Improve Plant Performance Research Articles

Synthesis and application of a multifunctional poly (vinyl pyrrolidone)-based superabsorbent hydrogel for controlled fertilizer release and enhanced water retention in drought-stressed Pisum sativum plants

Water scarcity poses a significant challenge to agricultural production, prompting the development of sustainable technologies to optimize water resource utilization. This study focuses on the synthesis and application of a multifunctional poly (vinylpyrrolidone); PVP-based superabsorbent hydrogel (SAH) for controlled release of essential fertilizers (nitrogen, phosphorus, and potassium) and enhanced water retention in soil. The hydrogel was prepared via a facile one-step approach and compared to a control soil without hydrogel amendment. The reaction was initiated in the presence of poly(vinylpyrrolidone) (PVP) to produce a PVP-based copolymer hydrogel. The hydrogel was then subjected to a basic treatment using either sodium hydroxide (hydrogel #1) or potassium hydroxide (hydrogel #2). The PVP-based SAH exhibited excellent swelling capacity, water retention, and fertilizer release properties. When applied to Pisum sativum plants under drought stress, the hydrogel significantly improved soil moisture levels, nutrient availability, and plant growth parameters compared to the control. The hydrogel #2-amended plants demonstrated enhanced biomass, chlorophyll content, and photosynthetic efficiency, highlighting the hydrogel’s effectiveness in mitigating the adverse effects of drought stress. These findings demonstrate the potential of the PVP-based SAH as a promising strategy for sustainable agriculture, offering using readily available and inexpensive raw materials, suggesting a relatively low-cost and scalable production process. Furthermore, the hydrogel facilitates water conservation, controlled nutrient delivery, and improved plant performance under drought stress conditions.

Mitigating the Adverse Effects of Salt Stress on Pepper Plants Through Arbuscular Mycorrhizal Fungi (AMF) and Beneficial Bacterial (PGPR) Inoculation

This study investigates arbuscular mycorrhizal fungi (AMF), plant growth-promoting rhizobacteria (PGPR), and their combined application under salt stress (200 mM NaCl), emphasizing their synergistic potential to enhance plant resilience. Conducted in a controlled climate chamber, key parameters such as plant height, biomass, SPAD values, ion leakage, relative water content (RWC), osmotic potential, and mineral uptake were assessed. Salt stress significantly reduced plant growth, chlorophyll content, and nutrient absorption. However, AMF and PGPR improved plant performance, with co-inoculation showing the highest efficacy in increasing RWC, nutrient uptake, and maintaining membrane stability. AMF and PGPR treatments enhanced potassium retention and reduced sodium and chloride accumulation, mitigating ionic imbalances. The improved chlorophyll content and water relations under co-inoculation demonstrate the potential of these biostimulants to boost photosynthesis and plant resilience. These findings highlight AMF and PGPR as eco-friendly solutions for sustainable agriculture, promoting crop productivity and stress tolerance under saline conditions.

Effects of Thinning Practices on Soil Properties and Arbuscular Mycorrhizal Fungi in Natural Pure Oriental Beech Forests

Thinning intensities in Fagus orientalis Lipsky. stands may influence the soil properties, arbuscular mycorrhizal (AM) fungi symbiosis, and their interaction through soil quality enhancement. We aimed to investigate the impact of four thinning intensities—control (no thinning); moderate (15%), moderately intense (35%), and intense thinning (55%)—implemented five years ago in pure oriental beech forests. In this context, the percentage indicates the proportion of trees removed by each thinning intensity, based on the total number of trees before thinning. Our focus encompassed soil physical–chemical properties, AM fungi community composition, and root colonization. At the intense thinning sites, the soil organic carbon, total nitrogen, available potassium, AMF spore density, and root colonization increased by 209.7, 88.9, 115.8, 404.9, and 448.5%, respectively, when compared to the control sites. This suggests a potential rise in AMF spore density and root colonization—a vital aspect for natural regeneration. These findings highlight the importance of considering management practices in forest systems that can enhance the root system in a sustainable manner to improve plant performance, soil fertility, and symbiosis with AM fungi.

