Gibberellic Acid Levels Research Articles

Gibberellin-related genes regulate dwarfing mechanism in wintersweet.

Chimonanthus praecox (wintersweet) is an important cut flower and pot plant with a high ornamental and economic value in China. The development of dwarf wintersweet varieties has become an important research topic for the wintersweet industry. The lack of natural dwarf germplasm has hindered research into the molecular mechanisms of developing dwarf wintersweet, limiting its cultivation. After a long-term investigation and collection of germplasm resources of C. praecox, we obtained the germplasm of a dwarf C. praecox (dw). Here, the dwarf and normal C. praecox (NH) were used to identify the types of hormones regulating dw formation using phenotypic identification and endogenous hormone determination. Differentially expressed genes in the dw and NH groups were screened using transcriptome analysis. The functions of key genes in the dwarf trait were verified by heterologous expression. It was found that the internode length and cell number were significantly reduced in dw than in NH, and the thickness of the xylem and pith was significantly decreased. The dwarfness of dw could be recovered by exogenous gibberellic acid (GA) application, and endogenous GA levels showed that the GA4 content of dw was substantially lower than that of NH. Transcriptome differential gene analysis showed that the elevated expression of the CpGA2ox gene in the GA synthesis pathway and that of CpGAI gene in the signal transduction pathway might be the key mechanisms leading to dwarfing. Combined with the results of weighted gene co-expression network analysis, we selected the CpGAI gene for analysis and functional verification. These results showed that CpGAI is a nuclear transcriptional activator. Overexpression of CpGAI in Populus tomentosa Carr. showed that CpGAI could lead to the dwarfing in poplar. We analyzed the dwarfing mechanism of C. praecox, and the results provided a reference for dwarf breeding of wintersweet.

Humic Acid-Coated Fe3O4 Nanoparticles Confer Resistance to Acremonium Wilt Disease and Improve Physiological and Morphological Attributes of Grain Sorghum.

Acremonium wilt disease affects grain quality and reduces sorghum yield around the globe. The present study aimed to assess the efficacy of humic acid (HA)-coated Fe3O4 (Fe3O4/HA) nanoparticles (NPs) in controlling acremonium wilt disease and improving sorghum growth and yields. During the season 2019, twenty-one sorghum genotypes were screened to assess their response to Acremonium striticum via artificial infection under field conditions and each genotype was assigned to one of six groups, ranging from highly susceptible to highly resistant. Subsequently, over the two successive seasons 2020 and 2021, three different concentrations of 10, 40 and 80 mg L−1 of Fe3O4/HA NPs were tested against A. striticum. The concentrations of 40 and 80 mg L−1 were found to be highly effective in controlling acremonium wilt disease on different sorghum genotypes: LG1 (highly susceptible), Giza-3 (susceptible), and Local 119 (resistant) genotypes. After harvest, the physiological (growth and yield) and biochemical (peroxidase, catalase, and gibberellic acid) attributes of sorghum plants were determined, and the results demonstrated that concentrations of 40 and 80 mg L−1 increased peroxidase and catalase activities in healthy (uninoculated) sorghum genotypes compared to inoculated sorghum genotypes. Additionally, the toxicity of Fe3O4/HA NPs on male albino rats was investigated via hematological (CBC), chemical (ALT and AST) and histopathological analyses. The concentration 80 mg L−1 of Fe3O4/HA NPs caused a marked increase in ALT and creatinine level after 51 days of feeding. Severe pathological alterations were also observed in liver and kidney tissues of rats administered with grain sorghums treated with 80 mg L−1. In comparison with the untreated control plants, a concentration of 40 mg L−1 significantly increased the growth, yield and gibberellic acid levels (p ≤ 0.05) and was found to be safe in male albino rats. Conclusively, a concentration of 40 mg L−1 of Fe3O4/HA NPs showed promising results in curtailing A. striticum infections in sorghum, indicating its great potential to substitute harmful fertilizers and fungicides as a smart agriculture strategy.

