Biology Commons^™

Mojave Applied Ecology Notes Winter 2011, Scott R. Abella, Alice C. Newton, Kenneth Chittick, Pam Sinanian

Mojave Applied Ecology Notes

Lake Mead’s collaborative applied science research program; “annoying the elephant” - ruminations on active management by Alice Newton, Lake Mead NRA vegetation manager; 2012 NWRA Lake Mead symposium sneak peak; assessing forest change using dendrochronology in the Spring Mountains.

The Arabidopsis Trithorax-Like Factor Atx1 Functions In Dehydration Stress Responses Via Aba-Dependent And Aba-Independent Pathways, Yong Ding, Zoya Avramova, Michael Fromm

School of Biological Sciences: Faculty Publications

Emerging evidence suggests that the molecular mechanisms driving the responses of plants to environmental stresses are associated with specific chromatin modifications. Here, we demonstrate that the Arabidopsis trithorax-like factor ATX1, which trimethylates histone H3 at lysine 4 (H3K4me3), is involved in dehydration stress signaling in both abscisic acid (ABA)-dependent and ABA-independent pathways. The loss of function of ATX1 results in decreased germination rates, larger stomatal apertures, more rapid transpiration and decreased tolerance to dehydration stress in atx1 plants. This deficiency is caused in part by reduced ABA biosynthesis in atx1 plants resulting from decreased transcript levels from NCED3, which …

A Survey Of The Chemical Content And Medicinal Activity Of Shrub-Steppe Plants Of The Pacific Northwest, Aaron M. John

Undergraduate Honors Theses

A need for new modes of antibiotic therapy has resulted from the increasing incidence of bacterial resistance to drugs. One approach to this problem involves the search for plant compounds that may help to overcome multi-drug resistance. Many plant genera have been utilized in Native American traditional medicine for their beneficial properties. Such plants include the shrub-steppe genera, Eriogonun and Collomia, which have been used as cold remedies, pain relievers, and for antibiotic-related uses. Limited chemical studies of these genera have revealed medicinally useful compounds such as flavonoids and terpenoids, and further research may result in the identification of …

Biology Department Newsletter, No.1, Sacred Heart University

Biology Newsletter

No abstract provided.

Floristic And Environmental Characteristics Of Sub-Boreal Peatlands Of Minnesota And Western Wisconsin, Kevin Douglas Clement

All Graduate Theses, Dissertations, and Other Capstone Projects

Peatland communities in the sub-boreal region of Minnesota and western Wisconsin were characterized by floristic composition, structure and environmental characteristics to determine the natural variation among peatland communities in the region and their shared associations with the boreal and temperate peatlands of North America. Floristic classification revealed five, distinct peatland community types, identified as Sphagnum Bogs, Herbaceous Fens, Forested Fens, Rich/Calcareous Fens and Phalaris anrundinacea dominated peatlands. Differences among sub-boreal peatlands largely reflected changes in the significant indicator and dominant plant species identified, which were found to exhibit high fidelities to a particular peatland community type. Floristic variations among sub-boreal …

Distributions And Abundances Of Microstegium Vimineum Along Forest Roadsides At The Grassy Hill Natural Area, Franklin County, Virginia, Gregory D. Turner

Virginia Journal of Science

In summer 2005, plots were surveyed along roads passing through forest habitats at the Grassy Hill Natural Area Preserve in Franklin County, Virginia to assess the distributions and abundances of Microstegium vimineum in transects located at increasing distances away from roadsides into forest interiors. Across plots, Microstegium was encountered almost exclusively in roadside transects, where abundances were relatively high. While forest composition and topographic features were similar across plots, percent canopy cover and leaf litter depth were greater in interior compared to roadside transects due to undisturbed tree canopies and ground cover located in interior plot areas. Results imply that …

Nitrogen Addition Shapes Soil Phosphorus Availability In Two Reforested Tropical Forests In Southern China, Xiankai Lu, Jiangming Mo, Frank S. Gilliam, Hua Fang, Feifei Zhu, Yunting Fang, Wei Zhang, Juan Huang

