蕨菜黄酮分离鉴定

采用75%的乙醇提取经乙醚脱脂的蕨菜粉末,提取液回收乙醇后以石油醚、氯仿、乙酸乙酯、正丁醇依次萃取粗分段,硅胶柱层析、乙酸乙酯-甲醇系统对乙酸乙酯部位梯度洗脱,对其乙酸乙酯洗脱部分反复凝胶柱层析获得2个黄酮单体,分别鉴定为紫云英苷(1)、芦丁(2),其中化合物1为首次从蕨菜中分离得到。     

Long-term recovery of bracken (Pteridium aquilinum (L.) Kuhn) after asulam spraying

This paper investigates the effects of a single asulam application, sprayed from the air, on the rhizome biomass, bud density, fronds and carbohydrate reserves of bracken (Pteridium aquilinum (L.) Kuhn) using a time sequence approach. Regression models were used to investigate how these characteristics varied with time after spraying, and were used, where appropriate, to calculate the time taken for full recovery after treatment. Frond density and biomass recovered in approximately eight years, bud numbers in seven, but rhizome biomass and total carbohydrate reserves required 10 to 12 years to recover. The consequences of these results are compared with predictions from a computer model and discussed in relation to the best timing of re-treatment and the management needed for long term control.     

Ultrastructural Aspects of Sporogenesis in a Fern, Pteridium aquilinum (L.) Kuhn

The meiotic process of sporogenesis in Pteridium is accompaniedby a regular cycle of ultrastructural events. These includethe dedifferentiation and redifferentiation of organelles, andthe elimination and restoration of ribosomes. Although similarin nature to corresponding stages in other land plants, sporogenesisin Pteridium provides several unique features. During prophase the plastids pass through a stage during whichno envelope can be resolved at the periphery of the stroma.They appear to survive this period and there is no evidencethat plastid lineage is broken from primary archesporium tospore. The plastid cycle is accompanied by the presence of theiron-protein complex phytoferritin. The repopulation of the spore cytoplasm with ribosomes, followingthe prophase elimination, is achieved through the agency ofnucleoloid-like bodies. These bodies, however, are not synthesizedwithin the nucleus, but form within membrane-bound regions ofthe early prophase cytoplasm. Prophase is also characterized by the development of nuclearvacuoles, expansions of the perinuclear space, which progressivelyramify through the karyoplasm prior to the dissolution of thenuclear envelope at metaphase I. The significance of these events, their similarities with, anddifferences from, comparable stages of meiosis in other plantsare discussed. Pteridium aquilinum (L.) Kuhn, bracken, meiosis, sporogenesis     

The effects of Fungi on the Gametophytes of Pteridium aquilinum (L.) Kuhn

I. The prothalli have been shown to be convenient subjects forthe study of some fungal relationships with green plants. Purecultures have been established from all the populations examinedby germination of young spores, and it has been shown that duringdormancy the number of spores which can germinate in pure culturedecreases more rapidly than the number which can germinate incultures containing contaminant fungi. Previous reports of thestimulatory effect of fungi on prothallial growth and developmenthave been confirmed and extended. 2. Prothalli growing on mineral agar have been shown to be potentiallysusceptible to the attack of a wide variety of pathogens ofhigher plants, but only two naturally occurring species of fungipathogenic to prothalli have been found during an examinationof growth on a variety of soils from bracken-infested areasin the west of Scotland. 3. The aetiology of the disease incited by Botrytis cmerca inprothalli has been shown to be similar to that of this diseasein higher plants. The pathogen is some-times restricted to lesionsof limited size around the sites of successful infections andthis is associated with changes in the cell walls of the host.A protopectinase solution prepared from a culture of germinatingspores by Brown's method induced symptoms in the prothallialcells similar to those induced by the attack of the fungus.The cell-attacking properties of the solution were greatly reducedwhen the protopectinase content was inactivated by low heatfor a short time, but they were not entirely destroyed. Thisconfirms previous indications that more than one complex maybe involved in the attack, but since the second moiety demonstratedis at least partially thermolabile the evidence does not supportjudgement of its relative significance in the attacking process.     

