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Continuous Mowing Differentially Affects Floral Defenses In The Noxious And Invasive Weed Solanum Elaeagnifolium In Its Native Range, Alejandro Vasquez, Alexa Alaniz, Robert K. Dearth, Rupesh R. Kariyat

Biology Faculty Publications and Presentations

In weeds, disturbance has been found to affect life history traits and mediate trophic interactions. In urban landscapes, mowing is an important disturbance, and we previously showed that continuous mowing leads to enhanced fitness and defense traits in Solanum elaeagnifolium, Silverleaf Nightshade (SLN). However, most studies have been focused on foliar defenses, ignoring floral defenses. In this study we examined whether continuous mowing affected floral defenses in SLN using mowed and unmowed populations in South Texas, their native range. We found flowers of mowed SLN plants larger but lighter than unmowed plants. Additionally, flowers on plants that were mowed …

Toward A Coordinated Understanding Of Hydro-Biogeochemical Root Functions In Tropical Forests For Application In Vegetation Models, Daniela F. Cusack, Bradley O. Christoffersen, Chris M. Smith-Martin, Kelly M. Andersen, Amanda L. Cordeiro, Katrin Fleischer, S. Joseph Wright, Nathaly R. Guerrero-Ramírez, Laynara F. Lugli, Lindsay A. Mcculloch

School of Integrative Biological and Chemical Sciences Faculty Publications and Presentations

Tropical forest root characteristics and resource acquisition strategies are underrepresented in vegetation and global models, hampering the prediction of forest–climate feedbacks for these carbon-rich ecosystems. Lowland tropical forests often have globally unique combinations of high taxonomic and functional biodiversity, rainfall seasonality, and strongly weathered infertile soils, giving rise to distinct patterns in root traits and functions compared with higher latitude ecosystems. We provide a roadmap for integrating recent advances in our understanding of tropical forest belowground function into vegetation models, focusing on water and nutrient acquisition. We offer comparisons of recent advances in empirical and model understanding of root characteristics …

Comparative Analysis Of A Secondary Metabolite Profile From Roots And Leaves Of Iostephane Heterophylla By Uplc-Ms And Gc-Ms, Diana V. Navarrete-Carriola, Alma D. Paz-González, Lenci K. Vázquez-Jiménez, Erick De Luna-Santillana, María A. Cruz-Hernández, Debasish Bandyopadhyay, Gildardo Rivera

School of Integrative Biological and Chemical Sciences Faculty Publications and Presentations

Iostephane heterophylla is a traditional Mexican medicinal plant and is an important source of secondary metabolites with antimicrobial and cytotoxic activity. The aim of this work was to conduct a comparative analysis of secondary metabolites of different roots and leaf extracts of I. heterophylla from two zones in Mexico using ultraperformance liquid chromatography (UPLC) and gas chromatography (GC) coupled with mass spectrometry (MS). Twelve secondary metabolites from roots were identified in the leaves. Five new molecular weight secondary metabolites not previously reported were found. Six bioactive metabolites were quantified (quercetin ≤0.151 mg/mL in root and ≤0.041 mg/mL in leaf; hesperidin …

Effects Of Mars Global Simulant (Mgs-1) On Growth And Physiology Of Sweet Potato: A Space Model Plant, Karthik Chinnannan, Prapooja Somagattu, Hyndavi Yammanuru, Padma Nimmakayala, Manohar Chakrabarti, Umesh K. Reddy

School of Integrative Biological and Chemical Sciences Faculty Publications and Presentations

Growing food autonomously on Mars is challenging due to the Martian soil's low nutrient content and high salinity. Understanding how plants adapt and evaluating their nutritional attributes are pivotal for sustained Mars missions. This research delves into the regeneration, stress tolerance, and dietary metrics of sweet potato (Ipomoea batatas) across different Mars Global Simulant (MGS-1) concentrations (0, 25, 50, and 75%). In our greenhouse experiment, 75% MGS-1 concentration significantly inhibited sweet potato growth, storage root biomass, and chlorophyll content. This concentration also elevated the plant tissues' H2O2, proline, and ascorbic acid levels. Higher MGS-1 exposures (50 and 75%) …

