly integrated metabolism and morphogenesis previously accumulated by lengthy natural selection. Such disturbance of the genome produces altered physiological and morphological development which, although deleterious in nature, serves mankind better and has been selected.     

Genetic variation for disease and nematode resistances and forage quality in perennial diploid and tetraploid lucerne populations (Medicago sativa L.)

Summary Twenty-five lucerne populations of the Medicago sativa complex, which were either diploid or tetraploid and wild or cultivated, were analysed for their resistance to four different fungal diseases and to stem nematode. Forage quality, including stem digestibility and saponin content, was also tested.Populations varied in susceptibility to the diseases caused by Colletotrichum trifolii, Verticillium albo-atrum, Sclerotinia trifoliorum and Pseudopezizza medicaginis, and to the nematode Ditylenchus dipsaci. Except for Sclerotinia rot, sativa and falcata subspecies differed in susceptibility, but this grouping of populations did not account for the full range of variation among them. However, the resistance to P. medicaginis was much lower in the sativa than in the falcata populations.Populations also varied significantly in stem fiber content and digestibility. Stem digestibility was negatively correlated to forage yield. Wild sativa and falcata populations had lower fiber content and higher digestibility than cultivated sativa populations. The medicagenic acid was the sapogenin responsible for the anti-nutritional effect of the lucerne measured by the yellow mealworm larvae Tenebrio molitor. The medicagenic acid content was lowest for the pure sativa populations, highest for the pure falcata populations, and intermediate for the French sativa varieties that have some traits originating from falcata germplasm. Some populations could be used in breeding programs to improve disease and nematode resistance, and forage quality.     

Review of Effects of Active Components of Gastrodiae Rhizoma on Central Nervous System

In order to explore the pharmacological effects of active components of Gastrodiae Rhizoma on the central nervous system,through consulting related literatures,...     

Effects of Pb on Rhizosphere Soil Enzyme Activity and Chemical Constituents of Achyranthes bidentata Blume

[Objectives]The purpose of this study was to investigate the effects of Pb on rhizosphere soil enzyme activity and chemical constituents of Achyranthes bidentat...     

不同P-Zn配比对小麦幼苗微量元素营养的影响

采用了螯合-缓冲营养液培养方法对小麦进行了苗期培养试验,在3个P水平(0,0.6,3.0 mmol/L)和3个Zn水平(0,3,30 μmol/L)的完全组合下对小麦苗期生长及Zn、Fe、Cu、Mn营养进行了研究,旨在为小麦微肥施用提供理论依据.结果表明,P、Zn的正常供应促进了小麦生长,二者的缺乏与过量均会抑制小麦发育,且这种影响在冠部表现得更为明显.在小麦苗期,Zn与Cu的吸收存在明显的拮抗作用,但供Zn则促进了Zn和Cu的转运,而Mn转运则受到了抑制;过量供Zn时,大量Zn被转运到冠部,同时明显抑制了(Fe+Cu+Mn)的吸收总量;P的供应显著地抑制了Fe的吸收,但P的供应提高了Zn、Cu、Mn的转运率;P、Zn在对Zn与Fe、Cu、Mn间吸收竞争的影响中,Zn本身的影响要比P的影响更为明显,供Zn明显促进了小麦幼苗对Zn的吸收;在小麦幼苗冠部,Zn与Fe的竞争中,供P利于Zn的吸收,缺P则利于Fe的吸收;而Zn与Cu以及Zn与Mn间的竞争中,缺磷时利于Zn的吸收,供磷后则利于Cu和Mn的吸收.总之,小麦幼苗Zn、Fe、Cu、Mn营养中,P、Zn的不同配比会不同程度地改变Zn与Fe、Cu、Mn的协同或拮抗效应.     

Isozyme variation between diploid and tetraploid cytotypes of Glycine tabacina (Labill.) Benth.

Summary Glycine tabacina (Labill.) Benth. is a wild perennial species related to the cultivated soybean, G. max (L.) Merr. It is composed of diploid (2n=40) and tetraploid (2n=80) cytotypes. Currently, to differentiate the cytotypes, plants are grown out in the greenhouse and chromosome counts made on pollen mother cells. It is a laborious and time consuming process. The objective of this study was to determine whether electrophoretic techniques could be utilized to separate the cytotypes. Electrophoretic examination of seven isozyme systems from seed of 67 G. tabacina accessions revealed banding patterns that could be used to differentiate between diploid and tetraploid cytotypes in the species. Among the tetraploid accessions, the number of bands observed were always greater than the diploids. Some tetraploid banding patterns consisted of bands similar to the diploid tabacina and/or additional bands previously identified in other Glycine species. The patterns of isozyme multiplicity and variation in the tetraploid tabacinas suggests more than one mode of origin for the tetraploids.     

Some physiological and photosynthetic characters of rice × sorghum and rice × wheat hybrids

Summary Some photosynthetic characters as-leaf anatomy, leaf photosynthetic rate and CO₂ compensation pointdistinguishing C₃ and C₄ plants and physiological characters as leaf area ratio, nitrogen content, leaf stem ratio and total shoot-to-root and deep root-to-shoot ratios have been studied in rice × sorghum and rice × wheat hybrids. Rice × sorghum 1. has lower values of photosynthetic rate, leaf nitrogen, total root and deep root-to-shoot ratio and CO₂ compensation point as of rice parent where as, rice × sorghym 2. is superior in all these characters. Both hybrids lack kranz anatomy. Though both rice × sorghum hybrids show characters of C₃ rice plant but rice × sorghum 2. has improved drought tolerance and leaf characters in relation to yield. Rice × wheat hybrid have higher assimilatory area and higher total root-to-shoot ratio. Grains of rice × wheat hybrids are identical to rice grain. However, as grains of rice × wheat hybrid does not contain seed coat, it could be exploited as novel rice germplasm after improvement.Abbreviations T CO₂ compensation point - T21 CO₂ compensation point at 21% O₂ - T2 CO₂ compensation point at 2% O₂ - dR/sR deep Root-to-shoot Ratio - LAR Leaf Area Ratio - CER photosynthetic rate - TR/SR Total Root-to-Shoot Ratio