Biological Sciences Faculty Research

Scant information is available on how soil phosphorus (P) availability responds to atmospheric nitrogen (N) deposition, especially in the tropical zones. This study examined the effect of N addition on soil P availability, and compared this effect between forest sites of contrasting land-use history. Effects of N addition on soil properties, litterfall production, P release from decomposing litter, and soil P availability were studied in a disturbed (reforested pine forest with previous understory vegetation and litter harvesting) and a rehabilitated (reforested mixed pine/broadleaf forest with no understory vegetation and litter harvesting) tropical forest in southern China. Experimental N-treatments (above ambient) …

A Phylogenetic Assessment Of Breeding Systems And Floral Morphology Of North American Ipomoea (Convolvulaceae), J. Andrew Mcdonald, Joshua R. Mcdill, Debra R. Hansen, Beryl B. Simpson

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Biology)

A phylogenetic investigation of 68 species and two varieties of tropical and temperate North American Ipomoea (Convolvulaceae) using sequence data from the internal transcribed spacer region (ITS) with parsimony and Bayesian analyses revealed multiple origins of autogamy. By assessing breeding systems and floral morphological characters in the context of this phylogeny, we estimate 16 independent origins of autogamy and 4 subsequent reversions to xenogamy. Transitions to autogamy are associated with reduced pollen-ovule ratios, decreased anther-stigma distance, and small flower size. Although the relationship between floral traits and breeding systems has been described in previous studies, this is the first investigation …

Techniques To Facilitate The Acquisition Of Accurate Spectral Measurements And Multispectral Imagery Of Plant Foliage Under Artificial Lighting Conditions, Yuridia Patricia Gandy, Ashish Mamachen, Adarsh Mamachen, Jonathan Lieman, Michael W. Persans, Jason Parsons, Elamin E. Ibrahim, James H. Everitt, Christopher R. Little, Kenneth R. Summy

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Biology)

Spectral measurements obtained in the laboratory under artificial lighting sources have been used for many years to develop spectral ‘libraries’ for various soil types, rocks and minerals, and other inanimate features occurring on or near the earth’s surface. Quartz halogen lamps have been shown to emit all of the electromagnetic (EMR) wavelengths required for the acquisition of quality multispectral imagery, and various techniques have been developed to facilitate the acquisition of accurate spectral measurements using such artificial lighting sources. Our objectives in this study were to evaluate the several factors of critical importance in obtaining accurate spectral measurements for plant …

Urban Dietary Heavy Metal Intake From Protein Foods And Vegetables In Dar Es Salaam, F. N. Ngassapa, O. C. Othman, E. Elisante

Tanzania Journal of Science

Contamination of food and food products by heavy metals has made dietary intake as one of the major routes of these harmful elements to human beings. The human dietary intake of heavy metals cadmium, copper, lead and zinc from protein-foods (beans, meat, fish, milk) and green vegetables consumed daily from restaurants and street food-vendor kiosks in Dar es Salaam were determined using the Total Diet Study (TDS) method. The cooked food was bought from the restaurants and street food-vendors at several city locations (i.e. Buguruni, Manzese, Mwenge, Temeke and Ubungo) over several months and analyzed. Heavy metal concentrations were determined …

[Accepted Article Manuscript Version (Postprint)] Pex5 Mutants That Differentially Disrupt Pts1 And Pts2 Peroxisomal Matrix Protein Import In Arabidopsis, Bibi Khan, Bethany Zolman

Biology Department Faculty Works

PEX5 and PEX7 are receptors required for the import of peroxisome-bound proteins containing one of two peroxisomal targeting signals (PTS1 or PTS2). To better understand the role of PEX5 in plant peroxisomal import, we characterized the Arabidopsis (Arabidopsis thaliana) pex5-10 mutant, which has a T-DNA insertion in exon 5 of the PEX5 gene. Sequencing results revealed that exon 5, along with the T-DNA, is removed in this mutant, resulting in a truncated pex5 protein. The pex5-10 mutant has germination defects and is completely dependent on exogenous Suc for early seedling establishment, based on poor utilization of seed-storage fatty acids. This …

