Amino acid sequence study of ferredoxin from a club moss,Lycopodium clavatum L

A ferredoxin was purified as the pure state from a club moss (Lycopodium clavatum L.) and sequenced. The ferredoxin was composed of 99 amino acids and had a molecular mass of 10,728, excluding iron and sulfur atoms. The ferredoxin sequence was rather distinct from that fromMarchantia polymorpha, Equisetum andGleichenia japonica. Based on comparison of ferredoxin sequences thus far established, the phylogenetic relationship between lower vascular plants is discussed.     

DEVELOPMENTAL PATTERNS IN STEM PRIMARY XYLEM OF WOODY RANALES. I. SPECIES WITH UNILACUNAR NODES

Patterns of protoxylem strands in vegetative stems of 11 species representing eight families of woody Ranales are illustrated and discussed. Primary vascular systems of many species examined tend to be pseudosiphonostelic. Protoxylem tissue, however, is discontinuous and consists of discrete strands which develop basipetally. The author assumes that data pertaining to the morphology of these protoxylem strand patterns can be significant in determining phylogenetic relationships among ranalean families and between these and higher angiosperms. The value of the primary vascular system in past taxonomic investigations is also considered. Results of this study indicate that the protoxylem strand patterns of 11 woody ranalean species are diverse even though the species are characterized by identical phyllotaxis and nodal structure.     

Comparative flavonoid glycoside biochemistry as a chemotaxonomic tool in the subdivision of the classical ‘genus’ Lycopodium

A wide variety of novel flavone 5-O-glucosides has been isolated from Lycopodium scariosum. The predominance of tricin derivatives in this species is not in accord with earlier proposed chemotaxonomic definitions of the sub-groups within the classical genus Lycopodium L. cernuum is the first lycopod found to contain flavone C-glycosides and its suggested taxonomic separation from other members of the group is thus substantiated. Flavonoid glycosides appear to offer more definitive chemotaxonomic characters than do the previously used aglycones and modification of the chemical definitions of the sub-groups in these terms is necessary.     

CAULINE VASCULATURE AND LEAF TRACE PRODUCTION IN MEDULLOSAN PTERIDOSPERMS

Medullosa and Sutcliffia specimens from the Paleozoic of North America and Europe are examined to determine the architecture of the cauline vasculature and mode of leaf trace production. Emphasis is placed on the identification and characterization of protoxylem strands and their relationship to leaf trace production. Organization of the primary xylem varies from a single protostele to a dissected stele composed of two to many more or less independent bundles. In Medullosa the bundles of primary xylem are each surrounded by secondary xylem, forming separate segments of vascular tissue (‘steles’ of previous workers). These vascular segments may divide and fuse at different levels in the stem. A definite number of protoxylem strands occur near the periphery of the primary xylem. The protoxylem strands divide at intervals producing protoxylem to the departing leaf traces. Leaf traces thus formed arise from all the vascular segments in a coordinated and predictable way and pass outward through emission areas in the secondary xylem. This type of cauline vascular architecture is compared to that of other seed plants. The vascular system of Medullosa stems is interpreted as a dissected monostele. Sympodial vascular architecture has apparently evolved from a protostele separately within the medullosan pteridosperms.     

Diphaladine A，扁枝石松中一个新的石松生物碱

从扁枝石松（Diphasiastrum complanatum）的95％乙醇提取物中分离得到1个新的石松生物碱,经波谱技术鉴定其结构,命名为diphaladine A（1）。同时还分离得到其它9个已知石松生物碱类化合物,其中obsctmmaine A（2）,L20,lycoposerramine—K,des—N—methyl—β—obscurine,des-N—methyl-α—obscurine,lycoflexion,和phlegmariurine B等7个化合物均为首次从该植物中分离得到。     

Ultrastructure of the spermatozoid of Lycopodium obscurum (Lycopodiaceae)

Ultrastructural observations reveal that the spermatozoid of Lycopodium obscurum is crescent shaped and contains two posteriorly directed flagella that are inserted at the front of the cell. The nucleus is broad and elongated with a narrow posterior projection or nuclear diverticulum. Spline microtubules (MTs) number 180 at their maximum and provide the framework for the cell. These MTs extend from the anterior of the locomotory apparatus and along the outermost surface of the nucleus, with a central shank of 14–17 MTs encircling the cell for at least one-third gyre beyond the nucleus. The two basal bodies are slightly staggered and positioned at the front of the cell over a highly elongated multilayered structure (MLS). The MLS extends laterally around the cell anterior and curves posteriorly over the nucleus. One large anterior mitochondrion is situated subjacent to the MLS, while numerous small mitochondria are scattered near or among the lobes of the single plastid. The plastid rests on the inner nuclear surface and contains numerous large starch grains. This cell differs from that of L. cernuum, the only other species of Lycopodium examined to date, in that it is more elongated and has an anterior-posterior orientation of the nucleus, basal bodies, MLS, and spline. Comparisons with coiled gametes of bryophytes and Selaginella suggest that some degree of coiling and cell streamlining may be ancestral in archegoniate spermatozoids.     

