Pteridium Aquilinum Var Research Articles

Exogenous preculture with sucrose and abscisic acid improves post-cryopreservation survival of eastern bracken fern gametophytes

Cryopreservation is an important technique used in the conservation of various plant tissues. This study proposes a cryopreservation method for the long-term conservation of eastern bracken fern gametophytes (Pteridium aquilinum var. latiusculum). Encapsulation–dehydration of the gametophytes was performed, and the exogenous sucrose and abscisic acid (ABA) preculture conditions were investigated. Gametophytes are sensitive to dehydration and drying, and the following treatment conditions were applied: encapsulation by alginate containing 0.75 M sucrose, 18-h loading treatment with 0.75 M sucrose, and 6-h drying treatment. The survival rate following cryopreservation was determined. The water content of < 27.5% in the alginate beads after dehydration and drying was found to be appropriate for ensuring survival. Additionally, performing an exogenous sucrose and ABA preculture was essential before encapsulation to achieve a survival of ≥ 90%. The high stress induced by cryopreservation and exogenous preculture regulated the expression of PaSuSy, PaLEA14, and PaABI1b and the endogenous ABA content. In eastern bracken gametophytes, ABI1 appears to be a negative regulator of ABA signaling. These results indicate that the encapsulation–dehydration method is effective for the long-term conservation of eastern bracken fern gametophytes, and exogenous preculture alleviates abiotic stress and increases the survival rate.

Effects of 1-Methylcyclopropene Combined with Tea Polyphenols Coating Treatment on Storage Quality and Cell Wall Metabolism of Bracken (Pteridium aquilinum var. latiusculum)

Effects of 1-Methylcyclopropene Combined with Tea Polyphenols Coating Treatment on Storage Quality and Cell Wall Metabolism of Bracken (Pteridium aquilinum var. latiusculum)

Combined effects of 1-methylcyclopropene and tea polyphenols coating treatment on the postharvest senescence and reactive oxygen species metabolism of bracken (Pteridium aquilinum var. latiusculum)

Bracken (Pteridium aquilinum var. latiusculum) is susceptible to senescence and quality deterioration after harvest, which seriously affects its commodity value and shelf-life. In this study, the individual and combined effects of 1-methylcyclopropene (1-MCP) and tea polyphenols coating (TPC) on the postharvest senescence and reactive oxygen species (ROS) metabolism of bracken during storage at 4 ± 1 °C for 15 d were investigated. The results showed that 1-MCP or TPC treatment significantly delayed the reduction of overall quality and nutritional value, suppressed the ethylene production, respiration rate, relative conductivity, malondialdehyde (MDA) content and the accumulation of ROS, increased the ability of antioxidant system in comparison with the control during storage (P < 0.05). Notably, the effect of combined treatment of 1-MCP and TPC was more prominent than that of 1-MCP or TPC treatment alone. Furthermore, the Pearson’s correlation analysis indicated that postharvest bracken senescence was accompanied by an elevation in ethylene production, respiration rate, relative conductivity, MDA content, ROS levels and decreasing in overall quality, thus further confirming the close relationship between ROS metabolism and bracken senescence. In conclusion, these results demonstrated that combined “1-MCP + TPC” treatment can effectively delay postharvest senescence and maintain the commodity quality of bracken by increasing the ability of antioxidant system and mitigating ROS accumulation during the storage.

Culture types and period impact gametophyte morphogenesis and sporophyte formation of eastern bracken

BackgroundLiquid suspension culture efficiently proliferates plant cells and can be applied to ferns because it rapidly increases the fresh weight of gametophytes. This study assessed gametophyte proliferation and sporophyte production of Pteridium aquilinum var. latiusculum using a suspension culture method.ResultsThe growth curve linear phase of gametophyte cells was confirmed between 9 and 18 days of culture, and the subculture cycle was determined to be 2 weeks. A double-strength MS medium (fresh weight, 18.0 g) containing 2% sucrose and NH4+:NO3− (120 mM, 40:80) was found to be the optimal liquid medium. Gametophytes obtained after suspension culture for 18 days did not normally form sporophytes in an ex vitro soil environment. However, this issue was resolved after changing the culture type or extending the culture period to 6 weeks. A short suspension culture period increased the fresh weight of fragmented and homogenized gametophytes but yielded numerous relatively immature gametophytes (globular forms of branching gametophytes, BG). Furthermore, differences in gametophyte morphogenesis and development were indicated by changes in endogenous phytohormone content. BG with immature development exhibited high accumulation of zeatin, jasmonic acid, and salicylic acid, and relatively low levels of abscisic acid and indole-3-acetic acid. The immature development of gametophytes directly affected sporophyte formation.ConclusionsThis study maximized the advantages of liquid suspension culture using eastern bracken gametophytes and provides data to resolve any associated issues, thus facilitating efficient bracken production.

