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Tomasz Pawlowski - One of the best experts on this subject based on the ideXlab platform.

  • Proteomic Analysis of Embryogenesis and the Acquisition of Seed Dormancy in Norway Maple (Acer Platanoides L.)
    International journal of molecular sciences, 2014
    Co-Authors: Aleksandra Maria Staszak, Tomasz Pawlowski
    Abstract:

    The proteome of zygotic embryos of Acer Platanoides L. was analyzed via high-resolution 2D-SDS-PAGE and MS/MS in order to: (1) identify significant physiological processes associated with embryo development; and (2) identify changes in the proteome of the embryo associated with the acquisition of seed dormancy. Seventeen spots were identified as associated with morphogenesis at 10 to 13 weeks after flowering (WAF). Thirty-three spots were associated with maturation of the embryo at 14 to 22 WAF. The greatest changes in protein abundance occurred at 22 WAF, when seeds become fully mature. Overall, the stage of morphogenesis was characterized by changes in the abundance of proteins (tubulins and actin) associated with the growth and development of the embryo. Enzymes related to energy supply were especially elevated, most likely due to the energy demand associated with rapid growth and cell division. The stage of maturation is crucial to the establishment of seed dormancy and is associated with a higher abundance of proteins involved in genetic information processing, energy and carbon metabolism and cellular and antioxidant processes. Results indicated that a glycine-rich RNA-binding protein and proteasome proteins may be directly involved in dormancy acquisition control, and future studies are warranted to verify this association.

  • Qualitative changes and dynamics of protein synthesis during cold and warm stratification of Norway maple [Acer Platanoides L.] seeds
    Acta Societatis Botanicorum Poloniae, 2014
    Co-Authors: Tomasz Pawlowski, Zofia Szczotka, Kazimierz Krawiarz
    Abstract:

    Protein synthesis in cotyledons and embryo axes of Norway maple ( Acer Platanoides L.) was studied in seeds stratified at 3 or 15 o C. At 3 o C stratification, germination of seeds starts after 9 weeks, at 15 o C stratification germination does not occur. The changes of protein synthesis level in both temperatures had two phasic character. In embryo axes (3 and 15 o C) protein synthesis grow up, but in cotyledons (3 o C) synthesis of proteins decrease. Generally, activity of protein synthesis was higher at 3 o C, as like as DNA level was higher. After imbibition, in cold and warm stratification, in embryo axes, many new protein are become visible. We expect, that two from this proteins, determined as A and B my be connected with the releasing from dormancy. In seeds stratified at 15 o C, these proteins are occuring in vestigal amount or are completely absent.

  • QUALITATIVE AND QUANTITATIVE CHANGES IN PROTEINS IN Acer Platanoides L. SEEDS DURING MATURATION
    Acta Biologica Cracoviensia Series Botanica, 2003
    Co-Authors: Tomasz Pawlowski, A. Kalinowski
    Abstract:

    Maturation of Norway maple (Acer Platanoides L.) seeds produces deep physiological dormancy and resistance to desiccation. This study used two-dimensional electrophoresis to investigate the protein products of genes activated during the complex developmental process of maturation. Qualitative and quantitative changes in protein composition during maturation were tracked in this species. The most intensive changes in protein content appeared at the end of seed maturation, in embryo axes and cotyledons. During this time their protein content increased significantly and new proteins appeared. Presumably the proteins Q (15 kDa, pI 8) and X (16 kDa, pI 5) separated from cotyledons are associated with maturation of seeds.

  • Qualitative changes in protein content during cold and warm stratification of Norway maple ( Acer Platanoides L.) seeds
    Seed Science Research, 1997
    Co-Authors: Tomasz Pawlowski, Zofia Szczotka
    Abstract:

    Protein synthesis in embryonic axes of Norway maple ( Acer Platanoides ) was studied in seeds stratified at 3 or 15°C. At 3°C stratification, germination of seeds started between 6 and 7 weeks; at 15°C stratification germination did not occur. During imbibition of embryonic axes undergoing cold and warm stratification many new proteins became visible. Two of these proteins may be connected with the release from dormancy at 3°C. In seeds stratified at 15°C, these proteins occur in low amounts or are completely absent.

Steven R. Wangen - One of the best experts on this subject based on the ideXlab platform.

