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1.
The root of Alnus sibirica is rich in tissue type,Phloem fibers are obvious and Plasmodesmas are well developed.The number of primary xylem bunches are not stable,there are triarch,tetrarch and pentarech types.The perforation plate of vessel is scalariform,The rays types are radial in shape and unicellular in structure,In root nodule,cortex is the best developed structure,the stele is small.The root nodule is branched.In root nodule tissues,actinomyces proliferate luxuriently,the actinomyces body is in different shapes.  相似文献   

2.
This paper presents the feed marketing systems of Ethiopia in terms of feed demand and supply, feed quality issues, feed prices and price trends based on qualitative data generated through rapid market appraisal methodology. The results indicate that, the demand for roughages, agro-industrial by-products (AIBP) and compound feeds is showing increasing trend. The use of feed from commercial sources is, however, very limited due to shortage of feed supply and inefficient marketing system. The AIBP mainly from flour and grind mills, oil processing plants and breweries are in short supply and directly marketed to user or through traders. Consequently, most of the exiting feed mixers/processing enterprises are operating under capacity estimated at about 20%-30%. The main marketed roughages, which are mainly cereal straws and baled hay, are also in short supply. Feed prices are increasing from time to time and mainly exacerbated by the increasing trend in export market of AIBP and double taxation in mixed rations. There is no any feed quality control or assurance mechanism in Ethiopia. Precaution needs to be taken in the area of taxation in order to avoid double taxation. Implications to improve the feed marketing systems and opportunities for livestock development are drawn.  相似文献   

3.
The conducting tissue structure of transverse and longitudinal sections was observed on leaves of Podocarpus and Nageia.Results showed:in Podocarpus leaves,there is only one midrib,the xylem tracheid of midrib vascular bundle is multi-form,transfusion tissue belongs to Cycas-type and transfusion tracheids are isodiametric,the accessory transfusion tracheids between palisade tissue and sponge tissue are developed;in Nageia leaves,there are plenty of parallel leaves,the xylem tracheids of each vein are relatively simple,transfusion tissue belongs to Taxus-type and transfusion tracheids are longer in longitudinal section than that in transverse section,the accessory transfusion tissue between palisade tissue and sponge tissue is absent.Considering other differences that in leaves of Podocarpus there are three resin ducts under vascular bundle of midrib,mesophyll cells are differentiated into palisade tissue and sponge tissue;in leaves of Nageia,there is only one resin duct under vascular bundle in each vein and no obvious differentiation in mesophyll cells,palisade tissue can be found on both sides,and sclereids can also be found in mesophyll tissue.The anatomical differences of leaf veins and mesophylls between Nageia and Podocarpus mentioned above support the viewpoint that Nageia and Podocarpus are two independent genera.  相似文献   

4.
Seed coating can make soybean seedling grow more strongly and reinforce the resistance of soybean plant.Sodium alginate and chitosan are high-molecular compound of two different kind,have the characteristic of promoting the crop growth,Using sodium alginate and chitosan as coating materials under different concentration can improve the growth and photosynthesis obviously and can decrease pollution because of their characteristics.The analysis show that the effects of Sodium Alginate on soybean plant are better than chitosan and the best concentration is 0.5g.kg^-1.  相似文献   

5.
The genetic analysis of soybean isoflavone content and its components were carried out based on the NC Ⅱ mating design in eight soybean varieties. The results showed that the isoflavone contents and its components of soybean seed are quite differences among the tested materials, the contents of isoflavone and daidzein are controlled not only by additive effects and but also by non-additive effects, while the content of genistin is dominated by non-additive effects, and genistein, glycitin and daidzin are mainly controlled by additive effects. There are significant differences in the contents of isoflavone and its components among the combinations derived from different parents. Results also indicated that the tested traits are negatively heterosis except for the contens of daidzein and daidzin are positively heterosis based on the data of the GCA and SCA in average heterosis values. In this research we have a suggestion that soybean variety with high isoflavone should be used as one of the parents in the breeding program, and it is the best choice that the combinations crossed between two high isoflavone varieties or a high variety and a low one.  相似文献   

6.
Aster albescens is a medicinal plant, The rust caused by Aecidium asterum is a new record in China and an important disease of A. albescens in Feng Tong-zhai national reservation area. The percentages of diseased plant and the diseased leaf reach 100 and 28% respectively when the disease is serious. The disease results in leaf spot and leaf cast. Tuberculina persicina is a natural hyperparasite ofA. asterum and is firstly reported in the world. The hyperparasite attacks aecium of A. asterum and hinderes the release of aeciospores. The symptom of the rust and the morphological characteristics of A.asterum is reported. The hyperparasitism of A. asterum and the morphological characteristics of the Tuberculina persicina are also reported.  相似文献   