Chemical Investigation Of Dichloromethane Extract Of Aloe Vera Peels: An Agricultural Waste, Nazmul Huda

Theses and Dissertations

Aloe barbadensis Miller, commonly called Aloe Vera, is a widely popular succulent plant species cultivated across subtropical regions worldwide from India to the Tex-Mex border. Besides its historical uses, Aloe juice has garnered attention as a potential remedy for various ailments, particularly in treating various skin conditions and facilitating wound recovery, including obesity, diabetes, hepatitis, Crohn's disease, and ulcerative colitis. Regrettably, the agricultural practice following sap extraction involves discarding Aloe vera peels, constituting agricultural waste. As part of our continuous research on extraction, isolation, separation, and spectral characterization of value-added chemicals present in waste botanicals herein, …

Regulatory Mechanisms Of The Lbd40 Transcription Factor In Arabidopsis Thaliana Somatic Embryogenesis, Sanjay Joshi, Kristine Hill, Manohar Chakrabarti, Sharyn E. Perry

School of Integrative Biological and Chemical Sciences Faculty Publications and Presentations

Somatic embryogenesis (SE) is a process by which an embryo is derived from somatic tissue. Transcription factors (TFs) have been identified that control this process. One such TF that promotes SE is AGAMOUS-like 15 (AGL15). Prior work has shown that AGL15 can both induce and repress gene expression. One way this type of dual function TF works is via protein interactions, so a yeast 2-hybrid (Y2H) screen was undertaken. One intriguing protein with which AGL15 interacted in Y2H was LBD40. LBD40 encodes a LATERAL ORGAN BOUNDARIES (LOB)-domain TF that is unique to plants and is primarily expressed during seed development. …

Coordination Of Rooting, Xylem, And Stomatal Strategies Explains The Response Of Conifer Forest Stands To Multi-Year Drought In The Southern Sierra Nevada Of California, Junyan Ding, Polly Buotte, Roger Bales, Bradley O. Christoffersen, Rosie A. Fisher, Michael Goulden, Ryan Knox, Lara Kueppers, Jacquelyn Shuman, Chonggang Xu, Charles D. Koven

School of Integrative Biological and Chemical Sciences Faculty Publications and Presentations

Extreme droughts are a major determinant of ecosystem disturbance that impacts plant communities and feeds back into climate change through changes in plant functioning. However, the complex relationships between aboveground and belowground plant hydraulic traits and their role in governing plant responses to drought are not fully understood. In this study, we use a model, the Functionally Assembled Terrestrial Ecosystem Simulator in a configuration that includes plant hydraulics (FATES-Hydro), to investigate ecosystem responses to the 2012–2015 California drought in comparison with observations at a site in the southern Sierra Nevada that experienced widespread tree mortality during this drought.

We conduct …

Fungal Plant Pathogens Affecting Crops In The Lower Rio Grande Valley, Isabel Martinez

Theses and Dissertations

The Lower Rio Grande Valley (LRGV) located in South Texas has a subtropical and humid environment which is conducive for plant disease. In Chapter 1, Southern blight caused by Athelia rolfsii was collected from Edinburg, Texas in tomato and bean crops. The present study focused on assessing the role of temperature on growth and sclerotia production. We found that there is an optimal growing temperature for both hyphal growth and sclerotia production. In Chapter 2, red rot fungal disease was collected from sugarcane in Texas. Morphology, pathogenicity, effects of temperature, and biocontrol agents were assessed. Isolate morphology closely resembled Fusarium …

Tamaulipan Thornforest Restoration: Factors Influencing Restoration Outcomes And Impacts Of Cover Crops During Replanting, Jerald Thomas Garrett

Theses and Dissertations

Though the rate of deforestation has slowed in recent years, it remains a primary cause of land cover change within forest ecosystems. The Lower Rio Grande Valley, Texas (LRGV) has lost nearly 95% of its native thornforest since the early 1900’s due to agricultural and urban expansion. The focus of this study is to assess the current vegetative state of restored thornforest sites located in the eastern LRGV and to evaluate the use of cover crops during replanting of native seedlings. Our assessment of restored thornforest sites revealed actively restored sites demonstrated higher overall averages of richness, abundance, and diversity …

