Exogenous Application Of Gibberellic Acid Research Articles

Exogenous application of gibberellic acid and silicon to promote salinity tolerance in pea (Pisum sativum L.) through Na+ exclusion

Salinity is a worldwide problem limiting the plant growth and risking food security. This study was conducted to examine exogenous application of silicon (Si), gibberellic acid (GA3) upon the ion transport, growth, yield, and antioxidant enzymes activities of pea plant in saline conditions. Two pea varieties Meteor-FSD and Samrina Zard were pre-treated with GA3 (10-4 M) for 12 h. Plants were allowed to grow with or without silicon in washed silica sand. Ten days old seedlings were shifted in pots with 10 kg soil. Twenty-five days old plants were exposed to 0 and 5 dS m−1 sodium stress. Results showed that exogenous application of GA3 + Si was the best treatment for increasing plant biomass and yield in the presence and absence of NaCl. Furthermore, application of Si or GA3 enhanced chlorophyll content in the leaves, thereby increasing the net assimilation rate of pea varieties under NaCl stress by increasing the antioxidant enzyme activity. Treatment of Si alone or in combination with GA3 significantly reduced Na+ movement in both pea varieties. Results showed that Si has more prominent role than GA3 alone to build-up high plant biomass, yield, soluble protein content and reduction of Na+ transport. Samrina Zard variety showed higher yield, shoot and root dry weight as compared to Meteor-FSD variety in presence and absence of salt. It was concluded that Si can be used as a nutrient for pea under saline or non-saline conditions. Moreover, application of GA3 has a potential role for increasing salinity tolerance, mostly in sensitive pea varieties.

Exogenous Application of Gibberellic Acid on Lateral Bud Development in Pineapple Propagated through Stem Cuttings

Exogenous Application of Gibberellic Acid on Lateral Bud Development in Pineapple Propagated through Stem Cuttings

Exogenous application of gibberellic acid and selenium to endorse quality and yield of fodder maize under rainfed conditions

Exogenous application of gibberellic acid and selenium to endorse quality and yield of fodder maize under rainfed conditions

Exogenous application of gibberellic acid and selenium to endorse quality and yield of fodder maize under rainfed conditions

Good quality and economical availability of fodder could be a substitute for crop production in the farming system of dryland areas. In Pakistan, the increasing demands of fodder crops for animal feed require immediate attention to find viable options for fodder production. Additionally, climate change, land detritions, and imbalanced use of chemicals led to an agro-ecological imbalance which needs to focus on mitigation strategies and practices. Therefore, the experiment was conducted three different rainfed areas of Punjab with aims to increase fodder maize quality by application of Gibberellic acid (GA3) and Selenium (Se) to overcome the forage scarcity issue in rainfed areas. The highest fresh biomass and leaf area were recorded by the application of GA75+Se0.75 followed by GA50+Se0.50 at 60 DAS. Similarly, the data about the silage quality traits indicated that more total dry matter (TDM), TDN, Crude protein (CP), neutral detergent fiber (NDF), Crude fiber (CF), acid detergent fiber (ADF), ash contents (AC) were recorded in Afgoi compared to Sohni Dhart 623. Among the experimental locations, the highest TDM, TDN, NDF, ADF and AC were found for the crop planted at NARC followed by URF, Koont and the least values of these traits were recorded for GRS, Attock. Among the different combinations of growth regulators, the highest TDM, TDN, CF, CP and NDF were recorded for GA75+Se0.75 followed by GA50+Se0.50. The above findings conclude that exogenously application of GA75+Se0.75 plays a promising role in the improvement of fodder growth and quality parameters of silage in Afgoi verity at different water stress agro-ecological zones.

Loss of Function of OsFBX267 and OsGA20ox2 in Rice Promotes Early Maturing and Semi-Dwarfism in γ-Irradiated IWP and Genome-Edited Pusa Basmati-1.