7.
The basic principles of the partial and multiple coherence ananlysis and their utilization on vibration source idenfification are discussed in detail in this paper,The partial coherence analysis is the effective method of vibration source identification in multiple input-single output systems.Formerly,there was not any this kind of unction in the signal processor,and there was not and special software too.The software which we developed and used in the 7T 17S signal processor has this function.This software can be used not only for the parial and multiple coherence analysis of signal,but also for the correlation analysis,power spectrum analysis,transfer function analysis et al.We used this software to make the identifcation of the vibration source of the car floor board of electrical measuring vehicle,and to find the main factors which effect the vibration of the ear board.The excellent result was obtained.This method can also be used for making the identifications of noise source and other sources.  相似文献   

8.
On the Kpinnou ranch in Benin, it was observed that the Girolando dairy cattle which graze Panieum maximum var. CI are more susceptible to infestation of ticks. The purpose of this study was to highlight the interactions between ticks and their bovine hosts and two types of artificial grazing pastures. Nineteen young Girolando dairy cattle were used during the big rainy season (March-June) 2009. All present ticks on the animals have been counted according to the body region. The bovine have been divided into two relatively homogeneous groups often and nine animals. The group I of 10 animals had been grazed on Panicum maximum whereas the group 2 of 9 animals had been grazed on Panicum maximum var. C 1. During the two months of grazing, a weekly monitoring of the evolution of the load in ticks has been achieved. Four genera of ticks were identified on the bovine Girolandos (Amblyomma, Hyalomma, Rhipicephalus and Boophilus). The Boophilus genus is the most abundant (P 〈 0.05). The animals having grazed Panicum maximum var. C I are more infested than those that have been grazed Panicum maximum. A variation of the rate of infestation of the animals has been observed in relation to the different body areas. The colour of the coat also has an effect on the load in tick of the bovine. The bovine of dark coat are in general more infested (P 〈 0.05) than those of clear colour.  相似文献   

9.
The aim of this research is to identify the most suitable land for forestry, afforestation and rangeland management in Hamadan province. This research has been accomplished using Makhdoum's model. In this research 30 digital data layers are used. The Geographic Information System (GIS) has been used as main tool and overlay method has been used to implement the mentioned model. The results of this research revealed that the extent of favorite areas for fifth grade forestry, favorite areas for fourth grade afforestation, and favorite areas for third grade and fourth grade range management in the studied area. Based on the results of this research, the studied area has limited potentials for forestry and afforestation activities. The obtained results of evaluation also showed that the rangelands of Hamadan province are extremely poor. Since the rangelands have a substantial role in preservation of soil and water, therefore it is necessary to take appropriate measures for better exploitation of rangelands.  相似文献   

10.
The Borana rangelands are important areas of cattle production in Ethiopia. However, these rangelands are threatened by the increasing changes in the natural vegetation from grass and forbs dominated into unpalatable bushy woody vegetation resulting in the loss of some of the highly desirable grass species. This study was conducted to assess the impacts of bush encroachment on the biodiversity, structure and cover of the native vegetation in bush encroached and non-encroached sites. Vegetation data were collected from both sites by laying quadrate plots along transects using a systematic sampling method. According to the results, higher number of species was recorded in the non-encroached sites than that in the encroached sites. The diversity indices for the non-encroached and the encroached sites were 3.16 and 2.67, respectively. The abundance and cover analysis indicated that there was high density and cover of herbaceous species in the non-encroached site. There was a significantly higher density of woody species cover in the encroached site. Generally, the bush encroachment in the Borana rangelands has hampered the diversity of the native vegetation, particularly the grasses and forbs and reduced the ground cover, exposing large parts of the rangelands for soil erosion and other degradation process.  相似文献   

11.
对天然橡胶现货和期货的销售过程、交易市场、交易所等进行比较,分析了我国天然橡胶现货和期货市场存在的问题并提出改进的方案,总结了国际天然橡胶定价中心成功因素。  相似文献   

12.
畦灌田面行水流动的模型与模拟   总被引:4,自引:0,他引:4  
根据我国地面灌现状提出极限灌水状态和最佳灌水状态及其灌水技术参数的概念。用NewtonRaphson法和Preissman法求解畦灌田面行水流动的零惯性模型,实现了畦灌田面行水流动的模拟。在此基础上探讨畦灌的行水和入渗机理。用计算机模拟试验方法建立极限灌水定额与灌溉技术参数和畦田规格关系的数学模型,并研究它们对极限灌水定额的影响,进而探讨了灌溉技术参数和畦田规格对灌溉系统性能的影响。提出了适宜畦长和单宽流量的确定方法并给出了其量值。  相似文献   

