Intraspecific Sequence Variation of Chloroplast DNA Reflecting Variety and Geographical Distribution of <Emphasis Type="Italic">Polygonum cuspidatum</Emphasis> (Polygonaceae) in Japan

Polygonum cuspidatum in Japan, we analyzed the chloroplast DNA sequences of a region from the rbcL to the accD gene (ca. 1,420 bp), and found nucleotide variations at 22 sites in 68 samples. The phylogenetic relationship deduced from the sequence variations revealed the existence of at least five groups. The first group consisted of P. cuspidatum var. cuspidatum in the central part of Honshu; in Nagano, Yamanashi, and Shizuoka. The second, a sister of the first, consisted of those plants in Shizuoka-Itoigawa Line. The third group consisted of plants in the northern part of Japan including P. sachalinense in Hokkaido, P. cuspidatum var. cuspidatum in Aomori and var. uzensis in Akita. The fourth consisted of var. uzensis in the Tohoku District. The fifth consisted of var. terminalis in the Izu Islands. P. cuspidatum are differentiated according to their distribution, and two varieties, var. terminalis and var. uzensis, are differentiated genetically. Polygonum sachalinensis, a distinct species morphologically, fell into the accessions of P. cuspidatum on the phylogenetic tree obtained in the present study. Received 9 July 2000/ Accepted in revised form 11 October 2000     

The annual growth period of some Sphagnum species on the Silver Flowe National Nature Reserve,south-west Scotland

Abstract

The length of the annual growing season of five Sphagnum species was investigated on the Silver Flowe N.N.R. It ranged from five to six months for S. papillosum and S. magellanicum through approximately seven and ten months for S. capillifolium and S. auriculatum var. inundatum to twleve months for S. cuspidatum A mechanism of hollow and pool enlargement is proposed.     

Arbuscular mycorrhizal colonization of the dominant plant species in primary successional volcanic deserts on the Southeast slope of Mount Fuji

Arbuscular mycorrhizal (AM) colonization was observed on four plant species in primary successional volcanic deserts on the Southeast slope of Mount Fuji. The AM colonization of the dominant species, Polygonum cuspidatum, contradicts the conclusion that Polygonaceae are often regarded as being non-mycorrhizal species. The secondary dominant species, Polygonum weyrichii var. alpinum, formed no mycorrhizas. The roots of Cirsium purpuratum, Clematis stans and Campanula punctata ssp. hondoensis, showed a higher percentage of AM colonization than P. cuspidatum. AM colonization and spore density in the rhizosphere soil of P. cuspidatum significantly decreased as elevation increased. AM colonization in roots of Cirsium purpuratum and Clematis stans also tended to decrease with increased altitudes. Cirsium purpuratum and Campanula punctata ssp. hondoensis formed single structural types of Arum- and Paris-type, respectively, whereas P. cuspidatum and Clematis stans formed both Arum- and Paris-type morphologies.     

Effects of arbuscular mycorrhizal fungi and soil developmental stages on herbaceous plants growing in the early stage of primary succession on Mount Fuji

A pot culture experiment was conducted to examine the effects of arbuscular mycorrhizal (AM) fungi and soil developmental stages on the growth and nutrient absorption of pioneer plants growing in the early stage of primary succession on Mt. Fuji. Four herbaceous plants, Polygonum cuspidatum (Polygonaceae), Miscanthus oligostachyus (Gramineae), Aster ageratoides var. ovatus (Compositae), and Hedysarum vicioides (Leguminosae), were grown from seed in soils collected from two different successional stages, bare ground and an herbaceous plant community. Spores of indigenous AM fungi collected from the herbaceous plant community were used as inoculum. The initial colonizer P. cuspidatum showed very low levels of AM colonization (<0.4%), whereas the average AM colonization levels of M. oligostachyus, A. ageratoides var. ovatus, and H. vicioides were within the range of 13–49%. AM fungi had positive effects on the growth and N acquisition of the leguminous species (H. vicioides) irrespective of soil developmental stages. In contrast, AM colonization did not increase the plant dry weight and N content of the non-leguminous species (P. cuspidatum, M. oligostachyus, and A. ageratoides var. ovatus) in both soil developmental stages. A positive effect of AM colonization on P content was observed in M. oligostachyus, A. ageratoides var. ovatus, and H. vicioides only in soil collected from the herbaceous plant community. P. cuspidatum showed no or a negative response to AM colonization in all cases. These results suggest that the effect of AM fungi on plant growth depends more on the plant species than soil developmental stages in the early stage of primary succession in this volcanic area.     

