Biology Commons^™

Ecophysiological Implications Of Low Lignin In Eastern Leatherwood (Dirca Palustris L.), Anna Cole, Kayla Marie Rigdon, D. Gordon Brown, Katharine Lora Cary

Biology Faculty Publications

Dirca palustris L. (eastern leatherwood) is an understory shrub found throughout much of eastern North America. Dirca palustris wood has a low concentration of lignin, which is a molecule that grants structural rigidity to cell walls. The branches of D. palustris are thus remarkably flexible, but their low lignin content could cause greater vulnerability to water stress. We examined the conductivity, vessel anatomy, and field water potential of D. palustris and conducted ecological surveys. The data showed that D. palustris was not experiencing substantial drought-induced dysfunction in the field, even during an exceptionally hot and dry summer. Its water potentials …

Increasing The Resilience Of Plant Immunity To A Warming Climate, Jong Hum Kim, Christian Castroverde, Shuai Huang, Chao Li, Richard Hilleary, Adam Seroka, Reza Sohrabi, Diana Medina-Yerena, Bethany Huot, Jie Wang, Sharon Marr, Mary Wildermuth, Tao Chen, John Macmicking, Sheng Yang He

Biology Faculty Publications

Extreme weather conditions associated with climate change affect many aspects of plant and animal life, including the response to infectious diseases. Production of salicylic acid (SA), a central plant defence hormone, is particularly vulnerable to suppression by short periods of hot weather above the normal plant growth temperature range via an unknown mechanism. Here we show that suppression of SA production in Arabidopsis thaliana at 28 °C is independent of PHYTOCHROME B (phyB) and EARLY FLOWERING 3 (ELF3), which regulate thermo-responsive plant growth and development. Instead, we found that formation of GUANYLATE BINDING PROTEIN-LIKE 3 (GBPL3) defence-activated biomolecular condensates (GDACs) …

Salicylic Acid And N-Hydroxypipecolic Acid At The Fulcrum Of The Plant Immunity-Growth Equilibrium, Alyssa Shields, Vanessa Shivnauth, Christian Danve M. Castroverde

Biology Faculty Publications

Salicylic acid (SA) and N-hydroxypipecolic acid (NHP) are two central plant immune signals involved in both resistance at local sites of pathogen infection (basal resistance) and at distal uninfected sites after primary infection (systemic acquired resistance). Major discoveries and advances have led to deeper understanding of their biosynthesis and signaling during plant defense responses. In addition to their well-defined roles in immunity, recent research is emerging on their direct mechanistic impacts on plant growth and development. In this review, we will first provide an overview of how SA and NHP regulate local and systemic immune responses in plants. We …

Salicylic Acid: A Key Regulator Of Redox Signalling 1 And Plant Immunity, Mohd Saleem, Qazi Fariddudin, Christian Castroverde

Biology Faculty Publications

In plants, the reactive oxygen species (ROS) formed during normal conditions are essential in regulating several processes, like stomatal physiology, pathogen immunity and developmental signaling. However, biotic and abiotic stresses can cause ROS over-accumulation leading to oxidative stress. Therefore, a suitable equilibrium is vital for redox homeostasis in plants, and there have been major advances in this research arena. Salicylic acid (SA) is known as a chief regulator of ROS; however, the underlying mechanisms remain largely unexplored. SA plays an important role in establishing the hypersensitive response (HR) and systemic acquired resistance (SAR). This is underpinned by a robust and …

Temperature Regulation Of Plant Hormone Signaling During Stress And Development, Christian Castroverde, Damaris Dina

Biology Faculty Publications

Global climate change has broad-ranging impacts on the natural environment and human civilization. Increasing average temperatures along with more frequent heat waves collectively have negative effects on cultivated crops in agricultural sectors and wild species in natural ecosystems. These aberrantly hot temperatures, together with cold stress, represent major abiotic stresses to plants. Molecular and physiological responses to high and low temperatures are intricately linked to the regulation of important plant hormones. In this review, we shall highlight our current understanding of how changing temperatures regulate plant hormone pathways during immunity, stress responses and development. This article will present an overview …

Mechanistic Insights Into Strigolactone Biosynthesis, Signaling And Regulation During Plant Growth And Development, Kaiser Iqbal Wani, Andleeb Zehra, Sadaf Choudhary, M Naeem, M. Masroor A. Khan, Christian Danve Castroverde, Tariq Aftab

