板栗花粉直感效应在坚果内在品质上的表现

为给板栗优良品种选育提供参考,以北方板栗品种"燕龙"、"燕山红栗"为父本,云南板栗品种"云富"、"云良"、"永丰1号"为母本进行授粉试验,探讨板栗花粉直感效应在板栗内在品质的表现。结果表明,可溶性总糖含量呈现出明显的花粉直感效应;在支链淀粉的含量上,由于供试北方板栗品种与云南板栗品种没有明显的区别,各授粉组合在支链淀粉含量上没有呈现明显的规律性。含水率在同一种授粉组合中不同年份含量的不同与成熟度和气候条件有关;以"永丰1号"、"云良"和"云富"为母本,以北方板栗品种"燕山红栗"、"燕龙"为父本的授粉组合,其果实可溶性总糖含量均在20%以上,支链淀粉含量在40%以上和直链淀粉在10%以上。     

板栗花粉管生长特性

为确定最佳授粉时期,解决板栗空苞率高的问题,对‘早板栗’和‘早大栗’2个板栗品种进行套袋隔离和人工辅助授粉试验。结果表明:早板栗,早大栗2个品种从花粉萌发至花粉管生长到达胚珠均需要1个月左右;早大栗胚珠5月初开始发育,经过1个月的发育在5月底可形成成熟的八核胚囊,早板栗整个雌配子体发育过程比早大栗晚4~7 d;早大栗5月4日~5月14日之间柱头接受花粉的能力均较强,早板栗5月9日~5月14日前后有接受花粉的能力。结合花粉管生长速度、有效授粉时期和雌配子体发育情况确定品种早大栗的最佳授粉时期应在5月4日~5月14日,品种早板栗的最佳授粉时期应在5月9日~5月14日。     

中国栗属植物花粉萌发特性研究

为探讨栗属植物花粉种质资源保存和利用方式,以中国栗属植物4个种的花粉为材料,采用室内培养方法,研究了不同花粉萌发率的变化规律。结果表明:4种栗属植物花粉形状基本一致,均为长椭圆形,经P×E测算,花粉粒大小依次为板栗、茅栗、锥栗、日本栗。4种花粉萌发对培养基糖类的种类及其浓度具有选择性,萌发率均以5%糖类浓度最高,并随糖类浓度的增大而显著降低;经5%浓度糖类处理后,板栗、日本栗和锥栗花粉在砂糖培养基上萌发率最高,而茅栗在蔗糖培养基上萌发率最高。在30～36℃下,4种花粉均保持较高萌发率,其中板栗、茅栗和锥栗的萌发率在33℃时达到最高,而日本栗在30℃时达到最高。栗属花粉萌发需要较长时间,培养至36 h各花粉萌发率均达到最大值,其中24 h内4种花粉萌发率迅速增加,超过24 h后萌发率变化不大,萌发数量明显减少。4种花粉经12 h自然干燥后萌发率达到最高,干燥24 h其花粉萌发率仍然保持在67%以上,超过24 h后快速下降,因此干燥时间不宜超过24 h。栗属4种花粉萌发集体效应明显,其萌发率均随花粉密度增大而快速提高,当花粉密度达到550粒/视野时,各种花粉萌发率均达最大值,其中日本栗最高,达79.5%。4种花粉在-20℃的贮藏环境里其萌发率明显高于-70℃和0℃低温,经30 d贮藏后萌发率均保持69%以上,其中板栗最高,达78.6%,其次为茅栗、日本栗和锥栗。     

早实核桃开花授粉特性研究

为了给核桃花粉的保存、人工授粉及授粉树的配置提供理论依据,测定了绿岭、辽宁1号、鲁果1号、绿早、中林1号、上宋6号等6个早实核桃品种花粉的形状、大小、生活力,并对绿岭核桃进行了授粉试验和授粉适期试验。结果表明:早实核桃花粉粒形状为近圆形至圆形,圆形花粉约占20.41%;花粉粒的平均直径为39.60μm,品种间、品种内均存在一定的差异,其中花粉粒平均直径最大的品种是辽宁1号,为43.32μm,最小的品种是中林1号,为36.67μm;6个品种的花粉均有较强的生活力,在-20℃冷冻条件下保存至第180天时花粉活力仍在20%以上,在常温条件下花粉仅能保存8d左右;在柱头呈倒"八"字形时授粉,坐果率为29.82%,显著高于柱头反卷时的21.39%。     

云雄板栗新品种栽培研究

云雄是云南省林业科学院经济林研究所历时20多年选育出的板栗新品种,通过优株选择、无性系评比试验、物候观测、授粉试验、花粉生活力测定、区域化栽培试验、产量和品质测定等多年的栽培研究.结果表明,该品种坚果大、品质优、产量高.用其授粉,平均成实率高达87.4％,且对主栽品种坚果增重明显,增重幅度为4.9％～26.3％.用云雄花粉人工辅助授粉,较自然授粉平均每公顷增产396.5 kg,增产率18.5％;坚果平均增重1.43 g,增长率16.4％.因此,在板栗栽培中,选用云雄作为授粉品种,对提高产量和品质具有重要作用.     

