Pollen morphology of the genera Polygonum s. str. and Polygonella (Polygoneae: Polygonaceae)

The pollen of 30 taxa (27 species, one subspecies and two varieties) in two genera, viz Polygonum s. str. and Polygonella was investigated with LM and SEM, and some selected taxa with TEM. In all genera investigated the pollen is prolate to spheroidal, and the aperture is mostly tricolporate, rarely panto-hexacolporate (especially Polygonum section Polygonum). The exine sculpturing pattern is the most variable feature. Three types of exine can be recognized. Type 1 (Avicularia-Type, sensu Hedberg) - All species of section Polygonum and section Tephis share the smooth tectate exine with spinules, sometimes the surface is more or less rough (Polygonum afromontanum in section Tephis). Type 2 (Pseudomollia-Type, sensu Hong) - Pollen of Polygonum molliaeforme (section Pseudomollia) has the exine, which is verrucose on both poles and nearby the mesocolpium, and mostly psilate around the ectoaperture. Type 3 (Duravia-Type, sensu Hedberg) - Pollen grains of Polygonum section Duravia and Polygonella have the exine which is semitectate-reticulate at the mesocolpium and the poles, and rugulate/reticulate or sometimes foveolate with microspinules around the ectoapertures. The pollen grains in four taxa (viz Polygonum section Pseudomollia, P. section Duravia and genus Polygonella) have a well-marked dimorphism of the ektexine, which is considered to be a synapomorphic condition. The differences of pollen grain between the genus Polygonella and Polygonum section Duravia are almost non existent and clearly interrelated. It is therefore postulated that the similarity in pollen of both taxa is not the result of convergency, but is interpreted as a homology. It is noteworthy that the pollen of Polygonum molliaeforme (section Pseudomollia) appears as intermediate between the Avicularia-type and the Duravia-type, and is well supported the value of separated section for its own. Additionally, in TEM, some exine ultrastructures (e.g. columellae, foot layer, endexine) appear to be valuable characters for comparison between/among taxa. The systematic potentialities of the pollen data of the studied taxa at various systematic levels are also discussed.     

Dyes from plants: Past usage, present understanding and potential

Prior to the synthesis of dyes from by-products of thepetrochemical industry all colour was derived from natural sources,including plants. As the awareness of the need to preserve ournatural resources increases and attitudes change towards achievingthis, interest is growing in finding renewable resources, which canbe used as alternatives. Recent work, to discover whether it ispossible to use plants as commercially viable sources of dyes hashighlighted a significant resource, which would benefit both industrial production and consumer choice. However, because of themultiplicity of products available, customer expectation is veryhigh. This means that in order to satisfy this demand for highquality and choice, the plants in question must be studied more closely to allow breeding of useful lines and improved economicreturns.     

Two new species of Myrsinaceae from French Guiana

Herbarium studies leading to a treatment of the Myrsinaceae for the Flora of Central French Guiana resulted in the discovery of two heretofore undescribed species,Cybianthus prevostiae andStylogyne incognita. The species are described and illustrated, and hypotheses regarding phylogenetic relationships with their respective congeners are provided.Cybianthus prevostiae is unusual among members ofCybianthus subgen.Weigeltia owing to its monoaxial habit and ellipsoid pistil, and deeply cupuliform calyx.Stylogyne incognita, a taxon often confused withS. micrantha, is most closely related toS. sordida but is separated from it by the corymbose inflorescence, entire leaves, longer petioles, and membranaceous perianth.     

A phylogenetic study ofPolygonum sect.Tovara (Polygonaceae) based on ITS sequences of nuclear ribosomal DNA

Polygonum sect.Tovara comprises three morphologically very similar species;P. virginianum,P. filiforme, andP. neofiliforme. Sequences of internal transcribed spacers (ITSs) of nuclear ribosomal DNA of these were determined to examine phylogenetic relationships and the levels of differentiation among them. The size of ITS 1 was 241 bp inP. filiforme andP. neofiliforme, and 242 bp inP. virginianum. The size of ITS 2 was 243 bp, and that of the 5.8S rRNA coding region was 163 bp. The ITS sequences clearly separate North AmericanP. virginianum from the eastern Asian species. Nucleotide divergence between them ranges from 3.3% to 3.8% for ITS 1 and from 9.3% to 10.7% for ITS 2. The molecular data also revealed that two eastern Asian species are closely related but should be treated as distinct species.     

