Life Sciences Commons^™

Assessing A Half-Century Of Change In Understory Plant Range And Frequency In The Klamath Mountains Of California, Emily Jean Jackson

Cal Poly Humboldt theses and projects

The effects of climate change have and will continue to impact plant communities, including by potentially shifting species’ ranges towards topographically sheltered, cooler locations or higher elevations. In 2024, I resampled 140 vegetation plots established in 1969 in the Klamath Mountains of Northern California to assess range shifts of 46 understory species over a 55-year period. During this time, the elevational distribution of all species has increased significantly by an average of 26.9 m, but this increase was slower than necessary to track historic temperature niches given regional warming (215-311 m). Despite this overall increase, only four species exhibited significant …

Contents, Discovery Editors

Discovery, The Student Journal of Dale Bumpers College of Agricultural, Food and Life Sciences

No abstract provided.

Discovery: The Student Journal Of Dale Bumpers College Of Agricultural, Food And Life Sciences - Volume 27 2026, Several Authors

Discovery, The Student Journal of Dale Bumpers College of Agricultural, Food and Life Sciences

No abstract provided.

Soil Nutrient Sufficiency Versus Plant Nutrient Status In Compost-Amended Soils: Plant Tissue Analysis As A Diagnostic Tool, Chandralekha Joga Miss

Murray State Theses and Dissertations

This study evaluated whether Mehlich III soil nutrient sufficiency ratings reliably predict plant nutrient status and chlorophyll response across contrasting compost application histories. A greenhouse pot experiment was conducted with Chijimisai (Brassica rapa) planted in three treatment soils that had no compost (T1), moderate compost history (T2), and long-term hog manure compost application (T3). Plant performance was assessed through weekly shoot length and chlorophyll content (SPAD) measurements, leaf number at maturity, and leaf tissue nutrient analysis conducted at harvest. Soil test results indicated adequate to high nutrient levels across all three treatments. Leaf tissue analysis, however, revealed substantial …

Hydroponics In The Classroom: Cultivating Plants, Captivating Young People, Stacy A. Adams, Christian Stephenson, Theresa James, Kim Todd

Department of Agronomy and Horticulture: Faculty Publications

Few students take the initiative to pursue coursework beyond that required for progression to graduation. Limited are opportunities that connect educational content to industry application, potentially inspiring young people towards impactful careers. The United States government has emphasized the importance of STEM education to ensure national security and to maintain economic competitiveness globally. STEM education is not a defined discipline but an approach for building knowledge through application and engagement. Developing and managing a hydroponics prototype provides numerous opportunities for embedding STEM content into a fun and interactive project. This poster provides inspiration for constructing a simple deep water culture …

Depth And Soil Physical Context Govern Soil Organic Carbon, While Woody Cover Moderates Native Vegetation Relationships In California Rangelands, Dabid Zuniga Garcia

Cal Poly Humboldt theses and projects

Soil organic carbon (SOC) is central to soil function and an important component of climate mitigation in rangeland ecosystems, but the controls on SOC across California’s working rangelands remain understudied. Using data from Point Blue Conservation Science’s Rangeland Monitoring Network, this study evaluated how soil properties, vegetation structure, and recent climate relate to SOC concentration at depths of 0–10 cm and 10–40 cm across 145 ranches spanning four California regions. Linear mixed-effects models showed that SOC was consistently higher in topsoil than subsoil and highest in coastal sites relative to interior valleys. Bulk density was the strongest negative predictor of …

American Elderberry's Next Top Pollinator: Evaluating The Role Of Arthropods In Pollination, Jenny K. Burrow

Graduate Theses/Dissertations

American elderberry (Sambucus nigra subsp. canadensis) is a woody deciduous shrub native to eastern North America. In addition to its long history of use by indigenous peoples, there is renewed interest in cultivating and consuming American elderberry, primarily driven by expanding health supplement markets. Despite recent advances in horticultural development of American elderberry, its pollination ecology remains poorly understood. In this field study, I evaluated the contribution of arthropod visitors to pollination of American elderberry. To do this, I first characterized the identities and abundances of arthropod visitors via timed arthropod collections and floral observations during peak flowering …

A New Dioecious Bush Tomato, Solanum Nectarifolium (Solanaceae), From The Northern Tanami Desert, Northern Territory, Australia, With Reassessment Of S. Ossicruentum And A Change In The Circumscription Of S. Dioicum, Christopher T. Martine, Kym Brennan, Jason T. Cantley, Aiden Webb, Geoffrey Newton

