Histopathological assessment of wheat seedling tissues infected by Fusarium pseudograminearum

Histopathological assessment of infection by the crown rot pathogen Fusarium pseudograminearum in wheat seedling tissues was performed using fluorescence microscopy. The coleoptiles and leaf sheaths of four host cultivars of differing susceptibility were examined. Leaf sheaths were most frequently penetrated via stomata, indicated by initial lesions forming at the guard cells. Internally, cell wall penetration was facilitated by penetration structures which appeared as hyphal swellings or septate foot‐shaped appressoria. Colonization of leaf sheaths resulted in the re‐emergence of hyphae from stomata on both surfaces of the sheath. These hyphae are hypothesized to have two major roles; first as exploratory hyphae for colonization of new tissues, and secondly as sites of profuse conidial production. The formation of conidia on the leaf sheath surface was only recorded on the most susceptible bread wheat genotype. No other major differences in host–pathogen interactions were observed among these cultivars. Almost all cell types in the leaf sheath tissues were extensively colonized, except for the vascular bundles and silica cells. This investigation provides the first comprehensive assessment of F. pseudograminearum infection structures and growth patterns during the infection of wheat seedlings.     

北京市13 个常见树种胸径估测研究

随着高分辨率遥感数据、LiDAR 技术在森林资源调查中应用的日益普遍,以及自动快速提取树木冠幅、树高 方法的日益成熟,需要建立新的树木模型来估测其他林分因子,以适应林业调查手段更新和发展的需求。在参考 国内外大量文献的基础上,选择常用的胸径鄄冠幅模型和树高鄄胸径曲线模型,根据北京市178 块森林样地调查数 据,建立了北京市13 个常见树种的胸径鄄冠幅模型,胸径鄄树高模型,胸径鄄冠幅、树高综合模型。结果表明:并不是 所有树种的冠幅、树高都与胸径有高相关性;13 个树种中,只有臭椿、雪松、栾树和加杨的胸径鄄冠幅模型的R2 大于 0郾7,胸径鄄树高模型R2 大于0郾5,胸径鄄冠幅、树高综合模型达到0郾8 以上;油松、杨树、槲栎、圆柏4 个树种的胸径鄄 冠幅模型的R2 小于0郾3;核桃、油松、火炬树、柳树、国槐5 个树种的胸径鄄树高模型R2 低于0郾3。并提出在下一步工 作中,把林龄,林分密度,立地条件如坡度、坡向、海拔、地位级等林分因子与树木冠幅、树高联合建立估测模型来提 高胸径估测的精度。该方法可用于现代遥感技术快速获取树木冠幅、树高之后,根据已有的数据库资料,用树种的 冠幅、树高估测胸径,再推算其他林分因子,实现森林资源的快速调查与更新。      

树木树冠阴影面积与种植间距的编程计算分析研究

主要是利用计算机编程软件Microsoft Visual C++6.0和现有的天文学公式以及对公式的分析计算处理,对决定树木所投射阴影大小起决定性因素的太阳方位角和太阳高度角进行编程化求解。然后根据所得出的实时数据和树木树冠模型化分析,最终计算得出不同的经纬度在某一时刻树木的投影面积,为果树等的合理种植间距分析提供依据。     

不同基质对小叶赤楠生长的影响

为缩短小叶赤楠出圃时间,采用3种不同栽培基质,研究其生长态势及光合日变化趋势。结果表明:蛭石+泥炭(体积比为1∶1,T1)处理小叶赤楠的株高、地径和冠幅最大,分别为45.80、0.68、29.20cm,蛭石+泥炭+黄泥(1∶1∶1,T2)处理的次之,分别为41.20、0.59、23.10cm,蛭石+黄泥(1∶1,T3)处理的最小;3个处理下小叶赤楠光合日变化趋势基本一致,呈双峰曲线,中午有明显的午休现象,日均净光合速率表现为T1>T2>T3。蛭石+泥炭作栽培基质小叶赤楠长势最好,出圃最早,但考虑生产成本,推广使用蛭石+泥炭+黄泥作为栽培基质。     