Biology Faculty Publications

Strigolactones (SLs) constitute a group of carotenoid-derived phytohormones with butenolide moieties. These hormones are involved in various functions, including regulation of secondary growth, shoot branching and hypocotyl elongation, and stimulation of seed germination. SLs also control hyphal branching of arbuscular mycorrhizal (AM) fungi, and mediate responses to both abiotic and biotic cues. Most of these functions stem from the interplay of SLs with other hormones, enabling plants to appropriately respond to changing environmental conditions. This dynamic interplay provides opportunities for phytohormones to modulate and augment one another. In this article, we review our current mechanistic understanding of SL biosynthesis, receptors …

Diversity, Function And Regulation Of Cell Surface And Intracellular Immune Receptors In Solanaceae, Jong Hum Kim, Christian Castroverde

Biology Faculty Publications

The first layer of the plant immune system comprises plasma membrane-localized receptor proteins and intracellular receptors of the nucleotide-binding leucine-rich repeat protein superfamily. Together, these immune receptors act as a network of surveillance machines in recognizing extracellular and intracellular pathogen invasion-derived molecules, ranging from conserved structural epitopes to virulence-promoting effectors. Successful pathogen recognition leads to physiological and molecular changes in the host plants, which are critical for counteracting and defending against biotic attack. A breadth of significant insights and conceptual advances have been derived from decades of research in various model plant species regarding the structural complexity, functional diversity and …

Effects Of Increased Precipitation On The Life History Of Spring- And Autumn-Germinated Plants Of The Cold Desert Annual Erodium Oxyrhynchum (Geraniaceae), Yanfeng Chen, Xiang Shi, Lingwei Zhang, Jerry M. Baskin, Carol C. Baskin, Huiliang Liu, Daoyuan Zhang

Biology Faculty Publications

Future increased precipitation in cold desert ecosystems may impact annual/ephemeral plant species that germinate in both spring and autumn. Our primary aim was to compare the life history characteristics of plants from spring-germinating (SG) and autumn-germinating (AG) seeds of Erodium oxyrhynchum. Plants in field plots with simulated increases in precipitation of 0, 30 and 50 % in spring and summer were monitored to determine seedling survival, phenology, plant size, seed production and biomass accumulation and allocation. Germination characteristics were determined in the laboratory for seeds produced by plants in all increased precipitation treatments. Increased precipitation in spring significantly improved survival …

A Stimulatory Role For Cytokinin In The Arbuscular Mycorrhizal Symbiosis Of Pea, Dane M. Goh, Marco Cosme, Anna B. Kislala, Samantha Mulholland, Zakaria M.F. Said, Lukáš Spíchal, R.J. Neil Emery, Stéphane Declerck, Frédérique C. Guinel

Biology Faculty Publications

The arbuscular mycorrhizal (AM) symbiosis between terrestrial plants and AM fungi is regulated by plant hormones. For most of these, a role has been clearly assigned in this mutualistic interaction; however, there are still contradictory reports for cytokinin (CK). Here, pea plants, the wild type (WT) cv. Sparkle and its mutant E151 (Pssym15), were inoculated with the AM fungus Rhizophagus irregularis. E151 has previously been characterized as possessing high CK levels in non-mycorrhizal (myc^-) roots and exhibiting high number of fungal structures in mycorrhizal (myc⁺) roots. Myc^- and myc⁺ plants were …

Refernment: An R Package For Annotating Rna Editing In Plastid Genomes, Tanner A. Robison, Paul G. Wolf

Biology Faculty Publications

PREMISE OF THE STUDY: In the absence of cDNA, the annotation of RNA editing in plastomes must be done manually, representing a significant time cost to those studying the organellar genomes of ferns and hornworts.

METHODS AND RESULTS: We developed an R package to automatically annotate apparent nonsense mutations in plastid genomes. The software successfully annotates such sites and results in no false positives for data with no sequencing or assembly errors.

CONCLUSIONS: Compared to manual annotation, ReFernment offers greater speed and accuracy for annotating RNA editing sites. This software should be especially useful for researchers generating large numbers of …

Structural Basis For Light Control Of Cell Development Revealed By Crystal Structures Of A Myxobacterial Phytochrome, Nicole C. Woitowich, Andrei S. Halavaty, Patricia Waltz, Christopher Kupitz, Joseph Valera, Gregory Tracy, Kevin D. Gallagher, Elin Claesson, Takanori Nakane, Suraj Pandey, Garrett Nelson, Rie Tanaka, Eriko Nango, Eiichi Mizohata, Shigeki Owada, Kensure Tono, Yasumasa Joti, Angela C. Nugent, Hardik Patel, Ayesha Mapara, James Hopkins, Phu Duong, Dorina Bizhga, Svetlana E. Kovaleva, Rachel St. Peter, Cynthia N. Hernandez, Wesley B. Ozarowski, Shatabdi Roy-Chowdhuri, Jay-How Yang, Petra Edlund, Heikki Takala, Janne Ihalainen, Jennifer Brayshaw, Tyler Norwood, Ishwor Poudyal, Petra Fromme, John C.H. Spence, Keith Moffat, Sebastian Westenhoff, Marius Schmidt, Emina A. Stojkovic