Soil Moisture Dynamics In Cover Cropping Systems: From Local To Global Scales, Manish Gautam

Theses and Dissertations

Cover cropping systems, which have gained recognition for their ability to enhance soil health and promote sustainability are also associated with potential risks related with declining soil moisture and pose a dilemma for farmers considering the adoption of cover crops in water deficit semi-arid settings worldwide. To address this pressing issue, we conducted a participatory cover cropping trial in the Lower Rio Grande Valley (LRGV) region, encompassing four different farms and supplemented this experiment with a meta-analysis to answer our soil moisture and climate parameters and quantify the impact of cover crops on soil moisture levels. The findings revealed that …

Cover Crops Influence Arthropod Community Dynamics Through Seasonal Variation And Cascading Effects, Adegboyega Fajemisin

Theses and Dissertations

Chapter 1: This chapter gives an overview of how cover crops influence soil’s physical, chemical, and biological properties, and their role on mediating arthropod community dynamics with implications for pest management in the subsequent cash crop.

Chapter 2: This chapter examines the effects of cover-cash crop rotation on arthropod community dynamics on four growers fields in the Lower Rio Grande Valley, Texas. We assessed the impact of cover crops planted in the summer months on the subsequent cash crops planted in the winter. Our results showed that cover crops had a differential effect on the population of beneficials and herbivores …

Comparative Analysis Of Soil Properties, Microbial Community Composition, And Yield Responses To Cover Crops In Different Ecoregions Of South Texas, Daphne Zapsas

Theses and Dissertations

Comprehensive understanding of soil properties, their interdependencies, and the effects of management practices is crucial for designing sustainable agricultural strategies. By adopting site-specific and need-based practices that enhance soil health, farmers can optimize crop growth, increase yield, and contribute to long-term environmental sustainability. Cover crops have been recognized for enhancing soil fertility, promoting microbial activity, and increasing organic matter content. However, while their effectiveness is well documented in temperate regions with readily available water, their impact in water limited systems in subtropical regions remains mixed. The aim of this study is to assess soil conditions in four different farms across …

Estimating The Functional Consequences Of Intra-Specific Trichome Variation Of Tomato, Solanum Lycopersicum On The Specialist Herbivore, Manduca Sexta, Satinderpal Kaur

Theses and Dissertations

Chapter 1: Plants have a wide array of defenses against herbivores and hence they must confer trade-offs between growth and defense related traits. By using Solanum as a model genus, the major plant defense fitness trade-off hypotheses are reviewed in this chapter along with their assumptions and examples.

Chapter 2: This chapter provides an overview of the enormous intra-specific diversity in trichome morphology in tomato, Solanum lycopersicum. Also, the trichome sub-types are analyzed for the variations in density and dimensions in 10 varieties of tomato by using desktop scanning electron microscope.

Chapter 3: This chapter examines the functional consequences …

Sweet Potato In The Lower Rio Grande Valley: Evaluating Performance Across Several Cultivars, Jon Dale

Theses and Dissertations

In Texas’ subtropical, semiarid Lower Rio Grande Valley (LRGV), citrus and sugarcane cultures have dominated specialty crop production for more than a half-century. However, the future of these high-dollar crops is becoming uncertain with increases in exotic pathogens, intensifying urbanization and the overarching complexities of both climate change and binational governance of Rio Grande Basin waters. For these reasons, the region’s specialty crop sector needs to be ready for alternatives that could benefit both market outlets and reduced input dependencies. Sweet potato (Ipomoea batatas), commercially grown in various similar climates worldwide with limited water resources, could be one …

Factors Influencing The Faunal Recolonization Of Restored Thornscrub Forest Habitats, Audrey J. Hicks

Theses and Dissertations

Tamaulipan thornscrub forests have high ecological and economic value, yet over 90% of these forests have been lost, primarily due to agriculture and urban expansion, and they remain threatened, making them a conservation hotspot. For decades, federal, state, NGO, and corporate entities have been acquiring land and actively or passively restoring these forests, but results have been mixed and seldom monitored. This study characterized and quantified faunal communities of restored thornscrub forest habitats in south Texas and examined the relationships between restored faunal communities and key site characteristics and environmental factors. We surveyed and analyzed mammals, birds, Lepidoptera, and herptiles …

Study Of Population Dynamics Of Sugarcane Aphid (Melanaphis Sacchari) In Rio Grande Valley, Texas, Neetu Khanal

Theses and Dissertations

Chapter 1: This chapter incorporates detailed information about the biotype concept, aphids, their types and their biotypes, importance of studying insect biotypes and their role in mediating host plant defenses.

