Sterile Shoots Research Articles

Appropriate Nutrient Economy in Phragmites australis at Different Phases of Estuarine Succession

The common reed Phragmites australis (Cav.) Trin ex Steudel – the dominant macrophytic plant species in the Kokemäenjoki River delta, western Finland – showed distinct and appropriate trends in the nutrient economy according to the previously determined successional phases of the vegetation development. The height and weight of individual aboveground shoots (ramets) decreased in the order: Pioneer stage > Mature stage > Regressing stage. The concentrations of the major nutrients nitrogen and phosphorus were determined only partly by amounts of these nutrients in the plants’ rhizospheres. The estuary is eutrophic, and the river water guarantees a continuous supply of nutrients, and thus the levels of nitrogen and phosphorus are high throughout the study area. The levels of nutrients correlated significantly with the contents of organic matter in the rhizospheres of the reed stands. On the basis of the relationships between the major nutrients’ concentrations in the leaf blades, nitrogen appeared to be the growth-limiting nutrients in the pioneer stage of succession in these estuarine habitats. The N/P-ratios in the three stages were as follows: Pioneer stage: 10.75, Mature stage: 13.59, Regressing stage: 14.67. In general, the values below 15 are considered to be nitrogen-limited. The actual levels of N and P in the leaf tissues were, however, high throughout the study. As evaluated by the concept of critical concentration, i.e. the level of a nutrient, which guarantees maximal growth potential, the habitats at all the three successional phases showed adequate level of nutrient availability for the maximal production of Phragmites. At the pioneer stage, where the rhizosphere resources of nutrients were poorest, the common reed showed an appropriate morphological adaptation. In the pioneering stands, the common reed produces considerable amounts of adventitious roots (water roots) on the underwater sections of the culms. In the pioneer stage, the average weight of the water roots was 675 mg/ramet in the fertile (flowering) shoots and 267 mg/ramet in the sterile (non-flowering) shoots, i.e. 2.6–5% of the total weight of the aboveground shoots. In the mature stage, the amount of adventitious roots was minor, but in the regressing stage – where growth enhancement and substantial flowering is essential for the future of the species – the reeds produced more adventitious roots again.

Antioxidant Constituents of Cotoneaster melanocarpus Lodd.

The aim of this study was the evaluation of the antioxidant capacity of Cotoneaster melanocarpus Lodd. and the identification of antioxidant active constituents of this plant. C. melanocarpus Lodd. is a shrub indigenous to Mongolia and used in Traditional Mongolian Medicine as a styptic. Before extraction, the plant material was separated into three parts: young sterile shoots, older stems and leaves. All these parts were extracted with water, methanol, ethyl acetate, dichloromethane and hexane, successively. The methanolic extract of the sterile shoots showed the highest antioxidant activity in the DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging assay (IC50 30.91 ± 2.97 µg/mL). This active extract was further analyzed with chromatographic methods. TLC fingerprinting and HPLC indicated the presence of the flavonol glycosides quercetin-3-O-rutinoside (rutin), quercetin-3-O-galactoside (hyperoside) and quercetin-3-O-glucoside (isoquercetin), ursolic acid as well as chlorogenic acid, neochlorogenic acid and cryptochlorogenic acid. The findings were substantiated with LC-MS. All identified compounds have antioxidant properties and therefore contribute to the radical scavenging activity of the whole plant.

Screening of Some Chemical Disinfectants for Media Sterilization During In Vitro Micropropagation of Sugarcane

Three antimicrobial compounds viz. mercuric chloride (HgCl2), sodium hypochlorite (NaClO) and bleaching powder, (CaOCl2) were tested at various concentrations to find out an effective chemical agent for sterilization of nutrient media for in vitro micropropagation of sugarcane. The best result was obtained in presence of NaClO at 0.1 % concentration where maximum 96 % shoot cultures were found contamination free, grew normally and were comparable to the cultures grown on autoclaved nutrient medium (control). Mercuric chloride (0.1 %), though prevented microbial contamination in about 85 % cultures, the shoots remained green for 4–7 days only and thereafter gradually turned brownish-yellow, showed rotting appearance and ultimately approximately half of the sterile shoots died within next one week. No microbial contamination was observed at higher concentrations (0.15 and 0.2 %) of HgCl2 and NaClO both, however the survival and growth of shoots were affected adversely. None of the chemicals was able to prevent microbial contamination up to the desired extent at concentrations below 0.1 %. Shoot cultures could be micropropagated successfully up to 10 subcultures (cycles) on medium supplemented with 0.1 % of NaClO, without any adverse effect on shoot growth. Addition of NaClO in rooting medium at a concentration of 0.1 % was also found equally effective. The results suggested that chemical sterilization of media with sodium hypochlorite, can be a cost effective option of autoclaving during micropropagation of sugarcane at commercial scale.

