Furanocoumarins from Heracleum canescens

The ethanolic extract of the fresh roots of Heracleum canescens has afforded, besides sitosterol, osthol, methyl 3,4,5-trimethoxybenzoate and 11 furanocoumarins.     

Furanocoumarins in seeds of wild and cultivated parsnip

The furanocoumarin content of ripe seeds of seven cultivars of Pastinaca sativa was compared to that of ripe seeds from a naturalized population in central Illinois. Five furanocoumarins were identified and quantified in the intact seeds. While seeds of wild and cultivated plants contain furanocoumarin components in identical proportions, seeds from wild plants contain almost three times the quantity of furanocoumarins on a dry weight basis as do seeds of cultivars.     

Epidermal features of Heracleum mantegazzianum Somm. & Lev., H. sphondylium L. and their hybrid

Leaf surfaces of the native Heracleum sphondylium, the alien Heracleum mantegazzianum and the interspecific hybrid were examined using SEM and light microscopy. The surfaces differed in hairiness, especially in the length of the hairs, although the hairs did not differ in general form, or distribution on the leaf surface. Stomata differed little in length, width or frequency, but there were differences in the sort of stomata in relation to the surrounding epidermal cells. The hybrid material was intermediate between the parental species, and sometimes displayed aberrant trichomes that were contorted in contiguous pairs. The results are discussed in relation to other work on the epidermal features of the Umbelliferae: as a means of discriminating the three taxa, and in relation to the ecological distributions of the species.     

Epidermal features of Heracleum mantegazzianum Somm. & Lev., H. sphondyliutn L. and their hybrid

Leaf surfaces of the native Heracleum sphondyliutn , the alien Heracleum mantegazzianum and the interspecific hybrid were examined using SEM and light microscopy. The surfaces differed in hairiness, especially in the length of the hairs, although the hairs did not differ in general form, or distribution on the leaf surface. Stomata differed little in length, width or frequency, but there were differences in the sort of stomata in relation to the surrounding epidermal cells. The hybrid material was intermediate between the parental species, and sometimes displayed aberrant trichomes that were contorted in contiguous pairs.
The results are discussed in relation to other work on the epidermal features of the Umbelliferae: as a means of discriminating the three taxa, and in relation to the ecological distributions of the species.     

Invasion by Heracleum mantegazzianum in different habitats in the Czech Republic

Abstract. Heracleum mantegazzianum, a tall forb from the western Caucasus invaded several different habitats in the Czech Republic. The relation between invasion success and type of recipient habitat was studied in the Slavkovskù les hilly ridge, Czech Republic. The vegetation of 14 habitat types occurring in an area of ca. 25 km² was analysed using phytosociological relevés, and the invasion success of Heracleum (in terms of number of localities, area covered and proportion of available area occupied) was recorded separately in each of them. Site conditions were expressed indirectly using Ellenberg indicator values. The hypothesis tested was that Heracleum spreads in the majority of vegetation types regardless of the properties of the recipient vegetation. Community invasibility appeared to be affected by site conditions and the composition of the recipient vegetation. The species is not found in acidic habitats. Disturbed habitats with good possibilities of dispersal for Heracleum seeds are more easily invaded. Communities with a higher proportion of phanerophytes and of species with CS (Competitive/Stresstolerating) strategy were more resistant to invasion. The invasion success was bigger in sites with increased possibilities of spread for Heracleum diaspores. Communities invaded by Heracleum had a lower species diversity and a higher indicator value for nitrogen than not-invaded stands. It appears that species contributing to community resistance against invasion of Heracleum, or capable of persisting in Heracleum-invaded stands, have similar ecological requirements but a different life strategy to the invader.     

Intraspecific variability in allelopathy of Heracleum mantegazzianum is linked to the metabolic profile of root exudates

Background and Aims Allelopathy may drive invasions of some exotic plants, although empirical evidence for this theory remains largely inconclusive. This could be related to the large intraspecific variability of chemically mediated plant–plant interactions, which is poorly studied. This study addressed intraspecific variability in allelopathy of Heracleum mantegazzianum (giant hogweed), an invasive species with a considerable negative impact on native communities and ecosystems.Methods Bioassays were carried out to test the alleopathic effects of H. mantegazzianum root exudates on germination of Arabidopsis thaliana and Plantago lanceolata. Populations of H. mantegazzianum from the Czech Republic were sampled and variation in the phytotoxic effects of the exudates was partitioned between areas, populations within areas, and maternal lines. The composition of the root exudates was determined by metabolic profiling using ultra-high-performance liquid chromatography with time-of-flight mass spectrometry, and the relationships between the metabolic profiles and the effects observed in the bioassays were tested using orthogonal partial least-squares analysis.Key Results Variance partitioning indicated that the highest variance in phytotoxic effects was within populations. The inhibition of germination observed in the bioassay for the co-occurring native species P. lanceolata could be predicted by the metabolic profiles of the root exudates of particular maternal lines. Fifteen compounds associated with this inhibition were tentatively identified.Conclusions The results present strong evidence that intraspecific variability needs to be considered in research on allelopathy, and suggest that metabolic profiling provides an efficient tool for studying chemically mediated plant–plant interactions whenever unknown metabolites are involved.     

