松科冷杉属植物的化石历史和现代分布

冷杉是北半球阴暗针叶林的优势种和建群种,现全世界共有52种1亚种12变种,在北半球形成南欧、北美和东亚三个分布中心,这三个地区也是冷杉属化石最丰富的地区。在垂直分布上,冷杉集中分布于1000～2000m（15种）和2500～4000m（13种）两个海拔地段。在中国,冷杉植物呈南北间断分布,集中分布在横断山地区。冷杉属的特有现象和孑遗分布现象都十分突出,有7个种呈孑遗分布。根据冷杉属的地史分布和现代分布的研究并结合最新的系统演化资料,本文推测冷杉属于白垩世中期起源于北半球的中高纬度地区,始新世以后,随着全球气候的变冷,逐步向南迁移,由于喜马拉雅山脉、阿尔卑斯山、落基山脉抬升及东亚季风气候的出现以及第四纪冰期的影响而形成了现代间断的分布格局。冷杉与银杉、金钱松等其它松科植物的形成模式十分相似。     

元宝山冷杉化学成分的研究

采用色谱技术对元宝山冷杉的化学成分进行分离,根据波谱学方法确定化合物的结构。结果从元宝山冷杉中分离得到5个单体化合物,分别鉴定为:3α-甲氧基-9β-羊毛甾-7,24-二烯-26,23R-内酯(1)、β-谷甾醇(2)、6-甲基-3,7-二甲氧基山奈酚(3)、3-氧代-羊毛甾(9,11)-烯-24S,25-二醇(4)、豆甾-4-烯-6β-羟基-3-酮(5)。所有这些化合物均为首次从该植物中分离得到。     

Growth and Wood/Bark Properties of Abies faxoniana Seedlings as Affected by Elevated CO2

Growth and wood and bark properties of Abies faxoniana seedlings after one year's exposure to elevated CO2 concentration (ambient 350 (=1= 25) μmol/mol) under two planting densities (28 or 84 plants/mz) were investigated in closed-top chambers. Tree height, stem diameter and cross-sectional area, and total biomass were enhanced under elevated CO2 concentration, and reduced under high planting density. Most traits of stem bark were improved under elevated CO2 concentration and reduced under high planting density. Stem wood production was significantly increased in volume under elevated CO2 concentration under both densities, and the stem wood density decreased under elevated CO2 concentration and increased under high planting density. These results suggest that the response of stem wood and bark to elevated CO2 concentration is density dependent. This may be of great importance in a future CO2 enriched world in natural forests where plant density varies considerably. The results also show that the bark/wood ratio in diameter, stem cross-sectional area and dry weight are not proportionally affected by elevated CO2 concentration under the two contrasting planting densities. This indicates that the response magnitude of stem bark and stem wood to elevated CO2 concentration are different but their response directions are the same.     

Ceratobasidiaceae mycorrhizal fungi isolated from nonphotosynthetic orchid <Emphasis Type="Italic">Chamaegastrodia sikokiana</Emphasis>

Mycorrhizal fungi were isolated from the nonphotosynthetic orchid Chamaegastrodia sikokiana and identified as members of Ceratobasidiaceae by phylogenetic analysis of the internal transcribed spacer (ITS) region of ribosomal deoxyribonucleic acid. The ITS sequences were similar among geographically separated samples obtained from Mt. Kiyosumi in Chiba Prefecture and Mt. Yokokura in Kochi Prefecture. One of the isolated fungi, KI1-2, formed ectomycorrhiza on seedlings of Abies firma in pot culture, suggesting that tripartite symbiosis exists among C. sikokiana, mycorrhizal fungi, and A. firma in nature, and carbon compounds are supplied from A. firma to C. sikokiana through the hyphae of the mycorrhizal fungi. To our knowledge, this is the second study to suggest the involvement of Ceratobasidiaceae fungi in tripartite symbiosis with achlorophyllous orchids and photosynthetic host plants.     

资源冷杉现状及保护措施研究

对资源冷杉的分布现状进行研究,揭示了目前资源冷杉的生存环境、资源数量、生长与自然更新能力,指出了实现有效保护所要面对的问题和应采取的措施。     

Effects of microsite conditions on seedling establishment on the foreland of Coleman Glacier,Washington

Abstract. Questions: How do physical microsite conditions of microsites affect germination and seedling survival in different successional stages? Do different species germinate in similar microsites in a given successional stage? Location: Coleman Glacier foreland, Mount Baker, Washington State, USA. Methods: Two methods were used to characterize safe sites. 1. Grids of 300 10 cm × 10 cm plots were located in four different age classes on the foreland. 2.105 pairs of plots, with and without seedlings of Abies amabilis, were located in each age class. For each plot we identified all seedlings and all individuals < 1 m tall. Microsite characteristics such as topography and presence of rocks or woody debris were noted for each plot. Microsite characteristics were compared between plots with and without each species. In addition we examined the effect of distance from seed sources on the presence of Alnus viridis seeds and seedlings in a newly disturbed area. Results: In early successional sites, seedlings of several species were positively associated with depressions and presence of rocks, and negatively associated with ridges. Patterns were generally consistent among species. In later succession, seedlings were not significantly associated with any microsite characteristics. For Alnus viridis, seed density decreased with distance from seed sources but seedling density did not. Conclusions: Because of harsh conditions in early succession, physical microsites are important, and most species have similar microsite requirements. In later succession, physical microsites characteristics are not as important and are more variable. Microsites appear to be more important than seed rain in controlling the distribution of Alnus viridis in early succession.     