Cearania heterophylla gen. nov. et sp. nov., a fossil gymnosperm with affinities to the Gnetales from the Early Cretaceous of northern Gondwana

Vegetative and fertile shoots of a shrub-like seed plant from the late Aptian Crato Formation of Brazil are described as Cearania heterophylla Kunzmann, Mohr and Bernardes-de-Oliveira, gen. nov. et sp. nov. Anatomical details of the axes, epidermal features and separate ovulate and pollen producing organs indicate the gymnospermous nature of this plant. The vascular tissue of the axes includes tracheids with bordered pits and fiber tracheids. Vegetative shoots comprising at least three branching orders bear opposite-decussately arranged ovate to lanceolate, dorsiventrally flattened, parallelodromous, rather thick leaves that vary tremendously in size. The amphistomatic leaves bear (brachy-)paracytic stomatal complexes arranged in simple longitudinal files. The ovulate structure is interpreted as a terminally attached single globular ovule/seed surrounded by at least five to six lanceolate bracts. A terminally attached pollen-cone like structure grows on a lateral leafy shoot. The unusual character combination may indicate that the fossils belong to a hitherto unknown group with affinities to ephedroid Gnetales. Sterile shoots formerly often described as Podozamites, Nageiopsis or Lilites that are at least partly congeneric with C. heterophylla Kunzmann, Mohr and Bernardes-de-Oliveira, gen. nov. et sp. nov. had a wide geographic distribution during the Early Cretaceous.

Contribution to the description of an endemic Turkish Salix species

Salix rizeensis A. Güner et J. Zieliński is an endemic species and was recorded from NE Turkey in 1993. Since the generative organs could not be collected, its description was based only on sterile shoots. In this study, specimens of both sexes were collected for the first time and their description, new to science, is given together with the line drawings. The species shows most resemblance to Salix caesia Vill. as regard to both generative and vegetative characters, and belongs to section Helix Dumort. Subsection Ceasiae A. Skvortsov.

HIGH ALTITUDE ANTARCTIC SOIL PROPAGULE BANK YIELDS AN EXOTIC MOSS AND POTENTIAL COLONIST

Soil samples from the summit of Coulman Island in northern Victoria Land, continental Antarctica (lat. 73o28'S, 169o45'E) were cultured and after nine weeks they have yeilded sterile shoots of a funarialean moss. Its identity is discussed and, on the basis of the leaf shape, it is determined, with some reservations, as Entosthodon subnudus (Taylor) Fife, a species native to the Australia-New Zealand biogeographical province. This example provides further evidence of the existence of soil propagule banks, sometimes containing taxa not known in the flora of the Antarctic biome. Because of the severity of the polar climate and permanently frigid dry desert conditions, many such propagules may never succeed in growing in situ. The occurrence of E. subnudus represents the highest elevation (2930m) at which a viable plant propagule has been recorded in Antarctica.

