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Articles 1 - 17 of 17
Full-Text Articles in Life Sciences
New Record Of Bacopa Egensis (Plantaginaceae) For The Flora Of Mexico, Daniel Gonzalez-Socoloske, Nicholas P. Tippery, Nelly Del Carmen Jiménez Pérez, Donald H. Les
New Record Of Bacopa Egensis (Plantaginaceae) For The Flora Of Mexico, Daniel Gonzalez-Socoloske, Nicholas P. Tippery, Nelly Del Carmen Jiménez Pérez, Donald H. Les
Faculty Publications
Bacopa egensis is newly reported for the flora of Mexico and an updated key is provided for the Mexican Bacopa species
Landscape Performance Of Buck Roses Under Minimal-Input Conditions In North-Central Texas, Derald A. Harp, Gaye Hammond, David C. Zlesak, Greg Church, Mark Chamblee, Steve George
Landscape Performance Of Buck Roses Under Minimal-Input Conditions In North-Central Texas, Derald A. Harp, Gaye Hammond, David C. Zlesak, Greg Church, Mark Chamblee, Steve George
Faculty Publications
Griffith Buck (Iowa State University) bred roses (Rosa sp.) to survive long, cold winters and hot, humid summers yet still retain their foliage without fungicides. Unfortunately, there is little known about the performance of Buck roses in the southern United States. Thirty-eight Buck rose cultivars were evaluated for flowering, disease resistance, drought tolerance, and overall landscape performance in alkaline soils with no fertilizer, no pesticides, and only limited irrigation. Flowering occurred on a bimodal basis, with the highest per plant mean bloom number (16.3 blooms) and bloom coverage (9.7%) in April, and a second flowering in the fall, with …
Visualizing Nutrient Effects On Root Pattern Formation, Robert E. Zdor
Visualizing Nutrient Effects On Root Pattern Formation, Robert E. Zdor
Faculty Publications
This lab gives students hands-on experience with visualizing the root architecture of plants exposed to varying concentrations of the vital nutrient phosphorus. By maintaining Brassica sp. seedlings in the presence of different quantities of phosphate, students can quantify changes in the number of lateral roots as an example of how the environment influences plant pattern formation. Additional variables in the experimental design, such as the use of plant mutants altered in plant regulator action or the presence of plant regulators in the plant growth medium, allow for exploration of how plant growth regulators are involved in root development. The quantitative …
Flowering, Drought, And Disease Tolerance, And Landscape Performance Of Landscape Rose Grown Under Low-Input Conditions In North Central Texas, Derald A. Harp, Gaye Hammond, David C. Zlesak, Greg Church, Mark Chamblee, Steve George
Flowering, Drought, And Disease Tolerance, And Landscape Performance Of Landscape Rose Grown Under Low-Input Conditions In North Central Texas, Derald A. Harp, Gaye Hammond, David C. Zlesak, Greg Church, Mark Chamblee, Steve George
Faculty Publications
Landscaping today involves the struggle to balance aesthetically pleasing plants while minimizing the impact on the environment, reducing water usage, decreasing fertilizer use, and eliminating or significantly reducing pesticide usage. Roses (Rosa sp.), although seen as challenging plants, remain the most popular flowering shrub in the United States. The identification of new cultivars that combine beauty, pest and disease resistance, and drought tolerance are important to Texas landscapes. Sixty roses were assessed over a 3-year period to determine flowering, drought tolerance, disease resistance, and overall landscape performance in minimal-input gardens in north central Texas. Atypical weather during the study …
Influential Herbal And Botanical Texts From The 16th Through 18th Centuries, Michael C. Goates
Influential Herbal And Botanical Texts From The 16th Through 18th Centuries, Michael C. Goates
Faculty Publications
Humans have always had an intimate and complex relationship with plants. Plants provide many of the basic necessities for survival, such as food, clothing, and shelter. Plants also play an important and rich part in human culture. This fascination with plants has led to detailed studies of their natural history as well as explorations into their unique and useful properties. Throughout recorded history, philosophers, herbalists, botanists, and others have captured their observations about plants. From the Middle Ages through the Early Modern Period, herbalists compiled these collective observations into large printed volumes, referred to as herbals. With the Scientific Revolution …
Photosynthetic Performance And Anti-Oxidative Response Of Cornus Controversa Seedlings Under Cadmium And Lead Stress, Xinyu Huang, Yonglei Jiang, Xiaomao Cheng, Lilan Deng, Xuncheng Liu
Photosynthetic Performance And Anti-Oxidative Response Of Cornus Controversa Seedlings Under Cadmium And Lead Stress, Xinyu Huang, Yonglei Jiang, Xiaomao Cheng, Lilan Deng, Xuncheng Liu
Faculty Publications