昭阳区坡地板栗早实丰产技术研究

以云南省林业科学院引进的云栗15、云栗22、云栗44及昭通大板栗等优良品种为试验材料,采用随机区组设计进行板栗早实丰产试验。探讨了板栗园的整地和建植方式、授粉树种的合理配置、整形修剪、适时摘心等种植技术措施以及优良种与合理密植对早实丰产的影响。进一步阐述适时适当合理施肥、林地水肥管理、管抚、林农间种、环割和倒贴皮以及病虫害防治等板栗田间管理措施。     

云雄板栗新品种栽培研究

云雄是云南省林业科学院经济林研究所历时20多年选育出的板栗新品种,通过优株选择、无性系评比试验、物候观测、授粉试验、花粉生活力测定、区域化栽培试验、产量和品质测定等多年的栽培研究。结果表明,该品种坚果大、品质优、产量高。用其授粉,平均成实率高达87.4%,且对主栽品种坚果增重明显,增重幅度为4.9%～26.3%。用云雄花粉人工辅助授粉,较自然授粉平均每公顷增产396.5 kg,增产率18.5%;坚果平均增重1.43 g,增长率16.4%。因此,在板栗栽培中,选用云雄作为授粉品种,对提高产量和品质具有重要作用。     

白龙江干热河谷地带油橄榄花期物候及花性特征研究

试验观察油橄榄7个品种花朵的物候期,研究油橄榄2个不同品种完全花与雄花的花粉粒的大小及形态、花粉生活力的变化及花粉畸形率。结果显示:(1)在油橄榄7个品种中,"莱星"花期时间最长达20天,"皮削利"花期最短仅为16天;(2)油橄榄花粉粒形态相近均为长球形,但大小略有差异,赤道面为近椭圆形,具3个萌发沟,外壁纹饰清晰且呈穴网状;(3)"城固32号"和"鄂植8号"2种品种完全花花粉大小为263.16~245.06μm×181.96~173.86μm、雄花花粉大小为267.32~244.09μm×180.41~161.55μm,花粉形状指数(P/E)的变幅范围为1.44~1.52;(4)"城固32号"和"鄂植8号"2种品种的完全花与雄花的花粉畸形率均低于16.00%;(5)在4h内"鄂植8号"完全花的花粉生活力最高可达93.38%,"鄂植8号"雄花的花粉活力较为稳定,4~36h时段花粉生活力为73.94%~62.08%,在36h时段"城固32号"完全花的花粉生活力最低仅为49.84%。     

3个南方枣品种花粉育性与花粉形态的观察

为给南方枣花粉育性的形态鉴定提供科学的依据,就南方枣品种磨盘枣、金丝小枣和冬枣的花粉发芽率进行了试验与观察,研究了其花粉育性与花粉生活力,并对其花粉量和花粉粒分别进行了测定与扫描电镜超微结构观察.结果表明:磨盘枣花粉的育性最高,其花粉颗粒饱满;金丝小枣的花粉育性次之,其花粉较饱满,部分出现畸形;而冬枣花粉育性最低,花粉多凹陷.因此,在我国南方宜用磨盘枣、金丝小枣作为枣树授粉品种,冬枣不宜用作授粉品种.     

不同倍性广东桑的花粉形态

【目的】针对桑树形态倍性鉴定及品种间鉴别问题,研究广东桑不同倍性及品种之间孢粉学上的异同,为桑树多倍体育种提供科学依据。【方法】利用扫描电镜对广东桑10个不同倍性品种花粉的形态、大小、萌发孔、外壁纹饰等孢粉学特性进行观察,并运用图片分析结合数理统计的方法对其花粉形态进行研究。【结果】供试广东桑不同品种的花粉微观形态相近,均为小型花粉,近球形,花粉粒极轴长16.98～24.46μm,赤道轴长15.37～23.86μm,极轴长与赤道轴长的比值为1.01～1.12;供试不同品种花粉粒萌发孔1～3个,圆形,直径为2.11～3.51μm,部分花粉粒萌发孔外壁内陷形成漏斗形,按照额尔特曼 G 的 NPC(萌发器官的数目、位置及特征)分类系统属N3P3C4类型;不同倍性间广东桑花粉的赤道轴长、极轴长和萌发孔大小存在显著性差异(P ＜0.05),均表现为四倍体＞二倍体,但花粉粒的极轴/赤轴比值差异不显著(P＞0.05);广东桑花粉外壁为分布不均的刺状突起－脑条纹复合纹饰,不同品种间花粉的表面纹饰有明显差别,根据外壁纹饰可将供试10个品种花粉分为细刺颗粒状突起－细条纹纹饰、细刺颗粒状突起－粗条纹纹饰、粗刺颗粒状突起－细条纹纹饰和粗刺颗粒状突起－粗条纹纹饰4种类型,花粉外壁纹饰体现了不同品种的遗传多样性和遗传分化;不同倍性间广东桑花粉表面的刺状突起密度及大小差异不显著(P＞0.05);供试四倍体广东桑品种花粉存在少数败育花粉粒,表现为干瘪而不充实,外形异常。【结论】供试广东桑不同倍性及品种间花粉形态特征具有差异,不同倍性间花粉粒和萌发孔大小存在差异,不同品种间花粉的表面纹饰存在明显差别,初步认为花粉的亚显微结构特征可作为广东桑倍性鉴定及品种间鉴别的重要标准之一。     

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.     

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.     

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.     

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.     

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。