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Full-Text Articles in Biology

[Accepted Article Manuscript Version (Postprint)] Pex5 Mutants That Differentially Disrupt Pts1 And Pts2 Peroxisomal Matrix Protein Import In Arabidopsis, Bibi Khan, Bethany Zolman Dec 2010

[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 …


Traversing Swanton Road, 2nd Ed., James A. West Oct 2010

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 Oct 2010

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


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

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


Biomechanical And Morphological Changes In Leaf Abscission Zones During The Ontogeny Of Kalanchoe Pinnatum, Jillian Hodge Apr 2010

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 …


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 Apr 2010

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


The Rare, Serpentine Endemic Streptanthus Morrisonii (Brassicaceae) Species Complex, Revisited Using Isozyme Analysis, Rebecca W. Dolan Mar 2010

The Rare, Serpentine Endemic Streptanthus Morrisonii (Brassicaceae) Species Complex, Revisited Using Isozyme Analysis, Rebecca W. Dolan

Rebecca W. Dolan

The Streptanthus morrisonii (Brassicaceae) complex is a group of six narrowly-distributed obligate serpentine endemic taxa whose habitat is threatened by geothermal development. Isozyme analysis of this little-studied complex supports the delineation of two species, S. morrisonii and S. brachiatus, but is at odds with the treatment of two subspecies based on morphology. These results may be influenced by small sample sizes but genetic studies of other Streptanthus taxa have shown patterns of relatedness that often transgress subspecies boundaries based on morphology. The present study further shows that members of the S. morrisonii complex share high genetic identity values (mean = …


Population Genetic Structure In Nolina Brittoniana (Agavaceae), A Plant Endemic To The Central Ridges Of Florida, Rebecca W. Dolan, Rebecca Yahr, Eric S. Menges Mar 2010

Population Genetic Structure In Nolina Brittoniana (Agavaceae), A Plant Endemic To The Central Ridges Of Florida, Rebecca W. Dolan, Rebecca Yahr, Eric S. Menges

Rebecca W. Dolan

Nolina brittoniana is endemic to the central ridges of peninsular Florida. Its scrub and sandhill habitats have suffered extensive anthropogenic modification. Analysis of isozymes from populations throughout its range revealed less genetic variation than generally reported for endemic plants. Populations were well differentiated, with significant clines in allele frequency along the north-south axis of distribution. Pair-wise F-statistics calculated at four levels of population geographic substructure revealed that current and inferred historical habitat patches had similar genetic structure. We found no evidence of recent bottlenecks or changes in genetic structure due to habitat loss and fragmentation, consistent with populations having always …


The Effects Of Seed Size And Maternal Origin On The Distribution Of Individual Plant Size In Ludwigia Leptocarpa (Onagraceae), Rebecca W. Dolan Mar 2010

The Effects Of Seed Size And Maternal Origin On The Distribution Of Individual Plant Size In Ludwigia Leptocarpa (Onagraceae), Rebecca W. Dolan

Rebecca W. Dolan

Seed size is normally distributed for many annual species, while mature plant size is frequently positively skewed. A study was conducted to determine the influence of seed size and the role of genetic differences in determining relative seedling size for Ludwigia leptocarpa. Seed size had a significant effect on percentage germination and time of seed germination but no effect on dry weight or leaf area of seedlings. Seed size and spacing had a significant effect on seedling dry weight for plants grown under competition, while relative day of emergence had no effect. Familial (genetic) differences were found in average seed …


Patterns Of Isozyme Variation In Relation To Population Size, Isolation, And Phytogeographic History In Royal Catchfly, Rebecca W. Dolan Mar 2010

Patterns Of Isozyme Variation In Relation To Population Size, Isolation, And Phytogeographic History In Royal Catchfly, Rebecca W. Dolan

Rebecca W. Dolan

The distribution of genetic variation within and among plant populations is influenced by both contemporary and historical factors. I used isozyme analysis of band phenotypes to examine genetic structure in the rare prairie forb Silene regia. Relationships between current-day population size, isolation, and phenotypic variation were assessed for 18 populations in two regions with differing postglacial history. Western populations from unglaciated southern Missouri and Arkansas were more genetically diverse based on the Shannon-Weaver index (H) and a polymorphic index than were more eastern populations. These differences may be due to loss of variation with repeated founding of new populations in …