Chapter 2: This chapter explains in detail about the biology, biotypes, feeding behavior, damage, and economic loss caused due to sugarcane aphid infestation. This chapter further elaborates on the need for studying population level differences and justifies the objectives and significance of this research study.

Chapter 3: This chapter provides information about the comprehensive work done on three different populations of sugarcane aphid collected from three different locations in Rio …

Detection Of A Diverse Endophyte Assemblage Within Fungal Communities Associated With The Arundo Leaf Miner, Lasioptera Donacis (Diptera: Cecidomyiidae), Marie-Claude Bon, John A. Goolsby, Guy Mercadier, Fatiha Guermache, Javid Kashef, Massimo Cristofaro, Ann T. Vacek, Alan Kirk

School of Earth, Environmental, and Marine Sciences Faculty Publications and Presentations

The larvae of Lasioptera donacis Coutin feed on fungal communities lining galleries within the mesophyll of leaf sheaths of Arundo donax in an aggregative manner. It has been stated that L. donacis could have established a fundamental symbiotic relationship with one fungus, although the fungal composition of these communities remains unsettled. Using a culture-dependent approach and ITS sequencing, the present work characterizes and compares the fungal communities associated with L. donacis in Eurasia with the endophytes of A. donax in Texas where L. donacis is absent. The 65 cultivable isolates obtained from L. donacis fungal communities were sorted into 15 …

Effective Farm Management Promotes Native Amf And Benefit Organic Farming Systems, Pushpa Soti, Rupesh R. Kariyat, Alexis Racelis

Biology Faculty Publications and Presentations

Highlights

• Agricultural practices have significant influence on the AMF community dynamics.

• Soil nutrients regulate AMF spore abundance and diversity.

• Using grass cover crops can promote native AMF in farms.

Abstract

Using soil inoculants containing naturally occurring beneficial microorganisms has become a popular practice in sustainable agriculture. However, an understanding of the environmental variables that affect plant-microbe interactions and the benefit of using commercial inoculum is relatively sparse. To address this, we examined the efficiency of three different methods to inoculate AMF (Arbuscular Mycorrhizal Fungi) in organic vegetable farms in south Texas: cover cropping, application of farm-produced (indigenous) AMF inoculum, …

Are Epicuticular Waxes A Surface Defense Comparable To Trichomes? A Test Using Two Solanum Species And A Specialist Herbivore., Sakshi Watts, Rupesh R. Kariyat

Biology Faculty Publications and Presentations

Although plants possess a suite of structural defenses, most studies have focused on trichomes. Trichomes can have both pre- and post-ingestive effects and have been consistently found to reduce herbivory. Along with trichomes, a few studies have focused on epicuticular waxes as an important defense; however, manipulated comparisons examining herbivore growth and development is limited. In this study, using two Solanum species (Solanum glaucescens and Solanum macrocarpon) that vary in both defenses, we tested the hypothesis that variation in defenses will affect herbivore feeding, primarily by restricting feeding commencement. We used electron microscopy together with a series of plant- and …

South Texas Wildlife Activity Across A Fragmented Landscape And Road Mitigation Corridor, Caitlin K. Brett

Theses and Dissertations

Wildlife crossing structures (WCS) and roadside fencing are commonly installed to mitigate habitat fragmentation, wildlife road mortalities, and other negative effects that roads can have on the surrounding landscape. Eight such WCS were constructed below Farm-to-Market (FM)106 in Cameron County, Texas, across a 16 km corridor transecting the Laguna Atascosa National Wildlife Refuge. These WCS, paired with adjacent roadside fencing, were intended to prevent road mortalities of the endangered ocelot (Leopardus pardalis) and to mitigate the barrier effect of FM106 on this and other meso-mammal species. This study will analyze camera trap data from roadside and habitat reference …

