福建省蕨类植物区系分析

对福建省蕨类植物的区系组成和地理成分进行了分析,其结果表明:(1)福建省共有蕨类植物46科、107属、396种,优势科为鳞毛蕨科、金星蕨科、水龙骨科、蹄盖蕨科、铁角蕨科和凤尾蕨科等11个科,优势属为鳞毛蕨属、毛蕨属和凤尾蕨属等;(2)从蕨类植物科、属分布区类型所占比例来看,该地区区系性质以热带成分为主;而从种的地理成分来看,则表现为热带成分与东亚成分的综合体,以中国特有种、中国-日本分布、热带亚洲最为丰富,反映了东亚与热带亚洲的蕨类植物区系的统一性及紧密联系;(3)区系起源古老。     

福建牛姆林自然保护区蕨类植物区系分析

在野外调查与资料查阅的基础上,对福建牛姆林自然保护区蕨类植物资源进行区系分析。结果表明:该区约有蕨类植物33科55属92种,主要科为水龙骨科、金星蕨科、乌毛蕨科、凤尾蕨科、卷柏科、蹄盖蕨科等;优势属为凤尾蕨属、卷柏属、线蕨属等;中华里白、金毛狗、福建莲座蕨、乌毛蕨、狗脊蕨等具有热带和亚热带性质的蕨类构成了天然林的主要草本层与林缘。科的分布区类型只有6个,热带分布型有22科,占总科数95.65%(世界分布除外);属的分布区类型有9个,热带分布型有41属,占总属数(世界分布除外)的93.18%,R/T值为13.67;种的地理分布分属7个类型,以热带分布成分(47.19%)、东亚分布成分(33.71%)、中国特有成分(17.98%)突出。在中国蕨类植物区系分区上,牛姆林自然保护区属东亚蕨类植物区,处于华东-华中植物地区与华南植物地区的过渡区域。     

九阜山杀虫抗菌蕨类植物资源调查初报

对福建省尤溪县九阜山省级自然保护区具有杀虫抗菌作用的蕨类植物资源进行调查,结果表明,该区可作为农药使用的野生蕨类植物共有21种,分属12科18属,主要集中在鳞毛蕨科(5种)、紫萁科(2种)、凤尾蕨科(2种)、乌毛蕨科(2种)、金星蕨科(2种),开发利用价值较大的种类有海金沙、紫萁、蕨、狗脊蕨、蜈蚣草、乌毛蕨、阔鳞鳞毛蕨等。介绍了每种杀虫抗菌蕨类植物的生境、主要化学成分、活性部位和作用方式,并提出开发利用建议。     

福建茫荡山自然保护区蕨类植物区系研究

福建茫荡山蕨类植物区系研究结果表明:①该区共有蕨类植物130种(含变种和变型)隶属于35科61属,其中水龙骨科、鳞毛蕨科、凤尾蕨科等少数几个科构成了该区的优势科,凤尾蕨属、卷柏属、鳞毛蕨属、瘤足蕨属等属构成了优势属;②从科、属分布区类型的所占比例来看,该地区区系性质以热带成分占优势;③该地区蕨类植物区系起源古老,有各种原始成分;同时又有一定数量的较进化的和处于两者之间的科、属,表明该地区的蕨类植物在系统发育或进化关系上的连贯性;④该地区的特有现象不明显;⑤福建茫荡山、广东石门台、浙江磐安和江西九连山这四者之间在蕨类植物区系分布上联系比较紧密;⑥发现12种蕨类植物在该区的新分布。     

云南省蕨类植物两个新纪录属——燕尾蕨属和黑心蕨属

在金平分水岭国家级自然保护区第二次综合科学考察期间,采集到蕨类植物双扇蕨科(Dipteridaceae)物种全缘燕尾蕨Cheiropleuria integrifolia(D. C. Eaton ex Hook.) M. Kato和凤尾蕨科(Pteridaceae)物种黑心蕨Doryopteris concolor(Langsd.&Fisch.) Kuhn。文献考证表明,两个物种所在的燕尾蕨属(Cheiropleuria C. Presl)和黑心蕨属(Doryopteris J. Sm.)均为云南省新纪录属。凭证标本存放于中国科学院昆明植物研究所标本馆(KUN)。     

广西花坪国家级自然保护区蕨类植物资源

广西花坪国家级自然保护区有蕨类植物44科88属207种,科、属、种分别占广西蕨类植物总数的75%、53%和21%。优势科为鳞毛蕨科、水龙骨科、蹄盖蕨科、金星蕨科,优势属为鳞毛蕨属、凤尾蕨属、卷柏属、铁角蕨属。蕨类植物资源丰富,主要分为药用、观赏和食用三大类。     