The photosynthetic efficiency of Cornus controversa leaves was decreased significantly under Cd treatment while it was not affected by Pb exposure. Cd decreased while Pb treatment increased the chlorophyll contents of Cornus controversa leaves. Furthermore, the peroxidase (GPX) activities were decreased after Cd treatment while elevated by Pb exposure in Cornus controvera seedlings. In addition, both Cd and Pb exposures increased the malondialdehyde (MDA) and proline contents and elevated the superoxide dismutase (SOD) activities of Cornus controvera seedlings. Collectively, these results indicated that Cornus controversa may be more tolerant to Pb than Cd toxicity. This finding will contribute to the …
Control Of Flower Size, Beth A. Krizek, Jill T. Anderson
Control Of Flower Size, Beth A. Krizek, Jill T. Anderson
Faculty Publications
Flowers exhibit amazing morphological diversity in many traits, including their size. In addition to interspecific flower size differences, many species maintain significant variation in flower size within and among populations. Flower size variation can contribute to reproductive isolation of species and thus has clear evolutionary consequences. In this review we integrate information on flower size variation from both evolutionary and developmental biology perspectives. We examine the role of flower size in the context of mating system evolution. In addition, we describe what is currently known about the genetic basis of flower size based on quantitative trait locus (QTL) mapping in …
Local Filters Limit Species Diversity, But Species Pools Determine Composition, Tara K. Rajaniemi, Deborah E. Goldberg, Roy Turkington, Andrew R. Dyer
Local Filters Limit Species Diversity, But Species Pools Determine Composition, Tara K. Rajaniemi, Deborah E. Goldberg, Roy Turkington, Andrew R. Dyer
Faculty Publications
In a series of three experiments, we tested for effects of species pools, resource stress, and species interactions on four aspects of community structure: species richness, evenness, species composition, and functional group composition. We also examined whether the impacts of species interactions on the community varied with resource availability or species pool. Communities of sand dune annuals grew from seed bank samples collected from two sites in three different years, so that the species pool differed at two levels: the source site and the year of seed bank collection. Communities experienced one of three irrigation treatments and a range of …
Auxin Regulation Of Arabidopsis Flower Development Involves Members Of The Aintegumenta-Like/Plethora (Ail/Plt) Family, Beth A. Krizek
Auxin Regulation Of Arabidopsis Flower Development Involves Members Of The Aintegumenta-Like/Plethora (Ail/Plt) Family, Beth A. Krizek
Faculty Publications
Auxin is an important regulator of many aspects of plant growth and development. During reproductive development, auxin specifies the site of flower initiation and subsequently regulates organ growth and patterning as well as later events that determine reproductive success. Underlying auxin action in plant tissues is its uneven distribution, resulting in groups of cells with high auxin levels (auxin maxima) or graded distributions of the hormone (auxin gradients). Dynamic auxin distribution within the periphery of the inflorescence meristems specifies the site of floral meristem initiation, while auxin maxima present at the tips of developing floral organ primordia probably mediate organ …
The Role Of Adaptive Trans-Generational Plasticity In Biological Invasions Of Plants, Andrew R. Dyer, Cynthia S. Brown, Erin K. Espeland, John K. Mckay, Harald Meimberg, Kevin J. Rice
The Role Of Adaptive Trans-Generational Plasticity In Biological Invasions Of Plants, Andrew R. Dyer, Cynthia S. Brown, Erin K. Espeland, John K. Mckay, Harald Meimberg, Kevin J. Rice
Faculty Publications
High-impact biological invasions often involve establishment and spread in disturbed, high-resource patches followed by establishment and spread in biotically or abiotically stressful areas. Evolutionary change may be required for the second phase of invasion (establishment and spread in stressful areas) to occur. When species have low genetic diversity and short selection history, within-generation phenotypic plasticity is often cited as the mechanism through which spread across multiple habitat types can occur. We show that trans-generational plasticity (TGP) can result in pre-adapted progeny that exhibit traits associated with increased fitness both in high-resource patches and in stressful conditions. In the invasive sedge, …
Are Botanists Becoming The Dinosaurs Of Biology In The 21st Century?, Dennis W. Woodland
Are Botanists Becoming The Dinosaurs Of Biology In The 21st Century?, Dennis W. Woodland
Faculty Publications
The number of botany students, botany classes, botany departments in universities and botanists attending conventions has been declining over many years in North America. This is part of a general trend throughout the field of organismal biology, not just botany. The history leading up to the situation today in North America, is discussed and reasons are given for this trend over the last century of time. Seven ways to keep botany a viable occupation are discussed otherwise botany, in the 21st century, may go the way of the dinosaur. © 2007.