Conservation Implications Of Genetic Variation In Three Rare Species Endemic To Florida Rosemary Scrub, Rebecca W. Dolan, Rebecca Yahr, Eric S. Menges, Matthew Halfhill Mar 2010

Conservation Implications Of Genetic Variation In Three Rare Species Endemic To Florida Rosemary Scrub, Rebecca W. Dolan, Rebecca Yahr, Eric S. Menges, Matthew Halfhill

Rebecca W. Dolan

Habitat conversion and fire suppression during the last 50 yr have greatly reduced and altered Florida scrub vegetation, resulting in threats to the persistence of its unique flora. As part of a larger conservation project, we investigated patterns of isozyme variation in three rare perennial scrub plants with overlapping ranges endemic to Florida rosemary scrub on the Lake Wales Ridge. All three species have low levels of genetic variation, comparable to or lower than those generally reported for rare plants with restricted geographic ranges. Liatris ohlingerae has more than twice the expected heterozygosity of the other two species, with little …


Conservation Implications Of Genetic Variation In Three Rare Species Endemic To Florida Rosemary Scrub, Rebecca W. Dolan, Rebecca Yahr, Eric S. Menges, Matthew Halfhill Mar 2010

Conservation Implications Of Genetic Variation In Three Rare Species Endemic To Florida Rosemary Scrub, Rebecca W. Dolan, Rebecca Yahr, Eric S. Menges, Matthew Halfhill

Rebecca W. Dolan

Habitat conversion and fire suppression during the last 50 yr have greatly reduced and altered Florida scrub vegetation, resulting in threats to the persistence of its unique flora. As part of a larger conservation project, we investigated patterns of isozyme variation in three rare perennial scrub plants with overlapping ranges endemic to Florida rosemary scrub on the Lake Wales Ridge. All three species have low levels of genetic variation, comparable to or lower than those generally reported for rare plants with restricted geographic ranges. Liatris ohlingerae has more than twice the expected heterozygosity of the other two species, with little …


Genetic Diversity And Reproductive Biology In Warea Carteri (Brassicaceae), A Narrowly Endemic Florida Scrub Annual, Margaret E.K. Evans, Rebecca W. Dolan, Eric S. Menges, Doria R. Gordon Mar 2010

Genetic Diversity And Reproductive Biology In Warea Carteri (Brassicaceae), A Narrowly Endemic Florida Scrub Annual, Margaret E.K. Evans, Rebecca W. Dolan, Eric S. Menges, Doria R. Gordon

Rebecca W. Dolan

Carter's mustard (Warea carteri) is an endangered, fire-stimulated annual endemic of the Lake Wales Ridge, Florida, USA. This species is characterized by seed banks and large fluctuations in plant numbers, with increases occurring in postdisturbance habitat. We investigated the mating system, patterns of isozyme variation, and effective population sizes of W. carteri to better understand its population biology and to comment on reserve designs and management proposals relevant to this species. Warea carteri is self-compatible and autogamous, and probably largely selfing. Measures of genetic variation in W. carteri were lower than values reported for species with similar ecological and life …


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 Mar 2010

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, …


Why Some Stems Are Red: Cauline Anthocyanins Shield Photosystem Ii Against High Light Stress, Dana A. Dudle Mar 2010

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 (ФPSII) 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 …


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

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

Mojave Applied Ecology Notes

Native species interactions with red brome (Bromus rubens), undergraduate and graduate programs at UNLV, what’s growing in the greenhouse?


