Predominant Growth Form Research Articles

Assessing Coral Reef Health in Northern Waters of Penata Besar Island West Kalimantan

Penata Besar Island is designated as one of the Coastal and Small Island Conservation Areas (KKP3K) in West Kalimantan, is a critical site for conserving coral reefs and reef fish. Currently, global climate change and anthropogenic activities have exacerbated coral reef bleaching worldwide. In the context of escalating global climate change and human-induced threats, this study evaluates the health condition of coral reefs in the northern waters of Penata Besar Island, Bengkayang Regency. An exploratory approach was employed, utilizing the Line Intercept Transect (LIT) method across four stations at two distinct depths (2-3 m and 5-6 m). The results revealed that coral cover varied with depth. At a depth of 2-3 m, live coral coverage was between 51.2% and 62.4%, classified as good, while at 5-6 m, coverage ranged from 30.4% to 49.4%, categorized as fair. Coral Massive (CM) was the predominant growth form observed. The diversity index (H') ranged from low to medium, the Evennes index (E) from medium to high, and the dominance index (C) was categorized as low. These findings highlight the varying health of coral reefs in different depths and provide a basis and essential insights for targeted conservation efforts.

Dental biofilm: control of formation, disorganization and means of regulation

In press Biofilm is a predominant growth form of a greater number of microorganisms in the oral cavity that has the differences in physiology and genetics compared to planktonic forms. It requires a review of methods of the diagnostics and management of patients with the diseases caused by dental biofilms. The literature review was conducted with the aim of summarizing modern scientific information related to the control of its formation and evaluation of means for disorganization and regulation that are used in clinical dentistry. Based on the results of these studies a close relationship between the level of hygiene and the microbiological state of the oral cavity has been justified. Carrying out individual and professional hygiene is an important component in the comprehensive treatment of dental patients. It has been proven that the pathogenicity of the dental biofilm can be significantly reduced by breaking the integrity of its structure and restoring the normal microflora with the help of high-quality professional hygiene. But long-term uncontrolled use of personal hygiene products can cause some changes in the quality of the microbiome of the oral cavity. Modern research is aimed at disorganization of the biofilm matrix by pharmaceutical and non-pharmacological means. But its destruction can lead to the release of living microorganisms and the dissemination of the pathogen. The presented results of the use of different groups of means for normalizing the microflora of the oral cavity have both advantages and disadvantages that requires further discussion. Qualitative control over the development of dental biofilm will permit to anticipate the course of teeth diseases and periodontal tissues, and objectively assess the effectiveness of the prescribed treatment. Conducting a microbiological study of the biocenosis of the oral cavity will be the basis for choosing personal hygiene products and implementing timely measures. All this will further contribute to increase in the efficiency of prevention and management of pathology of the teeth. Keywords: microorganisms, оral cavity, biofilm, hygiene.

A preliminary assessment of bryophyte diversity in some alpine areas of East Sikkim, India

In the East Sikkim district of India, a field survey revealed the presence of 49 distinct bryophyte taxa, with a significant representation from the Pottiaceae, Leucobryaceae, and Grimmiaceae families. Remarkably, this survey contributes 12 taxa as novel records for Sikkim. Among the bryophytes catalogued, 45 belong to the mosses, while four are liverworts, collectively spanning 18 families, which include 15 moss families and three liverwort families. The predominant growth forms observed are characterized by cushions, mats, or turfs, underscoring the adaptability of these bryophytes to diverse substrates and microenvironments. These bryophytes are recognized for their resilience in challenging environmental conditions, making them valuable indicators of extreme climate and the geological composition, including calcium rocks and gneiss, found in the area.

Bark production of generalist and specialist species across savannas and forests in the Cerrado.

