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Alan T. Whittemore - One of the best experts on this subject based on the ideXlab platform.

  • EXOTIC SPECIES OF Celtis (CANNABACEAE) IN THE FLORA OF NORTH AMERICA
    Journal of the Botanical Research Institute of Texas, 2008
    Co-Authors: Alan T. Whittemore
    Abstract:

    Two species of Celtis are naturalized in North America. Celtis australis escapes locally in riparian woodland in the Sacramento Valley of northern California, while C. sinensis (new to the adventive flora of North America) escapes in a variety of habitats from Widely separated sites in California and in the District of Colnmbia, with seedlings found up to 300 m from adult plants. Descriptions and illustrations of both species are provided.

  • Hybridization and Self-compatibility in Celtis: AFLP Analysis of Controlled Crosses
    Journal of the American Society for Horticultural Science, 2007
    Co-Authors: Alan T. Whittemore, Alden M. Townsend
    Abstract:

    ADDITIONAL INDEX WORDS. hackberry, sugarberry, Cannabaceae, interspecific hybrids, urban tree breeding ABSTRACT. Artificial cross-pollinations were carried out among seven species of Celtis L. (C. bungeana Blume, C. koraiensis Nakai, C. laevigata Willd., C. occidentalis L., C. reticulata Torr., C. sinensis Pers., and C. tenuifolia Nutt.) to test the potential for interspecific hybridization in Celtis breeding. AFLP profiles were used to assess the ancestry of progeny. Hybrids formed very rarely among these seven species of Celtis: only two interspecific hybrids were obtained. Self-pollination occurred occasionally in non-emasculated trees. AFLP analysis yielded false paternal markersataverylowfrequency,likelyduetoDNAmethylationdifferences.Plantswithunexpectedpaternalmarkers were confidently distinguished from hybrids by calculating the probability of obtaining the observed number of paternal markers by chance. The study clearly demonstrated the importance of using large numbers of markers. The genus Celtis (hackberries and sugarberries) is a group of trees with much promise for horticulture. Some of the American species, especially Celtis occidentalis and Celtis reticulata, are fast-growing trees with great tolerance to heat, cold, drought, periodic flooding, rapid changes in temperature and moisture, and a variety of soil types, making them very useful trees for arid or semi-arid regions with extreme temperature fluctuations (especially the western Great Plains and intermountain western United States) and promising for difficult urban habitats (Dirr, 1998; Krajicek, 1965; Krajicek and Williams, 1990). Celtis species often are recommended for attracting wildlife because the fruits are eaten by many bird species. Use of hackberries as landscape trees has been limited by susceptibility to several pathogens. Hackberries are susceptible to witches' brooms (incited by a mite (Eriophyes Siebold) and a powdery mildew (Sphaerotheca phytoptophila Kellerm. & Swingle)) and leaf galls (incited by a species of the hemipteran genus Pachypsylla Riley). Although these pathogens do not harm the plant, they can seriously disfigure it (Dirr, 1998; Elias, 1970). Several Celtis species native to eastern Asia are coming into use in American horticulture, and at least some of these Asian species are not susceptible to galls or witches' brooms. These species lack the extreme tolerance to environ- mental stress that is found in native American germplasm, but they are a potential source of disease-resistance genes for tolerant species. Interspecific hybridization experiments have not been car- ried out inCeltis. Species ofCeltis have often been presumed to hybridize based on patterns of variation observed in wild populations (Fernald, 1950; Mitchell, 1988; Wofford and Chester, 2002), but one recent study found no evidence of inter- specific hybridization in wild populations of Celtis laevigata and C. reticulata (Whittemore, 2005). We carried out cross-pollinations among seven Celtis spe-

  • Genetic Structure, Lack of Introgression, and Taxonomic Status in the Celtis laevigata—C. reticulata Complex (Cannabaceae)
    Systematic Botany, 2005
    Co-Authors: Alan T. Whittemore
    Abstract:

    The North American species of Celtis have been believed on anecdotal grounds to hybridize commonly in nature, and an understanding of the nature and frequency of natural hybridization among species of Celtis is necessary for understanding phylogenetic relationships within the genus. Extensive natural introgression has been strongly suspected between two species with ranges that overlap broadly in Texas, Celtis laevigata and C. reticulata. Statistical study of morphological and AFLP data was undertaken to test the extent and genetic consequences of natural hybridization between them. Results indicate that there is little or no natural hybridization between these species, contradicting past conclusions. The variability and apparent intergradation between the species that led to the hypothesis of introgression are apparently due to high levels of shared ancestral polymorphism at many loci, and exceptionally high levels of position-associated variation in leaf morphology within individual trees.