Poplar stem blister canker and its control strategies by plant extracts

Stem blister canker is a serious stem disease in the Populus genus in China. The pathogen was confirmed as Botryosphaeria dothidea (Moug. ex Fr.) Ces. et de Not. based on its morphological, pathological and molecular features. Seven selected plant species Artemisia annua, Gleditsia sinensis, Lonicera japonica, Macleaya cordata, Phyllodendron chinense, Polygonum cuspidatum and Scutellaria baicalensis, belonging to different families from China, were extracted with the solvent 95% (v/v) ethanol to yield ethanol extracts which were used to evaluate their antifungal activity against poplar stem canker pathogen by a mycelial radial growth inhibition test. Of them, the extracts of M. cordata, P. cuspidatum and S. baicalensis showed stronger antifungal activity, the median inhibitory concentration (IC₅₀) was 0.3125, 1.0219 and 0.9675 mg ml⁻¹ separately. The control effect of extracts of M. cordata, P. cuspidatum and S. baicalensis on poplar stem canker disease was between 62% and 85%. The inhibitory effect of the extracts indicated the importance of some plant species as possible natural source of fungicidal material.     

Seedling establishment ofPolygonum cuspidatum andPolygonum weyrichii var.alpinum at high altitudes of Mt Fuji

Seedling establishment ofPolygonum cuspidatum (Seib. et Zucc.) andPolygonum weyrichii (F. Schmit) var.alpinum (Maxim.), dominant early-successional species in a volcanic gravel area on Mt Fuji, Japan, was compared for current-year seedlings at 2500 m a.s.l. The rate of survival in the first winter after germination at 2500 m was 2% and 24% forP. cuspidatum andP. weyrichii seedlings, respectively, and correlated with the upper distribution limit of each (2500–2600 m forP. cuspidatum; 3200–3300 m forP. weyrichii). The critical size for survival was 12 mg dry weight for overwintering current-year seedlings of both species. At 2500 m, the percentage of seedlings that attained the critical size for survival at the end of the first growing season was 19% and 85% forP. cuspidatum andP. weyrichii, respectively. Growth curves indicated that the larger-seeded characteristic ofP. weyrichii contributed to larger end-of-season size and resulted in higher rate of seedling survival at 2500 m, compared with smaller-seededP. cuspidatum. Current-year seedlings ofP. weyrichii, at least up to 3250 m, attained the first year annual growth critical for overwintering and therefore for successful seedling establishment, due to the large-seeded characteristic. At the top (3770 m) beyond the upper distribution limit ofP. weyrichii, most seedlings raised artificially failed to attain the critical size for survival in the first growing period due to the reduced growing period. Failure of seedling establishment would thus appear to restrict the distribution of the species at altitudes higher than 3300 m.     

Examination of the food processes on mixed inferior host plants in a polyphagous grasshopper

The mass gain of polyphagous grasshoppers fed a mixture of intrinsically inferior plants is often greater than that of grasshoppers fed each inferior plant alone. We examined the cause of this greater mass gain by assessing the food processes of a polyphagous grasshopper in detail. Food processes were divided into five stages: consumption, fecal mass, assimilated food, approximate digestibility, and efficiency of conversion of digested food (ECD). Using final-stadium female nymphs of the polyphagous grasshopper Parapodisma subastris, we compared the mass gain of nymphs fed the inferior plants Polygonum cuspidatum and Weigela hortensis or the superior plant Artemisia princeps. The mass gain of nymphs fed a single inferior plant was less than that of nymphs fed the superior plant because of reduced ECD. However, the mass gain of nymphs fed a mixture of the two inferior plants was not only greater than that of nymphs fed a single inferior plant, but also did not differ from that of nymphs fed the superior plant. Since consumption by nymphs fed the mixture was greater than that by nymphs fed P. cuspidatum and smaller than that by nymphs fed W. hortensis, and since the ECD of nymphs fed the mixture was greater than that of nymphs fed W. hortensis and was not different from that of nymphs fed P. cuspidatum, consumption and ECD appeared to cause the greater mass gain in nymphs fed the mixture.     