Faculty Journal Articles

A new species of functionally dioecious bush tomato from the “Solanum dioicum + S. echinatum group” of Solanum subgenus Leptostemonum is described. Solanum nectarifolium Martine & Brennan, sp. nov., is a member of the taxonomically challenging Solanum dioicum W.Fitzg. species complex in Australia and differs from other species in the group by the presence of prominent and conspicuous extrafloral nectaries on the abaxial leaf surfaces, a tinge of purple on the new growth and young fruiting calyces, and curved prickles on young stems. Although fairly well represented in herbarium collections, this new taxon has historically been treated as a …

Clerodendrum Kelli (Lamiaceae), A New Species From Carranglan, Nueva Ecija, Philippines, And Lectotypification Of Clerodendrum Mindorense, David Justin R. Ples, Jacek Patykowski, John Charles A. Altomonte, Adriene B. Tobias, Rene Alfred Anton Bustamante

Biology Faculty Publications

Clerodendrum kelli (Lamiaceae), a new species from the montane forests of Carranglan, Nueva Ecija, Philippines, is described and illustrated. The species shares morphological features with Clerodendrum quadriloculare and C. mindorense, but differs in inflorescence structure, corolla tube length, and calyx shape and color. A lectotype for C. mindorense is also designated. Preliminary conservation assessment places C. kelli in the Critically Endangered category (CR B1ab(iii)+2ab(iii)). This study contributes to Philippine plant biodiversity knowledge and informs conservation strategies.

Oregon State Rank Assessment For Plumed Clover (Trifolium Plumosum Var. Plumosum), Nora Dunkirk

Institute for Natural Resources Publications

Oregon state conservation status assessment for Plumed Clover (Trifolium plumosum var. plumosum) using NatureServe methodology, 2025.

Exploring The Potential Of Martian Agriculture: Assessing Viability And Nutritional Composition Of Plants Cultivated In Martian Regolith, Abigail Ross

Honors Theses

In addition to sunlight and water, plants can utilize a small number of nutrients from the soil to biosynthesize all the materials that are needed for growth and development. However, plants require an environment where they are able to obtain those nutrients, such as iron, magnesium, potassium, sulfur, and nitrogen. Environmental factors determine the types and accessibility of nutrients available to plants. Plants then take up these nutrients from the soil to aid in biological mechanisms and the synthesis of important molecules needed for growth and development. Ascorbic acid, commonly known as Vitamin C, is a vital molecule that is …

Patch Mow Grazing: Investigating The Effects Of Mowing On Forage Nutritive Value, The Biomass–Nutritive Value Relationship, And Herbivore Selection, Trace R. Stauble

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

Herbivore foraging behavior plays a critical role in shaping grassland structural heterogeneity, with selection often driven by forage biomass and nutritive value. Currently, it is thought that herbivores primarily select areas that are greater in nutritive value, and low in biomass. More specifically, disturbances like fire and grazing have been thoroughly studied showing that recently burned and grazed areas are not only higher in nutritive value but disproportionately selected by herbivores in comparison to undisturbed areas. However, most studies address only narrow ranges of defoliation, comparing intensely defoliated sites (< 10 cm) to those that are either not defoliated or have experienced a much longer time since defoliation, thereby decreasing grazing pressure as biomass increases. However, one of the most widely used methods of defoliation in grasslands, mowing, hasn’t been thoroughly studied for its effects on nutritive value, and how it impacts herbivore selection. Our study aimed to (1) evaluate how mowing treatments—i.e., short (5 cm), medium (18 cm), and tall (>30 cm, unmown)—affect nutritive value and herbivore selection, (2) assess …

Cover Crop Influence On Arthropod Biodiversity And Soil–Water Dynamics In A Semi-Arid Maize–Soybean Sequence Of The Nebraska High Plains, Carlos Eduardo De Oliveira Martins

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

With the expansion of cover crop (CC) use in semi-arid regions, producers in the Nebraska High Plains are increasingly interested in understanding how CCs influence both beneficial arthropods and soil-water within maize-soybean (Zea mays L., Glycine max [L.] Merr.) rotations. Integrating CCs in these systems can enhance soil water availability and beneficial insect activity, but potential trade-offs include higher early-season water use by CCs and the risk of increasing potential pest populations. This thesis addresses these questions through two complementary studies conducted under field conditions near Brule, Nebraska. The first study evaluated the effects of a multi-species CC mixture …

Evaluating Metamitron Efficacy For Glyphosate-Resistant Palmer Amaranth (Amaranthus Palmeri) Management In Sugarbeet Across The Central High Plains, Abraham Akuoko

