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The propagation of citrus seedlings is accomplished through grafting, utilizing seeds for the production of rootstocks. The germination of certain seeds may be low and uneven, complicating the production of high-quality seedlings. The use of plant growth regulators (PGRs) is a viable alternative to improve the quality of seedling production, as these compounds can break dormancy, control the hydrolysis of reserves, induce cell division, and regulate permeability and protein functions. This study aimed to evaluate the germination of seeds and the growth of Rangpur lime (Citrus limonia L. Osbeck) seedlings under the influence of imbibition in solutions of gibberellic acid (GA3) and a combination of GA4+7 + 6Benzyladenine. The experiment was conducted under controlled laboratory and greenhouse conditions, using a completely randomized design in a 2 × 5 factorial scheme, with two types of plant regulators (GA3 and GA4+7 + 6BA) at five concentrations (0, 250, 500, 750, and 1000 mg L−1 a.i.). Quantitative and qualitative variables were evaluated, ranging from seed germination to seedling development and formation, including germination percentage and speed index, fresh and dry biomass of roots and shoots, enzymatic activity, and gas exchange. The results indicate that GA3 significantly accelerates the germination process of Rangpur lime cv. Santa Cruz seeds and promotes better seedling growth and development, resulting in vigorous seedlings. These findings demonstrate that the application of PGRs, particularly GA3, can substantially enhance the propagation efficiency of citrus rootstocks, offering a practical solution for improving the uniformity and quality of seedling production in commercial settings. [ABSTRACT FROM AUTHOR]

Water deficit (WD) promotes great losses in agriculture, and the development of new sustainable technologies to mitigate the effects of this stress on plants is essential. This study aimed to evaluate the morphophysiological and biochemical alterations induced by the priming of tomato seeds with different formulations in plants under field capacity and WD conditions. In the first experiment, the treatments consisted of nanoparticles of alginate/chitosan and chitosan/tripolyphosphate containing gibberellic acid (GA3) in different concentrations (0.5, 5, and 50 µg mL−1 GA3), in addition to control with deionized water. The alginate/chitosan (5 µg mL−1 GA3) provided the greatest gains in plant growth under field capacity. In addition, under WD this treatment reduced damage to photosystem II (−14%), stomatal conductance (−13%), and water loss (−38%) and increased the instantaneous carboxylation efficiency (+24%) and intrinsic water use efficiency (+12%). In the second experiment, the treatments were alginate/chitosan nanoparticles containing GA3 (NPGA3 5 µg mL−1), free GA3 (GA3 5 µg mL−1), nanoparticles without GA3 (NP), deionized water (WATER), and non-primed seeds (CONT). Under WD, GA3 and CONT maintained plant growth and lost water rapidly, reducing stomatal conductance (−87%) and net photosynthesis (−69%). In contrast, NPGA3 decreased leaf area (−44%) and increased root-to-shoot ratio (+39%) when compared to GA3, reducing water loss (−28%). Activation of protective mechanisms (e.g., superoxide dismutase and catalase activities) by WATER, NPGA3, and NP treatments also resulted in lower susceptibility to WD compared to CONT and GA3. The results highlight the positive effect of seed priming on plant response to WD, which was enhanced by the use of nanoencapsulated GA3. [ABSTRACT FROM AUTHOR]

