Growth Retardants Research Articles

USE OF PLANT GROWTH REGULATORS TO OBTAIN MINI TUBERS OF Dioscorea remotiflora Kunth IN MICROPROPAGATED PLANTS

<p><strong>Background:</strong> Camote de cerro (<em>Dioscorea remotiflora</em> Kunth) stands out as a crop option in protected agriculture in Mexico due to its agronomic benefits and its versatility in the food and pharmaceutical industries. Despite its potential, it is not commercially cultivated in the country motivating the need to develop an efficient propagation method from vegetative planting material. Previous research suggests that the use of growth retardants stimulates root growth and carbohydrates accumulation in tubers, while applying gibberellic acid (GA<sub>3</sub>) is strongly related with greater tuber production. <strong>Objective: </strong>To evaluate the effect of different growth regulators to obtain <em>D. remotiflora</em> mini tubers.<strong> Methodology: </strong>Two experiments to obtain mini tubers were carried out. The first one evaluated mediums of culture <em>in vitro</em>: MS and MS + 0.5 mg L<sup>-1</sup> paclobutrazol (PBZ). In the second, effects of foliar application of GA<sub>3</sub>, PBZ and trinexapac ethyl (TNE) were evaluated. Both experiments were carried out in two accesions of <em>D. remotiflora</em> plants propagated <em>in vitro</em> and adapted to greenhouse conditions. <strong>Results:</strong> An increase in mini tubers yield and in their weight was observed when seedlings were propagated in MS + 0.5 mg L<sup>-1</sup> PBZ and GA<sub>3</sub> was applied to foliage. <strong>Implications:</strong> The use of growth retardants showed efficiency in developing mini tubers; nevertheless, more research focusing on concentrations and combinations of these substances is needed to improve the protocol to obtain planting material. <strong>Conclusions:</strong> The observed effect of growth retardants and gibberellic acid application in <em>Dioscorea remotiflora</em> plants suggests a favorable influence in the development of mini tubers. In the long term, this phenomenon could contribute significantly to promoting viability of its commercial cultivation and rehabilitation of previously exploited areas.</p>

Positive Effects of Growth Retardants on Castor (Ricinus communis L.)

The perennial growth habit of castor plants (Ricinus communis L.) limits mechanical harvest because the plant grows very tall, when the environmental conditions are favorable and produces green flush interfering with mechanical harvesting. In order to prevent excessive growth plant growth, retardant are applied to modifying crop architecture. Present investigation was designed to study the effect of growth retardants on growth and yield parameters. The experiment was conducted at the regional agricultural research station, Palem farm of Professor Jayashankar Telangana Agricultural University, Nagarkurnool district, Telangana, taking locally available tall variety PCH-111. The experiment was laid out in Randomized Block Design with three replicates in Kharif, 2019. Treatments comprises of water spray, ethrel@500 ppm, ethrel@1000 ppm, CCC@1.5ml/lit, CCC@2.0 ml/lit and CCC@2.5 ml/lit and sprayings were done at expanding leaf in the 6th node of the primary stem, expanding leaf on the 8th node of the primary stem, appearance of the first inflorescence, one expanding leaf in a secondary stem after the appearance of the first inflorescence, and appearance of the second inflorescence. Results revealed that, plant growth retardants are effective in reducing plant height, whereas no spray recorded significant superior value for plant height (70.73 cm). For leaf number, there is no much deviations though ethrel treatment enhanced senescence in older leaves, newly developed leaves compensated the number but there was reduction in LAI, which were 1.70 and 2.18, respectively, in ethrel spray of 1000 ppm and 500 ppm. The yield reduction is lower in ethrel treatment due to lower capsule formation and lower spike length at higher concentration of ethrel. Hence, it is concluded that, retardant accelerates natural senescence and thus, acting as defoliants overcoming difficulties in mechanical harvesting.