  • genetic structure lack of introgression and taxonomic status in the Celtis laevigata c reticulata complex cannabaceae
    Systematic Botany, 2005
    Co-Authors: Alan T. Whittemore
    Abstract:

    The North American species of Celtis have been believed on anecdotal grounds to hybridize commonly in nature, and an understanding of the nature and frequency of natural hybridization among species of Celtis is necessary for understanding phylogenetic relationships within the genus. Extensive natural introgression has been strongly suspected between two species with ranges that overlap broadly in Texas, Celtis laevigata and C. reticulata. Statistical study of morphological and AFLP data was undertaken to test the extent and genetic consequences of natural hybridization between them. Results indicate that there is little or no natural hybridization between these species, contradicting past conclusions. The variability and apparent intergradation between the species that led to the hypothesis of introgression are apparently due to high levels of shared ancestral polymorphism at many loci, and exceptionally high levels of position-associated variation in leaf morphology within individual trees.

Sampath Kumar Belide - One of the best experts on this subject based on the ideXlab platform.

  • evaluation of antioxidant activity of two important memory enhancing medicinal plants Celtis timorensis and vanda spathulata
    2013
    Co-Authors: Rajaneekar Dasari, D Sathyavati, Sampath Kumar Belide
    Abstract:

    Background : Free radicals or highly reactive oxygen species are capable of inducing oxidative damage to human body. Antioxidants are the compounds which terminate the attack of reactive species and reduce the risk of diseases. Both Celtis timorensis and Vanda Spathulata are used in treatment of brain disorders in human and have almost similar effects.Objective : The study was conducted to determine the Antioxidant properties of two well known memory enhancer medicinal plants, Celtis timorensis and Vanda Spathulata.Results : The antioxidant activity of these two medicinal plants were evaluated by measuring reducing ability, free radical scavenging activity by DPPH and hydrogen peroxide methods. The antioxidant compounds like ascorbic acid , total phenols and tannins were also evaluated in these plants. Celtis timorensis and Vanda Spathulata exhibited significant differences (P<0.05) in their antioxidant values. The methanolic extract of whole leaf powder of Celtis timorensis exhibited significantly higher antioxidant activity than the Vanda Spathulata. The antioxidant components viz. ascorbic acid, total phenols and tannins were also found in a higher concentration in Celtis timorensis as compared to Vanda Spathulata.Conclusion : It can be concluded from the study that regular use of Celtis timorensis as a supplement could be more helpful compared to Vanda Spathulata in treatment of neurological disorders caused by free radical damage.

  • EVALUATION OF ANTIOXIDANT ACTIVITY OF TWO IMPORTANT MEMORY ENHANCING MEDICINAL PLANTS Celtis TIMORENSIS AND VANDA SPATHULATA
    2013
    Co-Authors: Rajaneekar Dasari, D Sathyavati, Sampath Kumar Belide
    Abstract:

    Background : Free radicals or highly reactive oxygen species are capable of inducing oxidative damage to human body. Antioxidants are the compounds which terminate the attack of reactive species and reduce the risk of diseases. Both Celtis timorensis and Vanda Spathulata are used in treatment of brain disorders in human and have almost similar effects.Objective : The study was conducted to determine the Antioxidant properties of two well known memory enhancer medicinal plants, Celtis timorensis and Vanda Spathulata.Results : The antioxidant activity of these two medicinal plants were evaluated by measuring reducing ability, free radical scavenging activity by DPPH and hydrogen peroxide methods. The antioxidant compounds like ascorbic acid , total phenols and tannins were also evaluated in these plants. Celtis timorensis and Vanda Spathulata exhibited significant differences (P

Gernot Michael Müller - One of the best experts on this subject based on the ideXlab platform.

Rajaneekar Dasari - One of the best experts on this subject based on the ideXlab platform.

  • evaluation of antioxidant activity of two important memory enhancing medicinal plants Celtis timorensis and vanda spathulata
    2013
    Co-Authors: Rajaneekar Dasari, D Sathyavati, Sampath Kumar Belide
    Abstract:

    Background : Free radicals or highly reactive oxygen species are capable of inducing oxidative damage to human body. Antioxidants are the compounds which terminate the attack of reactive species and reduce the risk of diseases. Both Celtis timorensis and Vanda Spathulata are used in treatment of brain disorders in human and have almost similar effects.Objective : The study was conducted to determine the Antioxidant properties of two well known memory enhancer medicinal plants, Celtis timorensis and Vanda Spathulata.Results : The antioxidant activity of these two medicinal plants were evaluated by measuring reducing ability, free radical scavenging activity by DPPH and hydrogen peroxide methods. The antioxidant compounds like ascorbic acid , total phenols and tannins were also evaluated in these plants. Celtis timorensis and Vanda Spathulata exhibited significant differences (P<0.05) in their antioxidant values. The methanolic extract of whole leaf powder of Celtis timorensis exhibited significantly higher antioxidant activity than the Vanda Spathulata. The antioxidant components viz. ascorbic acid, total phenols and tannins were also found in a higher concentration in Celtis timorensis as compared to Vanda Spathulata.Conclusion : It can be concluded from the study that regular use of Celtis timorensis as a supplement could be more helpful compared to Vanda Spathulata in treatment of neurological disorders caused by free radical damage.

