白榆不同造林密度与生长量关系的研究

营造株行距１＊１ｍ、１＊２ｍ，２．５＊３ｍ不同造林密度的白检试验林，１４年的试验结果表明，３种不同栽植密对林分的高生长影响不大，但对胸径生长影响非常明显。     

Evaluation of Dutch elm disease susceptibility and pathogenicity of Ophiostoma ulmi using micropropagated elm shoots

Elm (Ulmus sp.) shoots from in vitro micropropagated plants were tested with Ophiostoma ulmi culture filtrates, at different dilutions to determine the susceptibility of different host clones to Dutch elm disease (DED). ‘Commelin’, a susceptible Dutch hybrid, showed a high wilting index but that of American elm was higher. Although U. pumila × japonica (Sapporo gold 2) was the most tolerant to spore inoculation, its wilting index was as high as that of ‘Commelin’. The absorption capacity and wilting index of the elm shoots showed consistent correlation to isolate effectiveness (as determined by inoculation experiments), to production of toxin (cerato-ulmin) and to filtrate dilution. This method could be used to assess the effectiveness of the different O. ulmi isolates and for the detection of elm genotypes that are highly susceptible to Dutch elm disease.     

浑善达克沙地不同密度榆树种群空间格局

采用点格局分析方法对浑善达克沙地南缘不同密度下天然榆树种群的空间分布格局进行了研究,研究结果表明:1)榆树的生长指标随密度的增加有减小的趋势,当密度大于27株/hm2时天然榆树的各项生长指标趋于稳定;2)浑善达克沙地天然榆树种群空间分布格局在低密度下和中密度下随尺度的变化不大,在所有尺度下主要趋于集群分布,个别样方(样...     

Variation in phenology and height increment of northern Ulmus glabra populations: Implications for conservation

Abstract

Variation in budburst, height increment and growth cessation within and among five Norwegian Ulmus glabra (Huds.) populations was recorded in an experimental trial during the fourth and fifth growing seasons. Budburst occurred first in inland populations and last in coastal populations, and latitude of origin was less important for timing of budburst than distance from the coast. Height increment and date of growth cessation were correlated to latitude, height increment decreased with increasing latitude of origin, whereas growth cessation occurred first in northern populations and later with increasing southern origin. Thus, the phenological traits vary in accordance with the climate from where the populations have been derived. There was a general large within-population variation in phenological traits. The results are discussed in relation to conservation of adaptive trait variation of the species.     

白榆种源的地理变异和基因型稳定性

本文报道了在14个试验点所作46个种源的地理变异和生态稳定性研究结果。发现我国白榆种源间存在着极大的异质性。生长力随纬度方向呈渐变模式,分布区南部黄淮流域的种源生长快,分布区北部各种源生长慢。试验点生境的优劣,对白榆生长影响很大,并存在有一定的种源×地点的交互作用。因此,根据多点的综合分析,提出了各种源的生产力和生态稳定性参数,为各造林地区选用适宜种源提供了依据。     

观赏榆雄孔雀树栖蹲坐造型技艺

挑选2 点高位嫁接金叶垂榆成活1 个接穗的种苗,将白榆和金叶垂榆联合养育成上耸下垂的双色树冠,得到观赏榆作为毛胚树,着眼于成年雄性蓝孔雀整体面貌,抓住蹲坐在树上休息的典型动作,依附孔雀上身金属模具,由中部至上、下两端进行立体加工,采用修剪绑扎技术制作造型,利用绿色叶的白榆创造雄孔雀玲珑的上身,利用金叶垂榆创造雄孔雀硕大的下体,培育出观赏榆雄孔雀树栖蹲坐造型,配植于自然式园林的重要空间,仿佛蓝孔雀入驻植物园。     

Changes in root growth and relationships between plant organs and root hydraulic traits in American elm (Ulmus americana L.) and red oak (Quercus rubra L.) seedlings due to elevated CO2 level

The relationships between plant organs and root hydrological traits are not well known and the question arises whether elevated CO2 changes these relationships. This study attempted to answer this question. A pseudo-replicated experiment was conducted with two times 24 American elm (Ulmus americana L.) and 23 and 24 red oak (Quercus rubra L.) seedlings growing in ambient CO2 (around 360 μmol·L–1) and 540 ± 7.95 μmol·L–1 CO₂ in a greenhouse. After 71 days of treatment for American elm and 77 days for red oak, 14 American elm and 12 red oak seedlings from each of the two CO2 levels were randomly selected in order to examine the flow rate of root xylem sap, root hydraulic conductance, total root hydraulic conductivity, fine root and coarse root hydraulic conductivity. All seedlings were harvested to investigate total plant biomass, stem biomass and leaf biomass, leaf area, height, basal diameter, total root biomass, coarse root biomass and fine root biomass. The following conclusions are reached: 1) plant organs respond to the elevated CO2 level earlier than hydraulic traits of roots and may gradually lead to changes in hydraulic traits; 2) plant organs have different relationships with hydraulic traits of roots and elevated CO2 changes these relationships; the changes may be of importance for plants as means to acclimatize to changing environments; 3) biomass of coarse roots increased rather more than that of fine roots; 4) Lorentzian and Caussian models are better in estimating the biomass of seedlings than single-variable models.     

两种不同种源地白榆的组织培养与叶片再生研究

采用河北沧州市和内蒙赤峰市两种不同种源地的白榆茎段作为外殖体进行组织培养,在附加不同浓度激素的培养基上对其进行增殖、叶片再生及生根培养,建立其组织培养及叶片再生体系。结果表明,来自河北沧州市的白榆最适分化培养基是MS培养基+6-BA 0.10㎎/L+IBA0.005㎎/L,最适生根培养基是MS培养基+IBA0.01㎎/L,而来自内蒙赤峰市的白榆最适分化培养基是MS+6-BA 0.10㎎/L+IBA0.025㎎/L,最适生根培养基是MS培养基+IBA0.05㎎/L。两种白榆叶片再生的最适培养基均为MS+TDZ0.005㎎/L+IAA0.005㎎/L.     

榆叶白鹃梅的人工栽培及园林应用

榆叶白鹃梅(Exochorda serratifolia S.Moore)树姿优美,耐旱、耐寒,且较耐修剪,萌蘖性强,较耐瘠薄,野生分布在辽宁、河北省及朝鲜,生长于山坡、河边及灌木丛中,人工栽培种植后,适宜与其他乔木、花灌木及花卉等多种景观植物配置,能取得良好的观赏效果。     

Dutch elm disease in New Zealand: impacts from eradication and management programmes

Ophiostoma novo‐ulmi, the cause of the current pandemic of Dutch elm disease, is considered one of the 20 worst pests to have been introduced to New Zealand. An attempt to eradicate the pathogen came close to success, but was eventually stopped and replaced by management programmes. These programmes are slowing the spread of the pathogen. If left uncontrolled it is likely that New Zealand will lose 90% of its elm trees. Although elms are exotic trees in New Zealand, the loss of such a large number of popular amenity trees is likely to have numerous social, cultural, environmental and economic effects. It is estimated that this disease could cost public and councils over NZD $350 million in tree removal and replacement costs. Control of O. novo‐ulmi is limited, but biological control using d‐factor viruses has been proposed. Although O. novo‐ulmi was not eradicated from New Zealand, the eradication programme had many successes; in particular, the effective interaction of good management and science in the early years of the campaign. Also highlighted in this review are several tactics and steps that could be applied to eradication attempts for other species.