Effects Of Disturbance (Mowing) On Florivory And Floral Defenses In Solanum Elaeagnifolium, A Noxious And Worldwide Invasive Weed, Alejandro Rafael Vasquez Marcano

Theses and Dissertations

Chapter 1: Literature Review- In this literature review we have examined weed management as it concerns urban and agricultural ecosystems, as well as the need for mowing assessments as it relates to floral traits and defense against herbivory.

Chapter 2: Experiments- In the experiments we examined the role of mowing on floral growth traits, floral defense traits, and their effect on Manduca sexta specialist herbivores.

Chapter 3: Results- In the results we found SLN flowers to have larger diameters than unmowed flowers; however, flower mass was in line with our predictions as unmowed flowers were heavier in high mowing frequency …

Influence Of Pretreatments On Physiological Status And Post-Planting Survival Of Thornforest Seedlings In A Restoration Context, Douglas E. Mainhart

Theses and Dissertations

Semi-arid ecosystems across the globe have faced land conversion posing a threat to the important ecosystem services they provide. Revegetation-centered restoration efforts in arid regions have low success due to limited water availability and higher temperatures. Typically, practitioners utilize methods that modify field conditions around seedlings to mitigate these stressors. I evaluated the efficacy of in-nursery treatments to improve plant water status. Three pretreatments were applied: elevated CO2, drought hardening, and an antitranspirant foliar spray. My goal was to understand how these pretreatments would impact survival and growth in the field and what physiological traits they altered. Elevated CO2 and …

Production Of Distilled Spirits Using Grain Sorghum Through Liquid Fermentation, Thomas Weiss, Jikai Zhao, Ruijia Hu, Meicen Liu, Yonghui Li, Yi Zheng, Gordon Smith, Donghai Wang

School of Earth, Environmental, and Marine Sciences Faculty Publications and Presentations

The objectives of this research were to investigate the fermentation performance of US sorghum varieties for the production of distilled spirits as well as their associated coproducts and to study the formation of volatile compounds that are related to the flavor quality of the spirits. Three US sorghum varieties (red, white, and waxy sorghums) and four yeast strains (DADY, Ethanol Red, GR-2, and 71B) were used for distilled spirit production. Both sorghum variety and type of yeast strains had effects on alcohol concentration and alcohol yield. The alcohol concentration varied from 10.26 to 11.34% (v/v) while alcohol yield varied from …

De Novo Transcriptome Analysis Of Orange Jasmine (Murraya Paniculata) Infected With Citrus Greening Disease, Jeffrey Aquino Gomez

Theses and Dissertations

Citrus greening disease, also known as Huanglongbing, is one of the most devastating citrus diseases in the world. Candidatus Liberibacter asiaticus (CLas) is a non-culturable, phloem-limited bacterium that serves as one of two vectors for the transmission of any of the three kinds of greening disease. In cooler climates, the African variant transmitted by the African citrus psyllid (Trioza erytreae) is more prevalent. The Asian form transmitted by the Asian citrus psyllid (Diaphorina citri) where is predominant in warmer conditions and recently discover the American form who is also transmit by Diaphorina citri, was discover in Brazil but has also …

Examination Of The Realized Host Range Of North American Lacebug (Gargaphia Arizonica Drake & Carvalho) And Texas False Potato Beetle (Leptinotarsa Texana Schaeffer) As A Potential Biocontrol Agents For Silverleaf Nightshade (Solanum Elaeagnifoli Cav.), Samikshya Subedi

Theses and Dissertations

Silverleaf nightshade (Solanum elaeagnifolium Cav.) is a perennial forb native to South Texas and Central and South America, but it has become a serious agricultural weed across the world. Because silverleaf nightshade (SLN) is difficult and expensive to manage using chemical and mechanical controls, there is growing attention and research focused on biological control options. In this project, we used both field and laboratory studies to examine the suitability of two North American insects, namely North American lacebug (Gargaphia arizonica Drake & Carvalho) and Texas false potato beetle (Leptinotarsa texana Schaeffer) as prospective biological control agents for …