Effect of temperature and relative humidity on the viability and longevity of eastern bracken (Pteridium aquilinum var. latiusculum) spores for long-term storage

Desiccation conditions and storage temperature are crucial factors for the successful long-term storage of fern spores. This study aimed to determine the optimal desiccation conditions and storage temperatures for the long-term survival of eastern bracken (Pteridium aquilinum var. latiusculum) spores. The effect of different storage temperatures (25°C, 4°C, −20°C, −80°C, and −196°C for up to 48 weeks) on spore germination and sporophyte development was investigated in collected spores. The germination percentage remained constant in all spores, except in those stored at −20°C and 25°C. Spores stored at −20°C had the lowest germination percentage and were almost completely nonviable. The collected spores were desiccated for one week at various relative humidity (RH) levels equilibrated using saturated salt solutions. The water content was measured in desiccated spores, and the spores were stored in liquid nitrogen for up to 48 weeks. The water content of the spores desiccated at 15–55% RH was 5.0–5.4%, and their germination percentage remained constant with storage time. Desiccation at 94% RH increased the spore water content to 9.5% and decreased the germination percentage. The relatively high water content in spores was not suitable for their long-term storage. Long-term survival of the spores can be achieved by desiccating the spores at low RH to adjust the spore water content to 5% prior to their storage at low temperature.

1-Methylcyclopropene (1-MCP) retards the senescence of Pteridium aquilinum var. latiusculum by regulating the cellular energy status and membrane lipid metabolism.

1‐MCP is an ethylene inhibitor which can delay the ripening and senescence of fruits and vegetables effectively. Pteridium aquilinum var. Latiusculum (PA) is one of the wild vegetables which is famous and nutrient in China. However, the mechanism of PA preservation treated with 1‐MCP has not been reported. Consequently, the effects of postharvest 1‐MCP treatment on the changes in quality, energy metabolism, and membrane lipid metabolism of PA were investigated in this study. The results indicated that 1‐MCP treatment could effectively inhibit the decreases in firmness, titratable acid (TA) content and the increases in weight loss rate, malondialdehyde (MDA) content, membrane permeability, and membrane lipid metabolism‐related enzymes in PA. The cellular energy charge (EC) and the levels of ATP, ATP/ADP, and ATP/AMP, the activities of energy metabolism‐related enzymes, NAD+, and NADH were maintained, and the decreases in unsaturated fatty acids and the ratio of unsaturated‐to‐saturated fatty acids in the membrane of PA cells were effectively retarded by 1‐MCP treatment. A positive correlation was observed between cellular ATP levels and the ratio of unsaturated‐to‐saturated fatty acids, while negative correlations were observed between the ratio of unsaturated‐to‐saturated fatty acids and both lipid peroxidation and membrane permeability. These results indicated that higher levels of energy status, unsaturated‐to‐saturated fatty acid ratios, and lipid metabolism in the membrane could preserve the membrane integrity of postharvest PA and effectively extend its shelf life.

Synthetic Seed Technology Development and Production Studies for Storage, Transport, and Industrialization of Bracken Spores.

Bracken fern (Pteridium aquilinum var. latiusculum (Desv.) Underw. ex A. Heller) has long been grown industrially in South Korea. Conventional propagation methods, including planting rhizomes and in vitro seedling culture, are labor intensive and expensive, and thus not commercially suitable. We aimed to develop a system to produce synthetic seeds using fern spores (SFS). Synthetic seeds were prepared by mixing bracken spores and alginate matrix. Spore germination and gametophyte and sporophyte growth and development from SFS proceeded normally. Spore density affected gametophyte and sporophyte numbers. SFS prepared using cold (4 °C) long-term storage spores (even 7-year-old spores) could effectively form sporophytes. The highest germination was observed at 25 °C. Soaking-treated SFS successfully formed sporophytes, even after 30 days of storage at 4 °C; indeed, sporophytes formed even after five days of storage at 25 °C during transport conditions. SFS were sown in plug trays for commercial use. Young sporophytes grown from plug seedlings were greenhouse cultivated, and transplanting within eight weeks was effective for root growth and growing-point formation. Developing synthetic seeds is a feasible solution for facilitating efficient transport and the handling of small-sized fern spores; furthermore, this SFS technology provides the basis for fern seedling culture and fern spore industrialization.