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

Herbicide-resistant (HR) Palmer amaranth (Amaranthus palmeri S. Watson) is regarded as one of the most prominent weeds within sugarbeet fields across the Central High Plains, with limited chemical control options. Although a few herbicides are available, their use is restrictive due to crop injury concerns and can only be applied at or after the 2–4 true leaf (TL) growth stage, which will provide no control for already emerged weeds. However, Palmer amaranth often emerges between sugarbeet planting and the 2 TL sugarbeet growth stage. Consequently, as of 2023, there were no herbicide options to control Palmer amaranth in sugarbeet …

Characterizing The Germination Process And Establishing Best Practices For Seed Propagation Of Tamaulipan Thornscrub Species For Habitat Restoration, Saroj Dhakal

Theses and Dissertations

Tamaulipan thornscrub is an imperiled plant community of southern Texas and northeastern Mexico. Given its importance for biodiversity conservation, stakeholders have been involved in restoration programs using seedlings grown from wild seeds. However, stakeholders often report that insufficient seedling supply is a challenge. To address knowledge gaps in seed germination behavior limiting seedling production, this study was conducted on 18 Tamaulipan thornscrub species, identified by growers as difficult to germinate. Seeds of all studied species are orthodox except Amyris texana, which have recalcitrant properties. Nine species have physical dormancy that was successfully addressed with mechanical and/or chemical scarification. Other species …

Post-Fire Soil Health Assessment Of The Grasslands And Woodlands In The Semi-Arid Nebraska Sandhills, Stephanie M. Lugo

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

Grasslands in the Nebraska Sandhills are shaped by natural wildfires, which help maintain the structure and function of native grasslands. In recent decades, afforestation with ponderosa pine and eastern redcedar has introduced new woodlands that altered the region’s fire dynamics and raised important questions about the effects of wildfire on different vegetation types. As wildfires become more frequent, understanding their impacts on soil health in grasslands and woodlands becomes increasingly important. This study examines the short-term effects of the 2022 Bovee Fire on physical, chemical, and biological soil properties in native grasslands and ponderosa pine and eastern redcedar afforested woodlands. …

Comparative Cytogenetics Study Via Fluorescent Chromosome Banding Of Three Solanum L. Species, Mona Abd Elgawad, Rim Hamdy, Ibrahim El Garf, Amany Sallam Abdo

Turkish Journal of Botany

Solanum L. subg. Solanum sect. Solanum has a wide distribution in Egypt with multiple overlapping morphological features, rendering the taxonomy of the Solanum nigrum complex difficult at the species level. This study focused on the S. nigrum complex, which consists of S. nigrum L., S. sinaicum Boiss., and S. villosum Mill. Cytogenetic characterization can provide additional taxonomic data and can be used to evaluate genetic diversity at the species level. We performed karyotype analysis of 3 Egyptian species for the first time by studying fluorescence banding patterns via 4’6-diamidino-2-phenylindole (DAPI) and chromomycin A3 (CMA). The three species vary noticeably in …

Biochar Derived From Different Sources Ameliorates The Phytochemical And Physiological Characteristics Of Foxtail Millet (Setaria Italica) Under Water Stress, Mohammad Keshavarz, Ehsan Bijanzadeh, Hamid Reza Boostani

Turkish Journal of Botany

Organic material, such as biochar, can improve soil fertility and crop yield under water stress. A pot experiment was conducted to consider the effects of biochar on the pigment content, enzyme activity, physiological characteristics, and nutrient uptake of foxtail millet under water stress. Plants were tested under normal, mild, and severe irrigation regimes (100%, 75%, and 50% field capacity, respectively) using different biochar sources (licorice root biochar (LRB), cow manure biochar (CMB), cotton residue biochar (CRB), and municipal waste biochar (MWB)) and a control without fertilizer. Under severe water stress, the chlorophyll a content and total chlorophyll increased by 137.3% …

Protective Role Of Salicylic Acid Against Abiotic Stresses In Horticultural Crops: A Review, Faisal Hayat, Xiaoyun Zhang, Mohammed Alyafei, Fareeha Shireen, Ummara Khan, Sumeera Asghar, Sezai̇ Erci̇şli̇, Karthishwaran Kandhan, Mohamed S. Sheteiwy, Yali Zhang, Xiaoyan Lu

Turkish Journal of Botany

Environmental stressors such as drought, floods, salinity, extreme temperatures, and heavy metal toxicity are major threats to horticultural plants because they disrupt plant physiological mechanisms, leading to reduced yield and quality. Salicylic acid (SA) is a plant hormone that regulates various physiological and biochemical functions in plants. Moreover, it regulates hormonal balance, enhances the absorption of essential nutrients, promotes photosynthesis and the production of antistress compounds, and improves stress resistance. This comprehensive review explains several physiological and biochemical activities that are affected by SA under stressful conditions, such as stomatal regulation, antioxidant defense systems, osmotic adjustment and gene expression regulation. …