Biology Faculty Publications

Phytochromes are red-light photoreceptors that were first characterized in plants, with homologs in photosynthetic and non-photosynthetic bacteria known as bacteriophytochromes (BphPs). Upon absorption of light, BphPs interconvert between two states denoted Pr and Pfr with distinct absorption spectra in the red and far-red. They have recently been engineered as enzymatic photoswitches for fluorescent-marker applications in non-invasive tissue imaging of mammals. This article presents cryo- and room-temperature crystal structures of the unusual phytochrome from the non-photosynthetic myxobacterium Stigmatella aurantiaca (SaBphP1) and reveals its role in the fruitingbody formation of this photomorphogenic bacterium. SaBphP1 lacks a conserved histidine (His) in the chromophore-binding …

Mobile Elements Shape Plastome Evolution In Ferns, Tanner A. Robison, Amanda L. Grusz, Paul G. Wolf, Jeffrey P. Mower, Blake D. Fauskee, Karla Sosa, Eric Schuettpelz

Biology Faculty Publications

Plastid genomes display remarkable organizational stability over evolutionary time. From green algae to angiosperms, most plastid genomes are largely collinear, with only a few cases of inversion, gene loss, or, in extremely rare cases, gene addition. These plastome insertions are mostly clade-specific and are typically of nuclear or mitochondrial origin. Here, we expand on these findings and present the first family-level survey of plastome evolution in ferns, revealing a novel suite of dynamic mobile elements. Comparative plastome analyses of the Pteridaceae expose several mobile open reading frames that vary in sequence length, insertion site, and configuration among sampled taxa. Even …

Lethal Effects Of Leaf Leachate From The Non-Native Invasive Shrub Amur Honeysuckle (Lonicera Maackii) On A Model Aquatic Organism (Hyalella Azteca), Eric B. Borth, Kevin W. Custer, Ryan W. Mcewan

Biology Faculty Publications

The invasive shrub Lonicera maackii (Amur honeysuckle) is a problematic species in the eastern United States and there is growing evidence that materials from this species have toxic effects on some organisms. We used a sequence of microcosm bioassays to assess the influence of L. maackii leaf leachate on the macroinvertebrate Hyalella azteca, which is a standard aquatic organism for toxicity assessment. In a laboratory setting, H. azteca were exposed to a leaf leachate dilution series (6.25%, 12.5%, 25%, 50%, 100%) in 48-h toxicity tests. This was repeated throughout the growing season to assess the potential for changes in …

The Role Of Environmental Filtering In Structuring Appalachian Tree Communities: Topographic Influences On Functional Diversity Are Mediated Through Soil Characteristics, Julia I. Chapman, Ryan W. Mcewan

Biology Faculty Publications

Identifying the drivers of community assembly has long been a central goal in ecology, and the development of functional diversity indices has provided a new way of detecting the influence of environmental gradients on biotic communities. For an old-growth Appalachian forest, we used path analysis to understand how patterns of tree functional diversity relate to topography and soil gradients and to determine whether topographic effects are mediated through soil chemistry. All of our path models supported the idea of environmental filtering: stressful areas (high elevation, low soil moisture, low soil nutrients) were occupied by communities of low functional diversity, which …

Changes In Oxidative Patterns During Dormancy Break By Warm And Cold Stratification In Seeds Of An Edible Fruit Tree, Dilinuer Shalimu, Jia Sun, Carol C. Baskin, Jerry M. Baskin, Liwei Sun, Yujun Liu

Biology Faculty Publications

The transition from seed dormancy to germination is triggered by environmental factors, and in pomegranate (Punica granatum) seeds higher germination percentages are achieved by warm + cold stratification rather than by cold stratification alone. Our objective was to define the pattern of internal oxidative changes in pomegranate seeds as dormancy was being broken by warm + cold stratification and by cold stratification alone. Embryos isolated from seeds after 1–42 days of warm stratification, after 56 days of warm stratification + 7, 28 or 56 days of cold stratification, and after 1–84 days of cold stratification alone, were used …