Over and understory controls on red pine establishment and seedling survival in the largest remaining old-growth red pine forest

The ecological constraints on red pine (Pinus resinosa Ait.) regeneration in multi-cohort stands are not fully understood given the species’ long history of even-aged management. In this study a structural equation modelling approach is used to dissect the biotic and abiotic controls on seedling establishment and survival in North America’s largest remaining multi-cohort red pine forest. We characterized the under and overstory vegetation as well the soil and litter layer surrounding Wolf Lake in the Wolf Lake Forest Reserve (approx. 1600ha), Sudbury, ON. The understory of this pine dominated stand was found to be characterized by a feather moss-ericaceous community. Red pine establishment was primarily determined by favourable seed bed conditions, namely limited depth of the litter layer, and to some degree by light availability. Additionally, overstory species composition determined establishment of red pine and other shrub species, likely through distinct contributions to the litter layer. Our model suggests that red pine seedlings compete both in the shaded understory and in well-lit plots. We suspect that the northward migrating species, red maple (Acer rubrum) and white pine (Pinus strobus), exert strong competitive effects especially in canopy gaps. Given that uneven-aged management systems are likely to promote establishment of the competing species, red maple, paper birch (Betula papyrifera) and bracken fern (Pteridium aquilinum var. latiusculum), we suggest successful red pine regeneration is unlikely under these systems.

Island-Biogeographical Characteristics of Insular Flora in Southern Sea of Jeollanamdo, Korea

Present work aims to establish the countermeasure for the better maintenance and preservation of insular floristic diversity at the South Sea of Jeollanamdo Province, ROK, where unique ecosystems are under threat due to climate change, anthropogenic disturbance and habitat destruction. Numerous flora reports from 15 inhabited islands and 60 uninhabited islands as well as field survey data are collated for the compilation of floristic data base and island biogeographical analysis. Out of the 1,940 vascular plant species from 180 families occurring in studies areas, 30.1 percentage or 584 plant species are physiognomically belonging to arboreal plants. Average number of species at individual island is numbered about 222 species, but it varies from about 591 species at the inhabited islands to 129 species at the uninhabited islands. Only 0.15 percentage of species with high proportion above 0.9 in its relative occurrence rate occurs at 68 islands and it includes three species, such as Pinus thunbergii, Eurya japonica and Pteridium aquilinum var. latiusculum. However, about 68 percentage of plant species occurring in study area is confined their distribution to less than seven islands. Presence of high proportion of notable plants in small islands, i.e., 10 critically endangered species compared with 5.5 species in average, 9 endangered species (average 4.2 spp.) at Sonjookdo, and 7 critically endangered species, 8 endangered species at Sokomundo may due to existence of diverse geological and topographical environmental diversity as well as lower human population density and remoteness from the mainland. Since island is small in size and geographically isolated, minor environmental and ecological burdens can cause the critical damages to the diversity of flora and vegetation, urgent island biogeographical research is needed for the scientific conservation and management of island biodiversity.

