4个品种新西兰麻的抗旱生理研究及评价

为了研究新西兰麻的抗旱特性,以日落、红剑、山亚麻和青铜4个新西兰麻品种为试验材料,采用盆栽试验的方法,设置正常供水组和干旱胁迫组,研究持续2个月,测定相关生理指标。结果表明:新西兰麻不同品种在干旱环境下其生理响应和抗旱能力均存在差异。各新西兰麻品种在干旱胁迫下,叶片相对含水量和叶绿素含量降低,丙二醛含量、脯氨酸含量、可溶性糖含量、可溶性蛋白含量、超氧化物歧化酶活性、过氧化物酶活性和过氧化氢酶活性均有一定程度的上升。采用隶属函数比较表明,4个品种新西兰麻的抗旱能力大小从高到低依次为:山亚麻、日落、红剑、青铜。     

欧李分株繁殖技术研究初报

2014年在辽宁省朝阳市喀左县开展了欧李分蘖苗移栽试验,结果表明:沙培催根再转土培处理的欧李分蘖苗成活效果较好,较直接土培栽植的分蘖苗成活率高出20多个百分点;欧李分蘖苗移栽套塑料袋有增加地温和保湿的效果,可以提高其成活率;带土坨移栽欧李分蘖苗效果较优,比裸根移栽成活率高出30个百分点。该试验结果可为该地区欧李分蘖苗移栽、繁殖优质种质资源以及大规模生产提供参考依据。     

料慈竹百日苗生长发育规律的研究

通过对料慈竹百日苗生长发育规律的研究结果表明:(1)百日苗木高生长可用方程Y=-18.24 1.07t 0.01t2 5.4×10-0.5t3来拟合,呈相关性显著;(2)百日苗的地径不随高生长增高而增粗,而是生长到一定时期不再生长;(3)当幼苗高生长基本结束后,侧芽开始从秆基萌发,长出分蘖苗,分蘖苗逐次加粗;(4)百日苗主根的生长较强,一级、二级侧根生长较少,此时不宜进行造林。     

长白落叶松稀土浸种育苗效应的研究

采用4种质量浓度稀土溶液、2种浸种时间处理长白落叶松种子并播种育苗,结果显示:不同质量浓度的稀土溶液和不同的浸种时间对长白落叶松1 a生播种苗的苗高生长量、地径生长量、主根生长量、侧根数量、成苗率均有显著促进作用,以50 mg·L~(-1)的质量浓度浸种处理4 h的效果最好;使用该质量浓度处理后,苗高生长量较对照高出7.7%,地径生长量较对照高出24.1%,主根生长量较对照高出9.5%,侧根数量较对照高出43.0%,成苗率较对照高出28%。     

曼地亚红豆杉在昆明地区的引种成效及其扦插繁育技术研究

从2002年起对四川引进的曼地亚红豆杉进行了5年的引种试验,结果表明:曼地亚红豆杉(扦插苗)在云南昆明地区比云南红豆杉(扦插苗)具有良好的适应性、生长势和较高的紫杉醇含量。4年生植株平均高度为143 cm,单株生物量平均重1 122 g,紫杉醇含量达0.022%。因此昆明地区引种曼地亚红豆杉是可行的,并有一定的发展潜力。     

明溪县高紫杉醇红豆杉引种策略研究

紫杉醇是十分畅销的抗癌药物,采用红豆杉进行生物提取是生产紫杉醇的唯一商业途径。鉴于不同品种的红豆杉不同部位中紫杉醇含量差异明显,从可持续发展的角度考虑,确定选择枝叶中紫杉醇含量较高的云南红豆杉作为品种引进的方向。云南红豆杉主要分布在滇西的9个县市。这9个县的资源量分别占该云南红豆杉野外分布面积的77%,蓄积量的82%及株数的83%。9个产地中,腾冲居群的云南红豆杉紫杉醇含量最高,达0.025 8%,较丽江(纳西)居群的云南红豆杉高出了近20%,且腾冲的气候特征与引种目的地福建省三明市明溪县最为接近,因而选择腾冲地区作为云南红豆杉种质资源调查、收集的重点,有利于高紫杉醇红豆杉品种的选育和在明溪县的产业化发展。     