濒危植物元宝山冷杉的遗传多样性研究

元宝山冷杉(Abies yuanbaoshanensis)是仅分布于广西融水县元宝山的珍稀濒危物种。本研究采用AFLP分子标记分析了元宝山冷杉种群的遗传多样性。取元宝山冷杉种群43棵植株作为研究材料,4对引物组合用于AFLP扩增,共得到261条DNA扩增带。分析结果：元宝山冷杉种群的多态位点百分比率为50．96％,Nei's基因多样性为0．1510,Shannon多样性指数为0．1735。用NTSYS软件计算各个样品间的相似性系数,并用UPGMA法基于相似性系数进行了聚类分析。研究结果表明：元宝山冷杉种群的遗传多样性水平低,种群内个体间的相似性系数很大,无明显亚种群间的遗传分化。要保护或保存这个物种的遗传资源,建议应该选择种群内尽可能多的个体进行保护。     

两种落叶分解过程中养分和碳素的行为

利用分解袋法对日本亚高山针叶林的针叶(Abies veitchii Lindl,and A.mariesi Mast.)和阔叶(Betula ermanii Cham.and B.corylifolia Regal.et Maxim．)凋落物进行了分解实验研究。结果表明尽管分解初期的两种凋落物的养分以及分解后期凋落物剩余重量差异很大,但两种凋落物养分浓度在分解后期(30个月以后)趋于一致。这种趋同现象在不同养分中有不同的趋同机制。氮元素浓度升高到分解后期浓度差变小,这种现象是由于分解菌的固持作用及受木质素的束缚所致;钾和镁在分解初期浓度急剧下降,进而浓度差变小,是由于淋溶作用所致。在分解过程中这些元素非常容易被淋溶掉,直到和土壤中的浓度达到一致为止。钙是结构元素,它的行踪和有机物组分有密切关系。由于分解后期有机组分木质化和腐殖质化进而浓度趋同,所以钙的浓度也相应趋同。     

Structure and CO2 Exchange in the Needles of Pinus sylvestris and Abies sibirica

The morphological and functional organization of the needles of Scotch pine (Pinus sylvestris L.) and Siberian fir (Abies sibirica Ledeb.), which differ in their light requirement were studied. The characteristic properties of the high-light-requiring pine included high rates of apparent photosynthesis and dark respiration, high assimilation number, numerous folds in mesophyll cell walls, and increased partial volume of intercellular spaces and hyaloplasm in the mesophyll. In the needles of shade-enduring fir, the higher efficiency of photosynthesis at low light intensities depended on the higher number of membranes and higher pigment content in the chloroplasts. The low assimilation number in fir indicated a shortage of photosynthetic reaction centers. The relative volume of the vascular cylinder and the vascular bundles in the needles and the partial volume of chloroplasts in the hyaloplasm, are considered as indices of the rate of assimilate export from mesophyll cells and their possible damping at different levels of structural organization.     

Difference in microhabitat-related regeneration patterns between two subalpine conifers, Tsuga diversifolia and Abies mariesii, on Mount Hayachine, northern Honshu, Japan

Seedling and tree-establishment microhabitats of Tsuga diversifolia and Abies mariesii were examined on the herb- and dwarf bamboo-dominated forest floor on Mount Hayachine, a mountain under intermediate snow conditions in northern Honshu, Japan. The four microsite types were fallen logs, buttresses, rocks and ground. The ground substratum was further divided into four subtypes by dominant undergrowth species: Lycopodium, Pteridophyllum, Carex and dwarf bamboo. The establishment of T. diversifolia seedlings on the ground was scarce, and depended mostly on non-ground microsites (i.e. fallen logs, buttresses and rocks). The seedling establishment of A. mariesii was not dependent on specific substrata, although on the ground, establishment sites were limited to the Lycopodium subtype situated on convex sites. Among the microhabitats for seedling establishment, larger trees of A. mariesii rarely occurred on higher portions of the non-ground microsites. In contrast, T. diversifolia could grow up to the height of canopy-layer trees in such microsites. Thus, non-ground microsites seem to be unsuitable for tree establishment in A. mariesii, and are probably useful microhabitats for regenerating T. diversifolia to avoid competition with A. mariesii. We also compared seedling-establishment microhabitats for the two conifers between Mount Hayachine and two other mountain regions under different undergrowth conditions (moss-dominated and dense dwarf bamboo-dominated). Our findings suggested that seedling recruitment in non-ground microsites was primarily determined by undergrowth conditions; T. diversifolia preferred such microsites where the moss-covered area was low, and A. mariesii preferred where dwarf bamboo-covered area was high.