人为干扰对碧峰峡栲树次生林群落物种多样性及其优势种群生态位的影响

PDF HTML阅读 XML下载 导出引用 引用提醒 人为干扰对碧峰峡栲树次生林群落物种多样性及其优势种群生态位的影响 DOI: 10.5846/stxb201511212361 作者: 作者单位: 四川农业大学林学院,四川农业大学林学院,四川农业大学林学院,四川农业大学林学院,四川农业大学林学院,四川农业大学林学院,四川农业大学林学院 作者简介: 通讯作者: 中图分类号: 基金项目: 四川省教育厅一般资助项目（自然科学）（15ZB0020）；国家自然科学基金资助项目（31370628）；国家“十二五”科技支撑计划资助项目（2011BAC09B05） Effects of anthropogenic disturbances on the species diversity and niche of the dominant populations in a Castanopsis fargesii secondary forest community in Bifengxia, Sichuan Author: Affiliation: College of Forestry,Sichuan Agricultural University,College of Forestry,Sichuan Agricultural University,College of Forestry,Sichuan Agricultural University,College of Forestry,Sichuan Agricultural University,College of Forestry,Sichuan Agricultural University,College of Forestry,Sichuan Agricultural University,College of Forestry,Sichuan Agricultural University Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:为进一步了解人为干扰对碧峰峡生态旅游区的生态环境及不同种群利用资源、占据生态空间的能力的影响，并为该区植物资源、大熊猫栖息地的保护及旅游可持续措施的制定提供依据，调查了人为干扰下碧峰峡栲树（Castanopsis fargesii）次生林物种多样性及其优势种群生态位的组成情况。结果表明：7200m2的样方中共记录到156个植物种，隶属于70科114属，其中乔木16科23属33种，灌木39科67属95种，草本38科42属47种；乔木层总体物种多样性水平在中度干扰下最低，在轻度及重度干扰下差异不大。灌木层总体物种多样性水平在中度干扰下最高，在轻度干扰下最低。而草本层物种多样性随着干扰强度的加深有明显降低趋势；随着人为干扰强度的增加，乔木层中优势种栲树的生态位宽度均为最大，与其他树种生态位重叠值在中度干扰下有所降低，枹栎（Quercus serrata）的生态位宽度会变小，山茶科（Theaceae）植物的生态位变宽，同时其生态位重叠值增大；在灌木层中，重度干扰下，菝葜（Smilax china）生态位宽度减小，栲树幼苗的生态适应范围也骤减，其他大多数物种在中度干扰下，生态位宽度最低；在草本层中，蕨类植物及皱叶狗尾草（Setaria plicata）在重度干扰下生态位宽度及重叠值均增高，其适应范围变广，种间竞争加剧。综合分析表明，群落各层次物种多样性水平对人为干扰的响应各不相同，其中人为干扰对灌木及草本层物种多样性影响最大。同时人为干扰会改变群落物种组成及种间原有的关系，特别是中度干扰会使群落间优势种地位增强，种间竞争关系加剧，导致其原有生境被破坏，不利于群落发展。因此强化景区保护及合理经营迫在眉睫。 Abstract:To further understand the effects of anthropogenic disturbances on the ecological environments and on the ability of resources utilization and ecospace occupation of the dominant population in the ecotourism area of Bifengxia, we investigated the effects of anthropogenic disturbance on the species diversity and niche of the dominant population in a Castanopsis fargesii secondary forest in this area. The results showed that a total of 156 species belonging to 70 families and 116 genera were found in a 7200 m2 quadrat. Specifically, there were 33 tree species from 16 families including 23 genera, 95 shrub species from 39 families including 67 genera, and 47 herbaceous species from 38 families including 42 genera. The level of species diversity in arborous layer was lowest under intermediate disturbance, and no obvious difference was found between communities under slight and severe disturbance. However, species diversity level in shrub layer was highest under intermediate disturbance, and lowest under slight disturbances. An obvious decrease for the level of species diversity was found in the herbaceous layer. With increase in the strength of disturbance, the niche breadth value for the dominant species (C. fargesii) in arborous layer was consistently the highest, and the value overlapping with other species decreased at certain degree under intermediate disturbance. The niche breadth value for Quercus serrata decreased, but such value for Theaceae increase as well as the overlapping value. In the shrub layer, the niche breadth value for Smilax china decreased under severe disturbance, as well as C. fargesii seedings. The niche breadth values for the majority of other species were lowest under intermediate disturbance. In the herbaceous layer, the niche breadth values and overlap values for Pteridium aquilinum var. latiusculum and Setaria plicata both increased under severe disturbance, with wider adaptive range and intensifying interspecific competition. The results suggest that anthropogenic disturbances have significant impacts on the species diversity, species status in community, and interspecific relationship in the C. fargesii secondary forest, indicating urgent measures in ecological protection and appropriate management. 参考文献 相似文献 引证文献