Johanneshowellia (Polygonaceae: Eriogonoideae), a new genus from the Intermountain West

A new genus ofPolygonaceae subfam.Eriogonoideae is established for what has long been known asEriogonum puberulum. NamedJohanneshowellia in honor of the late John Thomas Howell (1903–1994), a new combination,J. puberula, and a new species,J. crateriorum, are established. The common name Howell's-buckwheat is proposed for the group. The new genus differs from other members of the subfamily in having its involucral structure reduced to a spiral of four to seven bracts each of which is associated with a flower-bearing pedicel and a basal bractlet. In bud and early anthesis the outer two (rarely outer three) bracts may be partially connate, but typically become separate at full anthesis. The connate, ternate, foliar bracts at the base of the node act as a traditionalEriogonum-like involucre surrounding the branches of the inflorescence, the involucral bracts, and the flowers. Members of the new genus are found in the arid Intermountain West of the United States from Inyo Co., California, across Nevada to western Utah.     

Relationships of Anagallis foemina and A. arvensis (Myrsinaceae): new insights inferred from DNA sequence data

We investigated the relationship between Anagallis arvensis and A. foemina using nuclear and plastid molecular data. Information from the nuclear rDNA internal transcribed spacer (ITS) region and four different chloroplast loci; ndhF, trnL-F, rpl16, and rps16 was analysed using both parsimony and Bayesian inference. Anagallis foemina was found to be most closely related to the perennial A. monelli, and not to A. arvensis. The existence of two different cpDNA haplotypes was revealed; one shared by Anagallis foemina, A. monelli, A. platyphylla, and one A. arvensis individual, while all other investigated A. arvensis individuals shared the second haplotype. Ancestral cpDNA polymorphism within Anagallis arvensis or hybridization are possible explanations, however, information in ITS data is too scarce to falsify any of these hypotheses.     

火炭母的一个新异名及其系统位置初探

该文将铺地火炭母(Polygonum chinense L. var. procumbens Z. E. Zhao et J. R. Zhao)处理为火炭母原变种(Persicaria chinensis var. chinensis)的异名,并讨论了火炭母在命名上的问题,及其系统学位置。     

Flavonoid chemistry ofPolygonum sect.Tovara (Polygonaceae): A systematic survey

Polygonum sect.Tovara includes three controversial species;P. virginianum, P. filiforme, andP. neofiliforme. The flavonoid chemistry of these was examined to provide additional information on their delimitation and levels of differentiation. Eight flavonoid compounds were isolated and identified, all of which were 3-O-glycosides of the flavonols kaempferol, quercetin, and myricetin, and their acylated derivatives. Although they exhibit relatively simple flavonoid profiles, the three taxa are readily distinguished by their flavonoid constituents. In addition, they show fundamental differences in flavonol types and glycosylation patterns. These results, in conjunction with evidence from the morphology, strongly suggest thatP. virginianum, P. filiforme, andP. neofiliforme are closely allied but distinct species.     

Host-specificity of a root borer,Bembecia chrysidiformis [Lep.: Sesiidae], a potential control agent forRumex spp. [Polygonaceae] in Australia

Bembecia chrysidiformis (Esper) [Lep.: Sesiidae] was examined for its natural history and specificity toRumex spp. (Polygonaceae) which are weeds in Australia. Adults of this southern European insect appear in late spring to summer. Eggs are laid on the dried, seed bearing stems of perennialRumex plants. The larvae tunnel inside the root during summer through to the next spring. In nature, the larvae are round inRumex species of the subgeneraRumex andAcetosa. In host-specificity tests with 1st instar larvae, the roots of a number of genera within thePolygonaceae were attacked. Larvae died on a range of plants from other families except inPersea americana Miller(Lauraceae), Helianthemum nummularium (L.) Miller (Cistaceae) andQuercus ilex L. (Fagaceae) where larvae fed on the stems. The insect was judged safe for release in Australia by assessing aspects of its biology, its known host plants, and the lack of reported attack on other plants.      

Taxonomy of the Polygonum douglasii (Polygonaceae) complex with a new species from Oregon

The taxonomy of the Polygonum douglasii complex is revised. A summary of relevant taxonomic information is provided, along with a key to the species and subspecies, plus typification, synonymy, discussion, distribution, and ecology. Morphology and micromorphology of stems, leaves, perianth, pollen, and achenes are analyzed and illustrated. Based on these data, 12 species and two subspecies are recognized. A new species, P. gabrielae, is described and illustrated from Oregon.     