Targeted mutagenesis is now becoming the most favored methodology to improve traits in popular rice cultivars selectively. Understanding the genetic basis of already available mutants could be the first step in designing such experiment. Improved White Ponni (IWP), a popularly grown South Indian rice variety, was subjected to γ irradiation to develop WP-22-2, an M6 line superior in semi-dwarfism, early flowering, and high yield, and it has grain qualities similar to those of IWP. The exogenous application of gibberellic acid (GA3) on WP-22-2 resulted in the elongation of shorter internodes to a level similar to IWP. The expression profiling of six genes regulating plant height showed their differential expression pattern at different time points post GA3 treatment. Furthermore, the sequencing of WP-22-2 and IWP genomes revealed several single nucleotide polymorphisms (SNPs) and large-scale deletions in WP-22-2. The conversion of functional codons to stop codons was observed in OsGA20ox2 and OsFBX267, which have been reported to have roles in regulating semi-dwarfism and early flowering, respectively. The loss of function of OsGA20ox2 and OsFBX267 in WP-22-2 resulted in reduced plant height as well as early flowering, and the same has been confirmed by editing OsGA20ox2 in the rice variety Pusa Basmati1 (PB1) using the CRISPR-Cas9 approach. The targeted editing of OsGA20ox2 in PB1 conferred shorter plant height to the edited lines compared with the wild type. Altogether, the study provides evidence on mutating OsGA20ox2 and OsFBX267 genes to develop early maturing and semi-dwarf varieties that can be released to farmers after functional characterization and field trials.

Germination Characteristics and Interspecific Variation in Seeds of Three <i>Rhododendron</i> Species Native to Korea

This study aimed to clarify the germination characteristics and seed dormancy type of three Rhododendron species (R. brachycarpum, R. micranthum, and R. mucronulatum var. ciliatum) native to Korea. The embryos of three Rhododendron species were linear and fully developed, indicating the absence of morphological dormancy (MD). R. brachycarpum and R. micranthum had non-dormant (ND) seeds at dispersal, whereas R. mucronulatum var. ciliatum seeds had some physiological dormancy (PD) at population level. The application of exogenous gibberellic acid (GA3) at 1,000 mg･L-1 broke the PD of R. mucronulatum var. ciliatum, while cold stratification at 4°C had no effect on seed dormancy. The optimal environmental conditions for seed germination were light･ 25/15°C for R. brachycarpum, darkness･20/10°C for R. micranthum, and light·25/15°C for R. mucronulatum var. ciliatum. Due to the interspecific variation of Rhododendron genus, the seed dormancy type or germination characteristics of all species were distinguished in this study. This study could be useful to understand the ecophysiological characteristics of Rhododendron species native to Korea.

Mitigation of deleterious phenotypes in chloroplast-engineered plants accumulating high levels of foreign proteins

BackgroundThe global demand for functional proteins is extensive, diverse, and constantly increasing. Medicine, agriculture, and industrial manufacturing all rely on high-quality proteins as major active components or process additives. Historically, these demands have been met by microbial bioreactors that are expensive to operate and maintain, prone to contamination, and relatively inflexible to changing market demands. Well-established crop cultivation techniques coupled with new advancements in genetic engineering may offer a cheaper and more versatile protein production platform. Chloroplast-engineered plants, like tobacco, have the potential to produce large quantities of high-value proteins, but often result in engineered plants with mutant phenotypes. This technology needs to be fine-tuned for commercial applications to maximize target protein yield while maintaining robust plant growth.ResultsHere, we show that a previously developed Nicotiana tabacum line, TetC-cel6A, can produce an industrial cellulase at levels of up to 28% of total soluble protein (TSP) with a slight dwarf phenotype but no loss in biomass. In seedlings, the dwarf phenotype is recovered by exogenous application of gibberellic acid. We also demonstrate that accumulating foreign protein represents an added burden to the plants’ metabolism that can make them more sensitive to limiting growth conditions such as low nitrogen. The biomass of nitrogen-limited TetC-cel6A plants was found to be as much as 40% lower than wildtype (WT) tobacco, although heterologous cellulase production was not greatly reduced compared to well-fertilized TetC-cel6A plants. Furthermore, cultivation at elevated carbon dioxide (1600 ppm CO2) restored biomass accumulation in TetC-cel6A plants to that of WT, while also increasing total heterologous protein yield (mg Cel6A plant−1) by 50–70%.ConclusionsThe work reported here demonstrates that well-fertilized tobacco plants have a substantial degree of flexibility in protein metabolism and can accommodate considerable levels of some recombinant proteins without exhibiting deleterious mutant phenotypes. Furthermore, we show that the alterations to protein expression triggered by growth at elevated CO2 can help rebalance endogenous protein expression and/or increase foreign protein production in chloroplast-engineered tobacco.

