Texas Plant Research Articles

Ecology and Phenotypic Variation of Leitneria floridana (Leitneriaceae) in Disjunct Native Habitats

Leitneria floridana is a rare woody species with a disjunct distribution in the southeastern and south-central United States. Although the distribution of L. floridana is well established, little is known about the comparative biology of its disjunct populations or the factors contributing to its rarity. We studied populations of L. floridana in Missouri, Arkansas, Texas, and Florida to characterize and compare population density, habitat, ecophysiology, morphology, and growth. Our results show that plants of the Missouri provenance are the most unique phenotypically, plants in Texas are the fastest growing, and plants in Arkansas seem particularly adapted to shade. We found that L. floridana grows in chemically and physically diverse soils and under a broad range of insolation. Soil moisture content appears to be the most important environmental factor governing the occurrence of L. floridana, with soil moisture and distribution density positively correlated.

Leaf-footed Bug, Leptoglossus phyllopus (Hemiptera: Coreidae), as a Potential Vector of Sorghum Fungal Pathogens

Leaf-footed bugs, Leptoglossus phyllopus, were collected from a field containing ergot-infected sorghum plants in Texas, USA. Ergot spores from the external body parts of the insects were germinated on water agar plates to determine viability. Spores from fungal pathogens of sorghum (Alternaria spp., Bipolaris spp., Claviceps africans, Colletotrichum spp., Curvularia spp., Fusarium spp., Trichothecium spp., Aspergillus spp., Rhizopus spp., and smut) were found on the external body parts of leaf-footed bugs from ergot-infested sorghum. Of the fungal spores recovered, leaf-footed bug carried significantly more Claviceps africans spores (4.4×105 spores/ml) because the bugs were collected from an ergot-infested field. The concentration and germination rates of Claviceps africans spores recovered from the external body parts of adult leaf-footed bugs collected on five dates are tabulated. The greatest germination (6.8%) was of spores collected on 17 September. There was no significant difference in the amount of germinated Claviceps africans spores was among the first four collection dates.

SWEDEN’S PERSTORP SPRINGS AHEAD

THE MANAGERS OF PERSTORP have been given a mission by the firm’s private equity owners: grow, and grow quickly, in a few chosen segments in the global specialty chemicals industry. And that is precisely what is happening. The Swedish company has embarked on a flurry of acquisitions to beef up a business portfolio that has polyol chemistry at its core. The firm’s latest deal, announced in mid-March, is also its biggest: intertwined agreements to take over Rhodia’s line of aliphatic isocyanates and LyondellBasell’s business in aromatic isocyanates. Aliphatic and aromatic isocyanates are reacted with polyols to produce industrial paint ingredients and flexible foams, respectively. The purchase includes plants in France and Texas and will add $460 million to Perstorp’s 2007 sales of about $1.27 billion. In February, Perstorp wrapped up its purchase of Solvay’s caprolactones business for nearly $310 million. The acquisition covered a plant in Warrington, England, a business with 2006 sales of about ...

Coastal Power Corpus Christi: Ramping Down (C)

Can a company diminish employees mistrust and distress when downsizing? Is there such a thing as an effective workforce reduction process? In this disguised, yet actual case, Peter Morris, manager of Coastal Power Corpus Christi Plant (Bayland) in Texas, tells his team leaders that they had to cut their workforce 10%. Throughout the (A) case a close approximation of how the dialogue went in that meeting offers several ideas for the reduction that include: length of service, experience, outsourcing, covering the plant with a single electrician, and reducing one person from each operating unit. The case includes data for students to use to generate their own assessment of who should go and who should stay. At the end of the (A) case, Morris shared his plan and asked team leaders to generate a ranking sheet of skills they value, rate employees, and build a consensus among them on where plant workers should be placed on the list. In the (B) case the assessment tool is revealed and all plant workers are ranked to identify the bottom performing employees. They are fired. Then the (B) case adds a new twist when two weeks later, Morris stood in front of the remaining employees to hear their reactions. As he explains how criteria was developed, Morris committed to a plant wide process using the same criteria for everyone remaining employed at the plant--including team leaders. We learn in the (C) case that the second all-hands round of rankings was consistent with the team leaders rankings.