The nutritional value of blue honeysuckle (Lonicera caerulea L.) fruit is abundant; however, its production faces challenges due to a short harvesting period and fruit drop issues. In this study, the effects and potential mechanisms of two different plant growth regulators, GA3 (Gibberellins acid) and 2,4-D (2,4-Dichlorophenoxyacetic acid), on blue honeysuckle fruit abscission and abscission layer formation were investigated. The main cultivated variety of blue honeysuckle, 'Berel', was used as the experimental material. GA3 and 2,4-D were sprayed on the plants from the veraison. The anatomical structure of the fruit abscission zone (FAZ) was observed after treatment. Key enzymes involved in cell wall degradation, pectinase, cellulase, polygalacturonase, and pectin methylesterase, were analyzed for their activities. Furthermore, the gene expression levels of cell wall detachment-related genes CX1, CX2, PL20, PE, and key genes for gibberellin and ethylene synthesis GA2OX1, GA1, ACO, and ACO3 were examined. The results indicated that the application of GA3 and 2,4-D could delay the formation of the abscission layer. In the FAZ treated with GA3 and 2,4-D at 5 DAT, the activity of key enzymes involved in cell wall degradation decreased, the expression of genes related to cell wall degradation enzymes and key genes for ethylene synthesis was inhibited, and the drop of fruit reduced. In conclusion, exogenous application of GA3 and 2,4-D suppresses the abscission of 'Berel' blue honeysuckle fruit, likely through the inhibition of cell wall degradation and abscission layer formation. [ABSTRACT FROM AUTHOR]

This study aims to predict the behavior of different tomato rootstocks under drought stress conditions. SCoT and CDDP analyses were employed to characterize the genetic relatedness among a commercial drought-sensitive tomato hybrid (cv. Bark) and four wild tomato accessions (LA2711, LA1995, LA3845, and LA4285) known for their tolerance to adverse conditions. The Bark plants were grafted onto the aforementioned wild accessions and self-grafted as control, and then the behavior of all graft unions was followed under normal and drought stress conditions. Our results showed a general genotype-dependent better growth and yield of heterografts than autografts under all growth conditions. Furthermore, clustering analysis based on growth, yield quantity and quality traits, and the leaf content of minerals, ABA, GA3, and proline, in addition to the activity of APX, POD, and DHAR reflected the same grouping pattern of the studied rootstocks exhibited by SCoT and CDDP. The identical grouping pattern supports the utilization of SCoT and CDDP as a robust screening tool helpful to predict the physiological and agronomical behavior of grafting on different tomato rootstocks. Furthermore, grafting could be a cost-efficient alternative method to improve drought tolerance in sensitive tomato genotypes.

This study was conducted to assess the influence of gibberellic acid (GA3) on the content of biologically active substances in Crocosmia × crocosmiiflora ‘Lucifer’ tubers. These tubers are a promising source of potential antioxidants, and their extracts can be used in pharmaceutical industry, as well as in cosmetics products and antifungal and antibacterial substances. Four groups of biologically active substances were determined from tubers: saponins, phenolic acid, flavonoids and carotenoids. The antioxidant activity of the extracts from tubers increased proportionally to the GA3 concentrations. GA3 at concentrations of 200, 400 and 600 mg dm−3 increased the content of medicagenic acid by 42.9–57.1% and the content of polygalic acid by 50% without affecting the content of medicagenic acid 3-O-triglucoside. The GA3 concentrations used in the experiment positively influenced the accumulation of caffeic acid, p-coumaric acid and gallic acid. The highest content of caffeic acid was noted in the tubers soaked in GA3 concentrated at 400 and 600 mg dm−3. GA3 at a concentration used in the study stimulated the accumulation of kaempferol by 15%, quercetin by 7–8.2%, quercetin 3-O-glucoside by 1.8% (when GA3 was applied at a concentration of 200 mg·dm−3) and by 4.1% and 3.6% (when GA3 was applied at concentrations of 400 and 600 mg·dm−3) and kaempferol 3-O-rhamnosylglucoside by 1.5–3.4%. The soaking of the tubers in GA3 increased the content of β-carotene by 7.9%, 5.2% and 7.9%, respectively, without affecting the content of crocin. For soaking of Crocosmia tubers, it is recommended to use GA3 at a concentration of 400–600 mg·dm−3.