Genetic Variation For Susceptibility To Storm-Induced Stem Breakage In Solidago Altissima: The Role Of Stem Height And Morphology, M. Wise, W. Abrahamson Dec 2009

Genetic Variation For Susceptibility To Storm-Induced Stem Breakage In Solidago Altissima: The Role Of Stem Height And Morphology, M. Wise, W. Abrahamson

Warren G. Abrahamson, II

While storms can have obvious ecological impacts on plants, plants’ potential to respond evolutionarily to selection for increased resistance to storm damage has received little study. We took advantage of a thunderstorm with strong wind and hail to examine genetic variation for resistance to stem breakage in the herbaceous perennial Solidago altissima. The storm broke the apex of nearly 10% of 1883 marked ramets in a common-garden plot containing 26 genets of S. altissima. Plant genets varied 20-fold in resistance to breakage. Stem height was strongly correlated with resistance to breakage, with taller stems being significantly more susceptible. A stem’s …


Spatiotemporal Variation Of Fruit Digestible-Nutrient Production In Florida's Uplands, J. Layne, W. Abrahamson Dec 2009

Spatiotemporal Variation Of Fruit Digestible-Nutrient Production In Florida's Uplands, J. Layne, W. Abrahamson

Warren G. Abrahamson, II

We examined annual total digestible nutrient (TDN) production by fruits of eight species (Quercus chapmanii, Q. geminata, Q. inopina, Q. laevis, Q. myrtifolia, Carya floridana, Sabal etonia, Serenoa repens) that account for the major proportion of TDN production by fruits and seeds in Florida’s xeric upland associations (southern ridge sandhill, sand pine scrub, scrubby flatwoods). Mean annual fruit TDN of all species combined over a 27-year span in sandhill and scrub and 24 years in scrubby flatwoods was highest (45.4 kg/ha) in sandhill, intermediate in scrubby flatwoods (28.8 kg/ha), and lowest in scrub (14.2 kg/ha). Sandhill fruit TDN production was …


Nomenclatural Changes For Some Grasses In California And The Muhlenbergia Clade (Poaceae), James Payne Smith Jr. Dec 2009

Nomenclatural Changes For Some Grasses In California And The Muhlenbergia Clade (Poaceae), James Payne Smith Jr.

James Payne Smith

No abstract provided.


Ducking As The Means Of Resistance In "Candy-Cane" Stems Of Goldenrod: Straightened Stems Lose Their Edge, M. J. Wise, W. G. Abrahamson, J. A. Cole Dec 2009

Ducking As The Means Of Resistance In "Candy-Cane" Stems Of Goldenrod: Straightened Stems Lose Their Edge, M. J. Wise, W. G. Abrahamson, J. A. Cole

Warren G. Abrahamson, II

Herbivores are among the most pervasive selective forces acting on plants, and the number of plant chemicals that presumably evolved for defense against herbivory is immense. In contrast, biologists are only beginning to appreciate the important roles that architectural traits can play in antiherbivore defense. One putative architectural-resistance trait is the nodding stem apex of some goldenrods (Solidago ; Asteraceae). Individuals of S. altissima genets that undergo temporary nodding in the late spring (i.e., “candy-cane ramets) have been shown to be more resistant than individuals of erect-stemmed genets to certain apex-attacking” herbivores. We tested the hypothesis that the greater resistance …


Nutrition As A Facilitator Of Host-Race Formation: The Role Of Food Quality In The Shift Of A Stem-Boring Beetle To A Gall Host, C. P. Blair, R. V. Schlanger, S. E. Diamond, W. G. Abrahamson Dec 2009

Nutrition As A Facilitator Of Host-Race Formation: The Role Of Food Quality In The Shift Of A Stem-Boring Beetle To A Gall Host, C. P. Blair, R. V. Schlanger, S. E. Diamond, W. G. Abrahamson

Warren G. Abrahamson, II

1. The importance of host-race formation to herbivorous insect diversity depends on the likelihood that successful populations can be established on a new plant host. A previously unexplored ecological aid to success on a novel host is better nutritional quality. The role of nutrition was examined in the shift of the stem-boring beetle Mordellistena convicta to fly-induced galls on goldenrod and the establishment there of a genetically distinct gall host race. 2. First, larvae of the host race inhabiting stems of Solidago gigantea were transplanted into stems and galls of greenhouse-grown S. gigantea plants. At the end of larval development, …