Investigating Heavy Metal Accumulation And Oxidative Stress Tolerance Of Non-Accumulators And Hyperaccumulators In The Brassicaceae Plant Family, Fritzie Joy Into

Theses and Dissertations - UTB/UTPA

Physiological and enzymatic analysis indicated that the non-accumulator A. thaliana showed an oxidative stress response in all assays except for protein carbonylation. Other non-accumulator plant species showed a significant difference in oxidative stress response in the TBARS assay; however, for some assays no stress response was evident. The hyperaccumulator plant species showed no significant difference in oxidative stress as indicated by the all of the assays with the exception of T. montanum var. montanum which showed an oxidative stress response in the SOD assay. Basal catalase enzyme activity was notably higher in the hyperaccumulators T. montanum var. montanum and T. …

Variation In Nutrient Resorption By Desert Shrubs, Rebecca E. Drenovsky, Jeremy J. James, James H. Richards

Biology

Plant nutrient resorption prior to leaf senescence is an important nutrient conservation mechanism for aridland plant species. However, little is known regarding the phylogenetic and environmental factors influencing this trait. Our objective was to compare nitrogen (N) and phosphorous (P) resorption in a suite of species in the Asteraceae and Chenopodiaceae and assess the impact of soil salinity on nitrogen resorption. Although asters and chenopods did not differ in N resorption proficiency, chenopods were more proficient than asters at resorbing P. Plant responses to salinity gradients were species-specific and likely related to different salt-tolerances of the species. During the three …

Traversing Swanton Road, 2nd Ed., James A. West

Academic, Government & Associated Organizational Research Resources

Situated at the northwest end of Santa Cruz County and occupying circa 30 square miles of sharply contrasted terrain, the Scott Creek Watershed concentrates within its geomorphological boundaries, at least 10-12% of California's flora, both native and introduced. Paradoxically, the use/abuse that the watershed has sustained over the past 140+ years, has not necessarily diminished the biodiversity and perhaps parallels the naturally disruptive but biologically energizing processes (fire, flooding, landslides and erosion), which have also been historically documented for the area for +60 years. This is an early edition of an extensive document by James A. West. Please visit the …

Mojave Applied Ecology Notes Fall 2010, Adria Decorte, Sharon Altman, Alex Suazo

Mojave Applied Ecology Notes

Adria DeCorte defense, Mojave desert inventory and monitoring mapping project, effect of burial depth on Brassica tournefortii seeds

Plasticity In Cavitation Resistance And Mechanical Strength Of Stem Xylem In Heteromeles Arbutifolia, Adults Versus Post-Fire Resprouts, Iolana N. Kaneakua, B. A. Bergman, F. W. Ewers, S. D. Davis

Biology

Background/Questions/Methods

Many species of chaparral shrubs of California undergo vigorous resprout success after wildfire. We hypothesized that the water transport properties of resprouts, as well as their biomechanical strength would differ from adults. In addition, we hypothesized that irrigated and shaded resprouts would display reduced cavitation resistance and biomechanical strength in comparison to controls and adults. We tested these hypotheses by using a centrifuge method to compare the vulnerability of xylem to water stress induced cavitation. We used 50% loss in hydraulic conductivity due to water stress (PLC₅₀) as our estimate of vulnerability to cavitation. A Universal Materials …

Mojave Applied Ecology Notes Summer 2010, Scott R. Abella, E. Cayenne Engel

Mojave Applied Ecology Notes

Survey of monitoring and management for conservation of rare plants, Roadside restoration techniques in Joshua Tree NP, and an update on renewable energy developments in the Southwestern deserts

Ethnobotanical History And Seed Oil Chemistry Of The Physic Nut, Jatropha Curcas, Nathan M. Leclear

Theses and Dissertations - UTB/UTPA

Jatropha curcas L., Euphorbiaceae, is a small tree native to the neotropics. Despite renewed economic interests in Physic Nut, mainly for biodiesel production, a comprehensive analysis of the ethnobotanical history of J. curcas is lacking. An account of the pre-Columbian neotropical distribution of this species and its historical uses are presented. Using capillary gas chromatography, studies were conducted to quantify the natural variation in seed oil content and fatty acid composition of the seed oil from several species of Jatropha, including assessment of how these parameters change during seed maturation. Natural variation in seed oil content was detected (F7,93 = …