Assessing the Synergistic Effects of Deficit Irrigation and Growth Retardants on Insitu Sprouting and Quality Parameters of Groundnut VRI 8

Background: Groundnut is a crucial oilseed crop cultivated year-round, with seed dormancy controlled by genetic and environmental factors. Preventing pre-harvest sprouting is essential, as it is a common issue. To study the effect of deficit irrigation management and foliar application of growth retardant chemicals on pre-harvest sprouting control efficiency to achieve higher yield of groundnut. Methodology: In a field experiment conducted during early summer 2024 at the Agricultural College and Research Institute, Madurai, the effectiveness of different growth retardant chemicals and deficit irrigation management on reducing in-situ sprouting of groundnut kernels was investigated. The experiment included three irrigation management strategies: conventional irrigation and two deficit irrigation treatments where irrigation was withheld from 90 to 105 DAS (Days After Sowing) and 85 to 100 DAS. Additionally, foliar sprays of growth retardant chemicals were applied at 75 and 90 DAS. The chemicals tested were maleic hydrazide (MH) @ 1250 ppm, cycocel (CCC) @ 1000 ppm, abscisic acid (ABA) @ 750 ppm, and salicylic acid (SA) @ 750 ppm. Proper agronomic practices were followed throughout the crop growth cycle. Results: Among the growth retardant chemicals tested, MH @ 1250 ppm proved effective in inducing dormancy. Withdrawal of irrigation from 90 to 105 DAS also significantly contributed to dormancy induction, extending dormancy by more than 5 days post-harvest as well as reduced the pod loss which significantly increased pod yield. It was because of the reduction in soil moisture content during harvest stage and alteration in the hormonal activities. Specifically, the combined treatment of foliar application of MH @ 1250 ppm and no irrigation from 90 to 105 DAS reduced germination percentage by 12.6%, 36.8% and 60.5% immediately 5, 10 and 15 days after harvest respectively. Conclusion: The reduction in soil moisture content during the harvest stage, coupled with changes in hormonal activities, significantly impacts seed sprouting. These factors can lead to stress conditions that hinder germination, ultimately affecting crop yields. Addressing these issues is crucial for ensuring optimal seed development and enhancing agricultural productivity.

Synthesis and Processing Strategy for High-Bandgap PbS Quantum Dots: A Promising Candidate for Harvesting High-Energy Photons in Solar Cells.

The wide tunability of the energy bandgap of colloidal lead sulfide (PbS) quantum dots (QDs) has uniquely positioned them for the development of single junction and tandem solar cells. While there have been substantial advancements in moderate and narrow bandgap PbS QDs-ideal for single junction solar cells and the bottom cell in tandem solar cells, respectively; progress has been limited in high-bandgap PbS QDs that are ideally suited for the formation of the top cell in tandem solar cells. The development of appropriate high bandgap PbS QDs would be a major advancement toward realizing efficient all-QD tandem solar cells utilizing different sizes of PbS QDs. Here, we report a comprehensive approach encompassing synthetic strategy, ligand engineering, and hole transport layer (HTL) modification to implement high-bandgap PbS QDs into solar cell devices. We achieved a greater degree of size homogeneity in high-bandgap PbS QDs through the use of a growth retarding agent and a partial passivation strategy. By adjusting the ligand polarity, we successfully grow HTL over the QD film to fabricate solar cells. With the aid of an interface modifying layer, we incorporated an organic HTL for the realization of high-performance solar cells. These solar cells exhibited an impressive open-circuit voltage of 0.824 V and a power conversion efficiency of 10.7%, marking a 360% improvement over previous results.

Effects of different cycocel doses and irrigation levels on grain production, quality characteristics and water use in bread wheat

Cycocel (CCC) is a synthetic substance widely used as a growth retardant in grain crops. The importance of CCC is greater under different stress conditions. In this study, the effects of different CCC doses (D0 = 0, D1 = 750, D2 = 1500, and D3 = 2250 g ha−1) and different irrigation levels (I0 = 100% as control, I1 = 75%, I2 = 50%, and I3 = 25%) on some agro-morphological characteristics, yield and quality parameters, and crop water use characteristics in a semi-dwarf bread wheat variety were investigated. The internode length, number of grains, grain weight per spike, biological yield and grain yield values showed significant reductions, especially under I3, regardless of CCC applications. Grain yields varied between 2.31-6.14 and 2.28-4.43 kg ha−1 in 2019-2020 and 2020-2021, respectively. There was no significant difference in crop water consumption among different CCC doses under the same irrigation level. The effects of increasing water stress on the decrease in plant height were greater than that of increasing CCC application. Under I3 and increasing CCC applications, the spike length was significantly reduced. The protein content, sedimentation, wet gluten ratio, and gluten index values increased significantly, especially under I2 and I3. Plant yield response factors for both biological (0.85-0.90 in 2019-2020 and 0.74-0.99 in 2020-2021) and grain yields (0.77-0.90 in 2019-2020 and 0.77-0.1.12 in 2020-2021) varied between years depending on CCC applications and climatic conditions. The foliar CCC application for the purpose of increasing crop yield during drought season might not be recommendable.