福建福罗山自然保护区蕨类植物区系研究

通过野外调查和资料整理,分析福建福罗山保护区蕨类植物的区系,为福罗山自然保护区的建立提供基础数据。福罗山有蕨类植物34科、61属、118种。主要科为水龙骨科、鳞毛蕨科、金星蕨科、凤尾蕨科,主要属为凤尾蕨属、铁角蕨属、鳞毛蕨属。科、属分布类型均以泛热带为主,种的分布类型以东亚分布和热带亚洲分布为主,表明福罗山蕨类植物区系具有明显的亚热带特征,并有向暖温带过渡的趋势。通过相似性的比较,表明福罗山与茫荡山蕨类植物区系亲缘关系最近,相似性系数为0.83。福罗山已记录有10种中国特有蕨类植物,具有较高的保护价值。     

武夷山自然保护区蕨类植物物种多样性与区系的研究

在野外调查和整理资料的基础上 ,调查分析了武夷山自然保护区蕨类植物的区系组成和分布类型。结果表明 :福建武夷山国家级自然保护区共有蕨类植物 4 0科、92属、2 95种和 9变种 2变型 ;主要科为鳞毛蕨科、水龙骨科、金星蕨科、蹄盖蕨科、铁角蕨科、卷柏科、凤尾蕨科 ,主要属为鳞毛蕨属、铁角蕨属、蹄盖蕨属、卷柏属、复叶耳蕨属、凤尾蕨属、瓦韦属。具有10个分布区类型 ,科的分布类型以泛热带分布及其变型为主 ;属以泛热带分布及其变型为最多 ;种类以东亚分布类型和特有成分为主 ,表现出亚热带的特点。与周边 7个地区蕨类植物区系相似性和丰富度的比较表明 ,与武夷山蕨类植物区系亲缘关系最近的是安徽九华山 ;武夷山的蕨类丰富度比纬度位置高的江西庐山、安徽黄山和浙江天目山大。武夷山拥有 92种中国特有蕨类及一些珍稀蕨类植物 ,有很高的保护价值     

福建圭龙山自然保护区蕨类植物区系地理的研究

福建省圭龙山自然保护区的蕨类植物有174种(包括变种),隶属于36科79属,其中发现福建地理分布新记录种1个,即灰绿耳蕨(Polystichum eximium)。优势科是鳞毛蕨科、金星蕨科、蹄盖蕨科、水龙骨科和凤尾蕨科,5科占总种数的57.5%。优势属是鳞毛蕨属、凤尾蕨属、铁角蕨属、复叶耳蕨属、卷柏属、短肠蕨属和毛蕨属,7属占总种数的36.2%。科的分布以世界分布和热带至亚热带分布为主,属以泛热带分布最多,种的地理分布则以中国—日本分布和中国特有分布为主。种的相似性分析表明:本区系与罗卜岩和三清山的关系密切,而与鸡公山等关系疏远。     

蕨菜的人工培育

蕨菜植物种类繁多，全世界约有10000多种，我国也有2000多种。蕨类植物用途广泛，特别是食用、药用、观赏及绿化方面利用历史悠久。据我国史书记载，可追溯到公元前。可食用的蕨类植物叫做蕨菜，各国人民均有采集其幼叶鲜食、盐渍或制干菜的习惯。我国居民采食的蕨类植物也有10多种，如菜蕨、水蕨、星毛蕨、凤尾蕨、假蹄盖蕨等。除部分自用外，大部分出品日本及东欧各国，每年为国家换回不少外汇。所以迄今蕨类植物仍具有重大开发价值。     

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.     

Growth of Mixed Birch-Coniferous Stands in Relation to Pure Coniferous Stands at Similar Sites in South-eastern Norway

Mean age, mean and top heights and yield were studied in 20 mixed stands of birch ( Betula pubescens Ehrh. and B. pendula Roth) and Picea abies (L.) Karst. and nine mixed stands of birch and Pinus sylvestris L. in south-eastern Norway. Each mixed stand and the adjacent pure coniferous stand (control) were growing under the same site conditions and had not been commercially thinned. There were no significant differences in mean age at breast height or in top heights between birch and conifers in the mixed stands, while mean height was significantly higher for birch than for spruce. A growth index was calculated based on total volume and age at breast height. For the spruce sites the growth in young mixed stands (birch < 17 m) was superior to that of pure spruce, while the difference was insignificant in older stands. The growth index correlated positively with the ratio between generatively and vegetatively regenerated birch trees, and negatively with the age of the oldest species in the mixture and with site quality. For the pine sites there was no significant difference in the growth index between mixed birch-pine and pure pine stands. A mixture effect of birch on the volume yield of spruce or pine could not be demonstrated.     