Biomechanical And Morphological Changes In Leaf Abscission Zones During The Ontogeny Of Kalanchoe Pinnatum, Jillian Hodge

Undergraduate Honors Thesis Collection

Kalanchoe pinnatum is able to asexually reproduce with the help of its leaves. In K. pinnatum, embryos are embedded in the notches of a leafs margin. Through the process of abscission, when the plant is disturbed a leaf with embryos falls to the ground and the embryos grow into new plants. Thus, as leaves mature, they face conflicting functional demands to stay on the plant and continue their role in photosynthesis or fall off the plant and asexually reproduce. To examine if there is a point in the leafs development where abscission occurs more readily, I examined breaking strength in …

Seasonal Patterns Of Arthropod Diversity And Abundance On Big Sagebrush, Artemisia Tridentata, Monte P. Sanford, Nancy J. Huntly

Biology Faculty Publications

The sagebrush biotype is the largest in the western United States. This vast sagebrush community is thought to harbor equally vast and diverse arthropod communities, but these remain little explored. Our objective was to examine the diversity, abundance, and seasonal phenology of arthropod taxa found on the dominant shrub of the sagebrush ecosystem, big sagebrush (Artemisia tridentata). We wanted to improve understanding of this little-studied arthropod assemblage that may play significant roles in the dynamics of sagebrush populations and the sagebrush ecosystem. We sampled free-living and gall-forming arthropods from a stratified random sample of sagebrush plants at the …

Japanese Stiltgrass: An Invasive Plant On The Move, Emily S.J. Rauschert, Andrea N. Nord

Biological, Geological, and Environmental Faculty Publications

No abstract provided.

Mojave Applied Ecology Notes Spring 2010, Anna San, Donovan J. Craig, Lindsay P. Chiquoine, Scott R. Abella, E. Cayenne Engel, Christina L. Lund, Jessica E. Spencer, Edward P. Weber Ph.D, Jill E. Craig

Mojave Applied Ecology Notes

Seed removal rates of Sahara mustard by rodents and ants, Mojave Desert Network exotic invasive inventory, gypsum roadside disturbance restoration update, new paper out on post-fire plant establishment, UNLV establishes school of environmental and public affairs

Slow Spread Of The Aggressive Invader, Microstegium Vimineum (Japanese Stiltgrass), Emily S.J. Rauschert, David A. Mortensen, Ottar N. Bjørnstad, Andrea N. Nord, Nora Peskin

Biological, Geological, and Environmental Faculty Publications

Microstegium vimineum (Japanese stiltgrass) is a non-native weed whose rapid invasion threatens native diversity and regeneration in forests. Using data from a 4 year experiment tracking new invasions in different habitats, we developed a spatial model of patch growth, using maximum likelihood techniques to estimate dispersal and population growth parameters. The patches expanded surprisingly slowly: in the final year, the majority of new seedlings were still within 1 m of the original patch. The influence of habitat was not as strong as anticipated, although patches created in roadside and wet meadow habitats tended to expand more rapidly and had greater …

Why Some Stems Are Red: Cauline Anthocyanins Shield Photosystem Ii Against High Light Stress, Dana A. Dudle

Biology Faculty publications

Red-stemmed plants are extremely common, yet the functions of cauline anthocyanins are largely unknown. The possibility that photoabatement by anthocyanins in the periderm reduces the propensity for photoinhibition in cortical chlorenchyma was tested for Cornus stolonifera. Anthocyanins were induced in green stems exposed to full sunlight. PSII quantum yields (Ф_PSII) and photochemical quenching coefficients were depressed less in red than in green stems, both under a light ramp and after prolonged exposures to saturating white light. These differences were primarily attributable to the attenuation of PAR, especially green/yellow light, by anthocyanins. However, the red internodes also …