The Effect of Growth Retardants on Reprodutive Efficiency and Yield of Groundnut (Arachis hypogaea L.)

A field experiment was carried out during Kharif, 2023 at dryland farm of S. V. Agricultural College, Tirupati campus of Acharya N. G. Ranga Agricultural University, Andhra Pradesh. The experiment was laid out in a split-plot design with three replications and two genotypes as main factor (G1- Dharani, G2- K-6), growth retardants as sub factor. The current experiment was conducted with an objective to study the impact of growth retardants on reduction of plant stature thereby enhancing the reproductive and assimilates partitioning efficiency along with yield. This article discusses various yield and reproductive efficiency related attributes of groundnut as influenced by growth retardants. The experimental results revealed that, the T5 (PBZ @ 250 ppm at 45 DAS) reported Maximum number of pegs per plant (58.50), number of pods per plant (28.89), shelling % (70.39) and harvest index (32.52 %). Among the two genotypes studied, G1 (Dharani) demonstrated more number of flowers (73), number of pegs per plant (50), number of pods per plant (26), shelling % (69) and harvest index (32 %).

Effect of photoperiod and chemical retardants on growth and flowering of pot mums (<i>Dendranthema grandiflora</i> Ramat)

Potted plants of chrysanthemum varieties namely Arun Kumar and Sweta Singar, were exposed to 8 h light and 16 h darkness and natural photoperiod, and spayed with maleic hydrazide (1000 and 2000 ppm), cycocel (1500 and 3000 ppm) and control (distilled water) in factorial complete block design with three replications. The results revealed that controlled photoperiod of 8 h light and 16 h darkness was found significantly superior over natural photoperiod with regard to minimum internodal length (2.85 cm), days to floral bud initiation (98.88), maximum flowering duration (23.14 days), flowers plant-1 (189.50), flower diameter (2.72 cm), fresh weight of flower (1.16 g) and vase life (14.86 days). Among growth retardants, maleic hydrazide (2000 ppm) significantly recorded minimum plant height, maximum branches plant-1 (18.85), flowering duration (25.25 days), flower diameter (2.95 cm), flowers per plant-1 (194.90) and weight of flower (1.20 g), while, maleic hydrazide (1000 ppm) recorded minimum internodal length (2.65 cm) and maximum vase life (18.00 days). The cv. Arun Kumar under controlled photoperiod recorded minimum internodal length (2.38 cm) and early floral bud initiation (91.04 days), however, maleic hydrazide (2000 ppm) recorded maximum flower diameter (4.05 cm), fresh weight of flower (1.53 g) and vase life (18.50 days). cv. Arun Kumar under controlled photoperiod treated with CCC-3000 ppm showed the best performance in recording the maximum number of flowers plants-1 (138.00) during first fortnight of flowering.

Studies on the Impact of Spacing, Pinching and Growth Retardants on Vegetative Growth and Flowering Behaviour of Salvia