Heracleum mantegazzianum in the Czech Republic: Dynamics of spreading from the historical perspective

The spread ofHeracleum mantegazzianum in the Czech Republic has been reconstructed on the basis of floristic data. The species has spread from several spatially independent localities which have originated from the West Bohemian population introduced in the 19th century. Its expansion first followed the courses of great rivers. An exponential increase in the number of localities reported in particular years and in the cummulative number of localities was found. The species abundance decreases from the region of original introduction, which is located in the westernmost part of the country, to the east. The rate of spread in the last sixty years was the same in the Czech Republic and in Great Britain. The species is, however, more widespread in the North of Europe presumably because of the more favourable climate. It is found most frequently in habitats that encourage the greatest movement of diaspores. Floristic data can be used to infer retrospectively the dynamics of invasion, of a species in a given area provided that there is a sufficient amount of floristic research over time.     

Furanocoumarin Content,Antioxidant Activity,and Inhibitory Potential of Heracleum verticillatum,Heracleum sibiricum,Heracleum angustisectum,and Heracleum ternatum Extracts against Enzymes Involved in Alzheimer's Disease and Type II Diabetes

Hexane extracts of Heracleum verticillatum, H. sibiricum, H. angustisectum, and H. ternatum were studied for their furanocoumarin content antioxidant potential and acetylcholinesterase and α‐amylase inhibitory activities. Quantification of the furanocoumarins was performed by ¹H‐NMR. Pimpinellin was found to be the main component in the roots of all studied species. Bergapten and imperatorin were the major compounds in the fruits of H. sibiricum and H. verticillatum, respectively, while byakangelicol dominated in H. angustisectum and H. ternatum fruits. The leaf and fruit extracts of H. angustisectum demonstrated the highest DPPH radical scavenging activity and TEAC (IC₅₀ 0.58 mg/mL and 1.83 mm , respectively). The root extracts of H. verticillatum and H. angustisectum were found to be the most effective against acetylcholinesterase (IC₅₀ 0.30 and 0.34 mg/mL, respectively). The studied extracts were not active or demonstrated a weak inhibitory effect (%Inh. up to 29.7) towards α‐amylase.     

Plant growth regulators from Heracleum lanatum

The plant growth regulating substances, pimpinellin, isopimpinellin, bergapten, isobergapten, vaginidiol, sphondin, scopoletin, umbelliferone, ferulic     

Steroids,chromone and coumarins from angelica officinalis

From the ethyl acetate extract of the fresh roots of Angelica officinalis var. himaliaca, besides sitosterol, pregnenolone, peucenin-7-methyl ether, osthol and 18 furanocoumarins have been characterized by spectroscopic methods, including ¹³C NMR, and some chemical transformations.     

Induced Disruption of Sieve Element Plastids in Heracleum mantegazzianum L.

Sieve element plastids of Heracleum mantegazzianum L. were disruptedin fresh tissue by treatment with iodine. Their breakdown andthe consequent release of starch grains into the sieve elementlumen was recorded by cin?micrography. We discuss how plastidsburst to release the particles so frequently seen in sieve tubesunder the light microscope.     

Predicting the distribution of the invasive alien Heracleum mantegazzianum at two different spatial scales

Modelling the distribution of invasive alien species is widely used for predicting future dispersal, response to climate change, and effects of management, but little information is available on the scale dependence of spatial models. This study is focused on Heracleum mantegazzianum , a problematic invasive plant in central and north-western Europe. The main objective was to model the current distribution of this species at national (43,000 km²) and regional scale (4900 km²) using autologistic regression with a Danish data set. Presence–absence data were used in a grid system with 5 × 5 km² or 2 × 2 km² as basic units. To avoid misleading presence–absence models and unreliable probability values due to unbalanced data, the prevalence was used as cut-off value, and a favourability function was applied to the model predictions. The national model showed a widespread distribution of H. mantegazzianum with highest habitat suitability in the eastern and northern parts of the country where human population density is high, winters more severe and/or loamy soils more common. At a regional scale the distribution of H. mantegazzianum is associated with alluvial sand cover, high human population density, spring precipitation, and presence of the species in neighbour grid units. The observed widespread national distribution is likely the result of anthropogenic spread of this ornamental plant, while the locally clumped distribution suggests that H. mantegazzianum naturally spreads mainly over short distances. The current distribution in Denmark resembles an intermediate invasion stage where long-distance dispersal is less important, while spread from suitable neighbour habitats is significant. The study demonstrates that the favourability function leads to improved mapping standards for invasive species.