Gibberellic acid alleviates cadmium toxicity in rice by regulating NO accumulation and cell wall fixation capacity of cadmium

Gibberellic acid (GA) has been implicated in the response of plants to cadmium (Cd) stress, but the underlying mechanism remains unclear. In the present study, our aim was to confirm the role of GA in regulating the accumulation of Cd in rice. We found that Cd stress elevated the endogenous GA level in the rice roots. Exogenous GA application not only decreased the fixation of Cd in the root cell wall through reducing the hemicelluloses content, but also decreased the expression of OsNRAMP5 (Natural Resistance-Associated Macrophage Protein 5) and OsCd1 (a major facilitator superfamily gene). Both OsNRAMP5 and OsCd1 are related to Cd absorption, therefore, less Cd was accumulated in the roots. Furthermore, GA increased the expression of OsHMA3 (Heavy Metal ATPase 3) and OsCAL1 (Cadmium accumulation in Leaf 1), which are responsible for sequestering the Cd to the vacuoles and effluxing the Cd outside the cell, respectively, as a result, less Cd was accumulated in the shoots. In contrast, more Cd was accumulated in GA deficient lines. Furthermore, GA decreased the endogenous NO levels and the activity of antioxidant enzymes, while application of a NO scavenger-cPTIO diminished the alleviatory role of GA. In summary, the GA accelerated cell wall Cd exclusion mechanism probably improved rice tolerance to Cd toxicity via regulating the accumulation of NO.

Plant Development of Early-Maturing Spring Wheat (Triticum aestivum L.) under Inoculation with Bacillus sp. V2026.

The effect of a plant growth-promoting bacterium (PGPB) Bacillus sp. V2026, a producer of indolyl-3-acetic acid (IAA) and gibberellic acid (GA), on the ontogenesis and productivity of four genotypes of early-maturing spring wheat was studied under controlled conditions. The inoculation of wheat plants with Bacillus sp. V2026 increased the levels of endogenous IAA and GA in wheat of all genotypes and the level of trans-Zeatin in Sonora 64 and Leningradskaya rannyaya cvs but decreased it in AFI177 and AFI91 ultra-early lines. Interactions between the factors “genotype” and “inoculation” were significant for IAA, GA, and trans-Zeatin concentrations in wheat shoots and roots. The inoculation increased the levels of chlorophylls and carotenoids and reduced lipid peroxidation in leaves of all genotypes. The inoculation resulted in a significant increase in grain yield (by 33–62%), a reduction in the time for passing the stages of ontogenesis (by 2–3 days), and an increase in the content of macro- and microelements and protein in the grain. Early-maturing wheat genotypes showed a different response to inoculation with the bacterium Bacillus sp. V2026. Cv. Leningradskaya rannyaya was most responsive to inoculation with Bacillus sp. V2026.

Yam Tuber Dormancy and Sprouting: The Role of Concentration Dynamics of Endogenous Gibberellic Acid

