ASHS 2025 Conference

The most economically important physiological process in sweetpotato is storage root initiation. The number of adventitious roots (ARs) that undergo storage root initiation can vary within and among individual plants. This extends to entire fields, which can vary in storage root yield by up to 50%. This unpredictability is further compounded by the fact that crop yield can only be evaluated post-factum and above-ground growth frequently provides little or no indication of productivity in commercial production settings. Significant progress has been achieved in understanding the environmental, physiological, and molecular cues of storage root formation but current evidence cannot be reconciled with root system architecture variability. Functional-Structural Plant Models (FSPM) such as OpenSimRoot are used to explore and understand the complex interactions among morphological and architectural traits, environment variables, and source-sink relations. OpenSimRoot is capable of simulating spatiotemporal dynamics of plant growth, including 3D root architecture, nutrient and water acquisition, and carbon processes underlying plant growth, but requires extensive parameterization. Here we describe the parameterization of OpenSimRoot to model the timing of storage root initiation and initial bulking stages. The model was parameterized using data from sweetpotato cultivar ‘Beauregard’ grown under greenhouse and irrigated field conditions, along with available data from literature. We will outline subsequent work that links root system architecture to storage root initiation, leading to future studies on the dynamics of carbon-related processes that determine the competency of adventitious roots to become storage roots.

Plastic pollution is an emerging concern for both aquatic and terrestrial ecosystems. Recent studies, primarily focused on cereals and vegetable crops, have demonstrated that nanoplastics (NPs) can enter root tissues and translocate throughout the plant. However, the accumulation and impact of NPs in woody perennial crops, particularly citrus, remain largely unexplored. This study investigated the effects of green, fluorescent polystyrene nanoplastics (PS-NPs) of two particle sizes (20 nm and 50 nm diameter) on citrus root development, nutrient uptake, and root anatomical features. ‘US-942’ citrus rootstock plants were grown under sterile aeroponic conditions and treated with PS-NPs for 15 and 30 days. Root system architecture traits, including total root length, surface area, and number of forks, were analyzed using WinRHIZO™ software. Concurrently, macronutrient and micronutrient concentrations (N, P, K, Mg, S, B, Fe, Cu, Mn) were assessed in plant tissues, and root anatomy was examined using fluorescence and light microscopy. Exposure to 20 nm PS-NPs significantly reduced total root length (–28%), surface area (–31%), and the number of root forks (–35%) at both timepoints compared to controls. Nutrient uptake was also adversely affected, with notable reductions in N, P, K, Mg, and several micronutrients. Microscopic analyses revealed that both PS-NP sizes were retained at the root surface, with no evidence of internalization or translocation into root tissues. However, alterations in epidermal and cortical cell layers suggested structural stress responses, despite the development of intact apoplastic barriers near root tips. These findings highlight the potential phytotoxic effects of PS-NPs on citrus, particularly at smaller particle sizes, and suggest that while internal uptake may be limited in woody perennials, surface-level interactions may disrupt root development and function. This study contributes to a growing understanding of nanoplastic interactions in horticultural tree crops and raises important questions regarding long-term impacts on soil-plant systems.

The plant root system is vital for nutrient uptake and plays a significant role in abiotic stress adaptation and defense. In sweetpotato, optimum root system architecture (RSA) development determines storage root (SR) yield potential. Root architectural responses to simulated natural lead levels (Pb) during the establishment and SR formation phases were characterized in two sweetpotato cultivars with known contrasting storage root yield potentials. Cultivars ‘Bayou Belle’ (BB) and ‘Beauregard’ (BX) grown on sand substrate were provided with 0.5X Hoagland’s nutrient solution with varying levels of Pb: 0, 10, 20, and 30 mg⋅L-1. The first experiment sampled entire root systems at 5, 10, and 15 days, corresponding to key adventitious and SR development stages. The cultivars varied in RSA attributes in response to Pb levels. In contrast to the cultivar BB, BX provided with 10 mg⋅L-1 Pb showed 83%, 21%, and 15% increases in main root length relative to the untreated controls at 5, 10, and 15 days, respectively. The cultivar BB consistently showed increased lateral root number and length relative to BX across all treatment levels. A second experiment was performed to produce SR samples at 50 days. The cultivar BX accumulated a 200- and 300-fold increase in Pb in SR at 20 and 30 mg⋅L-1 Pb, respectively, relative to BB storage roots at similar Pb levels. There were no differences in Pb accumulation across treatment levels in the cultivar BB. These findings are consistent with the hypothesis that increased root mass was associated with low accumulation of Pb and provide a basis for incorporating RSA traits in selecting Pb-tolerant cultivars.