STUDY ON DROUGHT STRESS OF SIX COMMON FERNS IN NORTH CHINA

Six common ferns (Pteridium aquilinum var. latiusculum, Adiantum pedatum, Polystichum tripteron, Matteuccia struthiopteris, Adiantum capillus-veneris, Athyrium multidentatum) in north China were selected to test for drought stress. During drought stress, ferns were randomly selected to determine photosynthetic rate, soil moisture content, chlorophyll content, leaf water content, leaf water-retention ability and electric conductivity. The plant growth information was investigated in different water conditions. The results showed that: the ranks of drought resistance of the six ferns were Adiantum capillus-veneris > Adiantum pedatum > Polystichum tripteron > Matteuccia struthiopteris > Athyrium multidentatum > Pteridium aquilinum var. latiusculum. Drought resistance was made clear by soil moisture content, leaf water content and net photosynthetic rate. The results indicated that the soil moisture content, leaf water content and net photosynthetic rate were the most reliable indexes; the leaf relative electric conductivity, chlorophyll concentration could be used as auxiliary indexes; and the leaf moisture retaining power and chlorophyll a/b rate partly reflected the drought tolerance, as reference indexes. Matteuccia struthiopteris applied in urban greening is abundant in parks of Beijing at present. The results of statistical analysis of related data showed that Adiantum capillus-veneris, Adiantum pedatum and Polystichum tripteron have strong drought tolerance, and good visual effect. Therefore there is an extremely widespread application prospect in landscaping of north China, especially in Beijing.

Ultrastructural and cytochemical studies on oogenesis of the fern Pteridium aquilinum

Egg development in Pteridium aquilinum var. latiusculum was studied using ultrastructural and cytochemical methods to examine structural features influencing fertilization in leptosporangiate ferns. Ultrastructural observations indicate a separation cavity is first formed above the egg during oogenesis with a pore region persistently connecting the egg and the ventral canal cell. The egg envelope is formed by deposition of amorphous materials in the separation cavity on the outer surface of plasmalemma. The egg envelope was not formed across the pore region; instead, a fertilization pore was formed. During oogenesis, the egg nucleus produced extensive evaginations containing osmiophilic bodies. Cytochemical experiments revealed that the egg envelope displays strong periodic acid-Schiff reaction indicative of polysaccharides, with negligible Sudan black B staining for lipids, suggesting that the egg envelope is composed principally of polysaccharides, and not lipids. The present manuscript provides new insights into egg structure and development of Pteridium, including discovery and characterization of the fertilization pore and observations on the chemical nature of the egg envelope, thus contributing to the understanding of the cytological mechanism of the sexual reproduction of ferns.

ChemInform Abstract: Pteridanoside, the First Protoilludane Sesquiterpene Glucoside as a Toxic Component of the Neotropical Bracken Fern Pteridium aquilinum var. caudatum.

Abstract Chromatographic fractionation, monitored by brine shrimp bioassay, led to the isolation of the first protoilludane-type sesquiterpene glucoside, pteridanoside (5), from a bioactive hot-water extract of the neotropical bracken fern Pteridium aquilinum var. caudatum (Dennstaedtiaceae). The enzymatic hydrolysis of 5 yielded its aglycon, pteridanone (6), and D-glucose. The absolute stereostructure of 5 was confirmed by the CD spectroscopic analysis of 6. Pteridanoside (5) exhibited toxicity (LC50 of 250 μg/ml at 24 h and 62.5 μg/ml at 48 h) toward brine shrimp, while the aglycon 6 did not.

Decomposition and nutrient release of four potential mulching materials for poplar plantations on upland sites

The application of organic residues and the release dynamics of nutrients during decomposition may be crucial to improving poplar growth in upland areas. Field experiments were conducted in Guizhou Province, southwestern China, to determine differences in biomass decomposition of four potential mulching materials in one-year-old poplar plantations. Results showed the initial total content of N, P, K, Ca and Mg in the mulches ranged from 30.0 to 35.0 g/kg and was significantly greater in Quercus fabri, Imperata cylindrica var. major and Pteridium aquilinum var. latiuscukum than in Coriaria nepalensis. The weight loss pattern of these four species during decomposition could be best described by a double exponential decay model, and monthly decay rate coefficients (k) were in the order Q. fabri > C. nepalensis > I. cylindrica > P. aquilinum over a one-year period. Total nutrient (N, P and K) release of the four mulching materials ranged from 74.2 to 90.8% of the initial content after one year of decomposition, while nutrients were released in the order K > P>N. Nutrient release was fastest in C. nepalensis followed by Q. fabri, I. cylindrica, and slowest in P. aquilinum. Thus, taking into account initial nutrient content, nutrient additions and decay rates, the sprouts of woody species (Q. fabri and C. nepalensis) with massive foliage proved to be more important as nitrogen sources than the grass or fern.