Bark allows species to survive fire, protecting their inner tissues and allowing new branches to resprout from aerial buds. Thus, bark production is likely to be selected with aerial bud protection in fire-prone ecosystems. By considering the coexistence of fire-prone and fire-free ecosystems, in addition to the different impacts of flames on different growth forms, in this study we tested whether: (1) species from areas with higher fire frequencies have a faster bark production; (2) bark growth rate differs between trees and shrubs; (3) generalists adjust their bark production according to their environment (fire-prone or fire-free ecosystems); and (4) fast bark production results in better aerial bud protection. We sampled two different types of forests and savannas in the Cerrado and registered every woody individual with height between 1.5 and 3 m tall (directly exposed to the flames). For the 123 species registered, we sampled three different individuals in each vegetation type where the species occurred to assess their bark production and aerial bud protection. We then checked, for each species, their preferred habitat (savanna and forest specialists or generalists) and their predominant growth form. A minimal threshold of 0.13 mm per growth unit of bark production differentiated woody communities from savannas and forests. Shrubs and trees did not differ in terms of bark growth rate, despite being exposed to the flames in a different manner. Generalist species in savannas were able to produce bark above the threshold. However, when these species were in forests they produced bark below the threshold. Finally, a higher bark growth rate accounted for a better aerial bud protection. Generalist species are likely to be capable of displaying plasticity in their bark production, which could be important for their success in contrasting ecosystems. The relationship between aerial bud protection and bark growth rate suggests that bark production plays an important role in protecting the dormant buds, in addition to being selected in fire-prone ecosystems.

Lagoons, rivers, weirs and their wet gardens in the semiarid: aquatic Eudicotyledons and Ceratophyllaceae of Ceará state, Brazil

Abstract Ceará state holds the second largest wetland extension in Northeastern Brazil and, thus far, there have been taxonomic studies developed about aquatic macrophytes richness for the clades of Monocots and Nymphaeales, and of two Eudicot families only. In this context, the present study is a synopsis of the aquatic representatives of Eudicotyledons and Ceratophyllaceae in Ceará state, providing further information about the biodiversity of aquatic ecosystems in the Brazilian semiarid. We present an updated survey based on material deposited at the EAC, IPA, R and RB herbaria and on images from digital platforms, including diagnostic descriptions, identification keys, photographs and comments about geographic distribution. We recorded 28 families, 43 genera and 82 species. The most representative families were Lentibulariaceae (12 spp.), Malvaceae (9 spp.), Plantaginaceae (9 spp.), Fabaceae (8 spp.) and Onagraceae (7 spp.), whilst Ceratophyllaceae was represented by one species only. Helophytes were the predominant growth form (64%), followed by the bottom-rooted emergent hydrophytes (20%), and Podostemaceae was the only family represented by haptophytes (4 spp.).

Flora of the core zones of the Monarch Butterfly Biosphere Reserve, Mexico: composition, geographical affinities and beta diversity

Background: Knowing the floristic composition of the Monarch Butterfly Reserve is a critical piece of information necessary for its conservation.
 Question/Hypothesis: i) How many plant species (total and endemic to Mexico) are found in the core zones of the Monarch Butterfly Biosphere Reserve (MBBR)? ii) What are the most frequent growth forms found in this reserve? iii) What is the species diversity for the different types of vegetation? and iv) What is the floristic similarity among the core zones?
 Studied species/ Data description/ Mathematical model : Ferns, Gimnosperms and Angiosperms.
 Study site and years of study: The three core zone (Cerro Altamirano, Cerro Pelón and Chincua-Campanario-Chivati) of the MBBR were studied from 2000 to 2006.
 Methods: A total of 49 field trips were conducted over three years (2004 to 2006) to the core zones, and previously collected specimens (2000-2003) were revised in the IEB herbarium. Beta diversity among the core zones was estimated by calculating Jaccard index (JI).
 Results: A total of 97 families, 337 genera, 694 species and 20 infraspecific categories were inventoried. Asteraceae (147 species) and Fabaceae (37), as well as Salvia (23), Quercus (12) and Stevia (12) were the most diverse taxa. Herbaceous plants were the predominant growth form (ca. 75 %). The vegetation types with the greatest number of species were forests dominated by Quercus (427) and by Abies (329). About 38 % of species documented are endemic to Mexico. The core zones show high beta diversity values (Jaccard index 0.03 to 0.11); more of the half of the total number of species documented (66.3 %) was found exclusively in one core zone.
 Conclusions: The core zones are complementary in terms of plant conservation purposes and require similar conservation resources in order to secure important long-term maintenance of the biodiversity and forest cover that serve as winter refuges of the migrant Monarch butterfly populations.