Mycorrhizal inoculation alters rhizosphere fungal community and root morphology to improve drought tolerance of resource-acquisitive but not resource-conservative Quercus species

The mutualistic association between mycorrhizal fungi and plants is well known to improve plant drought resistance. However, the influence of external inoculants on the interactions between soil microbial communities and plant functional traits and how these interactions improve plant drought tolerance under drought stress remain unclear. We conducted a pot inoculation experiment to assess the effect of two inoculated fungal strains (Clitopolius hobsonii NL-19 and C. sp. HSL-YX-7-A) on morphological traits and rhizosphere fungal communities of eight Quercus species seedlings. Plant and soil fungal traits were measured 2 months after inoculation and then underwent a short-term (33 days) drought rewetting treatment. The biomass of all tree species reduced significantly under drought stress followed by rewetting (drought treatment) compared with that in the control treatment (well-watered); however, inoculated mycorrhizal fungi (drought + mycorrhizal inoculation treatment) increased the biomass of five Quercus species (growth-promoting species (GPS) exhibiting a significant increase in biomass under mycorrhizal inoculation treatment than under the uninoculated treatment during drought stress, characterized by a resource-use acquisitive strategy) and had no effect on the other three Quercus species (non-growth-promoting species (NGPS) exhibiting no significant difference in biomass between mycorrhizal inoculation and uninoculated treatments during drought stress, characterized by a resource-use conservative strategy). The leaf traits of the two species groups (GPS and NGPS) varied little among the three treatments. The values of most root traits (e.g., specific root length and root length) of GPS increased significantly under drought and drought + mycorrhizal inoculation treatments compared with those in the control, whereas relatively minor variations were observed in NGPS among the three treatments. The fungal community composition and functional groups (primary trophic modes) in the drought treatment were altered for NGPS but not for GPS; additionally, they changed in the drought + mycorrhizal inoculation treatment for GPS but not for NGPS when compared with those in the drought treatment. Furthermore, the drought tolerance of GPS was improved directly by fungal functional groups (i.e., Pathotroph-Saprotroph- Symbiotrophs proliferation) and indirectly by root traits (e.g., increased specific root length), whereas NGPS may adapt to drought stress through other pathways (e.g., physiological and biochemical regulation). Overall, drought and mycorrhizal inoculation affected the root traits and fungal community structure of Quercus seedlings, which rely on plant resource-use strategies. Our results provide new insights into the relationship between plant resource-use strategies and soil microbes for improving plant performance under drought stress.

Reinforcement learning-trained optimisers and Bayesian optimisation for online particle accelerator tuning

Online tuning of particle accelerators is a complex optimisation problem that continues to require manual intervention by experienced human operators. Autonomous tuning is a rapidly expanding field of research, where learning-based methods like Bayesian optimisation (BO) hold great promise in improving plant performance and reducing tuning times. At the same time, reinforcement learning (RL) is a capable method of learning intelligent controllers, and recent work shows that RL can also be used to train domain-specialised optimisers in so-called reinforcement learning-trained optimisation (RLO). In parallel efforts, both algorithms have found successful adoption in particle accelerator tuning. Here we present a comparative case study, assessing the performance of both algorithms while providing a nuanced analysis of the merits and the practical challenges involved in deploying them to real-world facilities. Our results will help practitioners choose a suitable learning-based tuning algorithm for their tuning tasks, accelerating the adoption of autonomous tuning algorithms, ultimately improving the availability of particle accelerators and pushing their operational limits.

Molecular selection of soybean towards adaptation to Central European agroclimatic conditions.