Pb, Cu botanogeochemical anomalies and toxic effects on plant cells in Pb-Zn (Sn) ore fields, Northeast Guangxi Autonomous Region, China

In the Lingchuan-Daoping and Xinglu Pb-Zn ore fields in northern and eastern Guangxi Autonomous Region, Pb, Cu botanogeochemical anomalies may be ascribed to the excessive amounts of Pb and Cu taken up by the root system of plants, such as China fir (Cunninghamia lanceolata Lamb. Hook), mason pine (Pinus massoniana Lamb.) and bracken fern (Pteridium aquilinum var. latiusculum). Under transmission electron microscope (TEM), the excess Pb, Cu in the leaf cells of the plants are present as high electron-density substances, which were precipitated in the leaf cells, causing phytotoxic effects by deforming and injuring cellular tissues. The sorts of toxic elements accumulating in the leaf cells are consistent with those of the botanogeochemically anomalous elements in the polluted soil where the plants grow. In addition, the plants may also be capable of resisting the invasion of excess Cu (and Pb).

The Acentropinae and Musotiminae (Lepidoptera, Pyralidae) of the Galapagos Islands, Ecuador

The Acentropinae and Musotiminae (Lepidoptera, Pyralidae) are recorded for the Galapagos Islands, Ecuador for the first time. They are represented by one species each: Parapoynx fluctuosalis (Zeller, 1852) and Undulambia lindbladi Landry n. sp., respectively. The latter has been reared from the fern Pteridium aquilinum var. arachnoideum Herter (Polypodiaceae).

An Analysis of the Vascular Flora of Annapolis Heathlands, Nova Scotia

A description and analysis of the vascular plant composition of heathlands in the Annapolis valley were undertaken to provide a basis for biodiversity preservation within a system of protected sites. Species presence and abundance were recorded at 23 remnant sites identified using topographic maps, air photos, and Nova Scotia Department of Natural Resources records. A total of 126 species was recorded, of which 94 were native and 31 introduced. The Annapolis heathland remnants are strongly dominated by Corema conradii with Comptonia peregrina, Vaccinium angustifolium and Pteridium aquilinum var. latiusculum. A number of species, including Solidago bicolor, Carex tonsa var. rugosperma, Dichanthelium depauperatum, Lechea intermedia, Melampyrum lineare, and Rubus hispidus, were characteristic of heathland remnants, although they usually contributed little to the total cover. The most frequent alien species were Hieracium pilosella and Festuca filiformis, but Pinus sylvestris, present at 7 of 18 sites, appeared to have the greatest impact in displacing native species. Species listed as at risk and sensitive in Nova Scotia, including Helianthemun canadense, Hudsonia ericoides and Viola sagittata var. ovata, occur in open disturbed sand in the Corema heathlands. Distinctive patterns of variation occur in several species and variation in crop relatives is noted with particular reference to the genera Rubus (blackberries), Amelanchier (Juneberries, Saskatoon) and Vaccinium (Blueberries). The available evidence suggests that the heathlands and sandy barrens in the Annapolis valley differ from those further west in Canada and from anthropogenic and coastal heathlands of Nova Scotia in their species composition including particularly the presence of Corema conradii, Hudsonia ericoides and Amelanchier lucida. The need to protect representative examples is supported.