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, …

Crop Updates 2010 - Genetically Modified Crops, Nutrition And Soils, James Fisher, Désirée Futures, Peter Tozer, Mike Jackson, John Moore, Jamees Neilsen, Geoff Anderson, Wen Chen, Richard Bell, Paul Blackwell, Allan Herbert, Stephen Davies, Ross Brennan, Mike Bolland, James Easton, Ryan Guthrie, Rowan Madderm, Robert Belford, Wal Anderson, Ian Edwards, Reg Lunt, Bill Bowden, Nigel Metz, Peter Newman, Breanne Best, Chris Gazey, Joel Andrew

Crop Updates

GENETICALLY MODIFIED CROPS

1. Evaluation of the environmental and economic impact of Roundup Ready® canola in the Western Australian crop production system, James Fisher and Désirée Futures, York, Western Australia, Peter Tozer, PRT Consulting, Armidale NSW

2. Controlling wild radish (Raphanus raphanistrum) in Roundup Ready®¹ Canola: Outcomes from the Nufarm 2009 Roundup Ready small plot trial Program, Mike Jackson, Nufarm Australia Limited

3. Weed strategies for glyphosate tolerant crops, John Moore, Department of Agriculture and Food

4. Results of the 2009 Western Australia Roundup Ready® canola trials, Dr James Neilsen, Canola Systems …

Relative Allelopathic Potential Of Invasive Plant Species In A Young Disturbed Woodland, Nikki Pisula, Scott J. Meiners

Faculty Research & Creative Activity

Invasive plant species are often more successful within introduced areas when compared to their natural ranges. Allelopathy has been suggested as a potential mechanism for this success because invasive plants frequently establish monocultures and may produce allelochemicals evolutionarily novel to the recipient community. However, species are typically tested in isolation making the relative strength of allelopathy difficult to assess. We conducted laboratory bioassays for 10 co-occurring non-native species to determine the relative strength of their allelopathic potential. These species represented a suite of successful invaders within a young forest and were from a variety of plant life forms: trees, lianas, …

Land Use And Climatic Factors Structure Regional Patterns In Soil Microbialcommunities, Rebecca E. Drenovsky, Kerri L. Steenworth, Louise E. Jackson, Kate M. Scow

Biology

Aim Although patterns are emerging for macroorganisms, we have limited under- standing of the factors determining soil microbial community composition and productivity at large spatial extents. The overall objective of this study was to discern the drivers of microbial community composition at the extent of biogeo- graphical provinces and regions. We hypothesized that factors associated with land use and climate would drive soil microbial community composition and biomass. Location Great Basin Province, Desert Province and California Floristic Province, California, USA. Methods Using phospholipid fatty acid analysis, we compared microbial com- munities across eight land-use types sampled throughout the State of …

Plant Community And Tissue Chemistry Responses To Fertilizer And Litter Nutrient Manipulations In A Temperate Grassland, Rebecca E. Drenovsky, Jean J. Pan, Brittany Widner, Deborah Ammerman

Biology

Human-mediated nutrient amendments have widespread effects on plant communities. One of the major consequences has been the loss of species diversity under increased nutrient inputs. The loss of species can be functional group dependent with certain functional groups being more prone to decline than others. We present results from the sixth year of a long-term fertilization and litter manipulation study in an old-field grassland. We measured plant tissue chemistry (C:N ratio) to understand the role of plant physiological responses in the increase or decline of functional groups under nutrient manipulations. Fertilized plots had significantly more total aboveground biomass and live …

Relative Allelopathic Potential Of Invasive Plant Species In A Young Disturbed Woodland, Nikki Pisula, Scott Meiners

Faculty Research & Creative Activity

Invasive plant species are often more successful within introduced areas when compared to their natural ranges. Allelopathy has been suggested as a potential mechanism for this success because invasive plants frequently establish monocultures and may produce allelochemicals evolutionarily novel to the recipient community. However, species are typically tested in isolation making the relative strength of allelopathy difficult to assess. We conducted laboratory bioassays for 10 co-occurring non-native species to determine the relative strength of their allelopathic potential. These species represented a suite of successful invaders within a young forest and were from a variety of plant life forms: trees, lianas, …