The effect of temperature on growth and competition between <Emphasis Type="Italic">Sphagnum</Emphasis> species

Peat bogs play a large role in the global sequestration of C, and are often dominated by different Sphagnum species. Therefore, it is crucial to understand how Sphagnum vegetation in peat bogs will respond to global warming. We performed a greenhouse experiment to study the effect of four temperature treatments (11.2, 14.7, 18.0 and 21.4°C) on the growth of four Sphagnum species: S. fuscum and S. balticum from a site in northern Sweden and S. magellanicum and S. cuspidatum from a site in southern Sweden. In addition, three combinations of these species were made to study the effect of temperature on competition. We found that all species increased their height increment and biomass production with an increase in temperature, while bulk densities were lower at higher temperatures. The hollow species S. cuspidatum was the least responsive species, whereas the hummock species S. fuscum increased biomass production 13-fold from the lowest to the highest temperature treatment in monocultures. Nutrient concentrations were higher at higher temperatures, especially N concentrations of S. fuscum and S. balticum increased compared to field values. Competition between S. cuspidatum and S. magellanicum was not influenced by temperature. The mixtures of S. balticum with S. fuscum and S. balticum with S. magellanicum showed that S. balticum was the stronger competitor, but it lost competitive advantage in the highest temperature treatment. These findings suggest that species abundances will shift in response to global warming, particularly at northern sites where hollow species will lose competitive strength relative to hummock species and southern species.     

Biotransformation of piceid in Polygonum cuspidatum to resveratrol by Aspergillus oryzae

Biotransformation of piceid in Polygonum cuspidatum to resveratrol by Aspergillus oryzae was investigated in this study. Resveratrol is widely used in medicine, food, and cosmetic because of its pharmacological properties. However, it has a much lower content in plants compared with its glucoside piceid, which has a much lower bioavailability. Traditionally, the aglycone is acquired by acid or enzymatic hydrolysis of its glucoside, but the violent condition and the acid pollution in hydrolytic reaction and the high cost of the enzyme limit their industrial development. In this paper, fermentation of P. cuspidatum by A. oryzae was successfully performed, during which, piceid was converted to resveratrol with the highest yield of trans-resveratrol 1.35%, 3.6 times higher than that obtained from raw herb by microwave-assisted extraction. Scale-up production was also performed and the yield of trans-resveratrol was 3.1 times higher after 24 h incubation. Therefore, biotransformation is a better method to increase the yield of resveratrol because of its high yield and mild conditions.     

Nitrification and nitrogen accumulation in the early stages of primary succession on Mt. Fuji

The relationship between nitrification potential and nitrogen accumulation was studied in an early successional sere on Mt. Fuji. Soil organic nitrogen accumulated with the invasion ofPolygonum cuspidatum and successively withMiscanthus oligostachyus and other species. Laboratory incubation experiments showed a higher nitrification potential at theM. oligostachyus state. The numbers of nitrifying bacteria increased with the progress of succession. No significant difference in nitrate reductase activity was found between pioneer and succeeding species. The soil solution at theM. oligostachyus stage contained a lower level of nitrate than rainwater, while that of the bare ground and theP. cuspidatum stage contained a higher nitrate level than rainwater. It was concluded that the high nitrate levels in the soil solution of the bare ground and theP. cuspidatum stage were due to lower nitrate-absorbing activity, leading to loss of nitrogen with precipitation, while the lower nitrate levels at theM. oligostachyus stage when higher nitrification activity occurred were due to higher nitrate-absorbing activity, preventing net loss of nitrogen from the ecosystem.     

Notes on mosses from Ceylon and India, 7. Some species of Trichostomum

Abstract

Trichostomum bombayense C.M. is typified and T. cylindrotheca Mitt. reduced to synonymy under it. The records of Trichostomum species from Ceylon are critically examined and T. tenuirostre (Hook. & Tayl.) Lindb. removed from the Ceylon moss flora. Records of T. orthodontum (C.M.) Broth. and T. cuspidatum (D. & M.) D. & M. hitherto published are based on misidentifications, but new records are given of both. Differences between T. cuspidatum and T. stenophyllum (Mitt.) Broth., which latter binomial is not a homonym as Index Muscorum states, are dealt with and illustrated by S.E.M. photographs. T. stenophyllum is a good species which has been relegated to extraordinary synonymy in the past.     