  • Spatial characteristics of the invasion of Acer Platanoides on a temperate forested island.
    Biological Invasions, 2006
    Co-Authors: Steven R. Wangen, Christopher R. Webster, Jennifer A. Griggs
    Abstract:

    We examined the spatial pattern of an introduced population of Norway maple (Acer Platanoides L.) on a temperate forested island in order to quantify the influence of landscape context on invasion pattern. The spatial location of every Norway maple tree and sapling (≥0.5 m tall) that had invaded the island forest (n = 4496) was mapped using a global positioning system. The influence of landscape context was examined with the aid of a geographic information system and indices of spatial association. We found that the coniferous forest type was the most heavily invaded (71.9% of all Norway maple stems) when compared to either the hardwood or mixed conifer–hardwood forest types (5.4% and 19.3%, respectively). Across all forest types (excluding urban trees), the population was highly aggregated around roads and other Norway maple trees. For example, 90% of the population was within 40.8 m of a road with an average distance from road of 21.02 ± 0.40 m. This association around roads was significantly greater than would be predicted by chance alone (P < 0.001). Similarly, nearest neighbor distances averaged 4.5 ± 0.2 m with 90% of individuals within 8.3 m of another Norway maple. Measures of spatial association indicated that the invasion was significantly aggregated at both the stand and island scale. Nevertheless, a comparatively small but potentially influential set of individuals were observed at relatively long distances from the main invasion front. Ramifications of these disjunct establishments and other observed patterns are discussed in the context of current spread pattern theory, invasive species monitoring, and control efforts.

  • Stand dynamics of an insular population of an invasive tree, Acer Platanoides
    Forest Ecology and Management, 2004
    Co-Authors: Christopher R. Webster, Kathryn Nelson, Steven R. Wangen
    Abstract:

    Abstract Acer Platanoides L. (Norway maple) is an invasive exotic tree species in the eastern and central United States that poses a serious threat to native forests. In order to improve our understanding of how this species invades native forests, we conducted a retrospective analysis of the stand dynamics of an established population of A. Platanoides in a natural area on a temperate forested island in Lake Huron, Michigan, USA. Tree ring analysis was used to reconstruct the canopy recruitment of contemporary A. Platanoides overstory trees, and a simple gap capture method was used to investigate gap capture rates for A. Platanoides and native species. Given the extreme shade-tolerance of A. Platanoides, surprisingly few of the contemporary A. Platanoides overstory trees in the forest showed evidence of past suppression suggesting that most established under relatively open canopy conditions and/or in canopy gaps. Height growth comparisons with native species suggest that A. Platanoides should be able to capture canopy gaps at least a decade before most common tree species on the island. A. Platanoides displayed rapid juvenile growth rates that declined significantly (P

Wei Fang - One of the best experts on this subject based on the ideXlab platform.

  • Spatial analysis of an invasion front of Acer Platanoides: dynamic inferences from static data
    Ecography, 2005
    Co-Authors: Wei Fang
    Abstract:

    It is an open question whether the invading tree species Acer Platanoides is invading and displacing native trees within pre-existing forest stands, or merely preferentially occupying new stands of secondary forest growth at the edges of existing forests. Several threads of spatial pattern analyses were used to assess the invasibility of A. Platanoides, and to link the invasion to the structure of a plant community in the deciduous forest of the northeastern United States. The analyses were based on maps of a contiguous 100×50 m area along an A. Platanoides infestation gradient. The distribution of A. Platanoides was highly aggregated and the population importance value increased from 28.1 to 38.5% according to mortality estimated from standing dead trees, while the distribution of native tree species was close to random and importance value of Quercus spp. decreased from 33.4 to 26.9% over time. The size distributions of each tree species across distance indicated that A. Platanoides was progressively invading the interior of the forest while the native species (including A. rubrum) were not spreading back towards the A. Platanoides monospecific patch. The null hypothesis of no invasibility was rejected based on quantile regressions. There were negative correlations between A. Platanoides density and the densities of native species in different functional groups, and negative correlation of A. Platanoides density and the species diversity in forest understory. The null hypothesis that A. Platanoides invasion did not suppress native trees or understory was rejected based on Dutilleul's modified t-test for correlation, consistent with experimental results in the same study site. The combination of multiple spatial analyses of static data can be used to infer historical dynamical processes that shape a plant community structure. The concept of “envelop effects” was discussed and further developed.

Patrick H. Martin - One of the best experts on this subject based on the ideXlab platform.

  • Neighbourhood models of the effects of the invasive Acer Platanoides on tree seedling dynamics: linking impacts on communities and ecosystems
    Journal of Ecology, 2007
    Co-Authors: Lorena Gómez-aparicio, Charles D. Canham, Patrick H. Martin
    Abstract:

    Summary 1. Effects of invasive species on ecosystem processes are often thought to underlie the effects of invaders on community dynamics. Specifically, positive feedbacks in which invasive species alter ecosystem function in ways that favour their own growth have been suggested as an important mechanism contributing to the success of invasion. 2. In this study, we analysed the impacts of the invasive exotic tree Acer Platanoides on survival and growth of conspecific and native tree seedlings, and explored whether these impacts can be explained by the ecosystem effects of the invader. Seedlings of Acer Platanoides , Acer saccharum , Fraxinus americana and Prunus serotina were monitored in quadrats in three forest stands in northwestern Connecticut. Soil resources and light levels were quantified in the same quadrats. 3. Maximum-likelihood methods were used to predict seedling survival and growth as a function of the size and spatial configuration of A. Platanoides trees in the immediate neighbourhood (0‐25 m). 4. The abundance of A. Platanoides in the neighbourhood had moderate negative effects on survival of first-year conspecific seedlings, but did not affect survival of older conspecific or native seedlings. These negative effects on conspecifics were not correlated with soil nutrients or light levels, but were presumably related to Janzen-Connell effects. In contrast, A. Platanoides had strong positive effects on the growth of seedlings of all four species. These positive effects appear to be related to the positive impacts of the invader on soil fertility. 5. Our results support the importance of canopy-seedling feedbacks as a mechanism regulating the rate of invasion in forests. However, they also indicate that the net consequences of feedbacks on the process of invasion are probably determined by the balance of positive and negative feedbacks acting at the same time on different aspects of regeneration (i.e. survival vs. growth). 6. Synthesis . Because the species with the highest inherent growth rates were the most responsive to the ‘fertilizing’ effect of A. Platanoides , we conclude that the invasion of north-eastern forests by this exotic tree may facilitate canopy dominance by fast-growing native and exotic species associated with fertile soils.