Growth, flowering, and survival of firewheel (Gaillardia pulchellaFoug.) based on seed source and growing location

Home region failed to provide any clear short-term improvement in plant growth, vigor, flowering, quality, or survival of <i>Gaillardia pulchella</i> Foug. (Asteraceae; firewheel) when plants derived from natural populations in east Texas, northeast Florida, central west Florida, central east Florida, and southeast Florida were grown under low-input landscape conditions in northwestern, northern central, or southeastern Florida. During the 22-wk study, adaptability of east Texas plants was similar to that of northeast Florida and southeast Florida plants within the different sites. At the 2 northern sites, plant growth, vigor, and flowering were greater than for plants grown in southeastern Florida. The patterns of biweekly changes in plant vigor, flowering, and quality ratings were similar among plants of all seed sources within a site. Averaged over the entire study, these ratings were equally high for plants of all seed sources except central east Florida plants. Within a site, survival of northeast Florida, southeast Florida, and east Texas plants was equally high (83 to 100%). Also, 100% of central west Florida plants survived at the 2 northern sites, yet no central west Florida plants survived past week 16 in southeastern Florida. Differences in growth, vigor, flowering, quality, and survival were likely related to the loamier soils at the 2 northern sites and (or) flooding June rains in southeastern Florida.

Implications of rainfall temporal resolution for soil-moisture and transpiration modeling

Dimensionless groups of parameters characterizing an ecosystem are valuable indicators for the a priori assessment of the effect of rainfall data resolution on predictions of soil moisture and transpiration. Knowledge of these dimensionless groups enables identification of appropriate levels of rainfall data resolution, when using historical rainfall directly or when using it to derive rainfall model parameters for use in models of soil–plant–climate systems. Detailed simulation studies of the soil, plant, and climate systems in Colorado and Texas, highly resolved in time and vertical space, show that historical rainfall data resolved at the daily level allow accurate prediction of soil-moisture and transpiration dynamics for smaller time resolutions. These results support inferences based on the dimensionless groups. Furthermore, no significant improvement in the prediction of soil-moisture and transpiration dynamics is attained, when representing rainfall through a more complex Neyman–Scott model rather than the simple rectangular pulses Poisson model.

Fueling the fall migration of the monarch butterfly

Monarch butterflies in eastern North America accumulate lipids during their fall migration to central Mexico, and use them as their energy source during a 5 month overwintering period. When and where along their migratory journey the butterflies accumulate these lipids has implications for the importance of fall nectar sources in North America. We analyzed the lipid content of 765 summer breeding and fall migrant monarch butterflies collected at 1 nectaring site in central Virginia over 4 years (1998-2001), and compared them with 16 additional published and unpublished datasets from other sites, dating back to 1941. Virginia migrants store significantly more lipid than summer butterflies, and show significant intraseason and between-year variation. None of the Virginia samples, and none of the historical samples, with one exception, had lipid levels comparable with those found in migrants that had reached Texas and northern Mexico. This evidence suggests that upon reaching Texas, the butterflies undergo a behavioral shift and spend more time nectaring. The one exceptional sample led us to the discovery that monarchs that form roosts along their migratory routes have higher lipid contents than monarchs collected while nectaring at flowers. We propose that for much of their journey monarchs are opportunistic migrants, and the variation within and between samples reflects butterflies' individual experiences. The stored lipids appear to be of less importance as fuel for the butterflies' migration than for their survival during their overwintering period, in part because soaring on favorable winds reduces the energetic cost of flying. The conservation of nectar plants in Texas and northern Mexico is crucial to sustaining the monarch's migratory spectacle, and nectar abundance throughout eastern North America is also important. As generalists in their selection of nectar sources and nectaring habitats, monarchs are unlikely to be affected by small changes in plant communities. Agricultural transformations of natural communities in the eastern United States and Great Plains, however, and especially the extensive planting of genetically modified herbicide-resistant soybeans and corn, may be changing the availability of nectar for monarchs and other pollinators. This new technology is eliminating virtually all forbs in and surrounding agricultural fields, including the monarch's larval hostplants (milkweeds) and native and nonnative nectar sources. To evaluate whether changes in nectar availability are altering the butterflies' ability to accumulate energy, we recommend that monarchs' lipid contents be assayed annually at sites throughout eastern North America.