Petrified araucarian remains from Sonajori, Rajmahal Basin, India

Permineralized araucarian ovulate and pollen cones are described here for the first time in close association from Early Cretaceous intertrappean rocks of the Sonajori Locality in the Rajmahal Basin, Jharkhand. These cones were found associated with woods and leafy shoots bearing spirally arranged falcate to oblanceolate leaves. The leaf, in longitudinal section shows epidermis followed by parenchymatous mesophyll and transfusion tissue. Ovulate cones, elliptical-spherical in shape, with spirally attached bracts and ovuliferous scales bearing mostly one and rarely two ovules/seeds per cone scale complex. Cone scale complex is characterised by the presence of "circa" (ligular sulcus). In one specimen, cross-section shows close association of numerous pollen grains with the cone scale complex of the cone indicating the preservation of cone at pollination stage. In another specimen, cross-section shows cone scale with oblong inverted ovule/seed, ovule integument/seed testa with three distinct layers, nucellus free except at chalazal end, shrunken at micropylar region and the presence of an embryonic tissue shows a post fertilisation stage of cone preservation. Anatomical features of these cones indicate various stages of cone maturity. The microsporangiate cone elongated in shape, in tangential view shows microsporophylls as well as circular-oval sporangia in cross-section. Transverse-sections of cone shows a central axis surrounded by numerous elongated narrow sporangia in longitudinal section and rhomboidal tip of the microsporophyll. The microsporophyll shows only parenchymatous tissue in sectional view of distal part: dispersed circular alete pollen grains are found associated with ovulate/seed cone and sterile shoots. Morphological and anatomical features of all the Indian species of araucarian cone described earlier are also critically assessed.

Clonal distribution, fertility and sex ratios of the moss Plagiomnium affine (Bland.) T.Kop. in forests of contrasting age

Six populations of the clonal forest floor moss Plagiomnium affine from forests of different age were screened for genetic variation at 23 allozyme loci, of which nine were polymorphic. Samples consisting of two adjacent unconnected shoots were taken at regular intervals along one transect from each population. A total of 602 shoots was analysed. Almost 80% of the shoots were sterile (i.e. not expressing male or female gender). Sex remained unknown for only 10% of shoots after identification of genets based on electrophoretic data. We identified a mean number of 3.7 fertile clones per population. The mean length of clones along transects in each population ranged between 2 and 3 m. The size distribution within populations was bimodal, with a few dominant clones and a varying number of much smaller clones. The overall sex ratio was slightly female biased at the ramet level, but balanced at the genet level. Forest age was negatively correlated with percentage of sterile shoots and positively correlated with frequency of sporophytes. In both cases correlations were significant only if population 1, which was subject to extreme soil disturbance by badgers, was excluded. We conclude that the effective population size is larger, and the susceptibility to genetic drift is lower, in old forests.

Colonization dynamics of the clonal moss Hylocomium splendens on islands in a Baltic land uplift area: reproduction, genet distribution and genetic variation

Summary Islands representing four stage classes, dated by their height above sea level, in a Baltic land uplift area were used to study genet level dynamics during colonization of the clonal moss Hylocomium splendens. Allozyme electrophoresis involving 10 polymorphic loci enabled accurate identification of 103 haplotypes from a sample of 694 shoots collected along transects across 10 islands. The populations consisted initially of scattered colonies with single clones. The number of clones, and the tendency of colonies to be multiclonal, increased significantly with increasing age of islands, whilst their mean size decreased significantly. In the Skeppsvik Archipelago, H. splendens thus shows repeated recruitment. The percentage male or female fertile shoots relative to sterile shoots was positively correlated with age of the islands. The sex ratios were skewed during early colonization. Spore capsules were found only in the oldest succession stage‐classes. This can be explained by a greater chance for fertile males and females to grow within the fertilization range, which is limited to a few centimetres. Genetic variation was accumulating with increasing population age. Correlations were stronger for mean number of alleles per locus (A) than for gene diversity (HS). No isolation by distance was detected among populations, indicating efficient and essentially random gene flow, probably occurring via wind‐dispersed spores.

Shoot Development and Evolution in Pistia stratiotes (Araceae)

The development of the shoot of Pistia has never been well understood, as is evident by the conflicting interpretations that have been reported in the past. This most likely results from the extremely condensed stem, nonsheathing mature foliage leaves, misinterpretation of squamule(s) at the base of the inflorescence, and lack of three‐dimensional studies, all of which obscure the interpretation of shoot appendages. Pistia has a sympodial shoot system in which each diphyllous sympodial unit terminates with the production of an inflorescence. The primary bud of each prophyll develops precociously via a bifurcation of the shoot apex, continuing the growth of the shoot. Three supernumerary buds, which may enhance the plant's high vegetative reproductive capacity, develop in the axil of each prophyll, whereas no buds develop in the foliage leaf axil. The secondary bud develops into a stolon; the tertiary and quaternary buds appear to remain dormant. Understanding shoot development in flowering shoots has provided an explanation for the architecture of vegetative Pistia shoots. These shoots are a series of repeating foliage leaves and reduced leaves that appear to be sterile (monopodized) shoots and have likely evolved from the sympodial flowering shoot system.

