Biostimulant Treatments Research Articles

The insights into the activity of the extracts from Polygonum aviculare L. and Pseudomonas fluorescens for enhancing and modeling seed germination and seedling growth of Melilotus officinalis L. Lam

The empirical evidence indicated that chemicals in plants and selected microorganisms can promote the germination process and determine the growth, viability, survival and yield potential of industrial crop plants. The main objective of this study was exploring the phytochemical and microbiological synergistic activity between plant extracts from Polygonum aviculare L. and beneficial bacteria Pseudomonas fluorescens to enhance germination of Melilotus officinalis seeds and improve morphological characteristics of seedlings. The derived plant preparations were analyzed qualitatively, which showed that the aqueous extracts of P. aviculare were characterized by a higher content of phenolic compounds, micro- and macroelements and carbohydrates compared to the macerates, and that no phytohormones were detected in both the infusions and macerates. Pure macerates (MAC), infusions (IF), bacterial cultures (PF) and their mixtures (MAC+PF; INF+PF) were used for seed treatment of test plants. In the control group, lower values of M. officinalis seed germination and seedling growth rates were observed in relation to the applied treatments. The most effective germination rates were obtained after the application of pure infusions (IF) and their mixture with P. fluorescens (IF+PF), while the highest growth rates (including an almost twofold increase in the length of the nostril shoots compared to the control) were obtained after the application of P. fluorescens inoculum (PF) and the mixture of the infusion and these bacteria (IF+PF).The use of modeling, as a tool for predicting germination efficiency, has been shown to provide screening opportunities for identifying the effectiveness of biostimulant treatments. Thereby, this indicates the need to develop such an approach under field conditions.

Effect of Biostimulants on Plant Growth and Leaf Functional Compounds of Passiflora Plants

The influence of biostimulant treatments on Passiflora species was assessed by observing changes in the growth and leaf functional compounds of plants exposed to humic acids (HAs) and seaweed extracts (SEs) to determine their optimal application doses. Four different concentrations of HA irrigation (0, 144, 192, and 285 mg·L−1 per pot assigned as HI-1, 2, 3, and 4, respectively), HA spraying (0, 96, 128, and 192 mg·L−1 as HS-1, 2, 3, and 4, respectively), SE irrigation (SI-1∼4 at 0, 1, 1.33, and 2 g·L−1 per pot, respectively), and SE spraying (SS-1∼4 at 0, 0.5, 0.67, and 1 g·L−1, respectively) treatments were applied to ‘Tainung No. 1’ and Passiflora suberosa cultivars every week to study their responses in plant growth traits and metabolites. Results show that leaf dry weight (DW) and root DW of ‘Tainung No. 1’ plants under SS-3 and HI-4 treatments, respectively, were significantly increased compared with controls. Both HI-3 and HS-3 treatments remarkably increased vine length, fresh weight (FW), and DW of leaves and shoots in P. suberosa plants compared with controls. Furthermore, ‘Tainung No. 1’ and P. suberosa plants respectively subjected to HI-2 and SS-4 treatments contributed to developing biostimulant applications for obtaining higher total phenol and flavonoid content per plant. Both Passiflora species are recommended for treatment with SS-4 and SE to maximize orientin and isovitexin content, and for all their beneficial applications and sustainable use in agriculture.

Single or Blended Application of Non-Microbial Plant-Based Biostimulants and Trichoderma atroviride as a New Strategy to Enhance Greenhouse Cherry Tomato Performance