An operational perspective of the relationships between the headquarters and the maquiladoras

This paper explored the role of concurrent engineering (CE) and design for manufacturability and assembly (DFM/DFA) within the context of headquarters–maquiladora relationships. The objective of this paper was to determine which operational model was prevalent and describe the operational relationships between a headquarters and their maquiladoras. The maquiladora industry is a manufacturing model that utilises the Mexican workforce and foreign investment and technology on the border region between the USA and Mexico. This paper conducted an empirical investigation by distributing a survey instrument among maquiladora plants in El Paso, Texas and Juarez, Mexico. The reliability and validity tests, item correlation matrix, descriptive statistics, factor analysis, and structural equation modelling for design and manufacturing data were conducted. Appropriate conclusions and an assessment based on the results and 11 field interviews conducted with maquiladora managers were provided. The analyses indicated inconsistent results for design questions. There seemed to be a lack of understanding as to the role and function of design in the maquiladoras. It did not appear that maquiladoras were directly or heavily involved in the initial stages of design. Maquiladoras appeared, however, to be heavily involved in what is actually a re-design at the maquiladoras. The analyses indicated consistent and strong results for the important role that manufacturing played in the maquiladoras. Finally, future research directions were provided.

(358) A GIS Approach to Managing the Invasive Species of Texas

The state of Texas consists of roughly 4800 species of vascular plants. In 1970, it was estimated that 200 of these were introduced species. By 2003, the number of introduced species almost doubled to 350. Using the Atlas of the Vascular Plants of Texas, a database was compiled listing the invasive species in Texas and which of the 254 counties they inhabited. This database was then converted into a GIS platform that allowed us to analyze those data spatially. With these data, we were able to calculate the actual number of invasive species per county. In addition, these data were used to predict possible points of invasive species introduction, the rate of spread for certain problematic species, routes of migration, and to isolate counties under threat of possible infestation.

Seed Germination of Rhamnus caroliniana: Implications for Ecology and Horticulture

Little is known about the reproductive biology of carolina buckthorn [Rhamnus caroliniana Walt. or Frangula caroliniana (Walt.) Gray], an attractive North American shrub or small tree that might merit increased use in managed landscapes. The fecundity and high germinability of seeds of the Eurasian common buckthorn (Rhamnus cathartica L.), however, have been characterized as factors contributing to its invasiveness. We compared seed germination of these species to ascertain how easily carolina buckthorn could be grown from seed in nurseries and to acquire data for predicting whether carolina buckthorn might be invasive if introduced into managed landscapes. Fruits of carolina buckthorn were collected from indigenous plants in central Missouri, southern Oklahoma, and southern Texas. Fruits of common buckthorn were collected from shrubs naturalized in central Iowa. Seeds of both species were stratified for up to 112 days in darkness at 4 °C; germination at 24 °C in the dark was then evaluated for 56 days. Quadratic functions best described how time of stratification influenced germination value and germination percentage of common buckthorn, whereas these measures of carolina buckthorn were best represented by exponential (value) or linear (percentage) functions. Stratification for 112 days maximized germination value and percentage for carolina buckthorn within the 56-day germination period, but shorter stratifications were sufficient to optimize germination of common buckthorn. While the overall mean germination of carolina buckthorn was 40%, results varied by provenance and ranged from 25% (Missouri) to 56% (Oklahoma). Mean germination of common buckthorn over times of stratification was 71%, and the overall mean daily germination of common buckthorn, 1.3, was 86% greater than that of carolina buckthorn, 0.7. We conclude that seeds of carolina buckthorn are more resistant to germination than seeds of common buckthorn. Our results suggest that plant propagators should cold-stratify seeds of carolina buckthorn for up to 112 days, and suggest that carolina buckthorn has a lower potential to be invasive than does common buckthorn.