Impact of the non-indigenous shrub speciesSpartium junceum(Fabaceae) on native vegetation in central Spain

Aims The introduction of potentially invasive species through ornamental cultivation or for rehabilitation purposes is a serious environmental problem. They cause damage to biodiversity through loss, increased mortality or ‘in situ’ selection phenomena in natural flora. Spartium junceum is a Mediterranean shrub that is not native in most areas of the Iberian Peninsula, although it is extensively grown for the rehabilitation of roadsides. We have investigated the effect on the native vegetation of an old S. junceum (Fabaceae) plantation in a conservation area in the centre of the Iberian Peninsula: the Cuenca Alta del Manzanares nature reserve in Madrid. Methods We compared S. junceum stands with the native nanophanerophytic Cistus ladanifer community at different ecosystem properties: soil properties, temporal soil seed bank contents, standing vegetation and net primary production of annual grasslands growing in these shrublands. Important Findings The results highlighted S. junceum’s ability to become established in the new environment (marginal areas of the nature reserve) and ensure its successful growth. This is more apparent in northern and eastern exposures where this formation contacts with the core of the best conserved native vegetation in the nature reserve. Soils under Spartium showed a higher nitrogen content, indicating its capacity—in common with other legumes—to fix N, and conferring an advantage over Cistus, which is N-limited. Other soil nutrients such as phosphorus, magnesium and calcium and water availability are also higher in Spartium soils than in Cistus. Phosphorus is usually a constraint for N-fixers, but in our study, it is the most significant soil variable in both shrub formations and is important to the success of Spartium. Water availability is a key factor for Mediterranean vegetation, and particularly in autumn when soils are recharged. The Spartium formation is able to retain water as its growth produces a closer canopy than Cistus, thereby preventing water evaporation and contributing to the success of this species. Perennials are more frequent in the standing vegetation than in the seed bank, whereas therophytes are similar. The standing vegetation has therophytes and chamaephytes as the predominant growth forms in Spartium sites, and hemicryptophytes and phanerophytes in Cistus. Therophytes are dominant in Spartium and Cistus seed banks, although the first formation has more species. Spartium has a higher number of hemicryptophytes and Cistus is higher in phanerophytes. Northern and eastern aspects show significant differences in richness—with a predominance of annual weed species in Spartium—and in aboveground net primary production, probably as a consequence of the nutrients present in the soils. Ruderal annual species under Spartium (Bromus tectorum, Chenopodium album) have higher germination rates in the greenhouse than in the standing vegetation, suggesting they are at potential risk if environmental conditions change.

Floristic Composition and Vegetation Structure of The KNUST Botanic Garden, Kumasi, Ghana

The diversity, relative importance, canopy height and cover of plant species in the Kwame Nkrumah University of Science and Technology (KNUST) Botanic Garden were evaluated in five 1-ha plots using a stratified random sampling technique in order to build an understanding of its floristic composition and structure in two distinct parts of the garden (cultivated and uncultivated). We recorded 184 species which belonged to 146 genera, 51 families and six growth forms. The most dominant tree species in the garden were Elaeis guineensis Jacq., Hevea brasiliensis (Willd.) Muell.-Arg. and Parkia biglobosa (Jacq.) G. Don. with a combined importance index of 60.09 (20 % relative importance). The differences in importance value indices of species between the cultivated and uncultivated areas of the garden were statistically insignificant (p > 0.05), suggesting the presence of conducive growth environments for plants in both areas. The most dominant families were Fabaceae, Moraceae, Arecaceae and Euphorbiaceae whilst trees were the most predominant growth forms (62.5 %). Average crown height and percentage canopy were 28.8 ± 8.81 m and 66.4 ± 8.26 % respectively. These results show the floristic richness of the KNUST botanic garden and underscore the garden\'s potential as a centre for ex-situ conservation beside its traditional roles in education, research and recreation. Keywords: Floristic composition, structure, botanic garden, KNUST Journal of Science & Technology (Ghana) Vol. 28 (3) 2008: pp. 103-122