Tree Ring Reconstructions Of Streamflow For The Lower Rio Grande Valley Of Texas, Adedolapo Mutiyat Adeyanju

Theses and Dissertations

The Rio Grande River is a major water source for people living within the USA-Mexico border. The Rio Grande River has its headwaters in the San Juan Mountains in Colorado and the Sierra Madre Occidental in Mexico before flowing into Texas through El-Paso. The water supply issues facing the Lower Rio Grande Basin (LRGB) are extremely complex from international restrictions to severe climate change. The river shares its flow between the U.S.A and Mexico based on the provisions of the 1944 treaty between the U.S.A and Mexico. The LRGB flow is regulated by releases from Falcon and Amistad Reservoirs managed …

Revealing The Effects Of Climate Change And Fungicides On Soil Microbial Communities In The Lower Rio Grande Valley, Texas, Armida Rivera

Theses and Dissertations

Fungicide applications are effective to prevent fungal pathogens that are known to cause crop damage and decrease yields. However, these pesticides can exert toxic or inhibitory effects on non-targeted organisms such as soil microbial communities. In addition, it is unknown to what extent shifts in temperature and soil moisture resulting from global climate change, alter the activities of non-targeted soil organisms. The aim of this study was to evaluate soil biological parameters such as soil respiration and enzyme activities involved in the cycling of carbon, nitrogen, and phosphorous (Beta-glucosidase, Fluorescein Diacetate (FDA) Hydrolysis, urease, alkaline phosphatase, acid phosphatase, and N-acetyl-Beta-glucosaminidase) …

Differential Gene Expression In Tall Fescue Tissues In Response To Water Deficit, Manohar Chakrabarti, Padmaja Nagabhyru, Christopher L. Schardl, Randy D. Dinkins

School of Integrative Biological and Chemical Sciences Faculty Publications and Presentations

Tall fescue (Festuca arundinacea Schreb.) is a popular pasture and turf grass particularly known for drought resistance, allowing for its persistence in locations that are unfavorable for other cool-season grasses. Also, its seed-borne fungal symbiont (endophyte) Epichloë coenophiala, which resides in the crown and pseudostem, can be a contributing factor in its drought tolerance. Because it contains the apical meristems, crown survival under drought stress is critical to plant survival as well as the endophyte. In this study, we subjected tall fescue plants with their endophyte to water-deficit stress or, as controls with normal watering, then compared plant …

Harvester Ant (Pogonomyrmex Sp.) Seed Preferences And Distribution In A Suburban Setting, Lilly V. Elliott

Theses and Dissertations

Harvester ants (Pogonomyrmex sp.) are omnivorous ants native to Texas and are the main food source for the threatened Texas Horned Lizard (Phrynosoma cornutum). Little research has been conducted on harvester ants in the Lower Rio Grande Valley (LRGV) and their interactions with their environment. For this purpose, a variety of experiments were conducted to better understand these interactions and preferences. In CHAPTER I, suburban harvester ants were exposed commonly used cover crop seeds in the LRGV and inoculated seeds via seed depots over the course of 24 hours. We found that harvester ants do …

Winners And Losers In Dryland Reforestation: Species Survival, Growth, And Recruitment Along A 33-Year Planting Chronosequence, Clifton Albrecht, Zarek Contreras, Kimberly Wahl-Villarreal, Mitch Sternberg, Bradley O. Christoffersen

Biology Faculty Publications and Presentations

Reforestation in the Lower Rio Grande Valley (LRGV) of Texas began in the 1960s and to date over 6,475 ha of land has been reforested. However, there has been minimal assessment to understand differential species success, compositional trends, and the aboveground C sequestration potential of these developing forests. We coupled quantitative planting information of >50 native woody tree and shrub species with surveys of 5,223 stems of 4,606 individuals in a chronosequence of restored forests ranging in age from 1 to 33 years to estimate species-specific mortality rates, biomass accumulation and recruitment, as well as compositional trends in the herbaceous …