Assessment of genetic diversity of native species in Izu Islands for a discriminate choice of source populations: Implications for revegetation of volcanically devastated sites

In using native species for revegetation, it is necessary choose source populations carefully to reduce the risk of planting suboptimal germplasm. To make preliminary recommendations for native species to use in the revegetation of a volcanically devastated area on Miyake Is., Japan, we investigated the genetic variation of Alnus sieboldiana, Miscanthus sinensis ssp. condensatus, and Polygonum cuspidatum var. terminalis in the Izu Islands and on the Izu Peninsula based on chloroplast DNA (cpDNA) sequence variations and amplified fragment length polymorphisms (AFLPs). The amount and pattern of differentiation differ between organelle and nuclear markers, suggesting the necessity of evaluation based on both types of markers. Within-population diversity did not vary among populations, suggesting that it does not need to be considered in the choice of a source population. The pattern and degree of differentiation varied among species, and geographical proximity did not necessarily accord with genetic similarity, suggesting that the site of an appropriate source population varies among species and should be determined empirically rather than by assuming that close proximity predicts genetic similarity. The Izu Peninsula populations deviated from the island populations in all species. Comparison of cpDNA sequences with those of related species indicates the possibility of hybridization with related species on the Izu Peninsula, suggesting that seeds collected from populations where related species live sympatrically should not be used for revegetation. These findings indicate the need to assess the genetic diversity empirically by using organelle and nuclear markers to avoid unintended consequences of genetic mixing associated with revegetation.     

中国球藓属(丛藓科)植物分布新资料

报道了球藓密疣变种在中国的新分布。该变种主要分布于欧洲、大洋洲和北美洲,在中国为首次记录。该文对其形态特征进行了详细的描述与拍照,凭证标本存放于内蒙古大学植物标本馆(HIMC)。     

Soil nitrogen patterns induced by colonization of Polygonum cuspidatum on Mt. Fuji

Summary The spatial pattern of soil nitrogen was analyzed for a patchy vegetation formed by the colonization of Polygonum cuspidatum in a volcanic desert on Mt. Fuji. Soils were sampled radially from the bare ground to the center of the patch, and analyses were done for bulk density, water content, soil acidity, organic matter, organic nitrogen, and ammonium and nitrate nitrogen. The soils matured with succession from the bare ground through P. cuspidatum to Miscanthus oligostachyus and Aster ageratoides sites: bulk density decreased, and water content, organic matter, organic nitrogen, and ammonium nitrogen increased. Nitrate nitrogen showed the highest values at the P. cuspidatum site. Application of principal component analysis to the soil data discriminated two component factors which control the variation of soil characteristics: the first factor is related to soil formation and the second factor to nitrogen mineralization and nitrification. The effect of soil formation on nitrogen mineralization and nitrification was analyzed with a first-order kinetic model. The decreasing trends with soil formation in the ratios of mineral to organic nitrogen and of nitrate to ammonium nitrogen could be accounted for by the higher activity of immobilization by microorganisms and uptake by plants in the more mature ecosystem.     

克钦楼梯草, 缅甸荨麻科一新种

该文描述了自缅甸北部发现的荨麻科楼梯草属一新种,克钦楼梯草。此种在体态上与骤尖楼梯草甚为相似,与后者的区别在于本种的每一茎节具正常叶和一退化叶,托叶狭披针状条形和无脉,雌总苞苞片无角状突起,雌小苞片较大,呈楔状长圆形,雌花具一小花被片,以及雌蕊具一宽倒卵球形柱头。     

Taxonomic notes on Weissia subgenus Astomum,including Weissia wilsonii D.A.Callaghan,a new species from Europe

Introduction. The present study investigates the taxonomy of European members of Weissia Hedw. subgenus Astomum Hampe., a group considered taxonomically difficult and including species of high conservation concern.

Methods. A broad set of samples were subject to DNA sequencing and morphological analysis, plus a review of type material was undertaken.

Key Results and Conclusions. Three taxonomic additions and changes are supported. (1) Weissia longifolia var. angustifolia (Baumgartner) Crundw. & Nyholm is raised to species rank, W. angustifolia (Baumgartner) D.A.Callaghan, comb. et. stat. nov. (2) The type of W. multicapsularis (Sm.) Mitt. comprises an intermix of Phascum cuspidatum Hedw. and W. longifolia Mitt., and the protologue refers to unique features of P. cuspidatum but no such features of W. longifolia. Weissia multicapsularis is therefore described as a new synonym of P. cuspidatum. (3) Plants that have been named as W. multicapsularis by modern authors comprise an undescribed species, here named W. wilsonii D.A.Callaghan, sp. nov. An illustrated key to European species of Weissia subgenus Astomum is provided.     