Gibberellin signaling mediates lateral root inhibition in response to K+-deprivation.

The potassium ion (K+) is vital for plant growth and development, and K+-deprivation leads to reduced crop yields. Here we describe phenotypic, transcriptomic, and mutant analyses to investigate the signaling mechanisms mediating root architectural changes in Arabidopsis (Arabidopsis thaliana) Columbia. We showed effects on root architecture are mediated through a reduction in cell division in the lateral root (LR) meristems, the rate of LR initiation is reduced but LR density is unaffected, and primary root growth is reduced only slightly. This was primarily regulated through gibberellic acid (GA) signaling, which leads to the accumulation of growth-inhibitory DELLA proteins. The short LR phenotype was rescued by exogenous application of GA but not of auxin or by the inhibition of ethylene signaling. RNA-seq analysis showed upregulation by K+-deprivation of the transcription factors JUNGBRUNNEN1 (JUB1) and the C-repeat-binding factor (CBF)/dehydration-responsive element-binding factor 1 regulon, which are known to regulate GA signaling and levels that regulate DELLAs. Transgenic overexpression of JUB1 and CBF1 enhanced responses to K+ stress. Attenuation of the reduced LR growth response occurred in mutants of the CBF1 target gene SFR6, implicating a role for JUB1, CBF1, and SFR6 in the regulation of LR growth in response to K+-deprivation via DELLAs. We propose this represents a mechanism to limit horizontal root growth in conditions where K+ is available deeper in the soil.

Loss of COMT activity reduces lateral root formation and alters the response to water limitation in sorghum brown midrib (bmr) 12 mutant.

Lignin is a key target for modifying lignocellulosic biomass for efficient biofuel production. Brown midrib 12 (bmr12) encodes the sorghum caffeic acid O-methyltransferase (COMT) and is one of the key enzymes in monolignol biosynthesis. Loss of function mutations in COMT reduces syringyl (S) lignin subunits and improves biofuel conversion rate. Although lignin plays an important role in maintaining cell wall integrity of xylem vessels, physiological and molecular consequences due to loss of COMT on root growth and adaptation to water deficit remain unexplored. We addressed this gap by evaluating the root morphology, anatomy and transcriptome of bmr12 mutant. The mutant had reduced lateral root density (LRD) and altered root anatomy and response to water limitation. The wild-type exhibits similar phenotypes under water stress, suggesting that bmr12 may be in a water deficit responsive state even in well-watered conditions. bmr12 had increased transcript abundance of genes involved in (a)biotic stress response, gibberellic acid (GA) biosynthesis and signaling. We show that bmr12 is more sensitive to exogenous GA application and present evidence for the role of GA in regulating reduced LRD in bmr12. These findings elucidate the phenotypic and molecular consequences of COMT deficiency under optimal and water stress environments in grasses.

Evaluación de la incidencia de la aplicación foliar de ácido giberélico en la floración de árboles de Coffea arábica L. y su impacto frente al cambio climático

La giberelina es conocida como una fitohormona que participa activamente en el control de la floración de varias especies. En el presente estudio se evaluó la aplicación exógena de ácido giberélico (0.1% y 0.5%) a 2959 plantas de Coffea arabica L., variedad Castillo cultivar Rosario; con el objetivo de establecer la relación existente entre la floración del café y el número de entrenudos inducidos en la rama principal media y superior mediante la aplicación foliar de la hormona. El proyecto se desarrolló en la Finca “El Limón” del Municipio de Buriticá (Antioquia) durante los meses de agosto y febrero. Independientemente de la concentración de fitohormona aplicada, como resultado de la aplicación exógena se encontró un aumento en el número de entrenudos y en la producción de brotes florales. Finalmente determinar el análisis de significancia, los datos obtenidos en los diferentes parámetros fueron analizados mediante la prueba estadística T-Student del 95%.