PET fabric supported fixed site carrier membrane for selective metal ion transport

Development of a novel fixed site carrier membrane (FCM), supported by PET fabric for metal ion separation is reported. The membranes were prepared by dipping PET fabric into the methylene chloride solution of Poly(5-vinyl-m-phenylene-m′-phenylene-32-crown-10)_ (P(VCE)), a polymeric metal ion carrier. It was found that the flux of mono-valent metal ion transported across the membrane is significantly differed from each other and the flux decreases in the order Cs⁺>Rb⁺>K⁺>Na⁺>Li⁺ irrespective to the anion except perchlorate anion. It was explained in terms of the stability of the complex, formed by crown ether unit of the P(VCE) and the various metal ions, meanwhile, the lower rate of transport in the presence of perchlorate anion was ascribed to its low hydrophilicity.     

结合航空影像纹理和光谱特征的单木冠幅提取

随着航空摄影测量技术的不断发展与进步,为提高森林资源调查的工作效率,航空影像已经成功应用到林业资源监测中,但在单木冠幅提取上,研究多考虑影像光谱信息,使得分类结果存在偏差。本文提出同时结合航空影像的纹理及光谱特征,利用面向对象的影像分割方法,通过多次实验对比结果确定最优分割尺度,同时在结合正态分布法确定各光谱及纹理特征信息范围的基础上,提取单木冠幅信息。以2012年鹫峰国家森林公园航空像片为数据源,以ENVI5.0为数据处理平台,对影像进行面向对象的分割,提取试验区域内32株树木的冠幅,并结合传统外业实测数据以及立体像对观测数据进行精度分析。试验结果表明:文章所提出的方法试验精度达到90.05%,与传统立体像对量测方法精度相近,但数据获取速度快,满足林业调查基本需求。      

利用机载激光雷达数据提取单株木树高和树冠

机载激光雷达是一种主动遥感技术。在林业应用方面,高采样密度激光雷达能够获取单株木三维结构特征,采用不同的数据处理方法,可以得到不同精度的单株木参数。该文利用高采样密度的机载激光雷达数据（离散回波,平均激光点间隔0.52 m、平均光斑直径0.3 m）,研究了单株木的树高提取技术和树冠边界识别算法,针对单株木的树冠特征,提出了一种双正切角树冠识别算法;最后,使用重庆铁山坪林场的9个外业样地数据,对单株木树高和冠幅,以及样地平均树高和平均冠幅进行了验证。结果表明,单株木树高和冠幅的R2分别为0.34和0.03,样地平均树高和平均冠幅的R2分别为0.97和0.71,样地尺度的相关性明显高于单株木尺度的相关性。      

重大园林植物病害及其研究进展

系统地介绍了国内外重大的园林植物病害:松材线虫病、榆树荷兰病、五针松疱锈病、观赏植物冠瘿病、香石竹尖镰孢枯萎病和菊花叶枯线虫病, 综述了这些病害的国内外研究进展。     

The Pathogen of Crown Gall Disease on Flowering Cherry and its Sensitivity to Strain K1026

Six strains of crown gall bacteria were isolated from flowering cherry. It was revealed by Otten paper electrophoresis that of the six strains, only BYH18-4 possessed the octopine type Ti plasmid, the remainder having nopaline type Ti plasmid. BYH5-1 was identified by physiological and biochemical tests to be Agrobacterium tumefaciens (originally biovar 1). The other five were A. rhizogenes (originally biovar 2). It was demonstrated with Stonier's method of double layer medium that flowering cherry crown gall bacteria exhibited different sensitivities to agrocin produced by biocontrol strain K1026. Strain K1026 on greenhouse-grown sunflower seedlings exerted a relatively potent inhibitory action on flowering cherry crown gall bacteria. Artificial inoculation showed that K1026 produced 67–99% inhibition of flowering cherry crown gall disease, compared with the treatment of inoculation with crown gall bacteria only.