THE DEVELOPMENT PATTERN OF DOTHISTROMA NEEDLE BLIGHT AND ITS CONTROL     

He BingzhangNortheast Forestry UniversityDeng Xinglin Liu Chcngyu Liu Guiqin Yuc YupingXinlin Forestry Bureau of Daxing''''anling AreaWang FanJi Xi Mineral Bureau of Hcilongjiang ProvinceLiu ShuwenForestry Research Institute of Hcilongjiang Province 《林业研究》1992,3(1):48-53

From field investigations and inoculations,Dothistroma pini,the pathogen ofDothistroma needle blight was found to overwinter as mycelium and unmatured acervuli in infectedneedles.The conidia were spreaded mainly by rain splash.The disease became widespread by trans-porting discased seedlings and seions conidia spread throughout the growing season,but mainlyfrom May to July.The diseade was found in both stand locations in each summer of investigation.The outbreak severity was serious in pure stands of susceptible pine and mixed stands with largecomponents of suseeotuble pine.but slight in mixed stands of unsusceptible species with small com-ponents of suseeptible hosts.The disease was less severe in pruned stands than in unpruned stands.The disease was most serious near the infection centre.indoor and outdoor tests,it was shown thatChlorothalonil smoke,Chlorothalonil spray and Thiram and Asomate sprays were effective controlfungicides.  相似文献   

图书馆员职业倦怠工作的探讨     

孙琳  施小培 《农业网络信息》2013,(12):112-114,118

职业倦怠已经成为图书馆职业的隐形杀手，这种不健康的心态严重影响和谐图书馆的建设，是馆员与读者、同事之间交流沟通的最大障碍。分析了职业倦怠在工作中的具体表象、形成的原因以及对工作的影响，从心理介入和终身学习等角度提出了解决的对策。  相似文献   

老年人防跌倒健身体操运动干预的实验研究*     

代俊 《上海交通大学学报(农业科学版)》2015,(2):98-101

目的 以核心力量训练理论为指导研制一套老年人防跌倒健身体操，并通过12周运动干预实验检验其效果。方法 以56名六七十岁老年人为研究对象。实验组分别在干预前、中(第4、8周)、后进行11项体适能测试。采用2(实验前、后)×2(实验组、对照组)重复测量的方差分析进行差异比较，并采用简单效应及多重比较检验实验组不同干预阶段的锻炼效果。结果 所有指标训练主效应×组间主效应的交互作用显著（P <0.01），且实验组所有的测试结果在干预后均有显著提高（P <0.01）,但只有在运动干预的中期阶段是所有指标均有显著提高。结论 1）12周基于核心力量训练的健身体操运动干预能有效提高老年人的平衡能力、核心肌力等，对预防老年人跌倒具有积极作用；2）运动干预的中期对于改善老年人各项体适能具有重要意义。  相似文献   

核桃子叶不定根发生调控的研究   总被引：10，自引：0，他引：10  

裴东  袁丽钗  谷瑞升  蒋湘宁 《林业科学》2003,39(6):33-39

以核桃成熟或近成熟种实子叶为试材 ,在 1 4DKW基本培养基上其顶部 (近胚端 )的生根率达1 0 0 % ,而中部和基部 (远胚端 )的生根率为 0。在生根过程中顶部内源吲哚乙酸 (IAA)表现为初期上升 ,其后稳定在一定水平 ,当根原基开始生长时 (培养 4d)出现一个高峰 ;而中、基部内源IAA水平在培养初期下降 ,而后维持在一定的水平 ;蛋白凝胶电泳分析表明 :62 .8和 3 8.4kDa是与子叶不定根发生相关的蛋白条带 ,在不定根发生过程中 ,该带在子叶顶部表达增强 ,而中部、基部则消失。当培养基中附加一定水平的吲哚丁酸(IBA) ( 0 .5～ 1 0mg·L- 1 )时 ,子叶中、基部被诱导产生不定根 ;附加 2mg·L- 1 IBA ,其内源IAA的变化与子叶顶部在 1 4DKW基本培养基上发根时有相似的趋势 ;同时该处理启动表达了 62 8kDa蛋白条带和抑制表达3 8 4kDa蛋白条带。反之当培养基中附加 6-苄氨基腺嘌呤 (BAP)又抑制子叶生根 ,也抑制了与生根相关的IAA变化和蛋白表达。这一结果和良好的研究模式为从分子水平上深入认识木本植物不定根发生机制奠定了基础。  相似文献   