On Bragginsella, a New Genus of Jungermanniales from New Zealand

On Bragginsella, a New Genus of Jungermanniales from New Zealand

Plants regenerated from mesophyll protoplasts of white mulberry

Morus alba(white mulberry) mesophyll protoplasts were isolated from leaves of 30-45 day old sterile shoots, with protoplast yields of 2.5 × 107 g−1/F.W. after purification. The protoplasts were cultured in a modified K8P liquid medium containing 0.2 mg/L 2,4-D(2,4- Dichlorophenoxy acetic acid), 1 mg/L NAA(Naphthyl acetic acid) and 0.5 mg/L BA(6-benzylaminopurine). A low plating density (5 × 104/ml) proved to be favourable to the division of protoplast-derived cells. The first division occurred 4 days after culture, and the division frequency reached 24% at 10 days. A number of cell colonies and microcalli formed in 6 weeks. The microcalli were transferred onto MSB medium with 0.5 mg/L NAA and 0.5 mg/L BA for further proliferation. Shoot forrgation was initiated when the calli of 3-4 mm in size were transferred onto MSB differentiation medium with 0.1 mg/L NAA and 1 mg/L BA. The frequency of shoot formation was 35%. The shoots of 4-5 cm in height were excised from the callus and rooted on half strength MS medium with 0.5 mg/L IBA and 0.1 mg/L BA. After transplantation into pots, the regenerated plants grew vigorously in the phytotron.

Bryonolic acid production in hairy roots of Trichosanthes kirilowii Max. var Japonica Kitam. Transformed with Agrobacterium rhizogenes and its cytotoxic activity.

The hairy roots of Trichosanthes kirilowii Max, var. japonica Kitam. were induced by Agrobacterium rhizogenes (TCC 15834) on sterile shoots. The axenic culture of hairy roots proliferated 30 to 60-fold based on the initial fresh weight after three weeks of culture in Murashige & Skoog liquid media. Bryonolic acid as the main triterpenoid was isolated in a high yield, together with chondrillasterol from the hairy roots of this plant. Bryonolic acid showed strong inhibition of the growth of B-16 melanoma cells.

TheHedwigia ciliatacomplex in Sweden, with notes on the occurrence of the taxa in Fennoscandia

AbstractThe Swedish taxa of the Hedwigia ciliata complex are revised. In Sweden and Fennoscandia, there are three taxa, Hedwigia stellata Hedenas, sp. nov., H. ciliata (Hedw.) Ehrh. ex P. Beauv. var. ciliata and H. ciliata var. leucophaea B., S. & G. Hedwigia stellata is recognized by its mostly recurved or reflexed leaf apices in the upper sterile shoots when dry, its sharply pointed leaf apex and its uni- or occasionally bi-papillose median leaf cells, with pelt ate papillae on the abaxial side. In both varieties of H. ciliata the leaf apices are erect to patent (occasionally spreading) or following the leaf curvature when dry, many or most leaf apices are truncate or pluripapillose and the median leaf cells are 1-4(-5)- papillose, with most cells having more than one papilla and the papillae are not peltate. Hedwigia ciliata var. ciliata differs from H. ciliata var. leucophaea in the length of the hair-point ((4-)7-33% versus (15-)22-55(-65)% of leaf length), in having less strongly papillose hair-poin...

Shoot initiation in the leaflet axils of compound leaves from micropropagated shoots of juvenile and mature common ash (Fraxinus excelsiorL.)

Micropropagation of a mature ash tree has been achieved for the first time. The main obstacle encountered was contamination of the initial explants with microorganisms. However, once apparently sterile shoots had been obtained, shoot proliferation was achieved most effectively by culturing nodes on Driver and Kuniyuki walnut medium containing 22.2 μM benzyladenine. After several subcultures, a species of Bacillus appeared with the mature culture line, but it did not affect shoot or root development adversely. With successive subculturing, shoots of the mature ash clone became progressively easier to root. Pinnately compound leaf explants from micropropagated shoots of two seedlings and the mature tree, placed on to Murashige and Skoog-based culture media supplemented with 4.4μM-phenyl-N-1,2,3-thiadiazol-5-ylurea, produced shoot buds. Most buds developed from the rachis at the points of attachment of the leaflets. When transferred to Driver and Kuniyuki walnut medium, buds from one of the seedling lines and from the mature tree, elongated into shoots, and were subsequently transferred to media for micropropagation and rooting. Shoot initiation is discussed in relation to possible occurrence of vestigial meristems in the axils of leaflets and the partial shoot theory of leaf structure.