The present investigation entitled “Studies on the impact of spacing, pinching and growth retardants on vegetative growth and flowering behaviour of Salvia” was conducted at College of Agriculture, Odisha University of Agriculture and Technology, Bhubaneswar, Odisha during December 2021 to April 2022. The experiment was laid out in a Factorial Randomized Block Design (FRBD) with three replications, comprising of 12 treatment combinations which includes the first factor spacing with two levels i.e., S1 (20 cm x 25 cm) and S2 (25 cm x 25 cm), second factor pinching with two levels i.e., P0 (no pinching) and P1 (pinching) and the third factor application of growth retardants with three levels i.e., G0 (control), G1 (CCC @500ppm) and G2 (MH @100ppm). The findings revealed that pinching and the application of growth retardants had a greater impact on critical flowering attributes than the spacing experimented with in this study. Treatment combination S2P1G1 i.e., T11 was proved to be better and yielded significant improvements. Based on the results it was concluded that pinching and application of CCC resulted in better growth and development in salvia regarding vegetative and flowering characters. Thus, the treatment combination S2P1G1 i.e., T11 was found to be superior for vegetative growth characters like plant height, the number of branches, the number of leaves and flowering characters like the number of flower spikes per plant, length of flower spike, and length of florets.

Plant Growth Regulator from the Essential Oil of Syzygium aromaticum L. for Inhibition of Secondary Growth of Garlic Cultivated under Tropical Conditions

Garlic cultivation in tropical regions, such as the Brazilian Cerrado, faces the problem of secondary growth in the field induced by climatic conditions, which affects bulb quality and value. Clove essential oil (CEO) contains high levels of eugenol, which has the potential as an eco-friendly plant growth retardant (PGR) capable of reducing or inhibiting the secondary growth of bulbs in garlic cultivation. In this study, field experiments were carried out in two consecutive years (winter 2021 and 2022), spraying garlic plants with different concentrations of emulsion of CEO (0.0, 0.2, and 0.4%) in the differentiation phase; for comparison, the effects of water deficit, a prevalent agricultural technique in the region, were also evaluated. At a dose of 0.4%, the CEO reduced the prevalence of secondary growth and split bulbs without affecting yield. The mode of action of PGR was investigated by analyzing photosynthetic, enzymatic, and metabolomic parameters. The plants reduced amylolytic activity, and the photosynthetic parameters, after 7 days, were restored in both treatments. The analysis of the metabolomic profile of garlic leaves revealed changes in the pathways associated with the biosynthesis of fatty acids, wax, cutin, and suberin in plants treated with CEO, indicating possible damage to the surface coating of the leaf.

Flower Forcing: A Review

In the modern floricultural industry, scheduling plant production is essential due to fluctuating market demands. Flower forcing, which stimulates flowering at specific dates or during off-season periods, is a key technique employed. The manipulated flowering dates resulting from flower forcing may deviate from the plant's natural schedule, occurring either earlier or later than the standard flowering dates. This can be achieved by adjusting factors affecting flowering such as temperature, photoperiod, and irradiance etc. Implementation of special practices like pruning, leaf trimming, dormancy breaking helps in forcing operation in certain plants. Utilization of chemicals such as plant hormones like gibberellin and ethylene, growth retardants and some fertilizers also play an important role in forcing. Employing mechanical methods can be considered as a sustainable and environment friendly practice. Advancements in plant physiology, photomorphogenesis, metabolism, and greenhouse technologies have led to the development of multiple strategies to finely regulate the rate of plant growth and development across various crops.

Effect of Growth Retardants on Plant Yield and Seed Quality of Groundnut (Arachis hypogaea L.)

A field experiment was carried out during Kharif, 2023 at dryland farm of S. V. Agricultural College, Tirupati campus of Acharya N. G. Ranga Agricultural University, Andhra Pradesh. The experiment was laid out in a split-plot design with three replications and two Genotypes as main factor (G1- Dharani, G2- K-6), growth retardants as sub factor (T1- Control + RDF of NPK, T2- MH @ 2000 ppm at 20 DAS, T3- MH @ 2000 ppm at 45 DAS, T4- PBZ @ 250 ppm at 20 DAS, T5- PBZ @ 250 ppm at 45 DAS , T6- ABA @ 250 ppm at 20 DAS, T7- ABA @ 250 ppm at 45 DAS, T8- ABA @ 500 ppm at 20 DAS, T9- ABA @ 500 ppm at 45 DAS, T10- CCC @ 5000 ppm at 20 DAS, T11- CCC @ 5000 ppm at 45 DAS). The current experiment was conducted with an objective to study the impact of growth retardants on reduction of plant stature thereby enhancing the reproductive and assimilates partitioning efficiency. Results revealed that application of T5- PBZ @ 250 ppm at 45 DAS recorded higher Pod yield, Kernel yield, 100 kernel weight, protein content and oil content.