Europe is highly dependent on soybean meal imports and anticipates an increase of domestic plant protein production. Ongoing climate change resulted in northward shift of plant hardiness zones, enabling spring-sowing of freezing-sensitive crops, including soybean. However, it requires efficient reselection of germplasm adapted to relatively short growing season and long-day photoperiod. In the present study, a PCR array has been implemented, targeting early maturity (E1-E4, E7, E9, and E10), pod shattering (qPHD1), and growth determination (Dt1) genes. This array was optimized for routine screening of soybean diversity panel (204 accessions), subjected to the 2018-2020 survey of phenology, morphology, and yield-related traits in a potential cultivation region in Poland. High broad-sense heritability (0.84-0.88) was observed for plant height, thousand grain weight, maturity date, and the first pod height. Significant positive correlations were identified between the number of seeds and pods per plant, between these two traits and seed yield per plant as well as between flowering, maturity, plant height, and first pod height. PCR array genotyping revealed high genetic diversity, yielding 98 allelic combinations. The most remarkable correlations were identified between flowering and E7 or E1, between maturity and E4 or E7 and between plant height and Dt1 or E4. The study demonstrated high applicability of this PCR array for molecular selection of soybean towards adaptation to Central Europe, designating recessive qPHD1 and dominant Dt1, E3, and E4 alleles as major targets to align soybean growth season requirements with the length of the frost-free period, improve plant performance, and increase yield.

Steam & Power Dashboard

Abstract— The development of the Steam and Power Dashboard represents a significant advancement in energy management practices for industrial plants. By integrating data from steam and power systems, the dashboard offers real-time monitoring and analysis capabilities, allowing plant operators to identify inefficiencies and make informed decisions to optimise energy consumption. The research study delves into the design and implementation of the dashboard, highlighting its user-friendly interface and its ability to provide actionable insights for improving plant performance. Furthermore, the impact of the Steam and Power Dashboard on energy efficiency, cost savings, and greenhouse gas emissions is a key focus of the research. The findings demonstrate that the dashboard is effective in enabling plant operators to make data-driven decisions that lead to significant improvements in energy management practices. These improvements not only result in cost savings for the plant but also contribute to reducing the plant’s environmental impact by lowering greenhouse gas emissions. Overall, this research contributes to the advancement of sustainable energy strategies in industrial settings by showcasing the benefits of utilising innovative technologies, such as the Steam and Power Dashboard, to improve energy management practices and drive towards a more sustainable future. IndexTerms – – Python, SQL, EDA

Modulation of abscisic acid signaling via endosomal TOL proteins.

The phytohormone abscisic acid (ABA) functions in the control of plant stress responses, particularly in drought stress. A significant mechanism in attenuating and terminating ABA signals involves regulated protein turnover, with certain ABA receptors, despite their main presence in the cytosol and nucleus, subjected to vacuolar degradation via the Endosomal Sorting Complex Required for Transport (ESCRT) machinery. Collectively our findings show that discrete TOM1-LIKE (TOL) proteins, which are functional ESCRT-0 complex substitutes in plants, affect the trafficking for degradation of core components of the ABA signaling and transport machinery. TOL2,3,5 and 6 modulate ABA signaling where they function additively in degradation of ubiquitinated ABA receptors and transporters. TOLs colocalize with their cargo in different endocytic compartments in the root epidermis and in guard cells of stomata, where they potentially function in ABA-controlled stomatal aperture. Although the tol2/3/5/6 quadruple mutant plant line is significantly more drought-tolerant and has a higher ABA sensitivity than control plant lines, it has no obvious growth or development phenotype under standard conditions, making the TOL genes ideal candidates for engineering to improved plant performance.

Foliar Application of Seaweed Extract and Micronutrients on Plant Growth and Yield of Strawberry (Fragaria X ananassa Duch) CV. Winter Dawn

The review summarizes the findings from recent studies, assessing the impact of foliar application of seaweed extracts and micronutrients on strawberry plants. Improvements in growth parameters, nutrient uptake, TSS, and yield attributes were observed. The study also determines whether adding seaweed extracts and micronutrients to strawberry growth methods can improve plant performance in general and fruit yield in particular. Minerals, amino acids, and plant growth regulators are among the bioactive substances found in seaweed extracts that have been shown to have a positive impact on a number of plant physiological functions. Furthermore, vitamin shortages might result in decreased growth and yield because they are essential to the plant's metabolic processes. The combination of micronutrients and seaweed extract has synergistic effects that offer a promising way to boost the general health and yield of strawberry crops.