Cowpea is an excellent crop for growers with small-to-medium farms and marginal lands prevalent throughout the southeast, but a thorough understanding of its response and tolerance to aluminum toxicity is lacking. This study characterized the transcriptome of two cowpea varieties, the tolerant Mississippi Pinkeye 2 Purple Hull (MSP2PH) and sensitive White Acre (WA), using RNA sequencing 6, 24, and 48 hours after treatment with 50µM AlCl3. RNA integrity number (RIN) scores of all samples were above 9.0 indicating high-quality, and the total number of reads from each sample ranged from about 20,000,000 – 60,000,000. Sample groups clustered by variety, treatment, and time point after principal component analysis. A threshold of 1 log-fold change (logFC) and a false-positive discovery rate of p ≤ 0.01 was used to identify differentially expressed genes (DEGs) for all comparisons. The number of DEGs between plants of the same variety under control and aluminum-toxic conditions at 6, 24, and 48 hours after treatment were 308, 385, and 173 for MSP2PH and 935, 1029, and 1208 for WA. 12 and 58 of these DEGs were detected across all three time points for MSP2PH and WA, respectively. Among DEGs between MSP2PH and WA that were unique under aluminum treatment there were 401, 613, and 623 at 6, 24, and 48 hours, respectively, with 58 across all time points. The number of common DEGs detected that were unique between MSP2PH samples under aluminum and control and those between MSP2PH and WA under aluminum only were 24, 67, and 19 after 6, 24, and 48 hours, respectively. Furthermore, three DEGs across all time points were detected using these criteria, and all were up-regulated in MSP2PH. One of these genes is annotated as a leucine-rich repeat (LRR) receptor-like kinase, which are well-known to regulators of aluminum-toxicity response and tolerance. Arabidopsis homologues for corresponding genes from different up- and down-regulated DEG sets were subjected to Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways enrichment analysis. The number of enriched genes categorized into specific GO terms varied by time point, treatment, and variety. The number of transcription factors up- and down-regulated from specific transcription factor families were also evaluated for select comparisons and showed similar variability. These findings provide insights into expression pathways involved in aluminum toxicity tolerance and response while providing candidate genes that may be used to develop aluminum-tolerant cultivars.

Florida faces significant environmental challenges due to population growth and the widespread use of fertilizers and pesticides. Key concerns include water contamination from lawn and landscape chemicals, soil erosion, and the loss of biodiversity and wildlife habitat. Home landscapes offer a valuable opportunity to implement sustainable practices that conserve water, reduce chemical inputs, recycle yard waste, prevent erosion, and support local wildlife. The University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) Extension provides residents with research-based recommendations to promote sustainable landscaping. In 2024, the UF/IFAS Extension Hillsborough County residential horticulture program educated 1,477 residents on these practices. A six-month follow-up survey (n=55) revealed that participants adopted various sustainable strategies: 78% replaced high-maintenance plants with low-maintenance alternatives, 86% selected plants suited to site conditions, 51% used rain gauges to monitor rainfall, 66% applied a 2-3" layer of organic mulch, 76% enhanced landscapes with plants or water sources to attract wildlife, 88% opted for less toxic pesticides, 49% started composting, and 50% maintained a 10-foot no-treatment zone near water bodies. These changes contribute to reducing stormwater runoff and nutrient leaching, leading to cleaner water bodies and improved environmental health. The success of these educational programs highlights the impact of extension efforts in fostering sustainable landscapes and protecting Florida’s natural resources.

Green industry businesses face many challenges in production including finding and retaining employees as well as increasing materials and shipping costs. To address production hurdles, implementation of various types of automation are a key focus in many horticultural production operations. Automation has the potential to not only address key production challenges but can also improve working conditions and employee experience, including health and well-being. A focus on employee health and wages has been shown to be valued by consumers of a range of horticultural food crops and have been a key element in price premiums for food crops and businesses who demonstrate their positive benefit for worker or community well-being. However, less is known about consumer perceptions of green industry production practices or their valuation of businesses prioritizing employee well-being. Therefore, a nationwide consumer survey was undertaken to assess consumer knowledge and perception about automation overall and automation within horticultural production. While the focus on the survey was to investigate automation technologies in the nursery industry, the survey included a range of greenhouse and nursery crops to assess consumers’ understanding of the current use of automation as well as perceptions about automation as well as the impact of automation on employee health and well-being. The focus on the presentation will be on consumer knowledge and opinion on automation in plant production as well as the role of consumer demographics, work experiences, and industry knowledge. Results will be summarized to share opportunities for strengthening consumer valuation of horticultural crops.