Gibberellin Positively Regulates Tomato Resistance to Tomato Yellow Leaf Curl Virus (TYLCV).

Tomato yellow leaf curl virus (TYLCV) is a prominent viral pathogen that adversely affects tomato plants. Effective strategies for mitigating the impact of TYLCV include isolating tomato plants from the whitefly, which is the vector of the virus, and utilizing transgenic lines that are resistant to the virus. In our preliminary investigations, we observed that the use of growth retardants increased the rate of TYLCV infection and intensified the damage to the tomato plants, suggesting a potential involvement of gibberellic acid (GA) in the conferring of resistance to TYLCV. In this study, we employed an infectious clone of TYLCV to inoculate tomato plants, which resulted in leaf curling and growth inhibition. Remarkably, this inoculation also led to the accumulation of GA3 and several other phytohormones. Subsequent treatment with GA3 effectively alleviated the TYLCV-induced leaf curling and growth inhibition, reduced TYLCV abundance in the leaves, enhanced the activity of antioxidant enzymes, and lowered the reactive oxygen species (ROS) levels in the leaves. Conversely, the treatment with PP333 exacerbated TYLCV-induced leaf curling and growth suppression, increased TYLCV abundance, decreased antioxidant enzyme activity, and elevated ROS levels in the leaves. The analysis of the gene expression profiles revealed that GA3 up-regulated the genes associated with disease resistance, such as WRKYs, NACs, MYBs, Cyt P450s, and ERFs, while it down-regulated the DELLA protein, a key agent in GA signaling. In contrast, PP333 induced gene expression changes that were the opposite of those caused by the GA3 treatment. These findings suggest that GA plays an essential role in the tomato's defense response against TYLCV and acts as a positive regulator of ROS scavenging and the expression of resistance-related genes.

Exogenous application of bio-stimulants and growth retardants improve nutrient absorption and fiber quality in upland cotton

BackgroundNatural and synthetic plant growth regulators are essential for plant health, likewise these regulators also play a role in increasing organic production productivity and improving quality and yield stability. In the present study, we have evaluated the effects of foliar applied plant growth regulators, i.e., moringa leaf extract (MLE) and mepiquat chloride (MC) alone and in combination MC and MLE on the conventional cotton cultivar (CIM 573) and transgenic one (CIM 598). The growth regulators were applied at the start of bloom, 45 and 90 days after blooming.ResultsThe application of MC and MLE at 90 days after blooming significantly improved the relative growth rate, net assimilation rate, the number of bolls per plant, and seed cotton yield. Likewise, the combined application of MLE and MC at 90 days after blooming significantly boosted the nitrogen uptake in locules, as well as the phosphorus and potassium uptake in the leaves of both cotton cultivars. The application of MLE alone has considerably improved the nitrogen uptake in leaves, and phosphorus and potassium contents in locules of Bt and conventional cotton cultivars. Similarly, Bt cotton treated with MLE at 90 days after blooming produced significantly higher ginning out turn and oil contents. Treatment in combination (MLE + MC) at 90 days after blooming produced considerably higher micronaire value, fiber strength, and staple length in conventional cultivar.ConclusionThe natural growth enhancer, MLE is a rich source of minerals and zeatin, improving the nutrient absorption and quality of cotton fiber in both conventional and Bt cotton cultivars.