Effects of Biochar and Compost on Turfgrass Establishment Rates

Organic soil amendments are a sustainable option for modifying soil structure and improving plant performance in the face of abiotic stressors such as drought and soil salinity. Of these amendments, biochar and compost have the added benefits of carbon sequestration and waste recycling. Establishment studies were conducted on tall fescue (Festuca arundinacea Schreb.) (syn., Schedonorus arundinaceus (Schreb.) Dumort and Lolium arundinaceum (Scop.) Holub) to assess the potential inhibition of establishment by compost and biochar products. Both green waste and biosolid compost impaired establishment rates, while biochar did not. In the field study, the green waste treatments were slower to reach 50% coverage than the untreated control or when biochar was added to the soil, but all treatments reached 75% and final coverage at a similar rate. Field application of compost had a positive effect on final root length and volume but a negative effect on tall fescue roots in the greenhouse. The negative effect of higher salts and volatiles in the biosolids compost was reduced when biosolids and biochar were incorporated into the soil simultaneously. This work represents one of the only large-scale field studies on turfgrass establishment comparing the impact of biochar and compost products on turfgrass establishment.

Improving the growth parameters, yield, and oil quality of camelina in rainfed farming due to the combined use of biochar and supplementary irrigation

The main concerns for agricultural production nowadays are excessive crop cultivation, water scarcity, and poor soil quality. It is possible to amend agronomic soil with activated biochar (BC) to achieve high water-fertilizer availability and Camelina crop production under rainfed conditions by using an efficient and environmentally safe technology. A split plot experiment was arranged on a randomized complete block design with nine treatments and three replications. The main and second factors were supplementary irrigation (SI) and BC, respectively, with SI comprising of no irrigation (control), irrigation at the flowering stage and seed-filling stage, while BC included control (BC0), 5 (BC5), and 10 (BC10) t ha−1. The number of lateral branches and seeds in the silique, seed yield (2751.8 kg ha−1), 1000-seed weight (1.16 g) and oil yield (991.50 kg ha−1) were highest in response to irrigation at the flowering stage and the application of BC10. The gas chromatography analysis showed that the highest amount of unsaturated fatty acids (oleic, linoleic, linolenic, eicosadienoic and palmitic acids) was obtained in response to BC10 and irrigation at the seed-filling stage. Finally, the results showed that BC10 and the application of SI at the flowering stage increased the seed and oil yield, and unsaturated fatty acid content in Camelina. This study demonstrates that BC amendments can improve plant performance and preserve the environment, with significant implications for the alleviation of drought and sustainable Camelina production in arid regions. The study provides a practical way to produce Camelina in rainfed areas, which can benefit farmers economically.

Trunk injection of oxytetracycline improves plant performance and alters the active bark and rhizosphere microbiomes in huanglongbing-affected citrus trees

Trunk injection of oxytetracycline improves plant performance and alters the active bark and rhizosphere microbiomes in huanglongbing-affected citrus trees

Morfofisiologia de feijão-caupi sob estresse salino e aplicação de nanobioestimulante de carbono na fase vegetativa