A COMPARATIVE STUDY OF THE PRIMARY VASCULAR SYSTEM OF CONIFERS. I. GENERA WITH HELICAL PHYLLOTAXIS

The primary vascular system of 23 species belonging to 18 genera of conifers with helical phyllotaxis has been investigated with the intent of determining the architecture of the system. Special attention has been given to nodal and subnodal relations of the vascular bundles. The vascular system seems to be composed solely of relatively discrete sympodia, that is, axial vascular bundles from which leaf traces branch unilaterally. Although the discreteness of the sympodia is not immediately apparent because of their undulation and lateral contacts with neighboring ones, close examination, including a statistical analysis of the tangential contacts, seems to reveal that each sympodium maintains its identity throughout. Although two traces may be apparent at nodal levels, the trace supply to a leaf originates, in all species, as a single bundle. An analysis is made of the relationship between the vasculature and the phyllotaxis. It is observed that the direction of trace divergence can be accurately predicted when the direction of the ontogenetic spiral, the angle of divergence of leaf traces, and the number of sympodia are known.     

马尾伸筋草化学成分及抗骨质疏松活性研究

为研究马尾伸筋草(Lycopodium fargesii Hert.)的化学成分及其抗骨质疏松活性,采用硅胶、MCI、RP-18、Sephadex LH-20柱色谱及半制备高效液相色谱对马尾伸筋草的乙醇提取物进行系统分离,从乙酸乙酯部位中得到18个化合物,综合利用NMR、HR-ESI-MS等技术,分析鉴定化合物的结构,分别鉴定为α-芒柄蜡素(1)、26-去甲-8-氧化-α-芒柄蜡素(2)、serrat-14-en-3β,21α,24-triol(3)、serrat-14-en-3β,21β,24-triol(4)、1,20-eicosanediol(5)、二十三烷(6)、glycerolmonolinoleate(7)、glyceryl linolentate(8)、3-(4′-formylphenoxy)-4-methoxybenzaldehyde(9)、芹菜素(10)、对羟基苯甲醛(11)、香草酸(12)、3-羟基-4-甲氧基苯甲酸(13)、2-羟基-1-(4-羟基-3-甲氧基-苯基)-丙基-1-酮(14)、3-甲氧基-4-羟基桂皮醛(15)、8-acetoxy-5-hydroxyumbelliprenin(16)、trans-4-hydroxy-2-nonenoic acid(17)和正十烷硫醇(18)。化合物1~18均为首次从马尾伸筋草中分离得到,其中化合物16对破骨细胞活性具有显著的抑制作用,其IC₅₀为1.98μM。     

Phyllotactic transitions in the vascular system of Populus deltoides bartr. as determined by 14C labeling

Populus deltoides seedlings progress through 2/5, 3/8, and 5/13 orders of phyllotaxis in attaining Plastochron Index 16 (PI 16). The manner in which the vascular system was reoriented during these phyllotactic transitions was determined by anatomical analysis of serial microsections, whereas the positions of the transitions were determined by ¹⁴C labeling. The midvein at the tip of leaves representing plants of different PI and leaves of different Leaf Plastochron Index (LPI) was fed ¹⁴CO₂ photosynthetically, and primordia LPI 0 through LPI-9 were dissected from the buds and analyzed for ¹⁴C. By combining the labeling data with the anatomical observations it was possible to reconstruct the vascular system of a plant of PI 16 and to locate the phyllotactic transitions. Both the anatomical and the labeling data showed a high degree of reproducibility among plants suggesting that the phyllotactic pattern to which the vascular system conforms may be programmed in the plant and transmitted acropetally through the developing leaves and procambial strands. The origin of new primordia and the concepts of orthostichy, ontogenetic helix, and Fibonacci sequence are discussed as they apply to the vascular system of P. deltoides.     