  • Neighbourhood models of the effects of the invasive Acer Platanoides on tree seedling dynamics: linking impacts on communities and ecosystems
    Journal of Ecology, 2007
    Co-Authors: Lorena Gómez-aparicio, Charles D. Canham, Patrick H. Martin
    Abstract:

    13 pages, 4 figures, 4 tables, 63 references.Effects of invasive species on ecosystem processes are often thought to underlie the effects of\ud invaders on community dynamics. Specifically, positive feedbacks in which invasive species alter\ud ecosystem function in ways that favour their own growth have been suggested as an important\ud mechanism contributing to the success of invasion.\ud In this study, we analysed the impacts of the invasive exotic tree\ud Acer Platanoides\ud on survival and\ud growth of conspecific and native tree seedlings, and explored whether these impacts can be\ud explained by the ecosystem effects of the invader. Seedlings of\ud Acer Platanoides, Acer saccharum,\ud Fraxinus americana\ud and\ud Prunus serotina\ud were monitored in quadrats in three forest stands in northwestern\ud Connecticut. Soil resources and light levels were quantified in the same quadrats.\ud Maximum-likelihood methods were used to predict seedling survival and growth as a function of\ud the size and spatial configuration of\ud A. Platanoides\ud trees in the immediate neighbourhood (0–25 m).\ud The abundance of\ud A. Platanoides\ud in the neighbourhood had moderate negative effects on\ud survival of first-year conspecific seedlings, but did not affect survival of older conspecific or native\ud seedlings. These negative effects on conspecifics were not correlated with soil nutrients or light\ud levels, but were presumably related to Janzen-Connell effects. In contrast,\ud A. Platanoides\ud had strong\ud positive effects on the growth of seedlings of all four species. These positive effects appear to be\ud related to the positive impacts of the invader on soil fertility.\ud Our results support the importance of canopy-seedling feedbacks as a mechanism regulating the\ud rate of invasion in forests. However, they also indicate that the net consequences of feedbacks on\ud the process of invasion are probably determined by the balance of positive and negative feedbacks\ud acting at the same time on different aspects of regeneration (i.e. survival vs. growth).\ud Synthesis: Because the species with the highest inherent growth rates were the most responsive\ud to the ‘fertilizing’ effect of\ud A. Platanoides, we conclude that the invasion of north-eastern forests by\ud this exotic tree may facilitate canopy dominance by fast-growing native and exotic species associated\ud with fertile soils.This work was\ud supported by a Postdoctoral Fulbright Fellowship (FU2004-1288) to L.G.A\ud and a grant from USDA (2003-35320-13583) to C. D. Canham and P. L.\ud Marks.Peer reviewe

Ragan M. Callaway - One of the best experts on this subject based on the ideXlab platform.

  • facilitation and inhibition of seedlings of an invasive tree Acer Platanoides by different tree species in a mountain ecosystem
    Biological Invasions, 2006
    Co-Authors: Kurt O Reinhart, Fernando T. Maestre, Ragan M. Callaway
    Abstract:

    Facilitation is known to be an important process structuring natural plant communities. However, much less is known about its role in facilitating the invasion of ecosystems by non-native plant species. In this study we evaluated the effects of invasive (Acer Platanoides) and native (Pseudotsuga menziesii) forest types on the performance of A. Platanoides seedlings, and related these effects to structural and functional properties associated with the two forest types, in a native P. menziesii forest that is being invaded by A. Platanoides. Acer Platanoidesseedlings had higher densities, recruitment, and survival, and experienced less photoinhibition and water stress when beneath conspecific canopies than in the adjacent P. menziesii forest. Soil moisture and canopy cover were greater in the invaded patch than the native forest. There was no difference in soil fertility or understory light levels between locations. These demographic (i.e. seedling survival), physiological, and environmental differences appeared to be due to the effects of A. Platanoides and P. menziesii trees. Thus, Acer trees appear to produce a more mesic environment by modifying the structure and phenology of the forest canopy and by altering the timing of transpirational water loss relative to P. menziesii. Environmental modification by invaders that lead to positive effects on conspecifics may help us to understand the dramatic success and lag periods of some invasive species