This study was conducted to assess the influence of gibberellic acid (GA3) and arbuscular mycorrhizal fungi (AMF) on the flowering and quality of Zantedeschia albomaculata (Hook.) Baill ‘Albomaculata’ plants. Before planting, the rhizomes were soaked in water or an aqueous solution of GA3 at a concentration of 150 mg dm−3 for 30 min. A mixture of AMF was applied to the rhizomes a week after planting. The AMF treatment increased the yield of inflorescences of the ‘Albomaculata’ cultivar by 100%. AMF and GA3 had a favourable effect on the quality of inflorescences, expressed by the length of peduncles, whereas AMF individually positively affected the length of the spathes. AMF and GA3 had no effect on the level of macroelements in calla lily leaves, with the exception of calcium (Ca). The leaves of mycorrhized plants had a high content of sodium (Na) and micronutrients, except for iron (Fe). The results of the study showed that GA3 could be replaced by mycorrhizal inoculation when applied to Zantedeschia plants.

×Amarine hybrids are attractive ornamental geophytes grown for cut flower production. Their cultivation is limited due to lesser flowering percentages and lesser bulb weight gain. To optimize the growth and propagation of geophytes, plant growth regulators (PGRs) are used, but so far none have been tested in ×Amarine. We investigated the effect of gibberellic acid (GA3; 50, 100, and 200 mg dm−3) and methyl jasmonate (MeJA; 100, 500, and 1000 µmol dm−3) on growth, flowering, bulb yield, and select physiological parameters of ×A. tubergenii “Zwanenburg”. PGRs were applied as foliar sprays on the 70th and 77th day after planting. GA3 treatment at 200 mg dm−3 exhibited the greatest leaf number, leaf length, bulb weight, daughter bulb number, CO2 assimilation intensity, greenness index, total sugars, and total protein content in bulbs. GA3 application at 100 and 200 mg dm−3 accelerated flowering and at 50 and 100 mg dm−3 significantly increased the bulb flowering percentage. MeJA at all tested concentrations prolonged anthesis time and reduced the bulb flowering percentage. GA3 at all concentrations and MeJA at 500 and 1000 µmol dm−3 stimulated daughter bulbs formation. GA3, especially at 200 mg dm−3 can improve anthesis and increase ×A. tubergenii “Zwanenburg” bulb yield.

Hydroponics need water of good quality to prepare a balanced nutrient solution that could allow plants to reach their maximum yield potential. The rising difficulties in finding water with good quality have led to the compelling necessity of identifying sustainable ways to use saline water, limiting its negative effect on crop yield and quality. The exogenous supplementation of plant growth regulators, such as gibberellic acid (GA3), can be effective in increasing plant growth and vigor, thus helping plants to better cope with salt stress. The aim of this study was to evaluate the feasibility to increase the salt tolerance of leaf lettuce and rocket grown in a floating system by adding GA3 (10−6 M) to mineral nutrient solutions (MNS) with increasing salinity (0, 10, and 20 mM NaCl). Leaf lettuce and rocket plants suffered a significant reduction of growth and yield, determined by the reduction of biomass, leaf number, and leaf area, even with moderate salt stress (10 mM NaCl). The supplementation of exogenous GA3 through the MNS allowed plants to substantially counterbalance salt stress by enhancing various morphological and physiological traits, such as biomass accumulation, leaf expansion, stomatal conductance and water and nitrogen use efficiency. The effects of salt stress and GA3 treatment varied according to the species, thus indicating that this interaction may improve salt tolerance by activating different adaptation systems.

Gibberellins (GAs) are growth hormones strongly involved in a wide variety of physiological activities. Currently, gibberellins are commercially used to enhance phenotypic characteristics, earliness, and productivity of many vegetable and ornamental crops. In this work, the efficacy of supplementation of low levels of gibberellic acid (0, 10−8, 10−6, and 10−4 M GA3) through the mineral nutrient solution of a floating system on yield and quality of leaf lettuce and rocket plants was tested. The marketability of plants was lost when 10−4 M GA3 was added to the mineral nutrient solution. This study demonstrated that the addition of 10−4 M GA3 exceeded the acceptable threshold for use in hydroponics production systems. Below the concentration of 10−4 M, the presence of GA3 in the mineral nutrient solutions (MNS), especially at 10−6 M GA3, stimulated plant growth and enhanced the yield. Various morphological and physiological traits were enhanced by GA3 treatments (biomass accumulation, leaf expansion, stomatal conductance, water use efficiency (WUE), Nitrogen use efficiency (NUE), etc.), with superimposable trends in both lettuce and rocket. The addition of 10−6 M GA3 to the nutrient solution of a hydroponic floating system can promote growth and quality of lettuce and rocket plants.