  • EVALUATION OF ANTIOXIDANT ACTIVITY OF TWO IMPORTANT MEMORY ENHANCING MEDICINAL PLANTS Celtis TIMORENSIS AND VANDA SPATHULATA
    2013
    Co-Authors: Rajaneekar Dasari, D Sathyavati, Sampath Kumar Belide
    Abstract:

    Background : Free radicals or highly reactive oxygen species are capable of inducing oxidative damage to human body. Antioxidants are the compounds which terminate the attack of reactive species and reduce the risk of diseases. Both Celtis timorensis and Vanda Spathulata are used in treatment of brain disorders in human and have almost similar effects.Objective : The study was conducted to determine the Antioxidant properties of two well known memory enhancer medicinal plants, Celtis timorensis and Vanda Spathulata.Results : The antioxidant activity of these two medicinal plants were evaluated by measuring reducing ability, free radical scavenging activity by DPPH and hydrogen peroxide methods. The antioxidant compounds like ascorbic acid , total phenols and tannins were also evaluated in these plants. Celtis timorensis and Vanda Spathulata exhibited significant differences (P

William E. Rogers - One of the best experts on this subject based on the ideXlab platform.

  • Recruitment Limitation, Seedling Performance and Persistence of Exotic Tree Monocultures
    Biological Invasions, 2006
    Co-Authors: Evan Siemann, William E. Rogers
    Abstract:

    Many native plant communities are replaced by exotic monocultures that may be successional stages or persistent community types. We surveyed a stand of Sapium sebiferum (Chinese Tallow Tree) that replaced tallgrass prairie in Texas and performed experiments with seeds and seedlings to determine the contributions of recruitment limitation and natural enemy release to allowing such a forest type to persist or to allowing native species to reduce Sapium dominance. The stand was dominated by Sapium , especially for mature trees (>99) and annual seed input (97) but less so for saplings (80). Field sown Sapium seeds had lower germination and survival rates than Celtis seeds. Together with the extreme dominance of Sapium in seed rain this suggests that native species are currently recruitment limited in this stand by seed supply but not by germination, early growth or survival. To investigate whether Sapium may benefit from low herbivory or diseases, we transplanted Sapium and Celtis seedlings into the forest and manipulated foliar fungal diseases and insect herbivores with sprays. As predicted, insect herbivores caused greater damage to Celtis seedlings than to Sapium seedlings. However, suppression of insect herbivores caused significantly greater increases in survivorship of Sapium seedlings compared to Celtis seedlings. This suggests that herbivores in the understory of this Sapium forest may significantly reduce Sapium seedling success. Such a pattern of strong herbivore impact on seedlings growing near adult conspecifics was unexpected for this invasive species. However, even with insects and fungi suppressed, Sapium seedling performance was poor in this forest. Our results point towards Sapium as a successional species in a forest that will eventually be dominated by native trees that are currently recruitment limited but outperform Sapium in the understory.

  • Effects of temperature and light on chinese tallow (Sapium sebiferum) and Texas sugarberry (Celtis laevigata) seed germination
    Texas Journal of Science, 2002
    Co-Authors: Somereet Nijjer, Richard A. Lankau, William E. Rogers, Evan Siemann
    Abstract:

    Experiments were performed to assess germination requirements of seeds of Chinese tallow (Sapium sebiferum (L.) Roxb.) and Texas sugarberry (Celtis laevigata Willd.). Sapium and Celtic seeds were exposed to different combinations of light and temperature. It was predicted that Sapium would germinate under a variety of environmental conditions, but Sapium seeds germinated predominantly in fluctuating temperature conditions. Celtis seeds also germinated readily in such conditions but had less restrictive germination requirements. Since Celtis appears to be better adapted to a variety of germination conditions, a broader range of environmental germination tolerances does not explain Sapium's greater establishment success as an alien invader. Nevertheless, seeds requiring oscillating temperatures to germinate are most commonly found in canopy gaps or open areas suggesting that Sapium invasions may be especially problematic in disturbed habitats.