甜柿品种与栽培技术

<正> 柿(Diospyros kaki Linn.)的品种很多。依其果实成熟时在树上能否自行脱涩,可分为涩柿与甜柿两大类:果实成熟时在树上不能自行脱涩,需摘下后经人工脱涩方可食者称为涩柿;反之,果实成熟时在树上已经脱涩,摘下来食之脆甜者称为甜柿。我国原产的甜柿品种极少,而日本除涩柿外,甜柿品种亦多。由于甜柿无需进行人工脱涩,且果实保持硬度的时间比脱涩后的涩柿长2～3倍(一般可达30天以上),因而延长了果实贮运和经销时间,     

日本科柿果实发育期间单宁和糖类的变化

甜柿是柿(Diospyros kaki Linn.f.)树的自然类型,属日本主要栽培果树之一,其特点是果实采后不需人工脱涩即可食用,甜脆爽口,风味独特。近年来,日本甜柿已在我国大量引种栽培,国内对甜柿的生物学习性和栽培方法已作了不少观察和研究。但对甜柿果实的生长发育过程及果实发育期间生化物质消长规律的研究尚未见报道。作为柿果主要成份     

柿果的脱涩处理

<正> 1 柿子的涩昧 柿果有甜柿和涩柿两种类型。甜柿如湖北罗田甜柿、日本富有柿等在树上成熟后即可鲜食(单宁已转化为不溶性单宁),而涩柿如磨盘柿、大晶柿、镜面柿等难以在树上脱涩,虽然果实在树上已成熟了,仍具有强烈的收敛性涩味,不堪入口,必须进行人工催熟脱涩后才能食用。     

园林绿化与经济林兼用的好树种——柿树

<正>柿隶属于柿树科（Ebenacene）柿属（Diospyros　L.）植物。本属植物全世界约有250种,大多数为热带和亚热带植物,少数产于暖温带。原产于我国的柿属植物有49种。我国柿树品种较多,据统计,品种可达800个左右。柿从涩味上分为甜柿类和涩柿类;甜柿类果在树上自然脱涩,采收后即可食用;涩柿采收后有涩味,需人工脱涩后方可食用,我国所产的品种多属涩柿类。柿树适应性强,抗病性强,产量高,寿命长,不论是在平地。山地,还     

甜柿品种的引种栽培

甜柿，属于果实着色后无需脱涩，就可食用的柿类。果实供应期长，较耐贮藏与耐运输等。我所试图通过对甜柿的引种和栽培示范，筛选出适宜于黄山市栽培的甜柿品种，同时为活跃山区经济寻找优势项目。     

日本甜柿的促花保果技术

1990年我们山东省果科所引入日本甜柿富有、次郎进行试栽。由于甜柿具有果肉致密、硬脆、甜味浓、果实着色后不经加工脱涩即可食用等特点 ,而倍受市场和果农欢迎。但在栽培过程中我们观察到 ,日本甜柿同我国传统的栽培涩柿品种相比 ,存在着成花难、花粉量少、座果率低、落花落果严重等问题。为此 ,我们于近几年进行了日本甜柿的促花促果试验 ,取得了较好的效果。其主要技术是 :1　合理配置授粉树 ,实行人工辅助授粉富有、次郎两个品种 ,是日本甜柿中表现最好的品种 ,但这两个品种全株均无雄花 ,且单性结实能力不高 ,故此在生产中应严格配置…     

脆柿研制及其软化衰老机理的研究

柿子为我国盛产水果之一,其所含碘量为40.7 mg/100 g,处各水果之前列,加之水份、可溶性糖、Vc含量均较高,因此为补碘之优质水果.我国柿子有甜柿和涩柿两大类,其中涩柿种类多,分布广,贮量大;但存在一个采后脱涩问题.目前,柿果脱涩方法可分为两大类,一类果实脱涩后果胶分解成软柿;另一类果实脱涩后果胶保持为硬柿,硬柿较软柿果胶含量高.同时,更耐贮运,在柿子贮存保鲜中占重要地位.     

柿自然脱涩能力与单宁细胞发育规律的研究

研究了三种不同甘、涩类型柿果实中可溶性单宁含量，单宁细胞和薄壁细胞发育规律，结果表明，完全甜柿和不完全甜柿的主要脱涩期明显不同，前者在果实发育的早期，后者在近熟期；完全甜柿自然脱涩主要是由于薄壁细胞的持续增大和单宁铁早期停止发育，造成单宁细胞占果肉面积比下降所致，而不完全甜柿的树上脱涩主要依赖果实成熟前单宁的凝固作用。     

浅谈柿树栽培技术

柿树属于柿科、柿属,它适应性强,生长快、结果早,丰产稳产,管理容易,经济寿命长。柿树树姿优美,叶大浓绿,富有光泽,入秋叶色转红,可与枫叶比美。柿果金黄光亮、鲜丽悦目,色泽艳美,汁多味甘甜,营养丰富,不仅可供鲜食,并可加工成柿饼、柿蜜、柿霜等。颇具观赏价值和经济价值。深收广大群众喜爱,因此柿树适于建园、庭院载培以及园林绿化等。1建园1.1品种选择按果实在树上软熟前是否完成脱涩而把柿树分为甜柿和涩柿两大类,适宜本地栽培的柿树品种有:1.1.1甜柿:能在树上软熟前完成脱涩,采后即可食用的品种,主要有日本富有柿、次郎柿以及湖北罗田柿子。1.1.2涩柿:在树上软熟前不能完成脱涩,采后须经人工脱涩或后熟作用方可食用,主要品种有:磨盘柿(盒柿)、牛心柿(小萼柿)、镜面柿、火柿等。1.2苗木繁殖及嫁接由于柿树大多品种是单性结实,不产生种子。为了保持品种特性,多采用嫁接的方法进行繁殖。我地多采用君迁子(园枣子)作砧木。砧木繁育主要用播种法,嫁接是用芽接、枝接均可。需要注意的是柿树的嫁接要求比其它果树品种严格。这是因为砧木和柿树内均含有鞣酸物质(单宁),切面的蛋白质遇到空气极易氧化。形成一层隔离膜影响成活率。因此,在嫁接时要注意...     

关于将"罗田甜柿"更名为"中国甜柿"的建议

1　“罗田甜柿”名称的由来柿树 (ＤｉｏｓｐｙｒｏｓｋａｋｉＬ .ｆ.)属柿树科柿属 ,是我国重要的经济林树种 ,依果实能否在树上自然脱涩分为涩柿和甜柿 ,在我国仅有鄂、豫、皖三省交界处大别山一带分布有甜柿 ,一直通称为“罗田甜柿”。关于“罗田甜柿”名称的由来 ,说法比较统一 ,湖北省农科院果茶所张力田教授 2 0 0 1年 1 2月 2 5日在武昌召开的湖北省林木良种审定委员会经济林品种审定会上回忆 :1 95 7年一日本农业代表团到中国农业部农科院兴城果树试验站考察 ,问时任站长的蒲福慎中国是否分布有甜柿 ,在 1 95 8年召开全国果树会议上…     

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.     

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.     

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。     

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.