Regulating the transition between the two major fungal cell types; yeast cells and filamentous hyphal cells

Fungi are a large group of eukaryotic microorganisms that are of medical, agricultural and biotechnological importance. They are a diverse group, occupying their own kingdom, and range from single cells to what is arguably the largest mutlicellular organism on earth. Despite this diversity, fungi exhibit two predominant growth forms; unicellular yeast and multicellular filamentous hyphae. Some fungi can alternate between these two forms in response to an intrinsic or extrinsic stimulus, a process known as dimorphic switching.

Influence of different mixing and aeration regimens on pectin lyase production by Penicillium griseoroseum

Penicillium griseoroseum was grown in a 20 l fermenter under different degrees of mixing and aeration to evaluate the effect of these variables on fungal macroscopic morphology and growth, as well as on production of pectin lyase (PL). A 2 4−1 fractional factorial design was used. Growth time was divided into two periods: the initial phase, comprised the first 25 h and the final phase, 25 to 60–72 h of growth. Pellet formation was the predominant growth form and no morphological differences were observed between treatments. Increasing the initial mixing rate from 50 to 200 rpm favored increased PL activity (U/g), but increasing the final mixing rate from 200 to 300 rpm did not influence it significantly. Combined analyses of the initial and final aeration rates showed that only the combination of no initial aeration and a final aeration rate of 20 l/min reduced PL activity (U/g).

PLANT-MEDIATED CONTROLS ON NUTRIENT CYCLING IN TEMPERATE FENS AND BOGS

This paper reports on patterns in plant-mediated processes that determine the rate of nutrient cycling in temperate fens and bogs. We linked leaf-level nutrient dynamics with leaf-litter decomposition and explored how the observed patterns were reflected in nutrient cycling at the ecosystem level. Comparisons were made among growth forms (evergreen and deciduous shrubs and trees, graminoids and Sphagnum mosses) and between mire types (fens and bogs). A literature review showed that the predominant growth form was more important as a determinant of leaf-level nutrient-use efficiency (NUE) than mire type (fen vs. bog). Evergreens had the highest N and P use efficiency. The growth form differences in NUE were mainly determined by differences in N and P concentrations in mature leaves and not by differences in resorption efficiency from senescing leaves. Sphagnum leaves had lower N and P concentrations than the other growth forms, but because of a lack of data on nutrient resorption efficiency the NUE of these mosses could not be calculated. Nitrogen use efficiency did not differ among fen and bog species, whereas bog species had a higher P use efficiency than fen species. However, a complete evaluation of mire-type or growth-form effects on NUE is only possible when data become available about nutrient resorption from senescing Sphagnum leaves. As leaf-level NUE is negatively correlated with leaf-litter nutrient concentrations, there is a direct link between NUE and litter decomposition rate. Rates of litter decomposition of Sphagnum mosses are lower than in the other growth forms, but there is still much speculation about possible reasons. The role of litter chemistry of Sphagnum mosses (including decay inhibitors and decay-resistant compounds) in decomposition especially warrants further study. The strongly deviating nutritional ecology of Sphagnum mosses clearly distinguishes fens and bogs from other ecosystems. Moreover, N and P concentrations in mature leaves from vascular plant species from fens and bogs are in almost all cases lower and leaf-level N use efficiency is higher than in species from other ecosystems, irrespective of the growth form considered. Both literature data and data from a comparative study on soil nutrient cycling in temperate fens and bogs in the United States (Maryland), The Netherlands, and Poland showed that nutrient mineralization did not differ clearly between fens and bogs. The comparative study further showed that cellulose decomposition in bogs was lower than in fens and that nutrient mineralization was higher in forested than in herbaceous mires. The occurrence of dominant growth forms was clearly related to soil nutrient-cycling processes, and observed patterns were in agreement with patterns in the components of NUE as found in the literature study. We conclude that a protocol with standardized procedures for measuring various nutrient-cycling process rates that is used by scientists in various wetland types and geographical regions is a useful tool for unravelling large-scale patterns in soil nutrient-cycling processes in wetlands and for linking plant-mediated nutrient dynamics with ecosystem nutrient-cycling processes.