The Effect of Colchicine on Spermatogenesis in a Fern, Pteridium aquilinum (L.) Kuhn

Treatment of developing antheridia of Pteridium aquilinum for24 h with radioactive and normal colchicine resulted in spermatocyteswith restitution nuclei, binucleate spermatocytes with multipleimmature blepharoplasts, and spermatids in which the organizationof the microtubular ribbon and basal bodies, and the shapingof the nucleus were seriously disturbed. The results indicatethat the coiling of the multilayered structure and the condensationof the chromatin, two key events in spermatogenesis, are independentof tubulin polymerization. Transitional stages were observed between the granular materialof the blepharoplast and microtubules. Colchicine affected theassembly of the cartwheel structure of the basal bodies lessthan that of the triplets, which were often rudimentary or absent.Autoradiographs were only partially successful because of thefailure to devise a satisfactory method of embedding by freeze-substitution,but there was clear evidence of colchicine binding by nucleiin young spermatocytes. Pteridium aquilinum (L.) Kuhn, bracken, spermatogenesis, colchicine     

Effects of Dimethyl Sulphoxide on the Gametophytic and Sporophytic phases of Pteridium aquilinum (L.) Kuhn

Dimethyl sulphoxide (DMSO) at concentrations of up to 10 mlper litre of growth medium was found to have no significantinfluence upon Pteridium gametophyte growth or morphology However,significant effects upon embryo development and sporophyte morphologywere shown The most striking of these was that more than oneembryo developed from each fertilized gametophyte grown on DMSOmedium Two to five embryos regularly developed on each gametophytecultured on media containing this solvent, control gametophytesbore single sporophytes The significance of these findings inrelation to theories concerning polyembryony are discussed Pteridium, dimethyl sulphoxide, polyembryony     

The Morphology and Growth of Pteridium aquilinum var. esculentum (Forst.) Kuhn

Pteridum aquilinum var. esculentum has three main types of shoot;long, transitional, and short. All bear leaves and the shoottypes are distinguishable from one another only by the lengthof the internodes. The shoot structure is plastic, and eachtype may convert into either of the other types if subjectedto an appropriate environmental stimulus. Long shoots contributeabout 50 per cent. of the shoot length and grow all the yearround with peaks of activity in autumn and spring. Short andtransitional shoots grow only in the autumn and winter period.Frond buds appear macroscopically on the rhizome in spring andsummer but do not elongate rapidly till autumn and winter. Frondsemerge in early spring and continue to emerge till autumn. Somesurvive for two summers, but the majority survive only one summerand are killed by the autumn and winter frosts.     

Ethylene Production and Ethylene-induced Apogamous Bud Formation in Nine Gametophytic Strains of Pteridium aquilinum (L.) Kuhn

A comparative study of the abilities of nine gametophytic strainsof Pteridium aquilinum to produce ethylene and to undergo apogamywas conducted. Each gametophytic strain produced ethylene atits characteristic rate and all the strains, except one, formedapogamous buds in response to evolved ethylene which collectedwithin sealed culture vessels or to exogenous ethylene suppliedin a continuous-flow system. The number of apogamous buds producedby each strain was not directly related to the ability of thestrain to produce ethylene, but rather appeared to be dependenton the ability of the gametophytes to respond to ethylene.     