Effect of gibberellic acid, potassium nitrate and silicic acid on biochemical constituents of groundnut (Arachis hypogaea L.) seedling exposed to saline water

Salinity reduces the ability of plant utilize water and causes a reducing in growth rates, as well as changes in plant metabolic processes in most of the crops including groundnut. The molecules like silicic, gibberellic acid and potassium nitrate known to alleviates its adverse effect. Thus, green house experiment was conducted to investigate the effect of exogenous application of gibberellic acid, potassium nitrate and silicic acid under salt stress on biochemical parameters of groundnut. The observations were recorded for the biochemical parameters total soluble sugars, reducing sugars, total phenol, proline and glycine betaine. The result was suggested that the biochemical constituents were adversely affected due to salinity stress in groundnut. On application of GA3, KNO3 and silicic acid increased total soluble sugars, reducing sugars, total phenol, proline and glycine betaine. This investigation has suggested gibberellic acid, potassium nitrate and silicic acid, as a potential biomolecules affecting certain biomolecules related to osmotic adjustment as against the abiotic stress like salinity.

In Vitro Decoated Seed Germination and Seedling Development for Propagation of Wild Mandrake (Mandragora autumnalis Bertol.).

The establishment of an efficient in vitro propagation system for the conservation of the Mediterranean Mandragora autumnalis is highly desirable due to its scarcity, besides its potential medicinal and pharmacological properties. In a separate unpublished study, this species has proved to be resistant to laboratory plant regeneration from vegetative tissue cultures; therefore, an alternative decoated seed (i.e., endosperm enclosed the zygotic embryo) germination approach was conducted in this study. Pre-cold treatment of M. autumnalis seeds, removal of seed coats, and exogenous application of gibberellic acid (GA3) promoted in vitro seed germination and seedling emergence. In two separate experiments, approximately 10–27% of the germinated decoated seeds developed healthy seedlings within two weeks, compared to the non-germinated intact seeds of the potting soil controls. After 72 days, the highest rates of healthy seedlings development (67.4 and 69.4%) achieved in the in vitro decoated seed cultures supplemented with 60 and 100 mg/L GA3, respectively, compared to only 25% seedlings emergence rate of the in vitro cultures devoid of GA3, and 44.2% of the soil controls. The in vitro developed plants were healthy, survived transplantation conditions, and, significantly, grew faster, formed on average more than the double number of true leaves and shoot fresh weight (p ≤ 0.05), 90% more fresh weight of root system (p ≤ 0.05), and ultimately more than the double gross fresh weight (p ≤ 0.05) than that of the in vivo developed plants of the soil controls. Such in vitro seed germination approaches would be favorable due to the higher capacity of uniform seedling establishment year-round under lab-controlled conditions, facilitating proliferation and conservation of rare and threatened species, and providing fresh and axenic plant materials required for downstream studies such as those associated with leaf-derived protoplasts and genetic transformations.

A genome-wide identification of the BLH gene family reveals BLH1 involved in cotton fiber development