胭脂虫与寄主仙人掌的关系

对采自10个地方的仙人掌进行胭脂虫放虫试验,并对仙人掌进行解剖及营养成分分析,结合胭脂虫的生长情况对胭脂虫与仙人掌种类、内部构造及营养成分的关系进行研究,结果表明,胭脂虫在梨果仙人掌、朱耳掌及缩刺仙人掌上均能寄生,但以梨果仙人掌最好;从秘鲁引进的梨果仙人掌及云南禄丰的梨果仙人掌上胭脂虫生长较好;少刺型的梨果仙人掌上胭脂虫生长比多刺型梨果仙人掌好;仙人掌的表皮越厚,胭脂虫的生长越差,而胭脂虫的寄生能刺激仙人掌维管束的发育;仙人掌中蛋白质、水分含量对胭脂虫的生长具有显著影响。     

西藏林芝八一地区人参育苗技术研究

近10年来,人参种植面积不断扩大,不少省、市也在积极引种。西藏从1978年试栽,因多种原因中断至1988年又重新开始,试种所需参苗均从吉林、云南引进。由于长途运输不仅成本高且保苗率、成活率很低,经济损失严重。1988年从云南引进的3年生人参苗,存苗率为50％,1990年春引进的吉林参苗存苗率只有30％。由此可见,在西藏高原上推广扩大人参     

4组形态相似川茶花品种的分子鉴别

采用ISSR分子标记,对重庆南山植物园中花色、花型十分相似的4组10个川茶花品种进行分子鉴别。从23条引物中筛选出5条谱带清晰、重复性好的引物用于PCR扩增,共获得72条谱带,其中64条谱带呈现多态性,多态位点百分率为88.89%。利用5条引物所建立的DNA指纹图谱显示,第Ⅰ组的氅盔和吊金钟是2个独立的品种;第Ⅱ组的胭脂莲、胭脂鳞和鱼鳞甲是3个独立的品种;第Ⅲ组的泸州大红和泸州二红也是2个不同的品种;第Ⅳ组的红佛鼎与紫金冠、似紫冠可以区分,但后两者难以区分,很可能就是同一个品种。     

半枫荷播种育苗试验

采用容器(10cm×10cm营养钵)和田间苗床2种播种育苗方式,进行了半枫荷不同产地种源生长效果比较试验,结果表明:田间苗床播种苗的生长量较大,平均苗高、平均地径、平均主根长度、≥5cmⅠ级侧根平均条数分别比容器(营养钵)播种苗高出43.0%、58.5%、34.4%、47.8%;福建宁化县种源的苗木生长量较大,平均苗高、平均地径、平均主根长度、≥5cmⅠ级侧根平均条数分别比江西大余种源高出95.5%、19.3%、52.5%、50.0%、4.5%。     

Browsing Damage on Pine (Pinus sylvestris and P. contorta) by a migrating moose (Alces alces) Population in Winter: Relation to Habitat Composition and Road Barriers

In Scandinavia, moose (Alces alces L.) sometimes cause severe browsing damage to economically-important pine. Moose-vehicle accidents have spurred construction of fences along roads, and these may interfere with moose migration between summer and winter ranges, or the road alone may be a barrier. If this happens and moose build up along roads, landowners may suffer economically. Therefore, this study investigated whether roads, fences or other factors influence the use of young pine stands by moose. Eighty stands along roads in northern Sweden were evaluated in which individually-browsed branches were counted on 9972 pines. Moose browsing was not significantly related to birch (Betula pendula Roth, B. pubescens Ehrh.) density, nor did it differ between pines (Pinus contorta Douglas or P. sylvestris L.). However, increased pine density, site productivity and proximity to a highway were associated with increased browsing. Further large-scale studies are needed to understand moose habitat selection and the effects of roads.     

Effects of Root Freezing on the Physiology and Growth of Picea glauca,Picea mariana and Pinus banksiana Seedlings Under Different Soil Moisture Regimes

The root systems of 2-yr-old Picea glauca, Picea mariana and Pinus banksiana seedlings were submitted to various frost temperatures during an artificial frost to induce different levels of root damage. Frost-damaged and control seedlings were placed in a greenhouse under high and low soil moisture regimes. Seedling growth and physiology were evaluated periodically. Seedling survival was reduced when root damage reached levels of 60-80%. Root systems of all three species showed partial to total recovery by the end of the experiment. In general, root freezing damage caused reductions in seedling growth, with these reductions becoming less significant over time. Root damage had little to no effect on black spruce and jack pine seedling physiology, while white spruce CO 2 uptake decreased with increasing root damage. Shoot nitrogen content of all three species decreased slightly with increasing root damage.     

