共查询到20条相似文献,搜索用时 62 毫秒
1.
我国与缅甸、越南,印度、尼泊尔等12个国家毗邻,由于特殊的地理环境和传统的民族风俗,边民生产、生活关系密切,互市来往频繁。其互市特点主要有①边民出入方便;互市点多,零星而分散。②“互市”产品种类多,来源广;如云南瑞丽市场,“互市”的植物及产品主要有绿豆、大豆、豌豆、花生、大米、玉米、水果类、各种蔬菜种子共20多个品种;带有少量的苗木(主要是观赏花卉和树种)。③数量大,流向远;按规 相似文献
2.
兰花病毒的种类、检验和防治 总被引:2,自引:1,他引:2
兰科植物约有500多属,10000多种,其中栽培供观赏的约2000多种,分为两大类:气生兰和地生兰,气生兰约占兰科植物的80%,地生兰主要产在温带,全世界约50种,多数分布我国,现日本栽培的地生兰品种,多半引自我国。我国的主要地生兰约有10多个栽培种,如春兰 Cymbidium virescens蕙兰 C.faberi、建兰 C.ensifolium、秋兰C.Gyokuchin var.Soshin,Makino、寒兰 相似文献
3.
4.
山东葡萄产区主要病毒病发生危害调查 总被引:2,自引:0,他引:2
采用DAS- ELISA检测方法 ,对山东省葡萄主产区的葡萄病毒病害进行了调查 ,明确危害当地葡萄主要是葡萄扇叶病毒 (grapevine fanleaf virus ,GFLV)和葡萄卷叶病毒 (grapevine leafroll associated virus,GLRaV)。病毒感染率为 59.1% ,其中鲜食品种病毒感染率为57% ,酿酒品种的感染率为 62.5%。苗木与成龄树感染GFLV的比率分别为 78.4%和56% ,感染GLRaV的比率分别为55.3%和70%。病毒感染率较高的品种有霞多丽、梅露汁和佳丽酿。病毒病的发生与品种、栽培年限、繁殖方式和苗木来源有关 ,其中带毒苗木是葡萄病毒病传播的关键因素 相似文献
5.
香气,汁多,皮薄,水分含量高达86%。梨在我国具有悠久的栽培历史,其总产量仅次于柑桔和苹果。梨树普遍存在着“花多果少”的现象,这主要是授粉受精不良、树体营养过弱等多种因素造成,而授粉受精过程又受到品种、地理条件、气候、风、雨、昆虫等因素的影响。下面以栽培比较普遍 相似文献
6.
7.
8.
为马山县沃柑产业发展提供参考。采用实地调查、总结归纳法进行整理和分析,对马山县沃柑产业现状、存在问题和发展对策进行调查分析。产业发展现状:基本形成了生产有基地、产品有品牌、营销有组织、流通有市场、销售有渠道的发展格局。主要存在问题:生产基础设施薄弱,资金投入能力有限,果园单产水平低;采后技术处理覆盖率低,贮藏设施落后,品牌建设力度不够,市场运作水平低;产业开发起步晚,政策扶持少,生产和发展的研究相对滞后;苗木的生产、调运缺乏统一规范,乱调乱繁现象普遍。做好产业发展总体规划,加强新技术推广及扶持力度,做大区域规模。规范良种良苗繁育和扩大标准化生产规模。推进产业化经营,提升品牌创建能力,延伸产业链,增添发展新动力。切实转变政府职能,为产业发展提供保障。 相似文献
9.
10.
园林苗木常见病虫害防治 总被引:1,自引:0,他引:1
<正>病虫害的发生既影响园林苗木的正常生长,又影响其观赏价值和经济效益。因此,在园林苗木栽培管理中,病虫害的防治是不可忽视的问题。1常见病害及其防治1.1锈病1.1.1症状锈病主要为害苗木的叶、茎和芽。感病叶片一般 相似文献
11.
新疆奇台县近42a气候变化特征分析 总被引:5,自引:1,他引:4
根据新疆奇台县气象站的气温及降水资料,利用线性趋势函数及M ann-kendall突变检测法分析了该地区近42年的气候变化。结果表明:年平均气温与极端最低气温均呈上升趋势,而极端最高气温呈下降趋势;年降水量呈上升趋势。从季节变化来看,除夏季平均气温呈下降趋势,其它各季平均气温均呈上升趋势,其中以冬季增幅最大,秋季次之;各季降水均呈上升趋势,其中以夏季增幅最大,冬季次之。年平均气温未发生突变,而年降水量在1984年发生由少向多的突变。对气温和降水的异常分析得出,暖温年多发生在上世纪80年代后,冷温年多发生在上世纪60、70年代;多雨年主要在近20年,少雨年则多在上世纪60、70年代。此外,该县近42 a来增暖幅度小于全疆和北疆;增湿幅度大于全疆,小于北疆。 相似文献
12.
13.
14.