Bult-und schlenkenbildung in Hochmoortorf

Zusammenfassung Im Moorgebiet östlich von Emmen (Niederlande), einem Teil des Bourtanger Moores, ist zwischen den älteren, stark zersetzten Sphagnum rubellum-Torf und den jüngeren, schwach zersetzten Sph. imbricatum-papillosum-Torfim allgemeinen eine Übergangsphase eingeschaltet, die aus einem System stark zersetzter Bulte und schwach zersetzter Schlenken (mit anfänglicher Sph. cuspidatum-Torfbildung) besteht; diese umfaßt die Zeit zwischen etwa 2000 und 500 vor Chr. Geb. In einem relativ kleinen Teil des Moorgebietes ist dieser räumliche und zeitliche Übergang aus zwei verschiedenartigen Bult-Schlenken-Systemen aufgebaut: Das ältere System — mit großen, flachen, mäßig zersetzten Sph. rubellum-Bulten und großen, schwach zersetzten Sph. cuspidatum-Schlenken —bestand von etwa 1930 bis 1500 v. Chr. Es wurde abgelöst von einem System ausgeprägter, stark zersetzter, an Wollgras und Heidekraut reicher Bulte und kurzer, schwach zersetzter Sph. cuspidatum-Schlenken, das von etwa 1500 bis 540 v. Chr. vorhanden war. Die Ursache für diese besondere Art der Torfbildung ist vermutlich das Auftreten einer Wasserbewegung im Randbereich von Moorteilen mit gewölbter Oberfläche. Ein unmittelbarer Einfluß des Klimas auf die Art des abgelagerten Torfes oder auf die Entstehung von Humifizierungswechseln scheint im allgemeinen nicht vorhanden gewesen zu sein, vielmehr sind die lokalen hydrologischen Verhältnisse in erster Linie bestimmend für den Charakter der Torfbildung gewesen. Das stratigraphische Bild, aber auch die pollenanalytischen und rhizopodenanalytischen Befunde weisen darauf hin, daß von zyklischen Sukzessionen beim Moorwachstum keine Rede sein kann.

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Summary The peat district east of Emmen (The Netherlands) is a part of the immense raised bog Bourtanger Moor. There, between the highly humified Sphagnum rubellum peat (Schwarztorf) and the fresh Sph. imbricatum-papillosum peat (Weißtorf) an intermediate layer is situated. This consists of a system of highly humified hummocks and poorly humified pools or hollows (starting with Sph. cuspidatum). This system can be dated between 2,000-500 B.C.In a relatively small part of the raised bog, a transition in time and space is formed by two different systems of hummocks and hollows. The older system, with large, flat, moderately humified Sph. rubellum hummocks and large, poorly humified Sph. cuspidatum hollows existed between 1,930 B.C. (GrN-4624) and 1,500 B.C. It is overgrown by a system of more pronounced, highly humified hummocks, which are rich in Eriophorum vaginatum and Calluna, and small, poorly humified Sph. cuspidatum hollows. This younger system persisted from 1,500 B.C. to 540 B.C. (GrN-4623). This uncommon type of peat growing is most probably caused by water movement into the marginally drained lower edges of bog complexes with convex surfaces. An immediate climatic influence on the character of the formed peats, or on the developing of changes in humification, did not generally exist. The local hydrological conditions rank first in determining the type of peat formed. Stratigraphic information as well as pollen and rhizopod analytical results clearly demonstrate that peat growing is not a cyclic succession.

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Enhancement of fluoride activity against Streptococcus mutans biofilms by a substance separated from Polygonum cuspidatum

Polygonum cuspidatum is a plant with spreading rhizomes and numerous reddish-brown stems that has been used in Korean folk medicine to improve oral hygiene. Nevertheless, there are no reports related to its possible effect on the virulence of dental biofilms. In this study, the ability of a fraction (F1) separated from P. cuspidatum, alone or in combination with fluoride, to disrupt virulence factors and the composition of Streptococcus mutans biofilms was examined. F1 was mainly composed of resveratrol, emodin and physcion (approximately 16.2%, 18.9% and 2.07% of the weight of F1, respectively). F1 showed inhibitory effects on acid production and F-ATPase activity of S. mutans in biofilms, and could enhance fluoride activity against acid production and acid tolerance of S. mutans in biofilms. When S. mutans biofilms were briefly treated with F1 (10 min, a total of five times), the biomass accumulation, water-insoluble polysaccharides and intracellular iodophilic polysaccharides were reduced. Furthermore, the fluoride activity against biomass accumulation was enhanced by F1. These results suggest that F1 may be useful in the control of dental biofilms and in improving the cariostatic properties of fluoride without increasing its exposure.