The need to increase yield and enhance the sustainability of crop production systems has led to the development and employment of natural products, such as plant biostimulants. In recent years, a number of reports have researched the effects of biostimulants on plant performance; however, few studies have focused on the mutual application of microbial and/or non-microbial biostimulants. This research, conducted in the framework of the SO.MI.PR.O.N regional project, aimed to investigate the single or mutual application of three biostimulants, a tropical plant extract (PE), a vegetal protein hydrolysate (PH), and Trichoderma atroviride, on ‘Creativo’ F1 cherry tomato plants cultivated during two growing cycles (2022–2023 and 2023–2024). Our results showed that plants treated with the combination Tricho + PE + PH had statistically significant higher fresh shoot biomass (+64.2%, 1647.0 g plant−1), total fruit production (+37.9%, 1902.5 g plant−1), marketable fruit production (+52.9%, 1778.5 g plant−1), and average weight of marketable fruits (+53.1%, 17.0 g) compared to control plants (untreated plants). Furthermore, biostimulant treatments, especially T. atroviride, variably enhanced cherry tomato fruits’ qualitative traits, such as firmness, total soluble solids, ascorbic acid, lycopene, and total polyphenols compared to control plants. Overall, the best combinations to increase tomato fruit qualitative features were PE + PH, Tricho + PE, and Tricho + PH. From an economic point of view, the best treatment for achieving the highest net return was PE. This study underlines that biostimulant features (yield, qualitative aspects, and economic profitability) can be supported through the application of specific biostimulant combinations.

Morphological traits, yield, antioxidant activity and essential oil composition of oregano as affected by biostimulant foliar applications

Biostimulants are interesting products which can promote the plant growth and improve its qualitative traits. In this research, the effects of foliar applications of four biostimulants on oregano (Origanum vulgare L.) crop have been investigated by evaluating morphological parameters, fresh and dry yield, antioxidant activity, total phenolic content, and chemical composition of essential oil. The highest plant height (78 cm), inflorescence height (22.2 cm), inflorescences+leaves dry yield (0.5 t ha−1), dry matter yield (38.3 %) and essential oil yield (3.4 %) were obtained in plants treated with biostimulant BlueN®, composted of Methylobacterium symbioticum SB23. Plants treated with Acadian MPE®, containing vitamins, amino acids and proteins, and betaines, showed the highest total phenolic content (60.3 GAE mg mL−1). The combination of 21 traits with principal component analysis (PCA) allowed to discriminate the biostimulant Biostimol Plus plus Peptamin-V Plus®, based on Ascophyllum nodosum extract and other elements as nitrogen, carbon, manganese, zinc and iron chelates, in a correlated way with p-cymene, α-thujene, α-terpinene, β-myrcene contents, showing values significantly higher. The heat-map identified two main clusters where the treatments with biostimulants were clearly separated from the control. Biostimulant treatments influenced the chemical composition of essential oil by increasing the number of components, monoterpene hydrocarbons and sesquiterpene hydrocarbons contents. Therefore, biostimulants can play an important role with a view to sustainable oregano cultivation by representing a safe source of nitrogen and especially for organic farming.

Genotype and Plant Biostimulant Treatments Influence Tuber Size and Quality of Potato Grown in the Pedoclimatic Conditions in Northern Apennines in Italy

AbstractIn marginal mountain areas, farm management presents challenges, particularly the sustainable improvement of yield and quality. To ensure this agronomic result, it is crucial to select appropriate varieties and apply sustainable agricultural practices, such as the use of plant biostimulants. To address these challenges a two-year field study was conducted using three potato varieties (Désirée, Kennebec and Spunta) in the Tuscan-Emilian Apennines. These varieties were treated with two plant biostimulants: one based on hydrolyzed proteins from animal epithelial tissue (Fitostim®) and another based on seaweed extracts (FitostimAlga®). Agronomic and biochemical traits were used to evaluate the development of plants, yield and tubers quality. Significant interactions among factors were found, resulting in higher or lower efficiency of the plant biostimulant treatment depending on weather conditions and potato genotype. Furthermore, results demonstrated that plant biostimulant treatments increased the leaf chlorophyll content (+ 11.5%), the number of leaves per plant (+ 13.3%) and the height of potato plants (+ 6.5%), while no effects were observed on yield. The Désirée variety achieved the highest yield (0.54 kg plant-1), whereas Kennebec was shown as the best variety to use for production of French fries due to a lower tuber quantity of reducing sugars, which were reduced also by plant biostimulants treatment (-18%). Moreover, Spunta tubers had the highest content of polyphenols, and the best value was achieved by Spunta variety treated with Fitostim® alga in the second year. Our finding have proven that plant biostimulant treatments can increase the quality of potato tuber without compromising yield.