2005 Virginia Wildflower Of The Year: Bloodroot, Sanguinaria Canadensis, W. John Hayden

Biology Faculty Publications

Bloodroot is an herbaceous perennial that grows from a persistent, branched underground stem or rhizome. Early each spring, while the forest canopy is still bare, each well-developed rhizome tip produces one leaf and one flower stalk. The leaf is kidney-shaped in its overall outline, but it is also divided into a pattern of rounded lobes and sinuses, rendering a complex overall shape. At flowering time, bloodroot leaves form a loose vertically-oriented collar around the flower stalk with the bluish-green lower leaf surface forming the outside of the collar; as the season progresses, the leaves open flat and expand to their …

Seed Mass And Morphology In Outcrossing And Selfing Species Of Clarkia (Onagraceae): An Sem Study, Jennifer L. Knies, Veronique A. Delesalle, A. R. Cavaliere

Biology Faculty Publications

Seeds from three pairs of outcrossing-selfing sister taxa from the genus Clarkia (farewell-to-spring, Onagraceae)—Clarkia unguiculata, Clarkia exilis, Clarkia xantiana ssp. xantiana and ssp. parviflora, and Clarkia concinna ssp. concinna and ssp. automixa—were studied to assess the effects of contrasting mating systems on seed mass and seed morphology. For each outcrossing-selfing comparison, the seed mass of the selfing taxon was less than that of the outcrossing taxon. Seed mass typically differed significantly among populations within a taxon. Scanning electron microscopy showed that the seeds from all these taxa share several characteristics: a bullet to shield shape, a reticulate exotesta pattern, presence …

Floristic Diversity In Ten Tallgrass Prairie Remnants Of Eastern Nebraska, Judith F. Boettcher, Thomas B. Bragg, David M. Sutherland

Biology Faculty Publications

Ten eastern Nebraska tallgrass prairie remnants, varying in size from one to 18 ha, were studied or visited during the growing seasons from 1979 to 1993. A total of217 prairie plant species were recorded. Big bluestem (Andropogon gerardii), little bluestem (Andropogon scoparius), smooth brome (Bromus inermis subsp. inermis), New Jersey tea (Ceanothus herbaceus var. pubescens), false sunflower (Heliopsis helianthoides var. scabra), Kentucky bluegrass (Poa pratensis), and porcupine-grass (Stipa spartea) were prevalent in all the prairies although the specific floristic composition has been reported to vary depending on past management, topography, season of evaluation, and prairie size. Of the total species …

Woody Vegetation Of A Disjunct Bur Oak (Quercus Macrocarpa) Forest In East-Central Nebraska, Debra Ann Beightol, Thomas B. Bragg

Biology Faculty Publications

Woody plant composition was assessed for three tree-size classes in two ravines of Oak Glen Wildlife Management Area, a disjunct oak forest in Seward County, Nebraska, using Importance Values (IV) obtained by the Point-Quarter method. Bur oak (Quercus macrocarpa Michx.) dominated the large-size class (>30 cm dbh) (IV = 258) but elms (Ulmus americana L. and U. rubra Muhl.) (IV = 130) dominated the forest in one ravine in the medium-size class (10-30cm dbh) and elm and hackberry (Celtis occidentalis L.) (IV = 114 and 27 respectively) dominated the small-size class (

Review Of American Wildflower Florilegium By Jean Andrews, David M. Sutherland

Biology Faculty Publications

This book is a collection of 50 watercolor paintings of American wildflowers ("florilegium" means, literally, "a gathering of flowers"). Accompanying each full-page painting is a summary of general information about the plant, including notes about its botanical classification, the etymology of its name, life history, distribution, description, flowering period, pollination, and propagation.

Review Of The Wild Oat Inflorescence And Seed: Anatomy, Development And Morphology, M. V. S. Raju, David M. Sutherland

Biology Faculty Publications

This slim volume describes a detailed study of the reproductive parts of Avena fatua, the wild oat plant-a common weed in the northern plains and the probable ancestor of the cultivated oat. The book integrates the author's own work with information from available literature and includes lengthy technical descriptions of the structure and the growth of the inflorescence, the floret, the ovule, the pollen grain, the embryo, the seed, and the young seedling. Throughout the work, the author relates the wild oat's structure and development to other grasses, other monocotyledons, and other seed plants, offering evolutionary interpretations of many of …

New And Corrected Floristic Records For Nebraska, Steven B. Rolfsmeier, Robert B. Kaul, David M. Sutherland