高黎贡山自然保护区东坡水平带蚂蚁群落研究   总被引：2，自引：0，他引：2       下载免费PDF全文

徐正会  吴定敏  陈志强  蒋兴成 《林业科学研究》2001,14(6):603-609

研究了高黎贡山东坡水平带蚂蚁群落特征，结果表明，除中南段2500m等高线外，东坡各水平带的不同位置均有特有种。在1000m、1500m、2000m、2500m等高线上，从北到南特有种数目依次递增，但北段1500m和2000m等高线出现特有种增高例外。在东坡不同海拔等高线上，大多数物种只在1个样地中表现为优势种，北段与南段的优势种通常不同。在1000m和2000m等高线上北段的优势种多于南段，而在1500m等高线上南段优势种多于北段，2500m等高线上不同地段优势种趋于相等。东坡水平带上物种数目和密度表现出普遍规律性。从北到南，1000m和2500m等高线上物种数目和密度依次递增，在1500m等高线上物种数目和密度依次递减。在1000m等高线上优势度、多样性和均匀度具有明显规律性。从北到南，优势度依次递减，多样性和均匀度依次递增，但在北段出现例外。在1500m、2000m和2500m等高线上，蚂蚁群落的优势度、多样性和均匀度缺乏规律性，可能与植被的次生化和片断化等因素有关。尽管东坡水平带上同一海拔植被类型相似，但是蚂蚁群落之间差异显著，相似性系数在0－0．50之间。山体下部1000m等高线上蚂蚁群落之间相似性较大，相似性系数在0．25－0．50之间。随着海拔增加，同一水平带上群落之间相似性减小。  相似文献   

参与式林业规划过程中的利益相关群体分析     

叶敬忠 《绿色中国(A版)》2005,(24):43-46

通过对参与式林业规划过程中相关利益群体的实地调查,揭示了不同利益群体的思想世界。结果分析证明发展干预的话语将被不同的利益相关群体逐级解构与塑型;利益相关群体在技术领域的参与容易实现,但关键是造林的有关权属安排;利益相关群体之间存在利益竞争与冲突。因此,发展干预的话语应该进行基层可操作化;在权属制度保证的基础上应实现技术操作灵活化;应实现从角色间的利益相关向角色内利益相关的转变。  相似文献   

保护、修复与利用海珠湿地二期的实践思考     

梁曦亮  梁欣 《广东园林》2020,42(1):50-55

海珠湿地原是广州城市中央的万亩果林,是海珠生态城的核心。基于湿地一期风格过于"人工化",通过分析简单保留单纯果林的现状问题,海珠湿地二期提出尊重场地独特肌理,以"微改造、少干预"的生态修复理念,通过连通水系、调清活水、规划交通、修复生境、丰富植被等方式,为鸟类、鱼类、两栖类、昆虫等动植物营造良好的栖息地,提升生物多样性。此外,利用果园活化都市农业景观,利用湿地满足市民对科普、休闲的需求,适当配套观鸟屋、观鸟塔、园路、桥梁等设施。  相似文献   

Elastic Band Gaps in Two-dimensional Phononic Crystals Based on Multiple-scattering Theory     

ZHENG Ling  LI Yi-nong 《保鲜与加工》2007,(6):6-9

Two dimensional solid phononic crystals such as plates, shells can be widely applied to the control of vibration and noise as a kind of structural materials. It is very significant to study the band gaps in two dimensional phononic crystals to apply them in the vibration and noise control for structures and as a filter for acoustical signal. The multiple-scattering theory is integrated with wave equations to study the elastic wave band gaps in two-dimensional phononic crystals. The carbon/proxy system is used as numerical example. The results show that a full band gap is presented when carbon cylinder with high propagation velocity is arranged periodically in proxy with low propagation velocity.  相似文献   

PD Online Measurement of Transformers with Wide Frequency Band System and the Noise Eliminating Method by Cascaded IIR Lattice Notch Digital Filter     

LI Jian  WANG You-yuan  DU Lin  YANG Yang  NING Jia-xin 《保鲜与加工》2005,(8):22

The frequency band of conventional partial discharge (PD) measurement systems is selected just within several ten kilohertz. With the development of computer and digital signal processing techniques, wide frequency band (WFB) measurement systems have been used to detect PD in electrical equipment for its higher sensitivity. Nevertheless, the WFB measurement systems are easy suffered from the interference of strong field electromagnetism noises. A set of PD online monitoring system with frequency band from 50 kHz to 1 megahertz used for transformer is developed, in which pre-processing device and cascaded 2nd order IIR lattice notch digital filter are mainly used to suppress periodic narrow-band interference. With analysis of field monitored signal at a 220 kV substation, it is shown that the monitoring system not only can detect and extract the discharge pulse signal effectively, but also has the powerful capability of suppressing interference.  相似文献   

N Periodic Multiresolution Analysis with Band M     

MAO Yi-bo 《保鲜与加工》2007,(11):96-98107

N periodic multiresolution analysis with band M was introduced. By means of Fourier transformation and inner-product, N periodic orthogonal muhiresolution analysis with band M was studied. Expression of its scaling function space in frequency domain is obtained, the coefficients relationship of lowpass filter and highpass filter is investigated, and the elementary property of its mask is worked out. The results show that filter and mask of periodic wavelet is a series of coefficients.  相似文献