BackgroundCotton is the world’s largest and most important source of renewable natural fiber. BEL1-like homeodomain (BLH) genes are ubiquitous in plants and have been reported to contribute to plant development. However, there is no comprehensive characterization of this gene family in cotton. In this study, 32, 16, and 18 BLH genes were identified from the G. hirsutum, G. arboreum, and G. raimondii genome, respectively. In addition, we also studied the phylogenetic relationships, chromosomal location, gene structure, and gene expression patterns of the BLH genes.ResultsThe results indicated that these BLH proteins were divided into seven distinct groups by phylogenetic analysis. Among them, 25 members were assigned to 15 chromosomes. Furthermore, gene structure, chromosomal location, conserved motifs, and expression level of BLH genes were investigated in G. hirsutum. Expression profiles analysis showed that four genes (GhBLH1_3, GhBLH1_4, GhBLH1_5, and GhBLH1_6) from BLH1 subfamily were highly expressed during the fiber cell elongation period. The expression levels of these genes were significantly induced by gibberellic acid and brassinosteroid, but not auxin. Exogenous application of gibberellic acid significantly enhanced GhBLH1_3, GhBLH1_4, and GhBLH1_5 transcripts. Expression levels of GhBLH1_3 and GhBLH1_4 genes were significantly increased under brassinosteroid treatment.ConclusionsThe BLH gene family plays a very important role in many biological processes during plant growth and development. This study deepens our understanding of the role of the GhBLH1 gene involved in fiber development and will help us in breeding better cotton varieties in the future.

Effects of exogenous applications of gibberellic acid on the development and quality of jabuticaba fruits

The jabuticaba is a native species that is seeing increased industrial exploitation because of its organoleptic and functional characteristics, making it attractive for food and pharmaceutical products. However, the fruit composition is not favorable for processing because of the abundance of seeds. Techniques already established for other crops should be studied to improve industrial use characteristics. Thus, the objective of this study was to evaluate the development and organoleptic quality of jaboticaba fruits as a function of exogenous applications of gibberellic acid on the stem of plants in three reproductive stages. The treatments consisted of four concentrations of gibberellic acid (0, 50, 100 and 200 mg L-1) applied to jabuticaba plant stems in three reproductive phenological stages (flower buds, anthesis and post-flowering). A randomized complete block design was used with a factorial scheme (4×3) with six replications. It was observed that applications during anthesis and after flowering resulted in lower seed mass values and seed numbers and higher pulp yield, on average 23.08, 22.97 and 20.87%, respectively. The treatment with flower buds and increased gibberellic acid concentrations also resulted in an increased pulp yield, up to a maximum of 12.58%. Thus, it was concluded that the application of increasing concentrations of gibberellic acid, up to 200 mg L-1, improves pulp yield without altering the organoleptic characteristics of jabuticaba fruits and that applications at post-flowering or anthesis provide higher quality for industrial uses.

Efficacy of different primers on growth and yield of tulip (Tulipa gesneriana L.)

Tulip (Tulipa gesneriana L.) is an important and highly valuable flower of the cut flower industry. The most critical step in its cultivation is to break dormancy in order to initiate the growth, especially in tropical and sub-tropical areas of the world. Therefore, the current research was conducted to break bulb dormancy and foster the growth of tulip in Potohar region with the help of different primers. The objective of this study was the selection of best primer at appropriate concentration level to enhance growth, yield and vase life of the flower. Tulip bulbs were treated with different primers: T0 (distilled water), T1 (chitosan @ 5 g/L), T2 (gibberellic acid @ 0.15 g/L), T3 (humic acid 160 g/L), T4 (imidacloprid 19 g/L) and T5 (salicylic acid 0.1 g/L) for 24 hours, respectively. The experiment was laid out using Complete Randomized Design (CRD) with three replications. Statistical results revealed that characteristics including early germination, plant height, number of leaves, stalk length, fresh and dry weight of flower, weight of bulbs, diameter of bulbs and number of daughter bulbs were significantly increased in T2. Whereas, leaf area, diameter of stem and flower was maximum in T0. Plants under T3 showed an increase in chlorophyll content of leaves. While floral characteristics like early formation and opening of flower bud, more number of flowers and vase life were improved in T1. Thus, statistical results showed that priming can effectively help to improve morpho-physiological attributes of tulip.

Changes in Growth and Physiological Parameters of ×Amarine Following an Exogenous Application of Gibberellic Acid and Methyl Jasmonate

×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.

A gibberellin methyltransferase modulates the timing of floral transition at the Arabidopsis shoot meristem.