Biology Faculty Publications

Nineteen species (including eight Eurasian ones) are newly recorded for Nebraska: Alopecurus arundinaceus, Amaranthus californicus, Asclepias asperula, A purpurascens, Cardamine {lexuosa*, Centaurea diffusa, Dipsacus laciniatus, Eriochloa villosa, Euclidium syriacum, Gentiana alba, Geranium viscosissimum, Geum vernum, Goodyera oblongifolia, Haplopappus multicaulis, Heterotheca latifolia, Lathyrus tuberosus, Polygonum douglasii, Scirpus saximontanus, Veronica biloba. Twenty-one others are shown to be more widespread in Nebraska than previously known, one has a more restricted range than previously reported, two (Scirpus smithii, S. torreyi) are deleted from the flora based upon corrected identifications, and the status of some rarely-collected species is updated. Thirty-two additions, two …

A Taxonomic Study Of Variation In Leptochloa Fascicularis (Lam.) Gray In The Central Great Plains, Todd A. Templeton

Biology Faculty Publications

The morphology of Leptochloa fascicularis (Lam.) Gray (Poaceae) was studied in 25 locations in eastern and central Nebraska to determine if this grass was separable into two distinct taxa as suggested in several recent sources. Field collections were supplemented with herbarium specimens from other parts of the Central Great Plains. Glume and lemma lengths, the characters used in published keys, provided no separations useful in dividing the material into two species or varieties. However, individual local populations exhibited significant differences from each other in these characters. Such local differences appear to be reasonable given the high degree of inbreeding that …

An Annotated List Of The Vascular Plants Of Keith County, Nebraska, David M. Sutherland, Steven B. Rolfsmeier

Biology Faculty Publications

This study provides an annotated list of the vascular plants known to exist outside of cultivation in Keith County, Nebraska. Listed are a total of 599 species, subspecies and varieties belonging to 302 genera of 87 families. Notes are included about frequency and habitat for each of the taxa. 264 (44.1 %) of the taxa listed were previously unreported for Keith County. Additionally, the paper discusses vegetation regions in the county and gives information in tabular form about numbers of the flora in different taxa, the ten largest families, numbers of taxa of different growth habits, and numbers of taxa …

New And Corrected Floristic Records For Nebraska, Steven B. Rolfsmeier, Robert B. Kaul, Marjorie M. Garabrandt, David M. Sutherland

Biology Faculty Publications

New distributional data are given for 54 species of vascular plants in Nebraska. Twenty are newly recorded for the State. 23 are shown to be more widespread than was previously known, seven are shown to have more restricted ranges than previously reported. the records of one species attributed to the State are shown to be based on misidentifications. and the presence in the State of three species collected long ago is confirmed by recent collections.

Historical Notes On Collections And Taxonomy Of Penstemon Haydenii S. Wats. (Blowout Penstemon), Nebraska's Only Endemic Plant Species, David M. Sutherland

Biology Faculty Publications

Penstemon haydenii was originally described in 1891 by Sereno Watson and was named for its first collector, the geologist and explorer Ferdinand V. Hayden, who probably collected it in the late summer of 1857 in the" Sand Hills of Loup Fork," Nebraska. The Hayden specimen which Watson saw in the Gray Herbarium at Harvard University had evidently been labeled with an incorrect location. Watson did not base his description on that early specimen but upon a more complete specimen, also in the Gray Herbarium, taken by Herbert J. Webber in Thomas County in 1891; so the Webber specimen, not the …

New And Corrected Records Of The Flora Of Nebraska, Steven B. Rolfsmeier, Robert B. Kaul, David M. Sutherland

Biology Faculty Publications

New distributional data are provided for 27 species of vascular plants in Nebraska, eight newly recorded as growing wild in the State. The record of one species previously attributed to the State is shown to be based upon misidentified specimens, the range of another is shown to be much more restricted in Nebraska than previously reported, and nomenclature is corrected for two species.

Nebraska Plant Distribution, David M. Sutherland, Robert B. Kaul

Biology Faculty Publications

Distribution notes based on recent collections and herbarium work are provided for 46 Nebraska plant taxa, including 43 flowering plants, two ferns, and one liverwort. The list includes several plants that are new to the State and provides range extensions within the State for many others. Several previously- published distribution records believed to be erroneous are also discussed.

Vegetative Key To Grasses Of The Sand Hills Region Of Nebraska, David M. Sutherland

Biology Faculty Publications

All illustrated key is provided that will facilitate identification of grasses in the vegetative condition in the Sand Hills region of Nebraska. The key separates 97 species, varieties, and species groups and discusses or partially separates 14 additional taxa. It emphasizes characteristics that may be observed in the field with a hand lens and is illustrated with 109 camera lucida drawings.