Microbial Biocontrol Agents and Natural Products Act as Salt Stress Mitigators in Lactuca sativa L.

One of the major problems related to climate change is the increase in land area affected by higher salt concentrations and desertification. Finding economically and environmentally friendly sustainable solutions that effectively mitigate salt stress damage to plants is of great importance. In our work, some natural products and microbial biocontrol agents were evaluated for their long-term effectiveness in reducing salt stress in lettuce (Lactuca sativa L. var. romana) plants. Fourteen different treatments applied to soil pots, with and without salt stress, were analyzed using biometric (leaf and root length and width), physiological (chlorophyll and proline content), and morphological (microscopic preparations) techniques and NGS to study the microbial communities in the soil of plants subjected to different treatments. Under our long-term experimental conditions (90 days), the results showed that salt stress negatively affected plant growth. The statistical analysis showed a high variability in the responses of the different biostimulant treatments. Notably, the biocontrol agents Papiliotrema terrestris (strain PT22AV), Bacillus amyloliquefaciens (strain B07), and Rahnella aquatilis (strain 36) can act as salt stress mitigators in L. sativa. These findings suggest that both microbial biocontrol agents and certain natural products hold promise for reducing the adverse effects of salt stress on plants.

Biostimulant Effects of Algae Species, Arbuscular Mycorrhizal Fungi, and Their Combinations on Yield and Quality of Yellow Tomato Landrace Under Different Crop Cycles

Recent agricultural research has prioritized the development of environmentally friendly management strategies to ensure food security, among which the application of biostimulants such as brown algae extracts, arbuscular mycorrhizal fungi (AMF), and their combination are included. The experimental protocol was based on the factorial combination of two planting times (4 May and 1 June) and seven biostimulant treatments (three brown algae species, Cystoseria tamariscifolia—C.t.; Fucus vesiculosus—F.v.; Padina pavonica—P.p.; arbuscular mycorrhizal fungi—AMF; C.t. + AMF; F.v. + AMF; P.p. + AMF) plus an untreated control. The earlier transplant resulted in a higher yield, due to the higher number of fruits per plant, and a higher plant fresh and dry biomass. The treatments with P.p. and F.v. extracts and the combination P.p. + AMF led to the highest yields (56.7 t ha−1), mainly due to the highest fruit number per plant. The earlier planting time led to higher values of dry residue, soluble solids, firmness, and colour component ‘a’. The highest values of fruit dry residue were recorded under the F.v. and P.p. extracts, and the combinations F.v. + AMF and P.p. + AMF, the highest soluble solid content with P.p. treatment, and firmness under P.p. + AMF. The highest levels of ‘L’ and ‘a’ fruit colour components were obtained under the P.p. extract treatment, of ‘b’ upon the application of P.p. and F.v. extract, and AMF + P.p. and AMF + F.v. The later planting time led to significantly higher values of the antioxidant parameters, as did the application of the P.p. extract and P.p. + AMF. CAT activity was more intense corresponding to the later tomato crop cycle, P.p. extract, and AMF + P.p. Overall, our study highlights the potential of biostimulants, particularly brown algae extracts and their combination with AMF, to improve tomato yield, antioxidant properties, and biochemical activities.