Decomposition and nutrient loss from prunings of different contour hedgerow species in tea plantations in the sloping highlands of Sri Lanka

Contour hedgerows of multipurpose tree species in the sloping tea lands of Sri Lanka are expected to reduce soil erosion and also add significant amounts of plant nutrients to the soil via periodic prunings. The objective of this experiment was to characterize the biomass decomposition pattern and quantify the amount of nutrients added through prunings of six tree species (Calliandra calothyrsus, Senna spectabilis, Euphatorium innulifolium, Flemingia congesta, Gliricidia sepium and Tithonia diversifolia) currently being used in hedgerows associated with tea. Withered leaf and stem prunings (50 g) were enclosed in 2-mm litter bags, placed at 5-cm depth and retrieved after one, three, six, nine and 12 weeks. Loss of initial dry weight, N, P and K was measured. Single exponential decay function adequately described both dry weight and nutrient loss. Tree species differed significantly in their rate of breakdown with decomposition constants (k) varying from 0.0299 to 0.2006 week⁻¹ for leaves and from 0.0225 to 0.0633 week⁻¹ for stems. Gliricidia showed the highest k for leaves with the rest in the following descending order: Senna > Tithonia ≥ Euphatorium > Calliandra > Flemingia. A similar pattern was observed for loss of all nutrients with Calliandra and Flemingia always having lower k values than the rest. Although N immobilization was not observed, immobilization of P and K was observed during the first week of incubation in some species, particularly in stem prunings. Annual biomass of prunings differed significantly between tree species in the following descending order: Calliandra > Senna > Flemingia > Tithonia > Gliricidia > Euphatorium. Calliandra added the greatest amount of nutrients annually to the soil with Euphatorium adding the least. Calliandra prunings provided the annual total K requirement and 49% of the N requirement of mature tea. However, none of the species provided more than 5% of the P requirement. It is concluded that among the tree species tested, Calliandra and Flemingia are the most suitable for contour hedgerows in tea plantations of this agroclimatic region because of their higher soil nutrient enrichment capacity and slower decomposition rates which would minimize leaching losses. This revised version was published online in June 2006 with corrections to the Cover Date.     

Effects of Seed Weight and Seed Type on Early Seedling Growth of Pinus sylvestris under Harsh and Optimal Conditions

The effects of seed weight and seed type on seedling growth of Pinus sylvestris (L.) were studied by seeding individually weighed orchard and stand seed in different mixtures under harsh (direct seeding in field) and optimal (seeding in nursery) conditions. In the nursery experiment an increase in the seed weight from 3 to 7 mg increased the seedling height by 10-27% and total weight by 27-113%, and decreased the height/diameter ratio by 5-6% after 2 yrs. With elimination of seed weight effects, orchard seedlings were 2% taller than stand seedlings in year 2. Without elimination of seed weight effects, orchard seedlings were 7-13% taller. In the field experiment an increase in the seed weight from 3 to 7 mg increased seedling height by 18-65%, stem volume by 81-274% and the number of top-buds by 23-34% in year 5. After elimination of seed weight effects, orchard seedlings were 7-13% taller than stand seedlings and without elimination of seed weight effects 20-21% taller after 5 yrs. Even after elimination of both seed weight and genetic effects orchard seedlings were 3-9% larger than stand seedlings in the field experiment. In conclusion, the influence of seed weight and seed type on growth traits and slenderness is highly significant and the influence seems to be greater in harsh conditions.     

Stand Structure in Pine,Spruce and Deciduous Forests: A Comparison Between Finnish and Russian Karelia

This study investigated the stand structure in pine, spruce and deciduous forests in the border district of Finland and Russia. A total of 46 mature forest stands was selected as pairs, the members of each pair being as similar as possible with respect to their forest site type, age, moisture and topography. The stands were then compared between the two countries by means of basal areas and number of stems. The proportions of dominating tree species were 2-12% lower, and correspondingly the proportions of secondary tree species higher, in Russian forests. The density of the forest stock was also higher in each forest type in Russia. The forests in the two countries differed most radically in terms of the abundance of dead trees. The amount was two to four times higher in Russian deciduous and spruce forests, and in pine forests the difference was 10-fold. The stand structures indicated that Russian coniferous stands, in particular, were more heterogeneous than intensively managed pine and spruce stands in Finland.     