Paclobutrazol Residues in Recirculated Water in Commercial Greenhouses

Reusing irrigation water has technical, environmental, and financial benefits. However, risks are also associated with the accumulation of agrochemicals, in addition to ions, plant and food safety pathogens, and biofilm organisms. In this project, we measured the concentration of paclobutrazol (a persistent and widely used plant growth regulator) in recirculated water in greenhouses producing ornamental plants in containers. Solutions were collected from catchment tanks at nine commercial greenhouses across seven states in the United States in Spring and Fall 2014. Paclobutrazol was detected in all samples, with differences observed by season, greenhouse operation, paclobutrazol application method, and irrigation method. Across operations, the residual concentration of paclobutrazol was higher in spring for most greenhouses (ranging from 0 to 1100 µg·L−1) compared with the fall (ranging from 0 to 8 µg·L−1). The spray-drench application method resulted in the highest residual concentrations (up to 35 µg·L−1), followed by substrate drench (up to 26 µg·L−1) and foliage spray (concentrations under 3 µg·L−1). Residual concentrations were higher with overhead irrigation (up to 35 µg·L−1) compared with subirrigation systems (up to 15 µg·L−1). Our results indicate that paclobutrazol is likely to be a growth retardant risk in greenhouse operations recirculating water. A clear understanding of the risks associated with recirculated water intends to support the development and implementation of risk management strategies to ensure and promote safe use of recirculated water in greenhouses. Overall, the most effective preventative strategy is to ensure the use of the minimum amount of the a.i. necessary per unit of space and time.

Effect of Foliar Spraying with the Growth Inhibitor Paclobutrazol on the Quality of Chandler Strawberry (Fragaria ananassa) under Punjab Subtropics

The field experiment conducted during the Rabi season of 2022 aimed to investigate the impact of foliar spray with the growth retardant paclobutrazol at various timings on the strawberry cultivar Chandler (Fragaria ananassa Duch). The experimental design employed a Randomized Block Design (RBD) with eight treatments, each replicated three times. Paclobutrazol was administered at different intervals, specifically at 110, 115, 120, 125, 130, 135, and 140 days after planting, along with a control group receiving no spray. The results demonstrated a significant influence of Paclobutrazol spray timing on the quality parameters. Among the different treatments with the plant growth retardant, Treatment 4 (PBZ 250 ppm at 125 days after planting) exhibited the highest values for fruit length (31.40 mm), fruit width (25.70 mm), fruit thickness (1.79 mm), fruit weight (12.03 g), Total Soluble Solids (TSS) (9.50°Brix), Firmness (1.92 N) and Titrable Acidity (2.56%) whereas lowest values observed in the control.

Tree Canopy Architecture and Engineering: Physiological and Molecular Aspects

The fruit industry is a vital part of the agricultural economy, and the quality and quantity of crops depend heavily on the science of tree canopy architecture and engineering. The canopy is the most important part of a fruit tree as it affects photosynthesis, fruit quality, and yield. The study of canopy architecture and engineering increased in importance due to the need for efficient agricultural practices that optimize fruit production while reducing the environmental impact. Factors that influence canopy architecture, such as light, water, and nutrient availability, genetic makeup of the plants, hormones, management practices and innovative engineering techniques can optimize orchard management. Canopy can managed by the using different types of pruning (Proper pruning can enhance light penetration, airflow, and disease management, ultimately leading to higher yields and healthier fruits), thinning, by using dwarfing rootstocks and training (such as central leader system, modified central leader system and open Centre system etc.) and also by using the growth retardant & regulators and through gene regulation for higher yield as well as quality improvement.

Intercropping in maize silage versus solo‐seeding for alfalfa establishment in Wisconsin and Idaho

AbstractAlfalfa (Medicago sativa L.) intercropping with maize (Zea mays L.) silage is being developed in the northern United States to improve the profitability and environmental sustainability of forage production. This study, conducted under rainfed conditions in Wisconsin and semiarid irrigated conditions in Idaho, compared the establishment of alfalfa and dry matter yield of four intercropping systems to three conventional systems. The former systems included alfalfa interseeded at planting or the vegetative emergence (VE) stage of maize and grown with or without prohexadione growth retardant. The latter systems included alfalfa seeded in spring, summer‐seeded after barley (Hordeum vulgare L.), or late summer‐seeded after maize silage. Spring seeded and interseeded alfalfa in Wisconsin also received foliar fungicide and insecticide during establishment. During alfalfa establishment, yield of intercropped maize silage was 1.8‐ to 4.4‐fold greater than spring‐seeded alfalfa. Compared to spring‐seeded alfalfa, interseeded alfalfa had similar or somewhat lower stand density but similar first cut yield the following year, provided that intercropped maize was harvested near September 1 to allow ample alfalfa fall regrowth. Shifting interseeding from maize planting to the VE stage decreased early‐season alfalfa growth, but improved maize silage yield, with minor effects on alfalfa fall growth, stand density, and first cut yield. Prohexadione application had little impact on establishment or yield of interseeded alfalfa. While having high plant density, alfalfa seeded after barley or especially maize had less fall growth and low first cut yield. Overall, alfalfa establishment and yield of intercropping systems compared favorably with conventional systems.