ABSTRACT Several technologies have been implemented to improve plant performance in irrigated crops, and one of them is the use of nanobiostimulants. Therefore, the aim of the present study was to explore the effects of applying different concentrations of a carbon-based biostimulant on the morphophysiology of cowpea plants subjected to varying electrical conductivities of irrigation water. The experiment was performed in a completely randomized design, in a 2 × 6 factorial scheme, with two electrical conductivities of irrigation water (ECw: 0.35 and 4.0 dS m-1) and six concentrations of nanobiostimulant applied through the leaves (0, 80, 160, 240, 320, and 400 mg L-1), with four replications. Growth and gas exchange variables were evaluated 31 days after sowing (V9 stage). Concentrations between 240 and 320 mg L-1 of carbon-based nanobiostimulant promoted greater increases in growth and physiological variables, but they caused decreases in non-photochemical quenching. Water electrical conductivity of 4.0 dS m-1 reduced the number of leaves (17.1%), stem diameter (10.0%), SPAD index (10.3%), net photosynthesis (10.9%), stomatal conductance (46.4%), transpiration (34.5%), instantaneous carboxylation efficiency (22.4%), and photochemical quenching (4.5%); in contrast, it increased the ratio between internal and ambient CO2 concentration (18.0%), leaf temperature (2.9%), water use efficiency (32.5%), and non-photochemical quenching (12.4%). Concentrations of 240 to 320 mg L-1 of the nanobiostimulant enhance the development and gas exchange of cowpea plants under non-stress conditions, whereas the concentration of 240 mg L-1 promotes the maximum increase in plant height under salinity.

Nutrient availability and plant phenological stage influence the substrate microbiome in container-grown Impatiens walleriana ‘Xtreme Red’

BackgroundThe microbiome plays a fundamental role in plant health and performance. Soil serves as a reservoir of microbial diversity where plants attract microorganisms via root exudates. The soil has an important impact on the composition of the rhizosphere microbiome, but greenhouse ornamental plants are commonly grown in soilless substrates. While soil microbiomes have been extensively studied in traditional agriculture to improve plant performance, health, and sustainability, information about the microbiomes of soilless substrates is still limited. Thus, we conducted an experiment to explore the microbiome of a peat-based substrate used in container production of Impatiens walleriana, a popular greenhouse ornamental plant. We investigated the effects of plant phenological stage and fertilization level on the substrate microbiome.ResultsImpatiens plants grown under low fertilization rates were smaller and produced more flowers than plants grown under optimum and high fertilization. The top five bacterial phyla present in the substrate were Proteobacteria, Actinobacteria, Bacteriodota, Verrucomicrobiota, and Planctomycetota. We found a total of 2,535 amplicon sequence variants (ASV) grouped into 299 genera. The substrate core microbiome was represented by only 1.8% (48) of the identified ASV. The microbiome community composition was influenced by plant phenological stage and fertilizer levels. Phenological stage exhibited a stronger influence on microbiome composition than fertilizer levels. Differential abundance analysis using DESeq2 identified more ASVs significantly affected (enriched or depleted) in the high fertilizer levels at flowering. As observed for community composition, the effect of plant phenological stage on microbial community function was stronger than fertilizer level. Phenological stage and fertilizer treatments did not affect alpha-diversity in the substrate.ConclusionsIn container-grown ornamental plants, the substrate serves as the main microbial reservoir for the plant, and the plant and agricultural inputs (fertilization) modulate the microbial community structure and function of the substrate. The differences observed in substrate microbiome composition across plant phenological stage were explained by pH, total organic carbon (TOC) and fluoride, and across fertilizer levels by pH and phosphate (PO4). Our project provides an initial diversity profile of the bacteria occurring in soilless substrates, an underexplored source of microbial diversity.

Assisted phytoextraction as a nature-based solution for the sustainable remediation of metal(loid)-contaminated soils.