Nickel Toxicity To Safflower Seed Germination And Seedling Morphoanatomy, Uğurcan Baran, Sude Tanik, Mert Can Vardar, Güray Ülger, Ahmet Aksoy

Turkish Journal of Botany

The safflowers (Carthamus tinctorius L. cv Olas) grown hydroponically under nickel (Ni) stress were examined in this study. T he effects of 0, 0.75, 1, 3, 5, 10, and 15 mM Ni on seed germination rate, protein, and pigment content of germinating seeds were investigated. Also, the toxicity of 0.75 mM Ni on plant growth, malondialdehyde (MDA) amount, and anatomy of 21-day-old safflower seedlings were studied. Ni adversely affected the germination rate, radicle length, protein, and pigment content of safflower seeds, particularly when higher than 3 mM. It also negatively affected the biomass production, plant length, leaf number, and MDA …

Nepenthes Megastoma (Nepenthaceae), A Micro-Endemic Pitcher Plant From Puerto Princesa Subterranean River National Park, Palawan, Philippines, John Charles A. Altomonte, John Paul R. Collantes, Vernaluz Mangussad, Rene Alfred Anton Bustamante, Alastair S. Robinson

Environmental Science Faculty Publications

Nepenthes megastoma is described and illustrated as a new species from the Puerto Princesa Subterranean River National Park, a UNESCO World Heritage Site in Palawan Philippines. This carnivorous tropical pitcher plant is currently known from just three locations in the Mount Saint Paul karst formation, where it grows on vertical limestone walls. Morphologically, N. megastoma is characterised by its highly branched stems, campanulate pitchers, peltate tendril exsertion, dimorphic upper pitchers, and unidirectionally upturned female flowers. It is assessed as Critically Endangered under the IUCN Red List criteria, based on its restriction to three subpopulations comprising few total individuals. Pitcher morphology …

Modeling The Probability Of N Clonal Rosettes In A Bromeliaceae Genetic Individual, Erin N. Bodine, Layla K. Lammers

Annual Symposium on Biomathematics and Ecology Education and Research

No abstract provided.

Solvent Extracts Of Pulvigera Papillosa (Orthotrichaceae) Show No Antimicrobial Properties In Disk Diffusion Tests, Ryan A. Solorzano, Justin Paulin, Grayson Prater, Michael Lanier

Humboldt Journal of Microbiology

Abstract As antibiotic-resistant bacteria become more prevalent, the search for novel forms of antibiotics in the natural world has become an increasingly worthwhile endeavor. Many mosses have been found to contain antimicrobial properties, including those in the family Orthotrichaceae. Pulvigera papillosa, an Orthotrichaceous moss native to California, has thus far not been investigated to determine whether it contains antimicrobial properties. Extraction techniques using polar and nonpolar solvents have proven to be effective in extracting the secondary metabolites that allow mosses to defend themselves against a hostile microbial world. This study takes a preliminary look into the antimicrobial properties of P. …

Comparative Analysis Of Taproot And Fibrous Root System Microbiomes Under Flooding Stress, Natalie S. Kozlowski, Leighanna Jake

Humboldt Journal of Microbiology

There has been increased interest in understanding how the microbiomes of vascular plants respond to flooding stress and, many studies have focused on monocotyledonous plants with fibrous root systems. This leaves a gap in knowledge of dicotyledonous plants with taproot systems, as previous studies have been in the context of flooding to cropland affecting major food crops which are often monocotyledonous plants with fibrous root systems. Since the structural and functional differences between these root systems may influence microbial community stability and response to flooding conditions, a study looking at both is long overdue As such, this study aims to …

Evaluation Of Anti-Bacterial Efficacy Of Ginger, Resin Gum, And Nigella Sativa Irrigants Against Enterococcus Faecalis: An In Vitro Study, Iman El Ghazzawy, Leen Imad Hasbini, Reem Chamseddine, Wael Betbout, Roula Abiad

International Arab Journal of Dentistry

Objectives: To evaluate the antibacterial efficacy of Ginger, Resin Gum, and Nigella Sativa, against Enterococcus Faecalis.

Methods: Thirty-eight extracted single-rooted premolars were inoculated with E.faecalis, except the negative control, and incubated for 4 weeks. After instrumentation samples were divided into 4 groups (n=7) according to final irrigation: NaOCl+EDTA (Group A), Nigella sativa (B), Resin Gum (C), Ginger (D), plus 2 control groups (n=5): Saline (E), and Saline without bacterial inoculation (F). Cultures were collected at baseline and after irrigation.