Plant-Mediated Controls on Nutrient Cycling in Temperate Fens and Bogs

This paper reports on patterns in plant-mediated processes that determine the rate of nutrient cycling in temperate fens and bogs. We linked leaf-level nutrient dynamics with leaf-litter decomposition and explored how the observed patterns were reflected in nutrient cycling at the ecosystem level. Comparisons were made among growth forms (evergreen and deciduous shrubs and trees, graminoids and Sphagnum mosses) and between mire types (fens and bogs). A literature review showed that the predominant growth form was more important as a determinant of leaf-level nutrient-use efficiency (NUE) than mire type (fen vs. bog). Evergreens had the highest N and P use efficiency. The growth form differences in NUE were mainly determined by differences in N and P concentrations in mature leaves and not by differences in resorption efficiency from senescing leaves. Sphagnum leaves had lower N and P concentrations than the other growth forms, but because of a lack of data on nutrient resorption efficiency the NUE of these mosses could not be calculated. Nitrogen use efficiency did not differ among fen and bog species, whereas bog species had a higher P use efficiency than fen species. However, a complete evaluation of mire-type or growth-form effects on NUE is only possible when data become available about nutrient resorption from senescing Sphagnum leaves. As leaf-level NUE is negatively correlated with leaf-litter nutrient concentrations, there is a direct link between NUE and litter decomposition rate. Rates of litter decomposition of Sphagnum mosses are lower than in the other growth forms, but there is still much speculation about possible reasons. The role of litter chemistry of Sphagnum mosses (including decay inhibitors and decay-resistant compounds) in decomposition especially warrants further study. The strongly deviating nutritional ecology of Sphagnum mosses clearly distinguishes fens and bogs from other ecosystems. Moreover, N and P concentrations in mature leaves from vascular plant species from fens and bogs are in almost all cases lower and leaf-level N use efficiency is higher than in species from other ecosystems, irrespective of the growth form considered. Both literature data and data from a comparative study on soil nutrient cycling in temperate fens and bogs in the United States (Maryland), The Netherlands, and Poland showed that nutrient mineralization did not differ clearly between fens and bogs. The comparative study further showed that cellulose decomposition in bogs was lower than in fens and that nutrient mineralization was higher in forested than in herbaceous mires. The occurrence of dominant growth forms was clearly related to soil nutrient-cycling processes, and observed patterns were in agreement with patterns in the components of NUE as found in the literature study. We conclude that a protocol with standardized procedures for measuring various nutrient-cycling process rates that is used by scientists in various wetland types and geographical regions is a useful tool for unravelling large-scale patterns in soil nutrient-cycling processes in wetlands and for linking plant-mediated nutrient dynamics with ecosystem nutrient-cycling processes.

Isolated Pasture Trees and the Vegetation under their Canopies in the Chiapas Coastal Plain, Mexico1

ABSTRACTThe Coastal Plain of Chiapas (southern Mexico) was formerly covered by large tracts of subhumid tropical forests but is heavily deforested at present. In this region, 15 pastures were selected to characterize species composition of isolated trees, as well as to describe species composition, growth form patterns, and patterns of dispersal units in the vegetation growing under their canopies. The 65 recorded pasture trees belonged to 20 species and 11 families, of which Fabaceae and Moraceae were the most species‐rich. Coccoloba barbadensis (Polygonaceae) and Enterolobium cyclocarpum (Fabaceae) were the most abundant and frequent trees in the studied pastures. More than half (55%) of isolated tree species were fleshy‐fruited. In the vegetation sampled under pasture trees, 134 species and 45 families were found. Fabaceae and Poaceae had the largest numbers of species. Herbs were the predominant growth form (46.3%), followed by shrubs (23.9%), trees (23.1%), and lianas (2.2%); 6 species could nor be placed in any growth form category. Most species of this flora were fleshy‐fruited (43.3%), followed by heavy, gravity‐dispersed fruits (17.9%). The analysis of dispersal units by growth form category confirmed the prevalence of fleshy fruits, although their predominance was not so obvious among herb species. Almost half (49.2%) of the flora under pasture trees was typical of secondary vegetation; this pattern was true for herbs but not for most woody species, which were typical of primary vegetation. A numeric classification of the vegetation samples taken under pasture trees produced eight floristic groups, all of which were independent of the specific identity of pasture trees. No significant effect of dispersal unit type of pasture tree on the characteristics of the vegetation growing under them was found. Future attempts to re‐create the original forest cover using isolated trees in pastures as regeneration foci should pay more attention to the maintenance of a large specific diversity independently of the dispersal types among these components of tropical landscapes.