Soil contamination is a significant environmental issue that poses a threat to human health and the ecosystems. Conventional remediation techniques, such as excavation and landfilling, are often expensive, disruptive, and unsustainable. As a result, there has been growing interest in developing sustainable remediation strategies that are cost-effective, environmentally friendly, and socially acceptable. One such solution is phytoextraction: a nature-based approach that uses the abilities of hyperaccumulator plants to uptake and accumulate metals and metalloids (potentially toxic elements [PTE]) without signs of toxicity. Once harvested, plant biomass can be treated to reduce its volume and weight by combustion, thus obtaining bioenergy, and the ashes can be used for the recovery of metals or in the construction industry. However, phytoextraction has shown variable effectiveness due to soil conditions and plant species specificity, which has led researchers to develop additional approaches known as assisted phytoextraction to enhance its success. Assisted phytoextraction is a remediation strategy based on modifying certain plant traits or using different materials to increase metal uptake or bioavailability. This review article provides a practical and up-to-date overview of established strategies and the latest scientific advancements in assisted phytoextraction. Our focus is on improving plant performance and optimizing the uptake, tolerance, and accumulation of PTE, as well as the accessibility of these contaminants. While we highlight the advantages of using hyperaccumulator plants for assisted phytoextraction, we also address the challenges and limitations associated with this approach. Factors such as soil pH, nutrient availability, and the presence of other contaminants can affect its efficiency. Furthermore, the real-world challenges of implementing phytoextraction on a large scale are discussed and strategies to modify plant traits for successful phytoremediation are presented. By exploring established strategies and the latest scientific developments in assisted phytoextraction, this review provides valuable guidance for optimizing a sustainable, nature-based technology. Integr Environ Assess Manag 2024;20:2003-2022. © 2024 SETAC.

Long-term tropospheric ozone pollution disrupts plant-microbe-soil interactions in the agroecosystem.

Tropospheric ozone (O3 ) threatens agroecosystems, yet its long-term effects on intricate plant-microbe-soil interactions remain overlooked. This study employed two soybean genotypes of contrasting O3 -sensitivity grown in field plots exposed elevated O3 (eO3 ) and evaluated cause-effect relationships with their associated soil microbiomes and soil quality. Results revealed long-term eO3 effects on belowground soil microbiomes and soil health surpass damage visible on plants. Elevated O3 significantly disrupted belowground bacteria-fungi interactions, reduced fungal diversity, and altered fungal community assembly by impacting soybean physiological properties. Particularly, eO3 impacts on plant performance were significantly associated with arbuscular mycorrhizal fungi, undermining their contribution to plants, whereas eO3 increased fungal saprotroph proliferation, accelerating soil organic matter decomposition and soil carbon pool depletion. Free-living diazotrophs exhibited remarkable acclimation under eO3 , improving plant performance by enhancing nitrogen fixation. However, overarching detrimental consequences of eO3 negated this benefit. Overall, this study demonstrated long-term eO3 profoundly governed negative impacts on plant-soil-microbiota interactions, pointing to a potential crisis for agroecosystems. These findings highlight urgent needs to develop adaptive strategies to navigate future eO3 scenarios.

Biochar and vegetation effects on discharge water quality from organic-substrate green roofs

Green roofs have been increasingly used to improve stormwater management, but poor vegetation performance on roof systems, varying with vegetation type, can degrade discharge quality. Biochar has been suggested as an effective substrate additive for green roofs to improve plant performance and discharge quality. However, research on the effects of biochar and vegetation on discharge quality in the long term is lacking and the underlying mechanisms involved are unclear. We examined the effects of biochar amendment and vegetation on discharge quality on organic-substrate green roofs with pre-grown sedum mats and direct-seeded native plants for three years and investigated the key factors influencing discharge quality. Sedum mats reduced the leaching of nutrients and particulate matter by 6–64% relative to native plants, largely due to the higher initial vegetation cover of the former. Biochar addition to sedum mat green roofs resulted in the best integrated water quality due to enhanced plant cover and sorption effects. Structural equation modeling revealed that nutrient leaching was primarily influenced by rainfall depth, time, vegetation cover, and substrate pH. Although biochar-amended sedum mats showed better discharge quality from organic-substrate green roofs, additional ecosystem services may be provided by native plants, suggesting future research to optimize plant composition and cover and biochar properties for sustainable green roofs.