The role of endogenous gibberellic acid (GA ) in the regulation of yam (Dioscorea spp.) tuber 3 dormancy was investigated by determining the changes in the endogenous GA levels during 3 natural dormancy progression. Two Dioscorea rotundata cultivars ('Pona' and 'Labreko') and one Dioscorea alata cultivar ('CRI-Ahoɔdenfoɔ') used in these studies have varying dormancy duration. Endogenous GA levels determined for the yam tubers ranged from 1.53 – 3.05 mg/g dw 3 and 1.23 – 1.58 mg/g dw for 'Pona'; 1.53 – 3.40 mg/g dw and 1.25–1.57 mg/g dw for 'Labreko'; 1.48 – 3.62 mg/g dw and 1.28 – 1.60 mg/g dw for 'CRI-Ahoɔdenfoɔ', respectively, for the outer and inner portions. 'Pona' and 'Labreko' had dormancy break at 60 days after harvest (DAH), but at 90 DAH for 'CRI-Ahoɔdenfoɔ'. Generally, GA levels increased from harvest to the maximum 3 at 30 DAH, then declined to the minimum at 60 DAH before finally increasing again at 90 DAH for the outer portions of the yam tuber. For the inner portions of the tuber, GA levels rather 3 declined significantly to the minimum at 30 DAH, increased at 60 DAH and then decreased again at 90 DAH. GA levels in the outer portions of the tubers increased by 84-122%, 65-77% and 61- 3 65%, respectively, in 'CRI-Ahoɔdenfoɔ', 'Labreko' and 'Pona', but decreased in the inner portions by 19-23%, 24-26% and 26-28%. Essentially, higher amounts of endogenous gibberellins in yam tubers induced longer dormancy duration whereas lower amounts were indicative of dormancy termination and subsequent initiation of sprouting.

Cloning and homologous characterization of geranylgeranyl pyrophosphate synthase (GGPPS) from Withania somnifera revealed alterations in metabolic flux towards gibberellic acid biosynthesis.

Overexpression of a novel geranylgeranyl pyrophosphate synthase gene (WsGGPPS) in planta resulted in increased levels of gibberellic acid and decrease in withanolide content. Withania somnifera (L.) Dunal, the herb from family Solanaceae is one of the most treasured medicinal plant used in traditional medicinal systems owing to its unique stockpile of pharmaceutically active secondary metabolites. Phytochemical and pharmacological studies in this plant were well established, but the genes affecting the regulation of biosynthesis of major metabolites were not well elucidated. In this study cloning and functional characterization of a key enzyme in terpenoid biosynthetic pathway viz. geranylgeranyl pyrophosphate synthase (EC 2.5.1.29) gene from Withania somnifera was performed. The full length WsGGPPS gene contained 1,104 base pairs that encode a polypeptide of 365 amino acids. The quantitative expression analysis suggested that WsGGPPS transcripts were expressed maximally in flower tissues followed by berry tissues. The expression levels of WsGGPPS were found to be regulated by methyl jasmonate (MeJA) and salicylic acid (SA). Amino acid sequence alignment and phylogenetic studies suggested that WsGGPPS had close similarities with GGPPS of Solanum tuberosum and Solanum pennellii. The structural analysis provided basic information about three dimensional features and physicochemical parameters of WsGGPPS protein. Overexpression of WsGGPPS in planta for its functional characterization suggested that the WsGGPPS was involved in gibberellic acid biosynthesis.

Heat stress during grain filling regulates seed germination through alterations of DNA methylation in barley (Hordeum vulgare L.).

Alterations in DNA methylation levels of ROS, GA and ABA related gene promoters cause transcriptional changes upon imbibition to induce seed germination in barley seeds exposed to heat stress during grain filling. Environmental changes, especially changes in temperature, during seed development affect germination in several plant species. We have previously shown that heat stress during rice grain filling alters DNA methylation, an epigenetic mark important for gene silencing, regulates transcript levels of phytohormone metabolism genes, and delays seed germination. However, whether this phenomenon is present in other plant species remained to be elucidated. In this study, we compared seeds germination of barley (Hordeum vulgare L.) plants grown at 15°C (control) or 25°C (heat stress) during grain filling. Heat stress during grain filling significantly promoted seed germination in comparison with the control. The phytohormone gibberellic acid (GA) and reactive oxygen species produced by NADPH oxidases promote seed germination, whereas phytohormone abscisic acid (ABA) suppresses seed germination. We found that in heat-stressed seeds, genes related to ABA biosynthesis (HvNCED1 and 2) were significantly suppressed, whereas genes related to ABA catabolism (HvABA8'OH) and GA biosynthesis (HvHA20ox, HvGA3ox), and NADPH oxidase (HvRboh) genes were significantly upregulated after imbibition. Using MeDIP-qPCR, we showed that the promoters of HvNCED were hyper-methylated, and those of HvABA8'OH1, HvABA8'OH3, HvGA3ox2, and HvRbohF2 were hypo-methylated in heat treated seeds. Taken together, our data suggest that heat stress during grain filling affects DNA methylation of germination-related genes and promotes seed germination in barley.