공단지역에 우점하고 있는 덩굴식물류의 식생변화

우리나라 공업단지 중 화학비료를 생산하고 있는 온산공단주변의 해송림이 쇠퇴된 이후 그곳에 덩굴식물류의 우점현상을 평가하기 위하여 식생조사를 실시하였다. 하층식생에 덩굴식물류의 중요치는 청미래덩굴(Smilax china)이 13.2로 가장 높았으며, 인동(Lonicera japonica)이 11.7, 계요등(Paederia scandens) 11.5, 댕댕이덩굴(Cocclus trilobus)이 7.7의 순으로 높아 대기오염으로 인한 생태계 훼손지역의 1차 식생으로 나타남을 알 수 있었다. 각 조사지별 목본류의 종수와 종다양도, 최대종다양도, 균재도, 우점도를 층위별로 나타낸 결과상층, 중층 식생에서는 종수, 종다양도, 최대종다양도, 균재도, 우점도가 산림지역이 공단지 역보다 높게 나타나 공단 주변 식생의 단순함을 보였으며, 하층 식생에서는 공단지역이 산림지역보다 높게 나타났는데 이는 덩굴식물이 차지하고 있는 비율이 높은 것이 원인인 것 같다. 초본류 조사에서는 총 59종이 출현하였으며, 고사리, 기름새, 닭의장풀, 미국자리공, 멍석딸기, 억새, 실새풀 등에서 중요치가 높아 대기오염지역의 우점종으로 나타났으며, 종수, 종다양도, 최대종다양도, 균재도, 우점도에서는 지역간의 구분이 뚜렷하게 나타나지는 않았지만 공단지역이 산림지역보다는 덩굴식물의 분포가 높게 나타났다. 이는 인접한 경기화학의 영향으로 상층식생의 쇠퇴에 따른 광조건에 의하여 열대성 식물인 덩굴식물이 우점종으로 나타나 생태계의 교란으로 인한 사막화 현상에 응용할 수 있을 것으로 생각된다. This study was carried out to on liana dominating at the vicinity of Onsan Industrial Complex declining P. thunbergii foersts. It was surveyed 16 species, 30 species and 50 species at upper, middle and understory, respectively. It was dominant P. thunbergii at upperstory, and P. densiflora, P. thunbergii, Quercus dentata and Q. serrata at middlestory, and Smilax china, Paederia scandens, Symplocos chinensis var. sinuata, Styrax japonica, Lonicera japonica and Q. serrata etc. at understory. It was the highest importance value(13.2) of S. china among all liana, and in order of L. japonica (11.7), P. scandens (11.5) and Cocculus trilobus (7.7). Number of species, Species diversity, Maximum species diversity, Evenness and Dominance of woody plants at upperstory and middlestory by each survey site were higher in forest areas than industrial complex, but those of understory highly showed at industrial complex, and ratio of liana at understory was high. It showed total 50 species at herbaceous plants, and was high I.V. of Pteridium aquilinum var. latiusculum, Spodiopogon cotulifer, Commerelina commuris, Phytolacca americana, Rubus parvifolius, Miscanthussinensis var. purpurascens and Calamagrostis arundinacea, etc.

Synthetic studies towards pteridanone, a novel protoilludane-type tricyclicsesquiterpenoid

A synthetic approach directed towards the total synthesis of the novel protoilludane sesquiterpene pteridanone, the aglycon of the glucoside pteridanoside from a bioactive hot-water extract of the neotropical braken fern Pteridium aquilinum var. caudatum (Dennstaedtiaceae), has been delineated. This endeavour has delivered an advanced pre-target having the complete protoilludane skeleton with strategic placement of the functionalities and set the stage for the total synthesis of the natural product. The key features of our approach are the ready availability of the starting material (1,5-cyclooctadiene), an interesting photochemical [2+2]-cycloaddition and a thallium(III) mediated ring expansion reaction.

A method for the practical quantification and kinetic evaluation of cyanogenesis in plant material. Application toPteridium aquilinum andPassiflora capsularis

A procedure for the quantitative determination of hydrogen cyanide (HCN) released by plants has been developed based on the UV–vis spectrum of the sodium picrate–cyanide complex. Fresh plant tissue mixed with toluene was placed in a gas flow system designed to carry the evolved HCN through 2,4-dinitrophenylhydrazine solution in acidic water:ethanol to trap interfering volatile carbonyl derivatives, and then into an alkaline solution of sodium picrate. After 18 h of gas flow at a rate of 6 mL/min, the absorbance of the solution was measured at 500 nm and the concentration of HCN was determined by calibration in the range 10−3–10−5 M. The molar absorptivity coefficient (1.385 L/cm M) yielded a detection limit of 2.6 × 10−6 mol/L and a 92.6 ± 2.6% recovery yield of HCN. The method was applied to determine the cyanide release capacity of Passiflora capsularis (up to 3.34 mg of HCN/g fresh plant tissue), and of croziers of Pteridium aquilinum var arachnoideum (10.4–61.3 mg of prunasin/g fresh plant tissue), and its rate of HCN production (K = 2.20 ± 0.01 × 10−4/s). Cymbopogon citratum, known to release large quantities of volatile, potentially interfering, monoterpene ketones and aldehydes, gave a negative reaction. Copyright © 2000 John Wiley & Sons, Ltd.