Seaweed Extract and Microbial Biostimulants Show Synergistic Effects on Improving Organic Strawberry Production

The application of seaweed extract and microbial biostimulants has been suggested as a promising approach to overcome yield-limiting factors in organic farming. Yet, information regarding their impact on organic strawberry production is limited. This 2-year field study evaluated the effect of seaweed extract and microbial biostimulants and their synergistic effects on strawberry plant growth, nutrient uptake, fruit yield, and quality under organic production. The biostimulant effects were compared on two strawberry cultivars: Sweet Sensation® Florida127 and Florida Brilliance. Over two seasons, the combination of seaweed extract plus microbial biostimulants applied biweekly consistently resulted in a significant increase of whole-season marketable and total strawberry fruit yields by 23% and 20% on average, respectively, compared with the no-biostimulant control. Application of either biostimulant alone did not consistently show positive effects on strawberry productivity. Modified strawberry root system architecture, enhanced N uptake, increased number of crowns, and higher soil respiration were observed in the biostimulant combination treatment in contrast to the no-biostimulant control. The biostimulant impact was not influenced by strawberry cultivar, but genotypic difference in yield performance under organic production was observed. ‘Florida Brilliance’ produced significantly higher total fruit number and yield than ‘Florida127’ by 26% and 12%, respectively, in the first season, and by 34% and 11%, respectively, in the second season. Marketable fruit number (by 18%) and yield (by 9%) of ‘Florida Brilliance’ were also higher in the first season, along with greater marketable fruit number (by 31%) in the second season. In addition, ‘Florida Brilliance’ showed significantly higher values of SPAD index, photosynthetic rate (early harvest), and fruit mineral contents based on dry weight (late harvest) than ‘Florida127’ in both seasons. Although the biostimulant treatments exhibited little influence on the fruit quality attributes including soluble solids content (SSC), titratable acidity (TA), SSC/TA, and total anthocyanin content, varietal differences were observed with significantly higher levels of SSC and lower contents of total anthocyanins in ‘Florida 127’ vs. ‘Florida Brilliance’ during each season. The benefits of combined application of seaweed extract and microbial biostimulants demonstrated in this study suggest the need to further elucidate their synergistic functions in promoting nutrient uptake and fruit yield in organic strawberry production systems under different soil and environmental conditions.

Biostimulant induce growth, chlorophyll content and fresh herbage yield of alfalfa (Medicago sativa L.) and variegated alfalfa (Medicago × varia Martyn) plant

The use of biostimulants is associated with promoting plant growth by stimulating cell division and improving nutrient availability and uptake. A study was conducted at the University of Debrecen, Hungary, to examine the effect of biostimulants on alfalfa growth, chlorophyll content and fresh herbage yield. The experiment was arranged in a randomised complete block design with three biostimulant treatments plus control replicated three times. Data collected were subjected to analyses of variance using Genstat, where significantly different means were separated at a probability of 5% using the least significant difference. The findings show no different variation in plant height or chlorophyll content (SPAD) throughout the early stages of growth. Nonetheless, a notable impact was noted in the latter stages (28 days after biostimulant treatment application) on the growth of the alfalfa plant. Biostimulant treatments did not had effect on fresh yield for second through fourth cuts, but the fifth cut showed a significant effect, with T1 treatment recording the highest herbage yield of 19745 kg ha-1 followed by T2 (Tricho Immun plus Ino Green) and T3 (Tricho Immun), with yields of 19528 kg ha-1 and 17273 kg ha-1, respectively, while the T0 (control) recorded the lowest herbage yield of 12060 kg ha-1. However, the average mean yield indicated the application of biostimulants significantly increased fresh yield herbage by 20.5%. Correlation coefficient values suggested plant height at both 14 and 28 DAH (days after harvest) strongly correlated with fresh herbage yield (r = 0.7756 and 0.7455) which reflected in the increase in fresh herbage yield. Therefore, our results suggest that the use of biostimulants in alfalfa cultivation holds promise for improving growth and yield potential through their positive effects on chlorophyll content and the growth of alfalfa plant.