Insights into the trihelix transcription factor responses to salt and other stresses in Osmanthus fragrans

BackgroundOsmanthus fragrans is an evergreen plant with high ornamental and economic values. However, they are easily injured by salt stress, which severely limits their use in high salinity areas. The trihelix transcription factor (TF) family, as one of the earliest discovered TF families in plants, plays an essential part in responses to different abiotic stresses, and it has potential functions in improving the salt-tolerance capability of O. fragrans.ResultsIn this study, 56 trihelix genes (OfGTs) were first identified in O. fragrans and then divided into five subfamilies in accordance with a phylogenetic tree analysis. The OfGTs were found to be located randomly on the 20 O. fragrans chromosomes, and an analysis of gene replication events indicated that the OfGT gene family underwent strong purification selection during the evolutionary process. The analysis of conserved motifs and gene structures implied that the OfGT members in the same subfamily have similar conserved motifs and gene structures. A promoter cis-elements analysis showed that all the OfGT genes contained multiple abiotic and hormonal stress-related cis-elements. The RNA-seq data suggested that the OfGTs have specific expression patterns in different tissues, and some were induced by salt stress. The qRT-PCR analysis of 12 selected OfGTs confirmed that OfGT1/3/21/33/42/45/46/52 were induced, with OfGT3/42/46 being the most highly expressed. In addition, OfGT42/OfGT46 had a co-expression pattern under salt-stress conditions. OfGT3/42/46 were mainly localized in the nuclei and exhibited no transcriptional activities based on the analysis of the subcellular localization and transcriptional activity assay. Furthermore, the expression levels of most of the selected OfGTs were induced by multiple abiotic and hormonal stresses, and the expression patterns of some OfGTs were also highly correlated with gibberellic acid and methyl jasmonate levels. Remarkably, the transient transformation results showed lower MDA content and increased expression of ROS-related genes NbAPX in transgenic plants, which implying OfGT3/42/46 may improve the salt tolerance of tobacco.ConclusionsThe results implied that the OfGT genes were related to abiotic and hormonal stress responses in O. fragrans, and that the OfGT3/42/46 genes in particular might play crucial roles in responses to salt stress. This study made a comprehensive summary of the OfGT gene family, including functions and co-expression patterns in response to salt and other stresses, as well as an evolutionary perspective. Consequently, it lays a foundation for further functional characterizations of these genes.

The miR166 mediated regulatory module controls plant height by regulating gibberellic acid biosynthesis and catabolism in soybean.

MicroRNAs (miRNAs) are endogenous small non-coding RNAs that play critical roles in regulating plant growth and development. Here, we used Short Tandem Target Mimic (STTM) technology to generate soybean (Glycine max (L.) Merr.) miRNA knockdown lines and identify miRNAs that regulate plant height, a key agronomic trait that affects yield. STTM166 successfully silenced miR166 in soybean and upregulated the expression of miR166 target genes, such as ATHB14-LIKE. The miR166 knockdown lines (GmSTTM166) displayed a reduced plant height phenotype. Moreover, GmSTTM166 plants contained lower levels of bioactive gibberellic acid (GA3) than wild-type plants, and application of exogenous GA partially rescued the dwarf phenotype of GmSTTM166. Knockdown of miR166 altered the expression of genes involved in GA biosynthesis and catabolism. Further analysis revealed that ATHB14-LIKE directly represses transcription of the GA biosynthesis genes GmGA1 and GmGA2, while activating transcription of the GA catabolic gene GIBBERLLIN 2 OXIDASE 2 (GmGA2ox2). Collectively, these results reveal a pivotal role for miR166 in the genetic control of plant height in soybean, thereby providing invaluable insights for molecular breeding to improve soybean yield.