This study aims to predict the behavior of different tomato rootstocks under drought stress conditions. SCoT and CDDP analyses were employed to characterize the genetic relatedness among a commercial drought-sensitive tomato hybrid (cv. Bark) and four wild tomato accessions (LA2711, LA1995, LA3845, and LA4285) known for their tolerance to adverse conditions. The Bark plants were grafted onto the aforementioned wild accessions and self-grafted as control, and then the behavior of all graft unions was followed under normal and drought stress conditions. Our results showed a general genotype-dependent better growth and yield of heterografts than autografts under all growth conditions. Furthermore, clustering analysis based on growth, yield quantity and quality traits, and the leaf content of minerals, ABA, GA3, and proline, in addition to the activity of APX, POD, and DHAR reflected the same grouping pattern of the studied rootstocks exhibited by SCoT and CDDP. The identical grouping pattern supports the utilization of SCoT and CDDP as a robust screening tool helpful to predict the physiological and agronomical behavior of grafting on different tomato rootstocks. Furthermore, grafting could be a cost-efficient alternative method to improve drought tolerance in sensitive tomato genotypes. [ABSTRACT FROM AUTHOR]

This study was conducted to assess the influence of gibberellic acid (GA3) and arbuscular mycorrhizal fungi (AMF) on the flowering and quality of Zantedeschia albomaculata (Hook.) Baill 'Albomaculata' plants. Before planting, the rhizomes were soaked in water or an aqueous solution of GA3 at a concentration of 150 mg dm−3 for 30 min. A mixture of AMF was applied to the rhizomes a week after planting. The AMF treatment increased the yield of inflorescences of the 'Albomaculata' cultivar by 100%. AMF and GA3 had a favourable effect on the quality of inflorescences, expressed by the length of peduncles, whereas AMF individually positively affected the length of the spathes. AMF and GA3 had no effect on the level of macroelements in calla lily leaves, with the exception of calcium (Ca). The leaves of mycorrhized plants had a high content of sodium (Na) and micronutrients, except for iron (Fe). The results of the study showed that GA3 could be replaced by mycorrhizal inoculation when applied to Zantedeschia plants. [ABSTRACT FROM AUTHOR]

This study was conducted to assess the influence of gibberellic acid (GA3) on the content of biologically active substances in Crocosmia × crocosmiiflora 'Lucifer' tubers. These tubers are a promising source of potential antioxidants, and their extracts can be used in pharmaceutical industry, as well as in cosmetics products and antifungal and antibacterial substances. Four groups of biologically active substances were determined from tubers: saponins, phenolic acid, flavonoids and carotenoids. The antioxidant activity of the extracts from tubers increased proportionally to the GA3 concentrations. GA3 at concentrations of 200, 400 and 600 mg dm−3 increased the content of medicagenic acid by 42.9–57.1% and the content of polygalic acid by 50% without affecting the content of medicagenic acid 3-O-triglucoside. The GA3 concentrations used in the experiment positively influenced the accumulation of caffeic acid, p-coumaric acid and gallic acid. The highest content of caffeic acid was noted in the tubers soaked in GA3 concentrated at 400 and 600 mg dm−3. GA3 at a concentration used in the study stimulated the accumulation of kaempferol by 15%, quercetin by 7–8.2%, quercetin 3-O-glucoside by 1.8% (when GA3 was applied at a concentration of 200 mg·dm−3) and by 4.1% and 3.6% (when GA3 was applied at concentrations of 400 and 600 mg·dm−3) and kaempferol 3-O-rhamnosylglucoside by 1.5–3.4%. The soaking of the tubers in GA3 increased the content of β-carotene by 7.9%, 5.2% and 7.9%, respectively, without affecting the content of crocin. For soaking of Crocosmia tubers, it is recommended to use GA3 at a concentration of 400–600 mg·dm−3. [ABSTRACT FROM AUTHOR]