Midwinter Cold Hardiness of Leitneria floridana from Three Provenances

Abstract Leitneria floridana Chapman (Florida corkwood) is native to the southeastern and south-central United States. This rare shrub has been cultivated north of its natural habitats. However, the cold hardiness of the species, and potential differences in hardiness among geographical provenances, have not been established. Our objective was to determine midwinter cold hardiness of stem segments from indigenous plants in Texas and Missouri, and from plants that had been cultivated for many years in northern Illinois, but were originally native to Missouri and Arkansas. After exposure to controlled low temperatures, the cortex and phloem were stained with 2,3,5-triphenyltetrazolium chloride (TTC) and compared with discoloration of the same tissues to determine midwinter cold hardiness. The two assays correlated positively, and marked provenance differences in cold hardiness were found. The estimated temperature at which 50% of stems were injured (T50) was ≈ −20C (−4F) in December and−10C (14F) in January for samples from Texas. The estimated T50 for stems from Missouri and Illinois was at or below the lowest temperature tested [−35C (−31F) in December and-60C (−76F) in January]. Stems from cultivated plants in Illinois and from plants indigenous to Missouri were similarly hardy within the range of temperatures used. Autumnal acclimation and vernal deacclimation of L. floridana remain uncharacterized, but midwinter cold hardiness of L. floridana seems sufficient to permit its use north of its natural habitat. Substantial provenance differences in cold hardiness should be considered when selecting plants for landscaping outside the native range of L. floridana.

Captive supplies and cash market prices for fed cattle: The role of delivery timing incentives

AbstractThe use of non‐cash methods of procuring fed cattle for slaughter has led to concern about the effect of these so‐called “captive” supplies on cash market prices. Some empirical evidence suggests that there is a negative short‐run relationship between the two: Cash market prices tend to be low in weeks in which captive supply shipments are high. We advance a different perspective on the relationship between captive deliveries and cash prices, arguing that the incentives that influence cattle delivery‐scheduling decisions could lead to a negative relationship, not between the contemporaneous levels of captive shipments and price, but between the volume of captive deliveries, on the one hand, and an ex ante expectation of a week‐to‐week price change, on the other. Econometric testing provides some evidence of this empirical regularity in the cattle procurement activities of four large packing plants in Texas in the mid‐1990s. [EconLit citations: Q130, L140.] © 2004 Wiley Periodicals, Inc. Agribusiness 20: 347–362, 2004.

Salmonella Contamination during Production of Cantaloupe: A Binational Study

Six cantaloupe farms and packing plants in South Texas (950 cantaloupe, 140 water, and 45 environmental samples), including the Rio Grande Valley area, and three farms in Colima State, Mexico (300 cantaloupe, 45 water, and 15 environmental samples), were sampled to evaluate cantaloupe contamination with Salmonella and Escherichia coli during production and processing. Samples collected from external surfaces of cantaloupes, water, and the environments of packing sheds on cantaloupe farms were examined for the presence of Salmonella and E. coli. Of a total of 1,735 samples collected, 31 (1.8%) tested positive for Salmonella. Fifteen Salmonella serotypes were isolated from samples collected in Texas, and nine from samples collected in Colima. Two serotypes (Poona and Oranienburg) that have been associated with three large Salmonella outbreaks in the United States and Canada linked to the consumption of contaminated cantaloupe were found in water samples collected at four farms (three from the United States). Susceptibility of Salmonella isolates to 10 antimicrobials was evaluated by disk diffusion. Eighty-eight percent of the isolates from the United States and Mexico were pansusceptible to the antimicrobials tested; eight isolates from the United States demonstrated an intermediate susceptibility to streptomycin and only two isolates were resistant to the same antimicrobial. From Mexico, four isolates showed an intermediate susceptibility to streptomycin and one isolate was resistant to nalidixic acid and streptomycin. Repetitive sequence-based PCR analysis of Salmonella isolates helped to trace potential sources of Salmonella contamination in source water and in subsequent water samples obtained after the filtration systems of U.S. and Mexican cantaloupe farms. No differences could be seen between the levels of Salmonella contamination in melons from both countries.