GROWTH AND QUALITY OF ‘PÉROLA’ PINEAPPLE AS A FUNCTION OF LEVELS OF GIBBERELLIC ACID

Gibberellin is a plant hormone capable of enhancing the productivity of plant’s productivity rants, due to its action in plant physiology, mainly in fruit formation. In this sense, this study aimed to evaluate gibberellic acid levels and application times on the growth and quality of ‘Pérola’ pineapple. The experiment was conducted under field conditions in the municipality of Pedras de Fogo, state of Paraíba, Brazil. The treatments consisted of five levels of gibberellic acid (0.0, 1.5, 3.0, 6.0, and 12.0 mg/plant), distributed in a randomized block experimental design, with four repetitions, in which three applications were made at 50, 80, and 110 days after flower induction. The soluble solids content, fruit height, fruit diameter, and weight were evaluated. The period of application and the levels of gibberellic acid altered the responses for the variables analyzed. The level of 7.5 mg/plant of gibberellic acid promoted an increase in the weight and diameter of the fruit. The application at 110 days after floral induction induced an increase in fruit weight and a greater concentration of sugar in the fruit. Further studies on the application of gibberellic acid and periods of application in different soil and climatic conditions should be carried out to determine more consistent results with this crop.

Ethylene and abscisic acid play a key role in modulating apple ripening after harvest and after cold-storage

An autocatalytic burst in ethylene production generally accompanies ripening of detached apple fruit. However, if apples are left to ripen attached to the tree, some cultivars, will not experience this autocatalytic ethylene production and the fruit will never acquire the organoleptic properties of detached ripened fruit. Accordingly, the present study aimed to understand how the hormonal crosstalk regulates ripening in ‘Golden Reinders’ apples, ripened on-tree, detached from the tree or after a period of cold storage, following the commercial harvest date. Our results showed that during on-tree ripening, ethylene production remained low, and no significant changes were observed in fruit colour or firmness. In fruit ripened detached from the tree, ethylene production was preceded by an increase of indole 3-acetic acid (IAA) and gibberellic acid (GA3) levels, whereas a cold-induced accumulation of jasmonic acid (JA) seemed to induce an earlier initiation of the climacteric burst in fruit ripened after cold storage. In both postharvest conditions, the accumulation of abscisic acid (ABA) may be either needed or facilitating the action of ethylene on triggering some ripening-related changes, pointing out the importance of both hormones in mediating apple ripening. In contrast, changes in sugars and ROS/antioxidants did not vary among the different ripening scenarios suggesting that none of the measured compounds may act as signalling molecules during apple ripening. Collectively, our results highlight that ethylene together with ABA played a crucial role in triggering ripening-related changes during postharvest ripening of ‘Golden Reinders’ apples.

Spatial control of cell division by GA-OsGRF7/8 module in a leaf explaining the leaf length variation between cultivated and wild rice.

Cellular and genetic understanding of the rice leaf size regulation is limited, despite rice being the staple food of more than half of the global population. We investigated the mechanism controlling the rice leaf length using cultivated and wild rice accessions that remarkably differed for leaf size. Comparative transcriptomics, gibberellic acid (GA) quantification and leaf kinematics of the contrasting accessions suggested the involvement of GA, cell cycle and growth-regulating factors (GRFs) in the rice leaf size regulation. Zone-specific expression analysis and VIGS established the functions of specific GRFs in the process. The leaf length of the selected accessions was strongly correlated with GA levels. Higher GA content in wild rice accessions with longer leaves and GA-induced increase in the leaf length via an increase in cell division confirmed a GA-mediated regulation of division zone in rice. Downstream to GA, OsGRF7 and OsGRF8 function for controlling cell division to determine the rice leaf length. Spatial control of cell division to determine the division zone size mediated by GA and downstream OsGRF7 and OsGRF8 explains the leaf length differences between the cultivated and wild rice. This mechanism to control the rice leaf length might have contributed to optimizing leaf size during domestication.