Recovery of Moorland Vegetation after Aerial Spraying of Bracken (Pteridium aquilinum (L.) Kuhn) with Asulam

Bracken (Pteridium aquilinum) is a major weed of seminatural vegetation in Great Britain, as in many other countries. As a consequence, large areas have been subject to control with the intention of restoring the former vegetation. The use of aerial spraying with asulam, a narrow spectrum, carbamate herbicide, has become a common method of control. However, its long‐term efficacy has not been assessed in terms of either controlling the bracken or in producing suitable restored habitats. This study undertook such an assessment by comparing the results of a 2002 survey of the sites subject to bracken control by aerial spraying of asulam with previous (1990/1991 and 1994) surveys of the same sites. This showed that a single application of asulam was effective in eradicating bracken (<1% cover remaining) on a third of sites. However, on 10% of the sites, the bracken had regenerated completely (cover >80%) and on the remainder it was still present in patches (>20% of quadrats), often at high density. More than half the sprayed sites had seen good recovery of moorland vegetation, the target of the restoration, because they were now classified as having upland heathland vegetation within the National Vegetation Classification. Considerable amounts of bracken control are grant aided as part of agri‐environment schemes. These schemes should be adapted to encourage good practice, namely, intensive follow‐up treatment by spraying any emerging fronds, and to encourage treatment of previously sprayed areas rather than spraying of new areas in order to protect previous investment of grant aid.     

蕨菜中的一个新高黄烷醇(英文)

运用柱层析等分离纯化方法,从蕨菜乙醇提取物的乙酸乙酯萃取部位中分离得到4个黄酮类化合物:3,4,6,2’,4’-五羟基高黄烷醇(1)、槲皮素3-O-β-D-葡萄糖苷(2)、芦丁(3)、槲皮素3-O-β-D-葡萄糖苷(4),其中化合物1为新化合物,也是从蕨类植物中分离出的第一个高黄烷酮,化合物2为首次从该植物中分离得到。采用MTT法对获得的黄酮类化合物的细胞毒活性测定结果表明化合物1具有明显的细胞毒活性。     

扫帚菜、蕨菜营养成分分析

对扫帚菜、蕨菜两种山野菜的粗蛋白、粗脂肪、膳食纤维、胡萝卜素、氨基酸、维生素及微量元素等营养成分进行了分析.结果表明,两种山野菜营养丰富,各种营养成分较为齐全,为开发食用山野菜等绿色食品提供科学依据和参考.     

Efficacy of bracken (Pteridium aquilinum (L.) Kuhn) control treatments across a range of climatic zones in Great Britain

Bracken control field experiments were conducted at six locations across Great Britain. The effects of various cutting and herbicide management regimes upon the seasonal dynamics of bracken fronds and rhizomes were examined over a three year period. This enabled a national overview towards bracken control to be constructed. Initially, spraying with asulam was the most effective treatment in reducing frond biomass and density but was least effective in reducing rhizome biomass. Differential reductions in rhizome biomass were observed in relation to cutting frequency, with cutting twice yearly giving superior control. The national trends confirmed a number of previous observations from independent single-site studies; however, others were contradicted. Comparable management options were ranked consistently between the current and former investigation, however, the initial importance of differences in cutting frequencies did not agree between studies. This multiple-site study improves understanding of the consequences of a national bracken control programme by reducing the influence of confounding site-specific factors, and recommendations for the most appropriate bracken control techniques are made. The extent to which individual sites reflect a national trend in response to bracken control is considered and sites are compared. The hierarchy of treatments identified at the national scale was found to apply generally within individual sites. However, several responses which proved significant at the countrywide level were not so clearly defined at the site scale. Cutting once yearly was the only management regime which appeared to give different bracken control between sites. All other treatments gave similar responses between sites. This result was found in the Scottish Borders, during the second year of control, when frond biomass and density (relative to untreated plots) were greater than that recorded at other sites. This contrast was not found in subsequent monitoring. In terms of rhizome biomass depletion, poorer control was achieved following cutting once yearly at the northern sites (Mull, Scottish Borders, Lake District) compared with the southern sites (Clwyd, Breckland, Devon). The implications of experimental results are discussed in relation to increased cost effectiveness of national bracken control programmes.     

The differential effects of bracken (Pteridium aquilinum (L.) Kuhn) on germination and seedling performance of tree species in the African tropics

Plant Ecology - Bracken fern Pteridium aquilinum (L.) Kuhn stands act as an ecological filter that influences regeneration of other plants. Woody species are often slow to re-colonise...