Morphological and chromosomal variation in Fallopia section Reynoutria (Polygonaceae) in Korea

We have examined morphological and chromosomal variation inFallopia sect.Reynoutria in Korea to clarify their taxonomic identities and to determine whether their morphological variability is associated with ploidy levels. Principal components analysis (PCA) of individuals from 21 populations, using major distinguishing characters, revealed the presence of four major entiries of sect.Reynoutria in Korea; these includeF. sachalinensis, F. japonica var.japonica, F. forbesii, and the Nonsan population consisting of presumed hybrids. Based on morphology, it is hypothesized that the Nonsan population was probably derived from multiple hybridization events involving the three named taxa. The results also indicate thatF. forbesii is distinct fromF. japonica var.japonica. Polyploidy is more prevalent in sect.Reynoutria than has been previously recognized.Fallopia sachalinensis in Korea occurs as dodecaploids with 2n=132; our count is the first dodecaploid count for the species, and represents the highest chromosome number known in the genus.Fallopia japonica var.japonica occurs as tetraploids (2n=44), hexaploids (2n=66), and octoploids (2n=88), whileF. forbesii occurs as hexaploids (2n=66) and octoploids (2n=88); our counts appear to be the first reported chromosome numbers forF. forbesii. Morphological analysis indicates that there is no apparent correlation between the ploidy levels in these taxa and the morphological characters that we have considered in this study except that the tetraploids ofF. japonica var.japonica tend to have somewhat thicker leaves.     

Foliar anatomy ofPolygonum (Polygonaceae): Survey of epidermal and selected internal structures

Several anatomical characters in leaves were described, and their distribution determined, for 153 species ofPolygonum, mostly from herbarium specimens. Structures surveyed were epidermal (glandular and nonglandular trichomes, nodules, specialized parenchyma, stomatal apparatus) and internal (cavities, crystals, laticifer-like cells, nodules, subepidermal fibers). Cleared leaves were supplemented by resin-embedded sections and SEM preparations of selected species. No feature defines any taxonomic section, but some features occur only within one section. Laticifer-like cells, epidermal and internal nodules, resin cups, and unique epidermal and subepidermal cavities seem to be unknown elsewhere; other features (invaginated epidermal cells; enlarged crystal cells confined to paraveinal layer) are rare among angiosperms.     

Chamaesphecia doryliformis [Lep.: Sesiidae], a second root borer for the control ofRumex spp. [Polygonaceae] in Australia

The host-specificity and biology ofChamaesphecia doryliformis (Ochsenheimer) [Lep.: Sesiidae] are described and the insect is assessed for its potential as a biological control agent for weeds of the genusRumex (Polygonaceae) in Australia. The insect is found in the western Mediterranean region, chiefly in north Africa. Adults emerge from pupation in late spring to summer when they lay eggs. The larvae feed inside the roots of post-reproductive plants belonging to the subgeneraRumex andAcetosa. In host-specificity tests 1^st instar larvae attacked only plants of thePolygonaceae. The insect was judged safe to release in Australia after assessing its level of host-specificity, and attributes of its biology which indicate that native AustralianPolygonaceae will not be endangered.      

The cation status of some indigenous plants from a Cango valley limestone-sandstone transition,South Africa

Leaf tissue of four representative species from a limestone-sandstone transition, together with their respective soils, were analysed for cations. The species studied comprisedLeucospermum cuneiforme (Proteaceae) from the acid sandstone,Indigofera sp. nov. (Fabaceae) from the base-rich limestone,Elytropappus rhinocerotis (Asteraceae) from the transition zone andDodonaea angustifolia (Sapindaceae) which occured on all three substrates. The sandstone substrate is low in cations, particularly K and it is suggested that the Leucospermum may supplement its K nutrition with Na. Despite growing on soils of differing cation content, Dodonaea maintained a constant leaf cation content over the three substrates.     