Consumer decision making is heavily influenced by not only the information made available about products but also the degree of trust consumers have in that information. As online sources increase, so do opportunities to find information about products that is both factual and misleading. Especially with regards to green products and sustainability claims, predatory marketing practices, undisclosed advertisements, and uninformed influencers contribute to consumer vulnerability regarding purchases. With regards to plant products - both plant-based foods and ornamental plants - and the environment, little research has been invested in understanding where and how consumers are getting information and what they trust. This study investigates how plant consumers access and trust information regarding environmental and climate issues, their purchases, and the sustainability qualities of plant products. Using the results of an online survey, consumer profiles were identified using Ward’s Linkage clustering so that stakeholders, such as science communicators, marketing professionals, consumer protection agencies, and consumers themselves can better understand the state of consumer trust in information about plant products.

Home propagation is a common practice among horticulturalists and green industry consumers due to the simplicity of the activity and the gratification of successfully growing new plants. While discussions of propagation often emphasize its environmental and economic benefits, far less attention has been given to its individualistic impacts. These impacts may include psychological, therapeutic, and social benefits. This study examines the relationship between home propagation and improvements in mood, self-confidence, and opportunities for interaction with other plant enthusiasts. Through surveys with plant propagators, we will learn how successful propagation attempts create a sense of personal fulfillment, accomplishment, and a desire for interaction with other propagators. By further investigating these benefits, this research aims to determine if home propagation functions as a therapeutic and community-building activity and should be acknowledged as something deeper than a casual hobby.

Identity has been used as a measure of individuals to better understand values and behavior, such as concern for the environment and subsequent behaviors. Applying the same approach to horticulture, measure of identity as a gardener can help researchers, educators, and industry stakeholders have knowledge of existing and potential clients to deliver relevant goods and services. In a 2023 national survey, respondents (n=2435) completed measures of gardener identity (GI) as well as assessments of five elemental and three functional gardening practices. Gardener identity scores were significantly higher among self-reported gardeners than nongardeners, with a weak positive correlation between GI score and spending on supplies and services (r = .310, p=.01). Despite perception that gardening is a solitary activity, findings highlight the role of social networks in positive, early gardening experiences that shape behaviors across the lifespan. Coupled with demographic data, these scores provide additional insight and guidance for developing and supporting individuals who spend money on green industry supplies and services.

Residential landscape pest management presents many challenges and pesticide management is accomplished via use of synthetic pesticide rotations. As consumer concerns related to pesticide use and the environment rise, landscapers have the opportunity to offer an integrated pest management (IPM) approach, using a combination of chemical and non-chemical control methods to reduce pesticide usage and reliance. However, consumer acceptance of and understanding of IPM is still not fully understood. We surveyed 1,000 respondents to quantify consumer knowledge of IPM. Questions were vetted using the Delphi method with nine industry and academic experts. Over 75% of respondents had some knowledge or were very knowledgeable of IPM. The more educated the respondents, the more knowledgeable they were of IPM. To capitalize on this to enhance economic outcomes for landscape service providers, future research should quantify how much consumers are willing to pay for IPM-grown plants or landscape services.

Join this open forum discussion to interact with your peers while exploring current issues facing consumer horticulture research and programming both nationally and internationally. The board of the Consumer Horticulture and Master Gardener Interest Group will serve as hosts for the session. The purpose of the discussion is to network with peers and to stay current in this evolving field of work. Climate change, soil erosion and quality, invasive species and preservation of native plants and food deserts are all open for discussion. Target audience issues such as generation differences in information sources and engagement are also important topics. All those working in any aspect of the field of consumer horticulture are encouraged to participate. Different perspectives from a broad stakeholder group with varying viewpoints are need for impactful and rich dialog.

Speakers:
Consumer Horticulture and Master Gardner (CHMG) Interest Group Board
Gerald Burgner, Chair, Texas A&M
Natalie Bumgarner, Vice Chair, University of Tennessee
Ruth Carll, Secretary, Rutgers