Growth in length of Carex rostrata stokes shoots in relation to water level

The pattern of growth leading to length increment and the influence of water depth on length of Carex rostrata Stokes shoots were studied in four different habitats in central Sweden. Individual shoots were studied in permanent plots from 1981 to 1986. The water level is an important factor for growth of C. rostrata shoots, especially during early summer, when most of the length increment takes place. There are differences in the size of shoots depending on their age. The sterile shoots can continue their length increment throughout the season and differ from the fertile shoots which cease their growth after flowering. This study illustrates that a clonal species which lives under fluctuating water conditions can adapt both size and density of its shoots, and considerably increase their size and reduce their density in years with unsually high water level.

The resource balance of Milium effusum with emphasis on environmental resource supply.

Growth of the broad-leaved graminoid Milium effusum, occurring in shady deciduous forests, was matched with periods of high light influx through the tree canopy in spring and autumn. Fertile shoots grew faster than sterile shoots. Leaves on flowering shoots were fully developed when the budbreak started on the trees, whereas nonflowering shoots had fully developed leaves when the tree canopy closed. Leaf concentrations of N and P were high (6.1 and 0.74% respectively) in spring but decreased as the leaves expanded. Maximum pool sizes of N and P in whole tillers were reached about one month after the onset of spring growth, whereas maximum spring pools of K, Mg, and Ca were timed with peak biomass about one month later. The leaves lost nutrients during summer when no growth took place. Since leaching losses were negligible, nutrients were probably allocated from the leaves to support root growth. Autumn reallocation to winter stores was low. The pattern of growth and nutrient use suggests that light availability, i.e., the resource in relatively lowest supply, regulates the investment of the resource in highest supply, i.e., nutrients. This is consistent with previously reported observations on Eriophorum vaginatum, a graminoid of low nutrient - high light environments. This species utilizes nutrients efficiently at the expense of less efficient acquisition of carbon. We suggest that selection for efficient utilization of the resource in lowest relative supply has been a strong driving force behind the physiological adaptation of both species to their environments.

In vitro propagation of some olive ( Olea europaea sativa L.) cultivars with different root-ability, and medium development using analytical data from developing shoots and embryos

Short- and long-term objectives for research on tissue culture of the olive are described. Sterile shoots were obtained from single-node woody explants or buds of 3 olive cultivars (‘Frantoio’, ‘Dolce Agogia’ and ‘Moraiolo’) with different root-ability, collected from shoots having different degrees of juvenility (suckers, vigorous nonfruit-bearing and fruit-bearing shoots, which are easy, medium and difficult to root, respectively). Because many of the media tested did not give a satisfactory growth rate and good quality shoots, a new medium was formulated by comparing data from analysis of the main mineral elements found in the apical shoots (4–5 mm long) and in mature embryos in olive and almond. Olive tissues were characterized by a high content of Ca, Mg, S, Cu and Zn compared to almond, which is easy to propagate on MS medium. In this newly derived medium, characterized by a high content of these elements, multiplication rate (number of nodes formed per explant) was about 9× in 40 days. The shoots grew more rapidly and were more tender than when grown in other media. Washing of the explants in water or GSH (reduced glutathione) solution, before sub-culturing, improved quality and growth rate of the shoots. Explants, with 2 or 3 nodes, rooted easily in half-strength MS, in Bourgin and Nitsch, or in half Knop macro and Heller microelements, agar media, with 1 mg 1 −1 NAA and 2% sucrose. Rooting was not affected by the different degrees of juvenility of the original explants used. Hardening-off was achieved by growing plants in a 1:1 mixture of perlite and peat-moss in a transparent plastic chamber with saturated circulating air for 1 month. GA 3 sprayed on the leaves was found to be beneficial in stimulating growth resumption of plantlets.

Shoot performance and population structure in pure stands of Mercurialis perennis L., a rhizomatous perennial herb.