Patterns of resource allocation in male and female plants of Rumex acetosa and R. acetosella

Summary Patterns of resource allocation in the dioecious Rumex acetosa and R. acetosella were investigated. Males were found to allocate more to reproduction during flower production than females, whereas females invested considerably more in reproduction during seed production. Altogether, females allocated both a higher total amount and a higher proportion of energy to reproduction than did males. By regression analysis, the influence of plant size on reproductive effort was examined separately for males and females. The results indicated that while reproductive effort is sometimes lower for tall plants than for small plants, size-independent effects have a greater influence on reproductive effort than size distribution. An analysis of variance was conducted to investigate the effects of population, season, sex and their interactions on plant size, and an analysis of covariance was used to study differences in resource allocation patterns. Different interaction effects were found to be most important in the two species of Rumex.     

Isoenzyme diversity in Reynoutria (Polygonaceae) taxa: escape from sterility by hybridization

The genus Reynoutria is represented by four taxa in the Czech Republic – R. japonica var. japonica and compacta, R. sachalinensis and R. × bohemica. Using isoenzyme analysis, we determined the degree of genotype variability in all taxa and compared clones of R. japonica var. japonica from the Czech Republic with those from Great Britain. While the rarely occurring tetraploid variety R. japonica var. compacta possesses low variability, the octoploid female clone of R. japonica var. japonica is genetically uniform in the 93 clones sampled and belongs to the same genotype that is present in the whole Europe. R. japonica var. japonica can be fertilized by the pollen of tetraploid R. sachalinensis and a hexaploid hybrid R. × bohemica is produced. In R. sachalinensis, 16 genotypes were found in the 50 clones sampled. R. × bohemica is genetically the most diverse taxon in the study area, with 33 genotypes recorded among 88 clones sampled.     

走马胎中大叶紫金牛酚的分离鉴定与生物活性评价

为了解走马胎(Ardisia gigantifolia)的化学成分,从其乙酸乙酯提取物中分离鉴定出大叶紫金牛酚。体外活性评价结果表明,大叶紫金牛酚具有良好的抗炎、抗肿瘤活性以及一定的神经保护作用。这是首次对大叶紫金牛酚进行系统研究,为综合开发与利用走马胎提供科学依据。     

Micropropagation of Psiadia coronopus (Lam.) Benth,a threatened endemic species from the island of Rodrigues

Psiadia coronopus, a threatened endemic species from Rodrigues in the Indian Ocean, could be micropropagated by axillary budding on a MS medium containing 5 M BA alternating with culture on a medium devoid of plant growth regulators. Microcuttings were rooted in vitro and reestablished.Abbreviations BA benzyladenine - IBA indole-3-butyric aicd - NAA naphthaleneacetic acid - 4-CPA p-chlorophenoxyacetic acid     

Effects of herbivory by chrysomelid beetles on the growth and survival ofRumex plants

The effects of herbivory by the guild of chrysomelid beetles on the growth and survival ofRumex plants were examined in relation to the distribution and size of the plants. Gastrophysa atrocyanea never appeared on solitary plants whereasMantula clavareaui showed even utilization of solitary and clumped plants.Galerucella vittaticollis utilized large solitary plants most frequently. In patches of the host plants, the frequency of withering of the aerial parts was higher on small plants. The regrowth rate was higher when the aerial parts withered in spring than in summer. In patches of the host plants, the regrowth rate was higher on small plants. On the other hand, it was lower on small solitary plants than on large solitary plants and small plants in patches. In large plants, no difference in survival rate was recognized between solitary and clumped plants, because both the frequency of withering of the aerial parts and the regrowth rate were lower in clumped than solitary plants. The high vigor against intense herbivory by the chrysomelid beetles brought on the delay in the phenology ofRumex plants. This shift permits in parts the existence ofG. vittaticollis in mid summer. The temporal and spatial interactions between herbivore guild and the host plants were discussed.     

Nitrogen retranslocation in plants of maize,lupin and cocklebur

Summary In a split root experiment translocation of N from shoot to root was studied using¹⁵NO ₃ ^– . The three plant species selected for this experiment differed significantly with respect to root NRA. For lupin, maize and cocklebur about 80, 50 and 6% of all absorbed NO ₃ ^– was assmilated in the roots, respectively.Although NO ₃ ^– was reduced in the roots of lupin and maize plants to a greater extent than required for the roots' demand for organic N, a significant phloem flow of N from shoot to roots was found in these plants. Unexpectedly, for cocklebur, the plant with the very low root NRA, the fraction of total N present in the root that has been imported from the shoot was only half that as found for lupin and maize.