Heat Stress Resistance Mechanisms of Two Cucumber Varieties from Different Regions.

High temperatures affect the yield and quality of vegetable crops. Unlike thermosensitive plants, thermotolerant plants have excellent systems for withstanding heat stress. This study evaluated various heat resistance indexes of the thermotolerant cucumber (TT) and thermosensitive cucumber (TS) plants at the seedling stage. The similarities and differences between the regulatory genes were assessed through transcriptome analysis to understand the mechanisms for heat stress resistance in cucumber. The TT plants exhibited enhanced leaf status, photosystem, root viability, and ROS scavenging under high temperature compared to the TS plants. Additionally, transcriptome analysis showed that the genes involved in photosynthesis, the chlorophyll metabolism, and defense responses were upregulated in TT plants but downregulated in TS plants. Zeatin riboside (ZR), brassinosteroid (BR), and jasmonic acid (JA) levels were higher in TT plants than in TS. The heat stress increased gibberellic acid (GA) and indoleacetic acid (IAA) levels in both plant lines; however, the level of GA was higher in TT. Correlation and interaction analyses revealed that heat cucumber heat resistance is regulated by a few transcription factor family genes and metabolic pathways. Our study revealed different phenotypic and physiological mechanisms of the heat response by the thermotolerant and thermosensitive cucumber plants. The plants were also shown to exhibit different expression profiles and metabolic pathways. The heat resistant pathways and genes of two cucumber varieties were also identified. These results enhance our understanding of the molecular mechanisms of cucumber response to high-temperature stress.

Fluoride tolerance in rice is negatively regulated by the 'stress-phytohormone' abscisic acid (ABA), but promoted by ABA-antagonist growth regulators, melatonin, and gibberellic acid.

The present manuscript aimed at investigating whether abscisic acid (ABA) promotes fluoride tolerance, similar to inciting salt adaptation in rice. Seeds of three salt-tolerant rice genotypes were maintained at 32°C under 16/8h light/dark photoperiodic cycle with 700μmol photons m-2s-1 intensity and 50% relative humidity in a plant growth chamber for 20days. Suppressed ABA biosynthesis, and downregulated expression of ABA-inducible genes like Rab16A, Osem, and TRAB1 triggered NaCl-induced growth inhibition and physiological injuries like chlorophyll degradation, electrolyte leakage, formation of H2O2, malondialdehyde, and methylglyoxal in Matla. Reduced ABA accumulation increased the levels of melatonin and gibberellic acid in NaF (50mgL-1)-stressed Nonabokra and Matla, which altogether promoted fluoride tolerance. Higher ABA content in NaF-stressed Jarava stimulated fluoride uptake via chloride channels, thus exhibiting severe fluoride susceptibility, in spite of higher production of ABA-associated osmolytes like proline, glycine-betaine and polyamines via the concerted action of genes like PDH, ADC, ODC, SAMDC, SPDS, SPMS, DAO, and PAO. Increased accumulation of compatible solutes in presence of high endogenous ABA promoted salt tolerance in Jarava; the same was insufficient to ameliorate fluoride-induced injuries in this cultivar. Treatment with ABA biosynthetic inhibitor, Na2WO4 promoted fluoride tolerance in Jarava, whereas further supplementation with exogenous ABA resulted in reversion back to fluoride-susceptible phenotype. Our work clearly established that ABA cannot always be considered as a 'universal' stress hormone as known in literature, since it acts as a negative regulator of fluoride tolerance which is more tightly regulated in rice via melatonin- and gibberellic acid-dependent pathways in ABA-independent manner.