Bio-stimulants as alternatives to mineral fertilizers: influence on chia (Salvia hispanica L.) growth, yield, and fatty acid composition

One of the main components of sustainable agricultural strategies in crop production is substitution of chemical fertilizers with alternatives. This study aimed to examine the effects of partial replacement of mineral fertilizers with bio-stimulants (yeast and/or moringa leaves extract). Field experiment was conducted during two successive seasons 2018/2019 and 2019/2020. The fertilization treatments were distributed in a factorial design. Treatments included 75%, 50% or 0% NPK combined with yeast, moringa extract, or their combination in comparison with control treatment (100% NPK). The partial substitution of mineral fertilizers with yeast and/or moringa extract had significant impacts on growth, yield and quality components. Decreasing NPK level significant decreased growth and yield components of chia plants, except for 75% NPK combined with yeast and/or moringa. In contrast, decreasing NPK level significantly increased the chemical and quality components of chia. Treating with 75% NPK combined with yeast and/or moringa gave the highest micronutrients and fatty acid content. GC analysis showed definition of nine main components, and the major components were linolenic and linoleic acids. Linolenic acid increased with decreasing NPK, and the highest values obtained with bio-stimulant treatments with zero % NPK. The results of this study recommended that partial substitution of 25% of mineral fertilizers with bio-stimulants (yeast and/or moringa) is the best alternative not only for maintaining the growth and yield component, but also improving the quality of chia plants.

The effect of biostimulants on parsnip seed germination and initial growth

Biostimulants are used for seed quality and performance improvement. However, the impact of biostimulants on parsnip seed quality has not been examined. Slow germination of parsnip is often further impeded by stress conditions. This study therefore aimed to assess whether treatments with different biostimulants could enhance seed germination and the initial seedling growth of parsnip. Amino acid and micronutrient-based biostimulants (0.2% solutions (v/v) of Technokel Amino Mix® and Megafol®) improved germination of parsnip seeds under optimal conditions, while biostimulant treatments with humic acid, fulvic acid and micronutrients (0.02% solution (v/v) of Organiko®) enhanced the initial growth. Our findings validate the potential of biostimulant application as a seed treatment. Determination of the main physiological causes of parsnip germination enhancement is needed in further research.

Evaluation of PSP1 biostimulant on Fusarium graminearum-wheat pathosystem: impact on disease parameters, grain yield, and grain quality.

Plant defense elicitors are valuable tools in sustainable agriculture, providing an environmentally friendly and effective means of enhancing plant defense and promoting plant health. Fusarium head blight (FHB) is one of the most important fungal diseases of cereal crops worldwide. The PSP1 is a novel biopesticide formulated based on an elicitor, the extracellular protein AsES, from the fungus Sarocladium strictum. The present work aimed to evaluate the effectiveness of PSP1 in controlling FHB under field conditions. Experiments were conducted during three consecutive growing seasons (2019, 2020, and 2021). Three biostimulant treatments were tested in different physiological stages (from late tillering to heading stage), and FHB inoculations were performed at anthesis. Disease parameters, seed parameters, grain yield, and grain quality parameters were evaluated. Depending on the year and the genotype, reductions in disease incidence (up to 11%) and disease severity (up to 5%) were reported, although these differences could not be attributed to the use of the PSP1 biostimulant. Occasional improvements in seed parameters and grain quality were observed, suggesting that early treatments could work better than late treatments, probably due to early activation/priming of defense response mechanisms. However, more studies are deemed necessary. The use of PSP1 biostimulant in commercial wheat crops could be a biological alternative or complement to traditional chemical fungicides to manage FHB. The reduced environmental impact and the potential benefits in grain yield and quality are other reasons that can generate new adherents of this technology in worldwide agriculture systems in the coming years. © 2024 Society of Chemical Industry.