Results: One-way ANOVA showed that in groups A-D a statistically significant reduction of bacterial load was observed at …

The Inherent Values Of Observation And Description: A Case Study In The Spiny Solanums Of Australia, Christopher T. Martine

Faculty Journal Articles

The basic exploratory effort of doing descriptive biology is an avenue by which we can deepen our knowledge about taxa and the natural phenomena that drive their diversification. As Conniff (2011) wrote in The species seekers, “we still live in the great age of discovery”, and much like that historically recognized period of the eighteenth and nineteenth centuries there remains today a distinct need for the sort of work that might have been attributable to the naturalists of that time. The careful observation of how organisms go about their lives, including how they interact with one another …

Symbiotic Aspergillus Terreus Alleviates Drought And Waterlogged Stress In Zea Mays L., Hazrat Ali, Fayaz Asad, Naveen Dilawar, Vasila Sharipova, Imtiaz Ahmad, Abida Zeb

Turkish Journal of Botany

The interaction concerning rhizospheric fungi and plants is essential for enhancing plant resilience in the face of abiotic stress conditions. This study investigated the effects of the rhizospheric fungus Aspergillus terreus on maize (Zea mays L.) growth under both drought and waterlogging conditions. Our findings confirmed that inoculation with A. terreus mitigated the adverse effects of drought and waterlogging conditions on maize growth. Plants treated with Aspergillus terreus (A. terreus) exhibited enhanced root and shoot length, fresh and dry weight as well as enhanced chlorophyll content in plants compared to control, under stress-related conditions. Compared to the control group, A. …

Advanced Deep Learning Approaches For The Accurate Classification Of Phallaceae Fungi With Explainable Ai, Eda Kumru, Fati̇h Eki̇nci̇, Koray Açici, Ömer Burak Altindal, Mehmet Serdar Güzel, Ilgaz Akata

Turkish Journal of Botany

In this study, deep learning (DL)-based models were developed for the classification of 5 fungal species from the Phallaceae family (Clathrus ruber, Colus hirudinosus, Mutinus caninus, Phallus impudicus, and Pseudocolus fusiformis). ConvNeXT achieved the highest performance with 98% accuracy, 98% precision, 98% recall, and 98% F1-score. EfficientNetB4 and Xception also performed well with 96% accuracy. In contrast, lighter models such as MobileNetV2 and MixNet S showed significantly lower accuracy (84% and 80%, respectively). Among the explainable artificial intelligence (XAI) techniques, gradient-weighted class activation mapping (Grad-CAM) and Integrated Gradients showed that high-accuracy models focus more effectively on biologically meaningful regions. In …

Erratum To “Anatomical And Palynological Studies On Turkish Primula Taxa (Primulaceae) And Their Taxonomic And Phylogenetic Significance [Turkish Journal Of Botany 49 (4) 2025 325-348 ] ”, Deni̇z Ulukuş, Esengül Özkaymakoğlu, Rebecca Stubbs, Hüseyi̇n Baykal, Kami̇l Coşkunçelebi̇, Osman Tugay, Barbara Keller, Elena Conti, Ferhat Celep

Turkish Journal of Botany

This erratum addresses an error concerning Figure 5 in the original published version of this article. During the typesetting process, Figure 5 was partially omitted, resulting in an incomplete figure being published.To correct this oversight and ensure the accuracy of the scholarly record, the complete Figure 5 is provided below for reference.

Link to the original article: https://doi.org/10.55730/1300-008X.2866

Next-Generation Biotechnology And Breeding Strategies For The Development Of Biotic Stress-Resistant Sugar Beet, Songül Gürel, Mehmet Cengi̇z Baloğlu, Pinar Baloğlu, Mehmet Kolçak, Ferhat Ulu, Ömer Can Ünüvar, Mehmet Örgeç, Özge Kaya, Ramazan Polat, Cemi̇le Köseoğlu, Yasemi̇n Çeli̇k Altunoğlu, Hati̇ce Korkmaz Güvenmez, Ekrem Gürel

Turkish Journal of Botany

Sugar beet is a high-sucrose crop primarily used for sugar production, and it is now gaining attention as a promising source for bioethanol production and cattle feed. This crop is also utilized for the extraction of pectin and the production of molasses. Despite its utilization across a wide range of industries, abiotic and biotic stress factors greatly reduce the productivity of the cash crop sugar beet. In this paper, we focus on the development of biotic stress-resistant sugar beet plants through various classical and biotechnological applications. In recent decades, omics technologies, next-generation sequencing, gene editing/silencing, and overexpression techniques have been …