CSR faces lawsuits relating to operations at carbon black plants in Oklahoma & Texas

CSR faces lawsuits relating to operations at carbon black plants in Oklahoma & Texas

Army Success Story: Ex‐Situ Biological Treatment of Perchlorate‐Contaminated Groundwater

AbstractGroundwater from the burning ground and landfill of the Longhorn Army Ammunition Plant (LHAAP) in Texas is currently remediated by pumping the water from an interceptor collection trench system, removing volatile organic compounds and metals in an ex‐situ treatment process, and discharging the treated water to a nearby stream. In early 2001, LHAAP's environmental restoration team supplemented the existing treatment process with an Envirogen biological fluid bed reactor (FBR) to remove the perchlorate prior to discharge. After a pilot test using site water at Envirogen's New Jersey laboratory, an FBR system designed to treat 50 gallons of groundwater per minute was installed. The FBR achieved complete perchlorate removal (&lt; 4 ppb) within three weeks of start‐up (February 2002). The FBR continues to remove perchlorate to less than 4 ppb. © 2002 Wiley Periodicals, Inc.

Determination of beta-adrenergic receptor blocking pharmaceuticals in united states wastewater effluent

Beta adrenergic receptor antagonists (β-Blockers) are frequently prescribed medications in the United States and have been identified in European municipal wastewater effluent, however no studies to date have investigated these compounds in United States wastewater effluent. Municipal wastewater effluent was collected from treatment facilities in Mississippi, Texas, and New York to investigate the occurrence of metoprolol, nadolol, and propranolol. Propranolol was identified in all wastewater samples analyzed ( n=34) at concentrations ⩽1.9 μg/l. Metoprolol and nadolol were identified in ⩾71% of the samples with concentrations of metoprolol ⩽1.2 μg/l and nadolol ⩽0.36 μg/l. Time course studies at both Mississippi plants and the Texas plant indicate that concentrations of propranolol, metoprolol, and nadolol remain relatively constant at each sampling period. This study indicates that β-Blockers are present in United States wastewater effluent in the ng/l to μg/l range.

RESULTS OF PILOT PROGRAM TO REUSE INDUSTRIAL BIOSOLIDS AT THE DUPONT, VICTORIA, TEXAS PLANT

RESULTS OF PILOT PROGRAM TO REUSE INDUSTRIAL BIOSOLIDS AT THE DUPONT, VICTORIA, TEXAS PLANTThe DuPont Victoria, Texas plant (DuPont), an industrial plant producing nylon intermediates and specialty products, is completing a 130 million improvement program that represents over a decade of commitment to environmental stewardship excellence. This program includes 13 process changes in operating units to recover and recycle valuable process materials. The remaining dilute waste streams are...Author(s)Ronald G. DuckworthJerry A. ColeTroy B. McIntoshJoseph H. ReitbergerRalph E. BeemanSourceProceedings of the Water Environment FederationSubjectSession 5: Land ApplicationDocument typeConference PaperPublisherWater Environment FederationPrint publication date Jan, 2002ISSN1938-6478SICI1938-6478(20020101)2002:3L.180;1-DOI10.2175/193864702785302618Volume / Issue2002 / 3Content sourceResiduals and Biosolids ConferenceFirst / last page(s)180 - 187Copyright2002Word count221