Effect of endogenous gibberellic acid content on physiological and yield related traits in late sown wheat

Terminal heat stress is becoming major factors in limiting wheat production with increasing evidence of heat stress in present scenario of climate change. Plant hormones are key player in determining plant response to these stresses from perception of stress to final adoptive response. Gibberellic acid is one of the major plant hormone playing crucial role in plant development from germination to seed development, but there is huge gap in knowledge about its role under heat stress. Present study was conducted in late sown wheat (i.e. on 5th January)to examine the inter-relationship between leaf gibberellic acid (GA3) level at reproductive stage with physiological and yield related traits under heat stress in 40 wheat genotypes. Genotypes were categorized into three classes namely tolerant, intermediate and sensitive based on heat stress tolerance ability for further analysis. The diversity in endogenous GA3 concentration was found among the cultivars. The unique inverse relationship between GA3 level in flag leaf and tolerance level of genotypes was found in this study through regression analysis (p<0.05). The path analysis showed that GA3 had direct negative influence on test weight under heat stress conditions. Thus, investigations of mechanism of GA3 influence on sink capacity have the potential to develop heat tolerant genotype and increase wheat production under heat stress.

Alleviating Role of Gibberellic Acid in Enhancing Plant Growth and Stimulating Phenolic Compounds in Carrot (Daucus carota L.) under Lead Stress

Toxicity of heavy-metals in soil is a major constraint for the production of carrots (Daucus carota L.). Different plant growth regulators are being used to overcome this problem. It has been found that plant growth regulators induce stress tolerance in plants. In this study, the role of exogenously applied plant growth regulator, gibberellic acid (GA3) was examined in soil grown two carrot cultivars under four different levels of lead (0, 50, 100, and 150 mg/kg) with one level of gibberellic acid (50 ppm). Results showed that Pb stress retarded the plant growth and reduced chlorophyll contents in the leaves of both carrot cultivars. A significant decrease was observed in photosynthetic attributes by Pb addition alone. However, exogenously applied GA3 ameliorated the plant growth and chlorophyll contents in the leaves of both carrot cultivars under Pb stressed conditions. Moreover, GA3 also decreased the uptake of Pb concentration in carrot leaves and roots. In addition, GA3 significantly regulated the phenolic compounds concentration in both carrot cultivars under Pb stress. In this study, cultivar T-29 was found to be more tolerant to Pb stress, however, cultivar Mevarick experienced higher damage regarding plant growth under Pb stress.

The Effect of Temperature Stress Associated With Different Planting Dates and Levels of Gibberellic Acid on The Growth of Sorghum Spring

A field experiment was carried out in the experimental field of the Department of Field Crops, College of Agriculture/University of Al-Muthanna during the spring season 2021 to determine the effect of planting dates on some growth characteristics of sorghum. The experiment was applied by arranging the split panels according to the RCBD design and with three replications. The main panels included three planting dates (4/15 ’ 4\\5 ’ 3/25) while the secondary panels included gibberellin treatments (0, 100ppm) and the results were as follows: The planting date exceeded the first date 3/25 in the number of days to 75% flowering (97.5 days), the height of the plant (143.74 cm) and the diameter of the stem(2.34 cm) and the number of leaves per plant (8.73 leaves). 75% flowering, giving(92.33) days, plant height (136.55 cm), stem diameter (2.04 cm) and number of leaves (8.10 leaves).