Winter water relations of timberline larch (Larix leptolepis Gord.) on Mt. Fuji

A krummholz mat of larch, Larix leptolepis, is the predominant growth form near the upper limit (near 2500 m) of the timberline ecotone on the south slope of Mt. Fuji, Japan. On the south-eastern slope, the tree line is lowered to 1600 m because of the last volcanic eruption. The extent and causes of winter desiccation were compared in timberline larch between 2500 m and 1600 m elevation over two winters. Bark abrasion due to wind-blown fine volcanic gravels caused a decrease in bark resistance to water loss and resulted in severe desiccation damage to current-year shoots of krummholz larches in the winter of 1986 – 87 at 2500 m, whereas abraded shoots at 1600 m maintained high water content during both winters. In the winter of 1985 – 86, shoots of krummholz larches at 2500 m did not experience bark abrasion and high water contents were maintained. Experimental abrasion of shoot surfaces resulted in similar results at each elevation. Thus, in timberline larch at 2500 m, abrasion by wind-blown fine volcanic gravels is the primary factor causing winter desiccation damage and krummholz formation. Based on field experiments, the estimated amount of water movement to non-abraded shoots was the same for the two elevations. At 2500 m, water movement to abraded shoots was less than to non-abraded shoots, but the reverse situation was noted at 1600 m. Water supply to abraded shoots at 2500 m was limited and insufficient to compensate for water loss. A cause of limited water supply at 2500 m may be xylem embolism.

A watershed level analysis of the lakeshore plant community

An investigation was conducted to determine whether the variables, standing crop and sediment organic matter content, related to species richness patterns at the local level, varied at the landscape level in accordance with differences in lake watershed area. Previous study had demonstrated the importance of watershed area as a predictor of species richness of all herbs and of rarities, in particular, on lakeshores. In this study, the reciprocal of watershed area (log units) accounted for over 75% of the variation in biomass at above and below summer waterline positions. Furthermore, watershed area accounted for most of the variation in sediment organic matter content. Above the waterline, shrubs were the predominant growth form at lakes with small watershed areas; the reciprocal of watershed area accounted for 92% of shrub biomass variation. Shoreline plant communities on the lowest watershed area lake were high-biomass, shrub assemblages above waterline and low-biomass, graminoid communities below the waterline. In contrast, above the waterline but below the upper shrub zone on the high watershed area lake, shorelines supported low-biomass assemblages composed of a mixture of shrubs, graminoids, forbs, and ferns. The strong relationships found here between biomass and organic matter and lake watershed area reconcile predictive models made at the within-lake level with those made at the landscape level. Key words: watershed area, landscape models, species richness, community biomass, lakeshores.

Las algas de El Salto, San Luis Potosí, México: un ejemplo de estudios florísticos en ambientes cambiantes

Se reseñan las especies algales que se desarrollan en las pozas de El Salto, sobre el cauce del río del mismo nombre. Varias de éstas pozas en época de secas se encuentran aisladas del cauce principal y presentan características similares a las de ambientes lenticos en cuanto a movimiento de agua y formas de crecimiento de las algas. En época de lluvias, éstas pozas quedan incorporadas al cauce principal, lo cual provoca un cambio en las formas de crecimiento predominantes. Se identificaron un total de 68 especies distribuidas de la siguiente forma: 42 especies de la Clase Bacillariophyceae (61.76%), 14 especies de la Clase Chlorophyceae (20.59 %), 3 especies de la Clase Charophyceae (4.41 %), 7 especies de la Clase Cyanophyceae (10.29 %) y las Clases Rhodophyceae y Dinophyceae representadas por 1 especie cada una (1.47 %). Las formas de crecimiento predominantes en las pozas aisladas, al igual que en otros cuerpos de agua estancada, son masas de filamentos flotantes, constituídas principalmente por especies del Orden Zygnematales, además de formas de vida fitoplanctónicas y metafíticas.