Growth and Terminal Bud Formation in Picea abies Seedlings Grown with Alternating Diurnal Temperature and Different Light Qualities

The root collar diameter and the height:diameter ratio are of particular importance in container-grown seedlings where a high density in the containers may produce spindly seedlings. Temperature regimes and light quality are known to affect plant growth. The aim of this study was to identify responses in Picea abies (L.) Karst. seedlings grown with light providing different red:far-red ratios and under temperature regimes with alternating day (DT) and night temperature (NT) from negative (DT < NT) to positive (DT > NT) difference (DIF) between DT and NT. Experiments were conducted in controlled environment chambers and in a daylight phytotron. Only limited thermoperiodic responses appeared in P . abies seedlings with respect to seedling height and dry weight accumulation. The formation of terminal buds, however, was clearly delayed in seedlings grown at negative DIF. The results indicate a requirement for day extension light that is high in far-red, to prevent terminal bud formation under natural short-day conditions. An extended study should be conducted to clarify the minimum level of light intensity and the optimal light quality needed to prevent terminal bud formation under natural short-day conditions.     

CAD与建筑设计的关系

本文分析了CAD在设计中引起的正面和负面影响,并进行了系统的阐述,从而使设计者在应用中能够保持客观的态度。     

Growth of Phlebiopsis gigantea in wood of seven conifer species

Heterobasidion parviporum and Heterobasidion annosum are widely distributed root‐rot fungi that infect conifers throughout Europe. Infection of conifer stumps by spores of these pathogens can be controlled by treating fresh stumps with a competing non‐pathogenic fungus, Phlebiopsis gigantea. In this study, growth of three Latvian strains of P. gigantea and the biological control agent ‘Rotstop’ strain was evaluated in stem pieces of Norway spruce, Scots pine, lodgepole pine, Douglas‐fir, Weymouth pine, Siberian larch and Sitka spruce. The growth rates of one H. parviporum and one H. annosum isolate were also measured in the same stem pieces. The growth rate of P. gigantea varied greatly in wood of different conifer species. It was higher in the three pine species, lower in Norway spruce and lowest in Sitka spruce and Siberian larch, and in Douglas‐fir, this fungus did not grow. The largest area of wood occupied by P. gigantea was in lodgepole pine. Growth of Latvian isolates of P. gigantea in the wood of Pinus and Picea species was comparable to that of the Rotstop isolate. Consequently, stump treatment with local P. gigantea isolates should be recommended. However, our results suggest that Douglas‐fir stump treatment against Heterobasidion by P. gigantea may be ineffective and other stump treatment methods should be considered.     

Potential to harness superior nutritional qualities of exotic baobabs if local adaptation can be conferred through grafting

Baobab leaves form an important part of the local diet in Sahel countries and elsewhere in Africa. Existing leaf nutritional data and agroforestry performance information are based solely on Adansonia digitata L., the baobab of continental Africa. The introduction potential of Adansonia species from the center of diversity in Madagascar and from Australia remains untapped. To assess this potential, the mineral contents and B₁ and B₂ vitamin levels of dried baobab leaves were determined for five-year old trees of A. digitata, A. gibbosa (A. Cunn.) Guymer ex D. Baum, A. rubrostipa Jum. & H. Perrier (syn. A. fony Baill.), A. perrieri Capuron and A. za Baill. grown in an introduction trial in Mali. Nutritional data were evaluated against survival and vigor to identify promising germplasm. Leaf vitamin and crude protein contents were highest in the Madagascar species, especially A. rubrostipa (B₁ 88 mg 100 g⁻¹, B₂ 187 mg 100 g⁻¹, protein 20.7% dry weight). However, the local species far outperformed the introductions in survival, tree height, basal diameter and resistance to termites. We suggest grafting as a way of harnessing the vigor of well-adapted local baobab varieties to the superior nutritional profiles of A. rubrostipa and others. Cross-species grafting tests in Adansonia were successful, thus creating new agroforestry possibilities with different scion/rootstock combinations.     

Modelling of adequate pretwist for obtaining straight timber

Abstract

Wood in general and wooden studs in particular are often distorted owing to uneven shrinkage during the drying process in the sawmill. Twist is often the most detrimental of all types of distortion, and it is caused by spiral grain in combination with variations in moisture content. For sawmills, the objective is to produce dried, straight boards, and one method of dealing with boards with excessive spiral grain is to sort them out and then dry them in a pretwisted position to obtain straight boards after drying. A model using the finite element (FE) method for the simulation of drying twist distortions was first calibrated against laboratory experiments in which boards were dried with and without restraints and pretwists. After the calibration, the FE results were compared with industrial test results for boards that were dried without restraints or with restraints with zero pretwist, i.e. straight restraints. The FE model used an elastic–ideally plastic material model to obtain permanent deformations. The calibration was to set the yield stresses so that there was a good match between FE results and results from the laboratory experiments. The comparison between the industrial test results and the FE results showed that the FE model is capable of realistic simulations of drying boards with and without restraints and presumably also pretwists.