Disruption of a DNA topoisomerase I gene affects morphogenesis in Arabidopsis

The genesis of phyllotaxis, which often is associated with the Fibonacci series of numbers, is an old unsolved puzzle in plant morphogenesis. Here, we show that disruption of an Arabidopsis topoisomerase (topo) I gene named TOP1alpha affects phyllotaxis and plant architecture. The divergence angles and internode lengths between two successive flowers were more random in the top1alpha mutant than in the wild type. The top1alpha plants sporadically produced multiple flowers from one node, and the number of floral organ primordia often was different. The mutation also caused the twisting of inflorescences and individual flowers and the serration of leaf margins. These morphological abnormalities indicate that TOP1alpha may play a critical role in the maintenance of a regular pattern of organ initiation. The top1alpha mutant transformed with the RNA interference construct for TOP1beta, another topo I gene arrayed tandemly with TOP1alpha, was found to be lethal at young seedling stages, suggesting that topo I activity is essential in plants.     

Arbuscular mycorrhizal associations in Lycopodiaceae

This study characterizes the molecular and phylogenetic identity of fungi involved in arbuscular mycorrhizal (AM) associations in extant Huperzia and Lycopodium (Lycopodiaceae). Huperzia and Lycopodium are characterized by a life cycle with long-lived autotrophic sporophytes and long-lived mycoheterotrophic (obtain all organic carbon from fungal symbionts) gametophytes. 18S ribosomal DNA was isolated and sequenced from Glomus symbionts in autotrophic sporophytes of seven species of Huperzia and Lycopodium and mycoheterotrophic Huperzia gametophytes collected from the Páramos of Ecuador. Phylogenetic analyses recovered four Glomus A phylotypes in a single clade (MH3) that form AM associations with Huperzia and Lycopodium. In addition, phylogenetic analyses of Glomus symbionts from other nonphotosynthetic plants demonstrate that most AM fungi that form mycoheterotrophic associations belong to at least four specific clades of Glomus A. These results suggest that most mycoheterotrophic plants that form AM associations do so with restricted clades of Glomus A. Moreover, the correspondence of identity of AM symbionts in Huperzia sporophytes and gametophytes raises the possibility that photosynthetic sporophytes are a source of carbon to conspecific mycoheterotrophic gametophytes via shared fungal networks.     

A new genus of lycopods from the Devonian of New York State

Drepanophycus colophyllus Grierson & Banks is transferred to llaskinsia Grierson & Banks on the basis of the morphology of its leaves and its anatomical structure. Slender, dichotomizing axes bear helically arranged leaves that are falcate, petiolate, simple, lanceolate and entire. A solid cylinder of metaxylem is surrounded by ridges of protoxylem. Pitting on tracheid walls is annular, helical, reticulate, scalariform to circular-bordered. This lycopod extends from early Givetian into early Frasnian time in the Catskill strata of eastern New York State. The effect of cleavage of fossiliferous rock on patterns observed on the exposed fossils and the bearing of recent research on the fossil history of lycopods are discussed.     

Putative dual pathway of auxin transport in organogenesis of <Emphasis Type="Italic">Arabidopsis</Emphasis>

In Arabidopsis, damage to the superficial acropetal polar auxin transport (PAT) inhibits generative but not vegetative organ initiation. In order to verify whether in a vegetative phase auxin can be transported to the meristem in a different way, the research on wild-type and plants with defective PAT was performed. Distance from the differentiated vascular elements to the shoot apical meristem (SAM) was measured for Arabidopsis cultured in different experimental systems. The influence of this distance on the ability to induce organogenesis as well as transport of the fluorescent dye to the SAM, and the LEAFY gene expression were analyzed. The youngest protoxylem elements were used as a marker of the vascular tissues. The distance of protoxylem to the SAM and organogenesis were interrelated. Organ initiation occurred only when protoxylem was localized near to the SAM. Experimental elongation of internodes in a vegetative rosette caused an increase in the distance between protoxylem and the SAM organogenic zone. Thus, the inhibition of organ initiation took place already during the vegetative phase. The results suggest the presence of at least two pathways of acropetal transport of auxin inducing organogenesis: one superficial way through PAT, and the second, putative one, internal through the vascular system. Possibly, organogenesis is completely blocked only when both these pathways are dysfunctional.     