Caracterización ficológica en manantiales de la cuenca baja del sistema hidrológico del Pánuco, México

Se presentan los resultados del estudio ficofloristico de tres manantiales en la región de la Huasteca Potosina, en el que se reportan 67 especies algales. Se analizan las diferencias y similitudes florísticas y su relación con algunos parámetros ambientales como la iluminación y velocidad de corriente, que fueron los factores más importantes que afectaron las formas de crecimiento predominantes en estos ambientes. En estos manantiales se definieron los microambientes y las principales asociaciones algales que los caracterizan.

Coppice growth and water relations of silver maple

Trees of silver maple (Acer saccharinum L.) planted in southern Illinois were cut at rootstock ages 2, 3, and/or 4 years. In all plantings a single main stem was the predominant growth form prior to initial harvest. The predominant post-harvest growth form was numerous coppice stems. The number of coppice stems per tree and percent tree survival decreased with greater stand density. Coppice growth, as measured by the number of stems and the height of the tallest stem, increased progressively with the number of harvest cycles. This growth was supported by a progressively older root system, and developed from an increasing number of cut stem bases. About 60% of the coppice were tall stems, over one-half the height of the tallest stem. Trees of the southernmost origin, from Mississippi, with high establishment rates had the highest dry weight production of two-year provenance coppice growth (equivalent to 59.5 Mg · ha −1 · 2 year −1, or 13.2 ton · acre −1 · year −1). The northernmost trees, from central Ontario, had low establishment rates and the lowest stand biomass. Dormant season macronutrient cropping losses were estimated related to biomass yield. Foliage density and stem elongation were greater in first-year coppiced compared to uncoppiced trees. Water relations of coppice growth differed from that of uncoppiced trees in both the first and the second year after harvest.

Dispersal and growth form patterns of some zonal páramo vegetation types

SUMMARY In zonal vegetation of the paramo Boca Grande (Sumapaz), in the Colombian Cordillera Oriental, the dispersal and growth form spectra of the different vegetation zones are described. With increasing altitude the abundance of the zoochorous plant species decreased while anemochory increased. A possible relationship between the mode of dispersal and the growth forms was also investigated. The most important modes of dispersal were not restricted to a special growth form but appeared to prevail in the predominant growth forms of the successive zones. In addition a global distribution of the weight of the diaspores and of the phenological state of the species is given.

Morphogenesis and Fine Structure of the Actinomycetous Endophyte of Nitrogen-Fixing Root Nodules of Comptonia peregrina

The morphogenesis and fine structure of the cultured endophyte isolated from root nodules of Comptonia peregrina have been studied, utilizing scanning electron microscopy, transmission electron microscopy, and Nomarski interference microscopy; comparisons were made with the endophyte in vivo The actinomycetous nature of the endophyte was confirmed Prokaryotic, branched septate hyphae, less than 1 μm in diameter, are the predominant growth form Some hyphae increase in diameter (ca. 1-1.5 μm) and undergo morphogenesis, forming club-shaped sporangia in vitro The sporangia produced numerous sporangiospores which are presumed to be the propagative state of the microorganism. Sporangia were formed by the growth of longitudinally and transversely oriented septa which compartmentalize the wider hyphae. Sporangia were not observed in vivo in Comptonia Club-shaped septate vesicles formed in vivo but not in vitro. The mature spores contained electron-dense inclusions resembling eukaryotic nucleoli, numerous vesicular structures, nucleoid regions, and a thick multilayered wall. The microorganism in vitro lacked a capsule which the organism possessed in vivo, providing further evidence for the role of the host in the deposition of this encapsulating wall material.