13.
主要养殖鲟鱼的生物学及养殖前景   总被引:10,自引:0,他引:10  
鲟鱼是世界上最古老的鱼类之一,现存鲟鱼种数有25~26种。由于多年的酷渔滥捕和生态环境恶化,鲟鱼资源日益衰退。1990年世界鲟鱼产量为2万y,1993年下降到1万t。本文作者综述了鲟鱼类的起源、地理分布、生态习性和生物学特性,分析和讨论了开展鲟鱼养殖应注意的问题及鲟鱼的养殖前景。  相似文献   

14.
古树名木保护中存在的问题与对策   总被引:4,自引:0,他引:4  
分析了古树名木保护的现状及古树名木保护过程中存在的问题,提出了保护古树名木正常生长的措施,旨在使古树名木得以科学有效的保护。  相似文献   

15.
侧柏球花的发端发育及物候学   总被引:1,自引:0,他引:1  
侧柏营养技端4月下旬萌动,5~10月为营养生长期,10月以后休眠。7月中旬至8月上旬,长日照中日照惭短的时期,营养枝端转化为生殖枝端。雄球花端圆球形,雌球花端圆柱状。8~10月为球花发育期,10月进入休眠。翌年3月末传粉受精,10月初球果成熟。成熟的雌球花枝较雄球花枝长,90°弯曲。雌球花数量少,多着生在当年生枝条基部近轴面的侧枝上。对侧柏球花发端的时间、特点和其他针叶树种进行比较与讨论。  相似文献   

16.
以宜兴太湖百渎港河口湿地区域内芦苇(Phragmites australis)为研究对象,采用现场围隔手段,研究了收割移出和自然保留2种处理方式下芦苇地上部分生物量、氮、磷含量和储量的动态变化。结果表明:(1)收割样地内芦苇群落的茎、叶和地上生物量(不包括收割部分)均低于保留样地的芦苇群落,且差异性均达到极显著水平;(2)收割样地与保留样地内芦苇茎和叶片的氮、磷含量变化趋势相近,且芦苇茎和叶的氮、磷含量差异都不显著;(3)收割样地内芦苇群落的茎、叶和地上氮、磷储量均低于保留样地内的芦苇群落,且差异性均达到极显著水平;(4)收割样地和保留样地芦苇的茎、叶和地上生物量与其氮、磷储量间均呈现显著的正相关。  相似文献   

17.
土壤中铅镉的化学形态和有效态的提取与分离研究   总被引:17,自引:0,他引:17  
对土壤中铅镉的形态和有效态的提取与分离进行了研究,比较了不同提取剂的提取能力,选择了铅,镉的最佳形态和有效态提取剂,建立了土壤中铅,镉的形态连续提取方法,并对提取剂的提取机理进行了初步探讨。  相似文献   

18.
介绍贵州草山草坡草资源的基本概况,分析该资源利用中存在的问题,并对如何利用这种资源提出建议。  相似文献   

19.
通过PCR、细菌培养鉴定和血涂片镜检对20例以高热为特征的疑似蓝耳病病例进行病原检测诊断,并根据病因提出综合防治措施。发现蓝耳病(PRRS)阳性率100%,圆环病毒病(PCV-2)阳性率40%,伪狂犬(PRV)阳性率40%,非典型性猪瘟(CSFV)阳性率10%,猪流感(SI)及猪传染性胸膜肺炎(APP)均为阴性,附红细胞体阳性率90%,并有少量细菌感染。结果表明我市猪高热病为高致病性蓝耳病,发病猪并分别不同程度地混合或继发感染了其他病原体,病原一般3~5种,病原多样化导致病情复杂化,增加了诊断和治疗难度,所以本病宜采取综合防治。  相似文献   

20.
国内外鱼类入侵的历史及途径   总被引:2,自引:0,他引:2  
近年来,由于鱼类入侵,对生态环境造成了严重破坏,经济也遭受巨大损失,现已引起国内外学者的广泛关注。鱼类入侵的前提是人类对其有意无意的相互引进。作者综合国内外大量资料,论述了国际范围内鱼类引种、入侵的历史,概括了国内外鱼类生物入侵的途径,旨在为进一步研究鱼类入侵的机制和防范控制措施提供依据。  相似文献   

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