Biochar amendments improve soil functionalities, microbial community and reduce Pokkah boeng disease of sugarcane

BackgroundBiochar is mainly used to enhance soil fertility, microbial activity, improve plant performance and reduce disease incidence.MethodsA greenhouse experiment was designed to investigate the response of biochar on rhizosphere soil chemical properties, enzyme activity, microbial communities, and sugarcane Pokkah boeng disease (PB). Two sugarcane varieties Zhongzhe 9 (Z9) and ROC22, susceptible/resistant to PB, were cultivated and treated with: no biochar, 15 t ha−1 biochar, and 30 t ha−1 biochar.ResultsThe amendment of 30 t ha−1 of biochar (B2) significantly improve soil pH by 1.50% and 9.61% compared with that of B1 and B0, followed by 0.51% increase by 15 t ha−1 of biochar (B1) compared with that of control (B0). The application of 15 t ha−1 biochar significantly increased available phosphorus (AP) and ammonium nitrogen (NH4+–N) by 209.93 mg kg−1 and 12.1 mg kg−1, while the application of 30 t ha−1 of biochar significantly increased 241.04 mg kg−1 of available potassium (AK) (P < 0.05). Furthermore, biochar application increased the activities of soil acid phosphatase (S-ACP), urease (S-UE), and sucrase (S-SC). Alpha diversity analysis showed that the addition of biochar significantly altered the variety and abundance of rhizosphere microorganisms (P < 0.01) and increased the relative abundance of beneficial microorganisms Rhodanobacteraceae, Stachybotryaceae, Agaricacea, Talaromyces, Nectriaceae, Sistotrema, and Bacillus (P < 0.01). There was a significant decrease in the relative abundance of the soil pathogen Fusarium (P < 0.01).ConclusionThese findings suggested that the application of 15 t ha−1 biochar could bring desirable variations in soil functionalities, modulate soil microbial community by increasing soil health and reduce the disease index of PB.Graphical

Biostimulants do not affect the performance of urban plant species grown under drought stress

Urban areas often have low soil water availability due to their impervious surfaces reducing rainfall infiltration. These water-limited conditions may be exacerbated by the projected increases in drought events caused by climate change. As a result, plants that grow in urban areas are vulnerable to drought stress. There are a range of practices that can be used to help mitigate drought stress, including the use of biostimulants. This study aimed to determine whether biostimulant application (1) improves plant performance and (2) mitigates the drought stress on urban plant species. To address these aims, we selected six woody and three graminoid plant species that are commonly planted in Australian urban areas and exposed them to different watering (drought-stressed, well-watered) and biostimulant (control, humic acid, protein hydrolysate, seaweed extract) treatments. We then measured their assimilation rate, growth metrics and biomass allocation. We found that drought stress reduced the assimilation rates and shoot growth of the study species. However, this did not translate into a biomass reduction because the drought-stressed plants reallocated resources towards root biomass. We found no evidence to suggest biostimulant application mitigated the impacts of drought stress on plant performance. Further, the only effect biostimulant application had on plant performance irrespective of the watering treatment was that the seaweed biostimulant increased the plant height growth of the woody species. These results show that the biostimulants used in this study will have a limited effect on the performance of plant species commonly planted in Australian urban areas.

Combined application of acetylcholine (ACh) and gamma-aminobutyric acid (GABA) mitigates the effects of water deficit in soybean

Bioregulatory substances, such as acetylcholine (ACh) and γ-aminobutyric acid (GABA), have shown promise in mitigating water deficit effects on plants. Their action on plant physiology, particularly in stomatal regulation and osmoprotection, contributes to enhanced agricultural productivity. Regarding soybean plants, changes in the metabolic profile that could justify the improvement in physiological performance and growth are still unknown. This study investigated the impact of combined ACh:GABA application during soybean V4 and R2 stages using physiological assessments and NMR-based metabolomics. Two equimolar doses (2 and 8 mM) of ACh:GABA were applied to soybean plants subjected to two water regimes: 100 % of field capacity (continuously irrigated) and water deficit (water suspension). Results demonstrated enhanced gas exchange, biomass, and chlorophyll content, alongside favorable enzymatic activity. NMR analysis revealed metabolites countering oxidative stress, supporting osmoprotection, and contributing to soybean development and energy supply. The 8 mM ACh:GABA application notably improved plant performance, showcasing potential for water deficit mitigation in soybeans.