综述了我国苜蓿主要病害的分布和危害、病原学、发生规律、抗性种质材料的遗传筛选和鉴定及综合防治等方面的主要研究进展,并提出了今后的研究方向和发展目标。 相似文献
15.
组蛋白修饰作为表观遗传修饰的一种主要形式,对基因表达和表型调控具有重要作用。组蛋白修饰的N端尾区可通过乙酰化、甲基化、磷酸化等修饰来改变染色质的状态以及调控基因的表达。与脊椎动物相比,昆虫种类繁多,且有变态发育、表型复杂等特征,可以成为探索动物社会行为、发育调控和毒理作用等表观遗传基础的模型。本文总结了昆虫组蛋白修饰的主要类型(乙酰化和甲基化修饰)及修饰酶的研究进展,对染色质免疫共沉淀测序技术(chromatin immunoprecipitation followed by sequencing,ChIP-seq)、染色质转座酶可及性测序技术(assay for transposase-accessible chromatin with high-throughput sequencing,ATAC-seq)、转录组测序技术(RNA-seq)、组蛋白修饰酶功能验证以及Western blot、免疫细胞化学(immunocytochemistry,ICC)、免疫组织化学(immunohistochemistry,IHC)、酶联免疫吸附测定(enzyme linked immunosor... 相似文献
16.
Cees Waalwijk Pieter Kastelein Ineke de Vries Zoltan Kerényi Theo van der Lee Thamara Hesselink Jürgen Köhl Gert Kema 《European journal of plant pathology / European Foundation for Plant Pathology》2003,109(7):743-754
The re-emergence of fusarium head blight throughout the world and especially in Western Europe prompted a survey of the situation in the Netherlands. To allow for a high throughput screening of large numbers of samples, a diagnostic PCR method was developed to detect the most common species of Fusarium occurring on wheat. Seven primer pairs were tested for their ability to identify isolates of Fusarium avenaceum, F. culmorum, F. graminearum, F. poae, F. proliferatum and Microdochium nivale var. majus and M. nivale var. nivale. Each primer pair only generated a PCR product with the corresponding Fusarium species and all PCR fragments had different molecular sizes. This allowed the generation of these amplicons using a mixture of all seven primer pairs. The robustness of this multiplex PCR encouraged us to screen a large series of isolates collected in 2000 and 2001. In both years 40 fields were sampled leading to a collection of 209 isolates from 2000 and 145 isolates from 2001. The results of the multiplex PCR demonstrated that F. graminearum was the most abundant species in the Fusarium complex on wheat in both years. This is in sharp contrast to reports from the 1980s and early 1990s, which found F. culmorum as the predominant species. Primers derived from the tri7 and tri13 genes, which are implicated in the acetylation and oxygenation of the C-4 atom of the backbone of the trichothecene molecule, were used to discriminate between deoxynivalenol and nivalenol (NIV) producers. The populations of F. culmorum and F. graminearum both showed a slight increase in NIV-producers in 2001. 相似文献
17.
18.
弹状病毒含有单链负义RNA基因组,寄主范围比较广泛,能侵染无脊椎动物、脊椎动物以及植物等寄主,对人类的健康、农作物产量和自然生态系统造成严重威胁。植物弹状病毒主要根据复制场所分为细胞质弹状病毒属Cytorhabdovirus和细胞核弹状病毒属Nucleorhabdovirus,其基因组由单股负链RNA组成。此外,Dichorhavirus和Varicosavirus病毒属是两个新鉴定的植物弹状病毒属,其特征是具有二分体基因组。本文着重介绍危害我国农作物的几类植物弹状病毒,对它们的病理学、病害流行、基因组信息以及传播媒介进行概述,为中国植物弹状病毒病害的研究提供理论依据。 相似文献
19.
Variation in pesticide residues in space and time has not been investigated systematically in spite of the large variability found at single scales (e.g. between trees or orchards). Information on variability at different scales will support the development of sampling methods and more reliable prediction of residues. Experiments were conducted to quantify the spatiotemporal variability in initial spray deposit on apple leaves and fruit using a substitute tracer (zinc EDTA chelate). Five hierarchical spatial scales were defined as (1) between orchards, (2) between plots within an orchard, (3) between trees within a plot, (4) between zones within a tree and (5) between leaves/fruit within a zone. Similarly, two temporal scales were defined as (1) between applications within a single year and (2) between years. The initial zinc concentration was approximately log-normally distributed; the variability in initial deposit concentration was greater on leaves than on fruit. The average initial zinc deposition was significantly greater in the top and outside zones than in the middle zones within individual trees. The most important scale for driving residue variability is the within-zone unit-to-unit variation, contributing to 71 and 49% of the observed variability for leaf and fruit samples respectively. Variability at other scales was related to the variation in the tree architecture. The results indicated that stratified sampling on the basis of within-tree zone structures, with the effort focused on within-zone sampling, should be used for the determination of pesticide residues. 相似文献