Adaptation of basil to salt stress: Molecular mechanism and physiological regulation

Although many molecular and physiological mechanisms behind plant responses to osmotic and nutritional stresses (primarily salinity) have been identified, the strong impact of genetics makes understanding their interconnections complex. Moreover, the dominant genetic effect often masks other potentially influential factors modulating plant response to environmental stimuli. Using three types of basil (Dark Opal, Italiano Classico, and Purple Ruffles) that have different counteracting potentials to react to NaCl (60 mM) salt stress, we showed that higher constitutive concentrations of osmolytes and antioxidant molecules improve basil adaptation to a saline environment. An already active ROS scavenging mechanism and unaltered NUE allowed Purple Ruffles to remain unaffected by the toxic effects of salt, unlike Italiano Classico and Dark Opal, which incurred fresh yield reduction by 46.34 and 33.33 %, respectively. Up-regulation of secondary metabolism in response to biostimulant treatments (protein hydrolysate and protein hydrolysate+leaf liquid integrator) ensured a higher fresh yield in all basil types, regardless of salt treatment. Understanding the key molecular traits implicated in plant response to salinity is undoubtedly valuable for future genetic improvement programs of tolerant genotypes and for the application of products with biostimulatory and ameliorative action.

Application of innovative biostimulants for growth and quality improvement in vegetable and ornamental crops

Research objective: This research aims to evaluate the biostimulant potential of some innovative products that can improve germination, growth and protection from biotic stresses on some vegetable and ornamental species. Materials and Methods: The experiments, which started in October 2022, were conducted in the CREA-OF greenhouses in Pescia (Pt), on Cichorium intybus and Crassula rupestris plants. The experimental groups were: i) group control, irrigated with water and previously fertilised substrate; ii) biofertiliser Ecklonia maxima, dilution 1:1000, 5 ml of this dilution once a week per plant; iii) Elixir lite, irrigated with water and substrate previously fertilised; iv) Immuno pro group, irrigated with water and substrate previously fertilised; Harvest boost group, irrigated with water and substrate previously fertilised. On 23 January 2024, plant height, number of leaves, vegetative weight, root volume and length, number of microorganisms and pH of the substrate were determined. In addition, the mortality of the plants in the nursery was assessed. Results and Discussion: The experiment showed that the use of biostimulants can significantly improve the vegetative and root growth of Cichorium intybus and Crassula rupestris plants. In general, a significant increase in plant height, vegetative and root weight and root length was observed, particularly in the Elixir lite treatment. There was also a significant increase in the microbial colonisation of the substrate with all innovative biostimulant treatments, while the pH remained practically unchanged. The Immuno pro treatment was the best in terms of reducing plant mortality in all two plant species. Biostimulants are widely used in horticulture because we often work with short-cycle crops, varying from a few weeks to a few months. The rapid succession of different crops implies a constant supply of nutrients and intensive use of soil. More intensive horticulture in particular often benefits from the effect of biostimulant treatments due to the increased resource use efficiency of the crops. Foliar biostimulants are mainly used by farmers to increase the production of both leaf and fruit vegetable crops. The positive effects of their use are exerted both on increasing the content of secondary metabolites and on a general improvement of nutrient uptake efficiency. These biological effects can be attributed to the presence in biostimulants of polysaccharides, extracted from algae, such as alginates and carrageenan, which are responsible for two important biological actions: sequestering or slowly releasing nutrients. In fruit vegetables, biostimulants can also improve the homogeneity of flowering and fruit size, as reported for peppers. Commercial biostimulants have increased the unit yield of many leafy vegetable species by acting on nutrient uptake by the plant. Conclusions: In horticultural production, in open field and in protected crops, the application of biostimulants is aimed at achieving one or more of the following objectives: to favour a rapid emergence of seedlings in direct sowing crops or a rapid overcoming of the transplanting crisis; to precociate the entry into production; to increase growth, flowering, fruit set and fruit growth; to improve product quality; to increase the efficiency of nutrient use and tolerance to environmental stresses.