Observations on phyllotaxis, stelar morphology, the shoot apex and gemmae of Lycopodium lucidulum Michaux (Lycopodiaceae)

Phyllotaxis in Lycopodium lucidulum consists of low alternating spirals, with the adult shoots corresponding to a system of 5 + 5 contact parastichies in which there are ten orthostichies. Each major stelar lobe is a sympodium of the leaf traces of two orthostichies and each lobe has two mesarch xylem poles, Differentiation of both the procambium and xylem of the leaf traces is bidirectional, that is differentiation first commences in the leaf base and then is acropetal into the leaf and basipetal into the stem. Furthermore, the procambium of the axis does not extend above that of the youngest leaf primordium and the axial procambium is in part a composite of that of the leaf traces. Thus, it is concluded that the stele in this taxon is not a strictly cauline structure. The shoot apex consists of four zones—a zone of surface initials, a zone of subsurface initials, a peripheral zone and a rib meristem. This zonation pattern is essentially the same as that of the seed plants. From their inception, gemma primordia also exhibit shoot apical zonation and are entirely different from leaves in their subsequent growth pattern and vascularization. Although the gemmae occupy leaf sites in the phyllotactic sequence, they are interpreted as arrested stem dichotomies on the basis of their development and vascular system.     

Stem vascular architecture in the rattan palm Calamus (Arecaceae-Calamoideae-Calaminae)

Climbing stems in the rattan genus Calamus can reach lengths of well over 100 m, are long-lived, and yet their vascular tissue is entirely primary. Such a combination suggests that stem vasculature is efficient and resistant to hydraulic disruption. By means of an optical shuttle and video recording of sequential images we analyzed the stem of a cultivated species. The stem has vascular features that are unusual compared with those in arborescent palms and seemingly inefficient in terms of long-distance water transport. Axial bundles are discontinuous basally because leaf traces, when followed downwards, always end blindly below. Furthermore, there is no regular distal branching of each leaf trace at its level of departure into a leaf, so that neither a continuing axial bundle nor bridges to adjacent axial bundles are produced as in the standard palm construction. Instead, the axial bundles in the stem periphery are connected to leaf traces and to each other by narrow and irregular transverse or oblique commissures that are not the developmental homologues of bridges. As in other palms, metaxylem within a leaf trace is not continuous into the leaf so that the only connection to a leaf is via protoxylem. Within the stem, protoxylem (tracheids) and metaxylem (vessels) are never contiguous, unlike in other palms, which suggests that water can only move from metaxylem to protoxylem, and hence into the leaf, across a hydraulic resistance. We suggest that this minimizes cavitation of vessels and/or may be associated with an unknown mechanism that refills embolized vessels. Also, the metaxylem can be significant in stem water storage in the absence of abundant ground parenchyma.     

STEM ANATOMY AND ASPECTS OF DEVELOPMENT IN TOMATO

Aspects of anatomical development were correlated with internodal growth in tomato plants, variety ‘Yellow Plum,’ grown for more than 3 months. Internodal length was measured weekly in control plants and those harvested for anatomical study. Gross structure indicated progressive development with increasing age. Primary xylem and phloem first mature in distinct strands and the strands are joined laterally by procambium to form a continuous vascular cylinder. Primary phloem occurs on the outer periphery of the procambium between the early-formed vascular strands. Successive periclinal divisions in the procambium during internode elongation give rise to pronounced radial seriations of the cells. Procambial derivatives are included in the cylinder of thick-walled, lignified vascular cells that become prominent after elongation ceases. Secondary xylem is of greater radial width in the stem sectors which include protoxylem. During early secondary growth, vessels develop in the secondary xylem only in these sectors. Nucleate fibers and rays constitute the remainder of the secondary xylem. The rays exhibit an organization noted in other plants of reduced growth habit. Some of these interpretations do not agree with those described for tomato in earlier studies, and they are discussed in relation to pertinent aspects of development.     

The developmental anatomy of Metaxya rostrata (Filicales: Metaxyaceae)

The systematically problematic fern Metaxya rostrata, commonly regarded as an ally of the cyatheoid and dicksonioid tree ferns, is investigated, and features of its organography, shoot vascular anatomy and development, soral initiation and early development, and gametophyte structure are described. The rhizome is creeping, dorsiventral, with an unusual four-seriate phyllotaxis. Typical protoxylem is lacking from the intemodes of the solenostele, but are present in the leaf trace and end blindly proximally. Tangential cells are found in the phloem of the stem. The early maturing “protoxylem” of the stem is scattered, and, apart from some identifiable protoxylem strands, is not clearly associated with the young leaves. Sori are initiated as groups of large cells on the abaxial side of developing leaflets, distant from the marginal meristem initials, and in close association with a lateral vein. Two sori may arise by the subdivision of a single large patch of cells. Soral maturation is of the simple type. Gametophytes are cordate to ribbonlike, with moderately primitive gametangia. Morphologically and systematically, Metaxya appears isolated. It shares few significant derived conditions with the tree ferns, and a separate family Metaxyaceae seems well justified.     