The transition from vegetative to reproductive growth is a key event in the plant life cycle. Plants therefore use a variety of environmental and endogenous signals to determine the optimal time for flowering to ensure reproductive success. These signals are integrated at the shoot apical meristem (SAM), which subsequently undergoes a shift in identity and begins producing flowers rather than leaves, while still maintaining pluripotency and meristematic function. Gibberellic acid (GA), an important hormone associated with cell growth and differentiation, has been shown to promote flowering in many plant species including Arabidopsis thaliana, but the details of how spatial and temporal regulation of GAs in the SAM contribute to floral transition are poorly understood. In this study, we show that the gene GIBBERELLIC ACID METHYLTRANSFERASE 2 (GAMT2), which encodes a GA-inactivating enzyme, is significantly upregulated at the SAM during floral transition and contributes to the regulation of flowering time. Loss of GAMT2 function leads to early flowering, whereas transgenic misexpression of GAMT2 in specific regions around the SAM delays flowering. We also found that GAMT2 expression is independent of the key floral regulator LEAFY but is strongly increased by the application of exogenous GA. Our results indicate that GAMT2 is a repressor of flowering that may act as a buffer of GA levels at the SAM to help prevent premature flowering.

Exogenous gibberellic acid application influences on vegetative and reproductive aspects in gladiolus

Abstract Ornamental plants like gladiolus are suitable option for growers with lower amount of land, as they are highly economic and have lower cost of production. An experiment was conducted with aim to study the exogenous application influence of gibberellic acid on vegetative and reproductive characteristics of gladiolus was conducted under the subtropical conditions. The experiment was laid out in two factors randomized complete block design and replicated three times. Gibberellic acid (GA3) was used in different concentrations (0, 50, 100, 150, 200 mg L-1) to corms of two cultivars of gladiolus (‘White Prosperity’ and ‘Red Advance’). Results showed that most of the parameters were significantly influenced by gibberellic acid at 200 mg L-1. The maximum sprouting, number of leaves plant-1, daughter corms per plant, less number of days to corm sprouting, days to spike emergence and flower opening were recorded in plants treated with 200 mg L-1 gibberellic acid (GA3). ‘Red Advance’ produced more number of leaves plant-1, corm diameter, corm weight, and less number of days to spike emergence and flower opening. It can be concluded from the present findings that the treatment of corms with 200 mg L-1 gibberellic acid can improve the growth and yield of cultivar Red Advance than White prosperity under the subtropical conditions.

The Effect of Exogenous Application of Gibberellic Acid on Two Salt Stressed Paddy Cultivars during Seed Germination

The Effect of Exogenous Application of Gibberellic Acid on Two Salt Stressed Paddy Cultivars during Seed Germination

Exogenous application of gibberellic acid mitigates drought-induced damage in spring wheat

Drought stress is a major problem in wheat production but it could be managed by using various exogenous protectants such as gibberellic acid (GA). Although GA is a plant growth hormone, it shows a potential to protect the plant in stress conditions. To investigate the possible role of GA in mitigating drought stress, we treated wheat (<em>Triticum aestivum</em> ‘BARI Gom-21’) seedlings with a GA spray under semihydroponic conditions. In the experiment, the combined effect of GA and drought stress (induced by 12% polyethylene glycol) was studied after 48 h and 72 h. In the absence of exogenous GA, drought-stressed wheat seedlings showed various physiological and biochemical changes in a time-dependent manner. Malondialdehyde (MDA), hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>) and free proline (Pro) concentrations were increased, whereas catalase (CAT) and ascorbate peroxidase (APX) activities were reduced under drought stress. Gibberellic acid played a role in restoring the ascorbate (AsA) level, decreased the reduced/oxidized glutathione (GSH/GSSG) ratio and reduced monodehydroascorbate reductase (MDHAR) and dehydroascorbate reductase (DHAR) activities. Gibberellic acid significantly affected the glyoxalase system. Under drought stress, the methylglyoxal (MG) concentration was increased but GA application stimulated glyoxalase I (Gly I) and glyoxalase II (Gly II) activities to protect the wheat seedlings against stress. The study concluded that the severity of drought stress in wheat depends on the growth stage and it increases with an increase in the duration of stress, whereas exogenous GA helped the seedlings to survive by upregulating antioxidant defense mechanisms and the glyoxalase system.