Using Upper Boundary Constraints To Quantify Competitive Response Of Desert Annuals, Laura M. Lessin, Andrew R. Dyer, Deborah E. Goldberg
Using Upper Boundary Constraints To Quantify Competitive Response Of Desert Annuals, Laura M. Lessin, Andrew R. Dyer, Deborah E. Goldberg
Faculty Publications
Using a target-neighborhood approach with six annual dicot species in the Negev Desert of Israel, we tested whether neighborhood biomass constrained the upper limit of plant performance and if the slope of the upper boundary was correlated to species trait means, such as relative growth rate (RGR) and seed mass. Target individuals were measured in early spring and then collected at the onset of the dry season along with all naturally occurring neighbors within a 5-cm radius of the target. Using a minimum of 50 samples for each of the six target species, we found no significant relationships between target …
Effects Of Competition On Resource Availability And Growth Of A California Bunchgrass, Andrew R. Dyer, Kevin J. Rice
Effects Of Competition On Resource Availability And Growth Of A California Bunchgrass, Andrew R. Dyer, Kevin J. Rice
Faculty Publications
In California, little is known about the sensitivity of native bunchgrasses to competition or to changes in resource availability. We investigated the effect of nonnative annual vegetation on resource availability and growth of a native bunchgrass, Nassella pulchra, in a pair of factorial field experiments that incorporated effects of both interspecific and intraspecific competition as well as variation in soil depth. Plots of differing target densities and neighborhoods were used to assess changes in aboveground (light) and belowground (water) resource availability over multiple seasons in two sites with differing soil depth. N. pulchra grown without interspecific competitors grew larger …
Intraspecific And Diffuse Competition: The Response Of Nassella Pulchra In A California Grassland, Andrew R. Dyer, Kevin J. Rice
Intraspecific And Diffuse Competition: The Response Of Nassella Pulchra In A California Grassland, Andrew R. Dyer, Kevin J. Rice
Faculty Publications
In inland California grasslands, the high densities of alien annual species have altered the growing environment for native perennial grasses. Using variable-density plots, we measured the influence of intraspecific competition (conspecifics only) and diffuse competition (mixed-composition neighborhoods that include conspecifics) on growth and survival of Nassella pulchra, purple needlegrass. We assessed the effects of intraspecific and diffuse competition in weeded plots and unweeded plots, respectively, across a density gradient of N. pulchra plants (16–356 plants/m2). We used summer fire and spring sheep grazing to reduce diffuse competition in unweeded plots. The potential effect of rooting volume on competitive interactions …
Osmophores, Floral Features, And Systematics Of Stanhopea (Orchidaceae), Kenneth J. Curry, Lorraine M. Mcdowell, Walter S. Judd, William Louis Stern
Osmophores, Floral Features, And Systematics Of Stanhopea (Orchidaceae), Kenneth J. Curry, Lorraine M. Mcdowell, Walter S. Judd, William Louis Stern
Faculty Publications
The floral fragrance glands (osmophores) of 18 species of Stanhopea and Sievekingia were examined through a series of developmental studies at light and electron microscope levels including late bud stages through postanthesis. Various characters were identified to be of potential systematic value and were recorded for each species. These characters included: texture of the osmophore surface, number of distinct cell layers comprising the osmophore, nature of lipid inclusions in osmophore cells, and presence or absence of plastoglobuli in osmophore amyloplasts. These characters were combined with traditional features of floral lip morphology for cladistic analysis. Sievekingia was the postulated outgroup. Stanhopea …
Initiation Of Terpenoid Synthesis In Osmophores Of Stanhopea Anfracta (Orchidaceae): A Cytochemical Study, Kenneth J. Curry
Initiation Of Terpenoid Synthesis In Osmophores Of Stanhopea Anfracta (Orchidaceae): A Cytochemical Study, Kenneth J. Curry
Faculty Publications
The terpenoid component of the osmophore fragrance in Stanhopea species is composed of isoprene units synthesized via the mevalonic acid pathway. Localization of hydroxymethylglutaryl CoA synthase in the pathway was achieved using a technique which elicits the formation of an electron- dense precipitate of uranyl ferrocyanide at the point where an acetyl group from acetyl CoA is transferred to acetoacetyl CoA, releasing free CoA-SH. Applying this technique to cells of the osmophore of S. anfracta resulted in a precipitate between the inner and outer mitochondrial membranes, in the smooth endoplasmic reticulum, and, to a lesser extent, on the outer surface …
Osmophores Of Stanhopea (Orchidaeceae), William Louis Stern, Kenneth J. Curry, Alec M. Pridgeon
Osmophores Of Stanhopea (Orchidaeceae), William Louis Stern, Kenneth J. Curry, Alec M. Pridgeon
Faculty Publications
Species of the Neotropical orchid genus Stanhopea produce a fragrance comprising terpenoids and aromatics which attracts euglossine bee pollinators. The secretory tissue, called an osmo- phore, is located in the adaxial region of a sac formed near the proximal portion of the floral lip. This region is easily recognized in Stanhopea oculata and S. wardii because it is papillate. The osmophore in these two species includes all the cells of the papillae and those directly below, that grade into fundamental tissue. Osmophore cells are more densely cytoplasmic than cells in the adjacent tissue. Numerous amyloplasts and mitochondria are seen in …