×Amarine hybrids are attractive ornamental geophytes grown for cut flower production. Their cultivation is limited due to lesser flowering percentages and lesser bulb weight gain. To optimize the growth and propagation of geophytes, plant growth regulators (PGRs) are used, but so far none have been tested in ×Amarine. We investigated the effect of gibberellic acid (GA3; 50, 100, and 200 mg dm−3) and methyl jasmonate (MeJA; 100, 500, and 1000 µmol dm−3) on growth, flowering, bulb yield, and select physiological parameters of ×A. tubergenii "Zwanenburg". PGRs were applied as foliar sprays on the 70th and 77th day after planting. GA3 treatment at 200 mg dm−3 exhibited the greatest leaf number, leaf length, bulb weight, daughter bulb number, CO2 assimilation intensity, greenness index, total sugars, and total protein content in bulbs. GA3 application at 100 and 200 mg dm−3 accelerated flowering and at 50 and 100 mg dm−3 significantly increased the bulb flowering percentage. MeJA at all tested concentrations prolonged anthesis time and reduced the bulb flowering percentage. GA3 at all concentrations and MeJA at 500 and 1000 µmol dm−3 stimulated daughter bulbs formation. GA3, especially at 200 mg dm−3 can improve anthesis and increase ×A. tubergenii "Zwanenburg" bulb yield. [ABSTRACT FROM AUTHOR]

Hydroponics need water of good quality to prepare a balanced nutrient solution that could allow plants to reach their maximum yield potential. The rising difficulties in finding water with good quality have led to the compelling necessity of identifying sustainable ways to use saline water, limiting its negative effect on crop yield and quality. The exogenous supplementation of plant growth regulators, such as gibberellic acid (GA3), can be effective in increasing plant growth and vigor, thus helping plants to better cope with salt stress. The aim of this study was to evaluate the feasibility to increase the salt tolerance of leaf lettuce and rocket grown in a floating system by adding GA3 (10−6 M) to mineral nutrient solutions (MNS) with increasing salinity (0, 10, and 20 mM NaCl). Leaf lettuce and rocket plants suffered a significant reduction of growth and yield, determined by the reduction of biomass, leaf number, and leaf area, even with moderate salt stress (10 mM NaCl). The supplementation of exogenous GA3 through the MNS allowed plants to substantially counterbalance salt stress by enhancing various morphological and physiological traits, such as biomass accumulation, leaf expansion, stomatal conductance and water and nitrogen use efficiency. The effects of salt stress and GA3 treatment varied according to the species, thus indicating that this interaction may improve salt tolerance by activating different adaptation systems. [ABSTRACT FROM AUTHOR]

Gibberellins (GAs) are growth hormones strongly involved in a wide variety of physiological activities. Currently, gibberellins are commercially used to enhance phenotypic characteristics, earliness, and productivity of many vegetable and ornamental crops. In this work, the efficacy of supplementation of low levels of gibberellic acid (0, 10−8, 10−6, and 10−4 M GA3) through the mineral nutrient solution of a floating system on yield and quality of leaf lettuce and rocket plants was tested. The marketability of plants was lost when 10−4 M GA3 was added to the mineral nutrient solution. This study demonstrated that the addition of 10−4 M GA3 exceeded the acceptable threshold for use in hydroponics production systems. Below the concentration of 10−4 M, the presence of GA3 in the mineral nutrient solutions (MNS), especially at 10−6 M GA3, stimulated plant growth and enhanced the yield. Various morphological and physiological traits were enhanced by GA3 treatments (biomass accumulation, leaf expansion, stomatal conductance, water use efficiency (WUE), Nitrogen use efficiency (NUE), etc.), with superimposable trends in both lettuce and rocket. The addition of 10−6 M GA3 to the nutrient solution of a hydroponic floating system can promote growth and quality of lettuce and rocket plants. [ABSTRACT FROM AUTHOR]