TLC-Bioautography-Guided Isolation and Assessment of Antibacterial Compounds from Manuka (Leptospermum scoparium) Leaf and Branch Extracts.

A rapid procedure for the targeted isolation of antibacterial compounds from Manuka (Leptospermum scoparium) leaf and branch extracts was described in this paper. Antibacterial compounds from three different Manuka samples collected from New Zealand and China were compared. The active compounds were targeted by TLC-bioautography against S. aureus and were identified by HR-ESI-MS, and -MS/MS analysis in conjunction with Compound Discoverer 3.3. The major antibacterial component, grandiflorone, was identified, along with 20 β-triketones, flavonoids, and phloroglucinol derivatives. To verify the software identification, grandiflorone underwent purification via column chromatography, and its structure was elucidated through NMR analysis, ultimately confirming its identity as grandiflorone. This study successfully demonstrated that the leaves and branches remaining after Manuka essential oil distillation serve as excellent source for extracting grandiflorone. Additionally, we proposed an improved TLC-bioautography protocol for evaluating the antibacterial efficacy on solid surfaces, which is suitable for both S. aureus and E. coli. The minimum effective dose (MED) of grandiflorone was observed to be 0.29-0.59 μg/cm2 against S. aureus and 2.34-4.68 μg/cm2 against E. coli, respectively. Furthermore, the synthetic plant growth retardant, paclobutrazol, was isolated from the samples obtained in China. It is hypothesized that this compound may disrupt the synthesis pathway of triketones, consequently diminishing the antibacterial efficacy of Chinese Manuka extract in comparison to that of New Zealand.

Assessing the Effect of Plant Growth Stimulants and Retardants on Cyclamen “Halios F1 Salmon Rose” Cultivar

In Eastern Europe, the traditional marketing of cyclamen is in the period from the middle of February to the middle of March. The poor light of winter months and the higher number of plants (because of the reduction in heating costs) often result in elongated plants. To avoid this, it is recommended to use plant growth retardants. At the same time, another problem is that flowers do not rise from the level of rosette due to the unfavorable cultivation conditions. This can be solved with growth stimulants. In the experiment, we tested the effect of growth regulators on the growth of a frequently used variety of cyclamen. We used daminozide and paclobutrazol plant growth retardants for height control and gibberellic acid (GA) and benzyladenine (BAP) as growth promoters for increasing the number of flowers and the length of stems. The results show that daminozide and paclobutrazol are both effective for height control in cyclamen production.

Agribusiness Small and Medium Entrepreneurs’ Overall Perceptions of Institutional Support Towards Facing Technology Challenges: A Case of Sri Lanka

Purpose: Technology challenges have been recognized as one of the growth retarding factors of Small and Medium Enterprises (SMEs), which further reduced their potential contribution to the national economy. Hence, this research aims to study the Sri Lankan agribusiness SMEs’ overall perception of institutional support towards facing technology challenges.Research Method: A qualitative case study-based methodology was adopted, and a series of key informant interviews were held with 10 SME owners in the Agribusiness sector, using purposive sampling. An in-depth thematic area analysis was used to analyze the data gathered from the interviews and identified five technology challenges faced by SMEs. Findings: SMEs repeatedly stated weak financial base, lack of technical know-how, lack of institutional support, and practical problems that arose when commercializing new products. Many respondents showed a low tendency towards adopting E-Commerce/M-Commerce/E-Marketing and database management systems. The study revealed that they had built network partnerships with other SMEs in the industry on their own. Most SMEs are currently facing difficulties in connecting with Multi-National Companies (MNCs)/ Trans-National Companies (TNCs)/ Large-scale companies. According to the SMEs' overall perception of institutional support, many had low satisfaction in most of the areas. Value: This study is important for the government institutions and relevant policymakers to identify the requirements of SMEs, and thereby, organize customized supportive programs to overcome technology challenges.