The Useful Wild Plants of Texas, The Southeastern and Southwestern United States, the Southern Plains, and Northern Mexico. Volume 2

The Useful Wild Plants of Texas, The Southeastern and Southwestern United States, the Southern Plains, and Northern Mexico. Volume 2

Wars of Attrition: Vietnam, the Business Roundtable, and the Decline of Construction Unions

The decline of the once quasi-monopolistic construction unions during the last quarter of the twentieth century was not unique: in the steel, automobile, rubber, clothing, and other industries unions also experienced severe decreases in membership. But unlike industrial unions, the building trades were not victims of cheap imports from an inexorably globalizing economy: high-wage union pipefitters building petrochemical and power plants in Texas did not lose their jobs to low-paid construction workers in or from China. Instead, their jobs were taken by compatriots, some of them until recently union brothers, employed by cut-rate antiunion construction firms — some of which had been union firms in good standing. Indeed, some nonunion contractors were subsidiaries of long-time respectable union contractors.Unlike their counterparts in manufacturing industries, where employment plummeted in tandem with unionization, construction workers significantly increased in number. Moreover, whereas the world market did not begin intimidating U.S. industrial workers until the latter half of the 1970s, construction unions became subject to economic and political attacks a decade earlier, during the Vietnam War. This asynchronous development was curious because competitive pressure on the construction industry was largely derivative. Since the primary source of these attacks was large industrial owner-customers, which complained that exploding construction wages were driving new plant construction costs to levels at which the products produced in them were becoming less competitive, manufacturing corporations, remarkably, did not focus on their own employees, but turned instead to construction workers, whose wages represented only a small share of the costs of manufactured products. And finally, much more so than their industrial colleagues, construction workers were attacked by a complex coalition of employers, the state, industrial customers, and the media, intent on breaking unions’ control of the supply of skilled building tradesmen.Against the background of the depletion of the industrial reserve army during the Vietnam War, this book explains how the complex interaction between the invisible hand of the labor market and the visible hands of large industrial customers, the Federal Government, and construction employer organizations inflicted a series of defeats on the building trades unions — the most entrenched segment of the labor movement in the United States — culminating in the vast expansion of the “union-free” sector of the construction industry.

Reduction of Greenhouse Gas Emissions through CO2 EOR in Texas

Energy and environmental questions no longer need to have conflicting perspectives. Solutions to problems in both arenas can satisfy multiple objectives. This paper explores the technical feasibility and economic potential of capturing CO2 from coal- or lignite-fired utility boilers and applying the CO2 to enhance oil recovery in the mature oil provinces of Texas. This capture accomplishes two goals: sequestering a substantial amount of CO2 for an extended period and increasing the efficiency of oil recovery. Previous research has indicated that a primary target of enhanced oil recovery (EOR) is estimated at 74 billion stock- tank barrels (BSTB) of residual oil. The present study finds that 8 BSTB of this resource is within a 145-km (90-mile) radius of the candidate coal- or lignite-fired plants in Texas. Modeling conducted in this study indicates that CO2 flooding can produce oil that would otherwise not be recovered, at an incremental cost of between $6.00 and $16.00/STB. In addition, probably between 12 and 20 years of CO2 production from the candidate lignite- or coal-fired boilers can be sequestered from these generation facilities. Preliminary analyses indicate that CO2 capture for lignite- and coal-fired plants in Texas may be cost-effective when compared with fuel switching these same boilers to natural gas. From a policy standpoint, it may be desirable to encourage CO2 capture retrofit initially, as opposed to fuel switching, because the former results in overall lower levels of CO2 emissions at a comparable cost. In conclusion, there is substantial potential for using utility plant boiler effluent as a CO2 supply source for flooding and using mature oil reservoirs for CO2 sequestration. Development of this potential resource base may be facilitated by further research and regulatory initiatives.