Defoliation by the Needle-shortening Pine Gall Midge,Thecodiplosis brachyntera,on Pines in Central Sweden

An outbreak of the needle-shortening pine gall midge, Thecodiplosis brachyntera , occurred on Scots pine, Pinus sylvestris (L.) and lodgepole pine, P. contorta (Dougl.) in central Sweden during 1995-1998. The larval feeding of T. brachyntera kills current-year needles and heavy infestation causes severe defoliation. A pattern of fluctuating defoliation among years and sites was found on both pine species. Defoliation was evenly distributed in the crown of P. sylvestris during years of high as well as low infestation; apical whorls had as much defoliation as basal whorls. In P. contorta , however, there was a tendency for defoliation to be concentrated on branches in the most apical whorls. Growth ring increments on P. sylvestris with high levels of defoliation (71%) did not differ from trees with moderate levels (26%) of defoliation. Shoot lengths were significantly shorter, however, on heavily infested trees the year after defoliation.     

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.     

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.     

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.     

Biogeochemical impacts of clearfelling and reforestation on blanket-peatland streams: II. major ions and dissolved organic carbon

Streams and drains in blanket-peatland forest in western Ireland were sampled weekly over 5 years, 1996–2000, using continuous, depth-proportional passive sampling. Analysis was for pH, alkalinity by Gran titration, anions by IC, metals by ICP, aluminium speciation by loaded-resin exchange, and dissolved organic carbon (DOC) by absorbance at 320 nm.

Effects of felling are identified graphically from two forest drains whose catchments (both about 1 ha) were clearfelled, and partial clearfelling of one larger catchment (somewhat over 1 km²), in summer 1999. Calcium concentrations and alkalinity were increased in the drain- and streamwater from the felled areas. The pH was increased in drains, while in the larger stream, pH range decreased while the mean increased. Phosphorus increased markedly with clearfell, in the absence of recent fertilising, and also increased with fertilising; these results are reported in an accompanying paper. Ammonium-nitrogen concentrations were increased in the two drains with felling, and temporarily decreased in the larger stream. Nitrate increased in some cases. Potassium and manganese concentrations also increased. Concentrations of DOC and organic monomeric aluminium increased gradually, subject to a continuing strong annual cycle. There were no clearfelling effects on concentrations of solphate, suspended solids or inorganic monomeric aluminium. In the two drains (fully clearfelled), concentrations of sodium, chloride and magnesium, and conductivity, were all reduced after felling. Fertilising effects other than for phosphorus were indistinct.

Effects of the combined clearfell–reforestation treatment were testable statistically, using randomised intervention analysis, between two larger streams (1 km²) as a treatment–control comparison. There were statistically significant positive responses in streamwater concentrations of nitrate, potassium, calcium, DOC and aluminium fractions. The implications for management practice depend on whether the loss of nutrients is sustainable for future crop productivity, and whether critical limits and loads of receiving ecosystems are exceeded.     

Effect of Drought on Growth and Mortality of Actively Growing Norway Spruce Container Seedlings Planted in Summer

Survival, root egress and height growth of 13-month-old actively growing Norway spruce ( Picea abies (L.) Karst.) container seedlings exposed to preplanting drying treatments (0, 4, and 8 days) and postplanting drought periods (1, 2, 3, and 4 weeks) were studied in the field between 5 July and 18 August 1999. The mortality of seedlings increased and the height growth and root egress decreased throughout the postplanting drought period. Postplanting performance was also affected by preplanting drying treatments. The results indicate that no risk of excessive mortality and growth restrictions occurs when actively growing seedlings are planted in summer, provided that seedlings are well watered before planting and the drought period does not exceed 3 weeks.     

Rehabilitation of diseased cacao fields in Peru through shade regulation and timing of biocontrol measures

The objective of this case study was to test the effectiveness of biocontrol for the rehabilitation of abandoned, diseased (moniliasis, witches' broom and black pod) cocoa and to develop testable hypotheses regarding the effect of shade and biocontrol timing. Three trial fields differed in their shade regimes. Biocontrol was administered starting either at flowering or pod filling. Disease incidence and yield were compared with cultural control alone. Biocontrol reduced moniliasis from 49% to 25%, independent of the shading regime and application time. Witches' broom was most severe without shade and unaffected by biocontrol. No significant effects on black pod were observed. Although biocontrol increased percentage healthy fruit independent of shading and timing, only the shaded plot with biocontrol from flowering onwards responded with increased yield. Our hypothesis is: 'In the rehabilitation of abandoned cacao, only fields under sustainable shade management and early onset of biocontrol can realise their production potential.' This revised version was published online in June 2006 with corrections to the Cover Date.