Shoot populations of the rhizomatous perennial herb Mercurialis perennis were studied in pure stands throughout a developmental cycle in a mixed deciduous wood in eastern England. Shoot cohorts exhibited exponential decay between May and October, with half-lives ranging from 2.1 to 7.1 months, although three out of five populations decayed at virtually the same rate. Differences in decay rates were interpreted on environmental grounds. Fertile shoots exhibited higher percentage survival than sterile shoots throughout their growth, and fewer than 5% of them died until well after flowering had been completed. At all dates fertile shoots were significantly taller and heavier than sterile shoots. Shoot growth rates were rapid until tree canopy closure; after canopy closure little change in size occurred. Similarities exist between several aspects of the behaviour of shoot cohorts of M. perennis and Solidago canadensis, another rhizomatous herb.

Pohlia andrewsii and P. tundrae, Two New Arctic-Alpine Propaguliferous Species from North America

Two new propaguliferous species, P. tundrae J. Shaw and P. andrewsii J. Shaw are described. Pohlia tundrae, a characteristic moss of mesic alpine tundra in the western United States may be endemic to North America. Pohlia andrewsii is recorded from arctic Alaska, the Yukon and Northwest Territories, Greenland, Spitzbergen, Norway and Czechoslovakia. The propagula of P. tundrae and P. andrewsii are structurally similar to those of previously described Pohlia species, but are distinguished by unique patterns of development. Quantitative data indicate that Pohlia tundrae and P. andrewsii are consistently distinct from similar, previously described propaguliferous Pohlia taxa. In the only revision of the genus Pohlia in North America, Andrews (1935) recognized 28 species, including six producing asexual propagula in the upper leaf axils of sterile shoots. Propaguliferous Pohlias have historically been distinguished on the basis of small differences in the structural complexity of their propagula, but the species have been inadequately understood because of nomenclatural and taxonomic problems. The six species recognized by Andrews (1935) are known to display considerable variability in propagulum form, and Andrews' revision included no taxa that did not also occur in northern and central Europe. However, I find that the extreme variability often ascribed by North American bryologists to these propaguliferous Pohlia species is actually the result of several unrecognized taxa being confused with and included in the six species described by Andrews. Pohlia tundrae J. Shaw, sp. nov. (Fig. 1-10) Plantae confertim caespitosae, fortiter nigrescentes. Caulis erectus, 2.0-10.0(-20.0) mm altus, dense foliosus. Folia sicca erecta, humida erecto-patentia. Dioica. Perichaetia terminalia, bracteis externis longioribus. Perigonia terminalia, capituliformia. Capsulae pyriformes, horizontales ad nutantes, 1.5-3.0 mm longae. Peristomia duplicia, exostomis dentibus 16. Annulus latus, duplex vel triplex. Gemmae abundantes, axillis foliorum summorum ortae, lineari-cylindraceae ad anguste obconicae, ca. 300-600 /m longae. Affinis Pohliae sectioni Pohliellae. Plants scattered or more often forming dense, compact mats on soil, occasionally more lax and elongate in protected sites, with a distinct gloss when dry; stems 2-5(-15) mm high, green above, red or often ? black below, simple or sometimes once innovating at the base when sterile, often innovating once or twice below the perigonia or perichaetia when fertile; leaves erect to ? spreading when dry, spreading to ? erect when moist, (0.6-)0.8-1.1(-1.4) mm long, (0.2-)0.3-0.4(-0.5) mm wide, narrowly to broadly lanceolate, acute, ? decurrent by 2-5 linear-rectangular cells or often nondecurrent on compact forms; margins plane to ? reflexed when dry, plane when moist, subentire to ? strongly toothed in the upper V2-V1; costa ending 2-4 cells below the apex, rarely in the apex; upper cells rectangular or rhombic to linear-rhombic, sometimes + vermicular, thin-walled, (45-)55-75(-100) /m 1 Present address: Herbarium, North University Bldg., The University of Michigan, Ann Arbor, MI 48109. 007-2745/81/65-74$1.25/0 This content downloaded from 157.55.39.45 on Fri, 02 Sep 2016 06:17:44 UTC All use subject to http://about.jstor.org/terms 66 THE BRYOLOGIST [Volume 84