The effect of root shaving and biostimulant application on the transplant success of six common Australian urban tree species

To enhance the establishment of container-grown trees, nursery and urban forest practitioners use root pruning to improve plant root structure. However, some methods of root pruning may cause stress to the plant and reduce shoot growth. One potential approach to mitigating tree stress is the application of biostimulants. This study aimed to determine the impact root shaving, a type of root pruning, has on the growth of urban plant species, and whether biostimulant application mitigates this impact. To address these aims, we applied root shaving (not shaved, shaved) and biostimulant (control, humic substance, protein hydrolysate, seaweed extract) treatments to six tree species that are commonly planted in the Sydney metropolitan area, Australia in a factorial design. The study consisted of a glasshouse and field experiment to simulate nursery production and urban field conditions, respectively. We found that the assimilation rate of the plants was not affected by root shaving but four of the species still experienced reductions in shoot growth in the short-term. This reduction was a result of the plants allocating resources to root growth to compensate for the root loss. However, in the long-term, the plants were able to compensate for this reduction in shoot growth. We found that biostimulant application did not mitigate the short-term impacts of root shaving on plant growth. We can conclude that root shaving and biostimulant application do not affect plant establishment in the long-term.

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.

Humic and Fulvic Acids Promote Growth and Flowering in Petunias at Low and Optimal Fertility

Humic substances are components of soil organic matter that influence soil structure and fertility. Humic and fulvic acids can be extracted from soil and other organic sources, and are used as biostimulants to promote plant growth and increase nutrient availability and uptake. The goal of this study was to determine whether selected humic and fulvic acid–based commercial products would promote growth and flowering of petunia (Petunia ×hybrida) ‘Picobella Blue’ grown in soilless media with low or optimal fertilizer rates. Plants were grown in 11.4-cm pots filled with peat-based media [80:20 peat:perlite (v/v); pH 5.4]. Three biostimulant products were evaluated at different rates and application frequencies: Huma Pro, a liquid humic acid biostimulant; Fulvi Pro, a liquid fulvic acid biostimulant; and Micromate, a powder containing both humic and fulvic acids. In Expt. 1, Huma Pro and Fulvi Pro were drenched weekly onto the growing media at a rate of 5, 10, or 20 mL⋅L–1; Micromate was drenched weekly at a rate of 5, 10, 20, or 40 g⋅L–1. Plants were fertilized with either 50 mg⋅L–1 nitrogen (N) (low fertility) or 100 mg⋅L–1 N (optimal fertility) from Jack’s Professional 20N–1.3P–15.7K Petunia FeED each irrigation. Control plants received fertilizer but no biostimulant treatments. In Expt. 2, biostimulant treatments were drenched once at transplant, biweekly, or weekly at a rate of 1.25, 2.5, 5, or 10 mL⋅L–1 for Huma Pro and Fulvi Pro; and at 5, 10, 20, or 40 g⋅L–1 for Micromate. All plants received constant liquid feed at the lower fertilizer rate of 50 mg⋅L–1 N. In Expt. 1, plants fertilized with 100 mg⋅L–1 N and treated with 20 g⋅L–1 Micromate had the best performance. The average shoot dry weight was 32% greater than that of the control plants. Micromate (20 g⋅L–1)-treated plants had an average of five more flowers per plant, and they flowered 4 days earlier than untreated control plants. In Expt. 2, plants treated with 40 g⋅L–1 of Micromate weekly had the greatest shoot dry weight compared with the other treatments. Weekly Micromate treatments (40 g⋅L–1) resulted in plants with an average of 13 more flowers per plant, which flowered 7 days earlier than control plants. Plants treated with Fulvi Pro and Huma Pro at 20 mL⋅L–1 had a significantly greater concentration of potassium in shoot tissue, whereas Micromate treatments at 20 and 40 g⋅L–1 resulted in a greater concentration of phosphorous in the shoots. The humic and fulvic acids in Micromate improved petunia crop quality by promoting vegetative growth, increasing flower numbers, and reducing the time to flower.