Xenobiotic pregnane X receptor promotes neointimal formation in balloon-injured rat carotid arteries

Pregnane X receptor (PXR) is a member of nuclear receptor superfamily and responsible for the detoxification of xenobiotics. Recent studies demonstrated that PXR was also expressed in the vasculature and protected the vessels from endogenous and exogenous insults, thus representing a novel gatekeeper in vascular defense. In this study, we examined the potential function of PXR in the neointimal formation following vascular injury. In the rat carotid artery after balloon injury, overexpression of a constitutively active PXR increased the intima-to-media ratio in the injured region. PXR increased cell proliferation and migration in cultured rat aortic smooth muscle cells (SMCs) by inducing the expressions of cyclins (cyclin A, D1, and E) and cyclin-dependent kinase 2. In addition, PXR increased the phosphorylation and activation of extracellular-signal-regulated kinase 1/2 (ERK1/2) and p38 mitogen-activated protein kinase (MAPK). Inactivation of ERK1/2 and p38 MAPK pathways using selective inhibitors (U0126 and SB203580) abrogated PXR-induced SMC proliferation and migration. Furthermore, cigarette smoke particles (CSP) activated PXR in SMCs. Knockdown of PXR by small interfering RNA suppressed the cell proliferation, migration, and activation of the MAPK pathways by CSP. These findings suggested a novel role for PXR in promoting SMC proliferation and migration, and neointimal hyperplasia. Therefore, PXR may be a potential therapeutic target for vascular disease related to xenobiotics such as cigarette smoking and other environmental pollutants.     

Organization of the vascular system in the stems of Diplazium and Blechnum (Filicales)

Detailed analysis of the three-dimensional vascular organization in species of Diplazium and Blechnum indicates that these ferns possess reticulate (dictyostelic) vascular systems that closely reflect the helical phyllotaxis of the shoot. In each species, the vascular pattern shows a specific relationship to the phyllotaxis, so that the phyllotactic fraction can be determined by examination of the number of cauline vascular bundles (meristeles) in cross section of the stem. The number of meristeles in a cross section equals the denominator of the phyllotactic fraction, i.e., the number of foliar orthostichies on the stem. The same numerical relationship also exists in the eusteles of seed plants between the number of axial (sympodial) stem bundles and the phyllotaxis. There is a further parallel between the three-dimensional reticulate pattern of fern dictyosteles and the reticulate patterns that characterize some herbaceous dicotyledons. However, the hypothesized separate origins of seed plant eusteles and fern dictyosteles from protostelic precursors preclude any direct homologies between these similar patterns. The parallel evolution of presumably more physiologically efficient reticulate systems in herbaceous seed plants and in ferns that have only a primary plant body is noteworthy. The similar relationships between the primary stem vascular patterns and phyllotaxy in both ferns and seed plants further emphasize the likely similarity of the morphogenetic events that occur at the shoot apex in these taxonomically disparate groups.     

Anatomical characteristics of individual roots within the fine-root architecture of Chamaecyparis obtusa (Sieb. & Zucc.) in organic and mineral soil layers

Nutrient availability and temporal variation of physical stress are usually higher in organic soil layers than in mineral soils. Individual roots within the fine-root system adjust anatomical, morphological, and turnover characteristics to soil conditions, for example nutrient availability and physical stresses. We investigated anatomical traits, including cork formation and passage and protoxylem cell numbers, in cross-sections of individual fine roots of the conifer Chamaecyparis obtusa (Siebold & Zucc.) growing under different soil conditions. The fine-root systems in different soil layers were compared by sampling ingrowth cores buried for 1 year and filled with organic and mineral soil substrates. The number of exodermal passage cells was lower in roots from organic soils than in those from mineral soils, suggesting that apical roots tend to be more stress-tolerant in the organic layer than in mineral soils. In contrast, both root tip and specific root tip density were higher in roots from organic soils than in those from mineral soil layers. The proportion of roots with two strands of protoxylem (diarch) was greater in organic (90%) than in mineral (25%) soils. Thus, although the absorptivity of individual apical roots decreases in organic layers, the absorptivity of the entire fine-root system of C. obtusa may be increased as a result of the increase in apical root density and the proportion of ephemeral roots. We found that the fine-root system had simultaneous plasticity in density, anatomy, and architecture in response to complex soil conditions.