Vegetative and Reproductive Responses Induced by Organo-Mineral Fertilizers on Young Trees of Almond cv. Tuono Grown in a Medium-High Density Plantation

Field experiments were conducted in three successive seasons (2019–2021) to evaluate the effects of four commercial organo-mineral fertilizers with biostimulating action (Hendophyt®, Ergostim®, and Radicon®) on the vegetative and productive performance of young almond trees (Prunus dulcis, cv. Tuono) grown in a semiarid climate in Southern Italy. Foliar treatments were applied three times during each season (at the swollen bud, beginning of flowering, and fruit set-beginning of fruit growth stages). Both 2020 and 2021 were adversely affected by late frosts, resulting in damage to the flowers and small fruits without any positive effect of the biostimulant applications. In contrast, the results obtained during the normal climate year (2019) indicated that the growth of trunk diameter and shoot length of trees tended to increase in biostimulant treatments compared to those of the control. The number of buds and flowers per unit length of the branch revealed no significant differences among years and all compared treatments. However, in 2019, the fruit set percentage, number, and weight of kernels per tree were significantly higher in the biostimulant treatments compared to those of the control. To this regard, the use of biofertilizers is suitable for maintaining soil fertility and improving crop productivity This information holds significance for almond tree growers.

Impact of Two Brown Seaweed (Ascophyllum nodosum L.) Biostimulants on the Quantity and Quality of Yield in Cucumber (Cucumis sativus L.)

Algal biostimulants are increasingly integral to vegetable cultivation due to their capacity to boost yield, alleviate abiotic and biotic stress, and enhance overall crop quality. This study evaluated the impact of two commercially available algal-based biostimulants on cucumber (Cucumis sativus L.), examining their effects on yield, number of fruits, dry weight, color, flesh thickness, skin thickness, plastid pigments, and tocopherol content. Both biostimulant treatments resulted in a roughly 13% decrease in yield and fruit number compared to the control treatment. Notably, the biostimulants positively influenced the fruit brightness parameter (L*), leading to darker fruits. Fitostim® algal biostimulant exhibited a positive effect on dry weight during the initial harvest. The predominant pigments were chlorophyll a and chlorophyll b (constituting 80% of all analyzed pigments), and the most abundant tocopherol was α-tocopherol, comprising 80% to 90% of tocopherols. Skin tissues contained significantly higher levels of pigments and tocopherols compared to flesh. Both biostimulants caused a notable decrease in total tocopherol content in the skin at the first harvest, with reductions of 19.91 mg/kg DW for Phylgreen® and 9.43 mg/kg DW for Fitostim® algae. The study underscores the variable efficacy of biostimulants, emphasizing their dependence on the specific biostimulant type and fruit part. The application of biostimulants has the potential to substantially enhance the internal quality of cucumbers, particularly in terms of plastid pigments and tocopherols, offering potential health benefits for consumers.

Uso de bioestimulantes no crescimento inicial da grama DiscoveryTM

Abstract The use of bacteria and seaweed extracts as biostimulants to enhance plant growth holds promise for sustainable turfgrass management. This study aimed to investigate the effects of soil application of Azospirillum brasilense (bacterium) and Ascophyllum nodosum (seaweed) extract on the initial growth of DiscoveryTM bermudagrass. The study was conducted using a completely randomized design with plots measuring 0.25 m², each with a 0.5 m border. Two separate experiments were conducted, each involving four doses of biostimulants and five repetitions. The biostimulant treatments consisted of 0, 2, 4, and 6 mL L¹ A. brasilense inoculant and 0, 5, 10, and 15 mL L¹ A. nodosum seaweed extract. These treatments were uniformly applied to the soil at a rate of 100 mL m², with applications at 0, 30, and 60 days after the start of the experiment. After 90 days, the parameters green color index, green cover rate, turfgrass height, and vegetation index (normalized difference), were evaluated. The results indicated that both biostimulants significantly promoted the initial growth of DiscoveryTM bermudagrass. As the doses of the biostimulants increased, there was a corresponding increase in biomass and improved development of the turfgrass. The most pronounced responses were observed with a dose of 6 mL L¹ of the bacteria inoculant and 15 mL L¹ of the seaweed extract. These biostimulants fostered better turf coverage, making it challenging for weeds to establish, and potentially accelerating the production of sod grass.