Effect of different levels of gibberellic acid and kinetin on quality and self-life of banana (Musa spp.) fruits

Artificial fruit ripening agents have become increasingly popular in recent years. During the ripening, various ripening agents are used for the ripening of banana fruits. The effects of various ripening agents of banana fruits (variety: Malbhog) were studied. Seven treatments consisting of distilled water, Gibberellic acid (GA3) @ 100 ppm, GA3 @ 200 ppm, GA3 @ 300 ppm, kinetin @ 3 ppm, kinetin @ 5 ppm, and kinetin @ 7 ppm were laid out in a Completely Randomized Design with three replications. The maximum loss in weight (9.195%), Total Soluble Solids (20.33˚B), the highest color score (6), pH (4.767), Total Soluble Solids/Titratable Acidity TA (34.23), and Pulp peel ratio (2.84) were observed in banana sprayed with distilled water whereas the minimum value for TSS (12.67˚B), pulp peel ratio (1.813), peel color rating (2.67), TSS/TA (15.32) were observed in GA3 @ 300 ppm treated fruits. The maximum (32.67 days) and the minimum (18.33 days) shelf-life was observed in GA3 @ 300 ppm and distilled water respectively. This research will help in the regulation of ripening as per the needs of consumers and the distance of the market. In horticulture, it will help to extend storage life and reduce quality and economic loss.

Selenium and zinc oxide nanoparticles modulate the molecular and morpho-physiological processes during seed germination of Brassica napus under salt stress

The advent of the nanotechnology era offers a unique opportunity for sustainable agriculture, and the contribution of nanoparticles (NPs) to ameliorate abiotic stresses became the new area of interest for researchers due to their special physiochemical characteristics in the biological system. Salinity is a key devastating abiotic factor that hinders the development and yield of rapeseed. On the flip side, the impact of nanoparticles on plant hormones upon salt stress during seed imbibition and germination has been poorly understood. Hence, we aimed to study the influence of nanopriming on plant hormones and germination processes using selenium and zinc oxide nanoparticles (SeNPs and ZnONPs) during seed imbibition and the early seedling stage upon salinity stress. Nanopriming showed a positive effect on final germination percentage, germination rate, seed microstructure, and antioxidant enzyme activity of two rapeseed cultivars under salt stress. Moreover, nano-treatment decreased the expression of abscisic acid related genes BnCYP707A1, 3, and 4 during the priming time and after sowing, where the levels of BnCYP707A1, and 3 genes showed a slightly significant difference between the nanopriming and hydropriming, which gave an evidence that the nanopriming influenced the ABA levels then elevated the seed germination with SeNPs and ZnONPs. Likewise, nanoparticles significantly elevated the expression levels of BnGA20ox, BnGA3ox and BnCPS genes during the germination stage, especially at 24 h after being sown in salt stress. That confirms the positive role of SeNPs and ZnONPs in regulating gibberellic acid level, which increases the germination in primed seeds as compared to unprimed seeds and hydroprimed seeds. Additionally, our results demonstrated that nanopriming regulated the expression level of BnCAM and BnPER during priming time and after sowing, along with the various levels of expression remarkably in BnEXP4 and BnRAB28, especially at 24 h of being sown under salt stress, which promoted seed germination and early seedling growth. Overall, this work provides new insights into mechanisms underlying the interactions of SeNPs and ZnONPs with plant hormones during the seed imbibition and early seedling stage, consequently enhanced plant growth and development. Additionally, these findings portrayed that the application of SeNPs and ZnONPs could be a new strategy and useful approach to enhance tolerance against salinity in rapeseed plants.

Seed storage protein changes and mobilization pattern in Bambaranut (Vigna subterranea) (L.) Verdc. during germination

The germination of seeds involves series of events during which mobilization and utilization of seed storage proteins occur. This study is aimed at determining the changes in total and fractions of seed storage protein in six bambaranut landraces during 96 hrs germination period. The study assessed the changes in seed storage protein content, storage protein profile, endopeptidase activity, free amino acids and gibberellic acid levels. Significant (p<0.05) decrease in total storage protein after 24 hrs, albumin from 48 hrs and globulin and glutelin after 72 hrs germination period were observed in the studied landraces. Prolamin showed significant (p<0.05) decrease after 48 hrs in all the landraces. Five peptide bands were detected in the six landraces with molecular weights corresponding to 97.4 kDa, 45 kDa, 29 kDa, 20.1 kDa and 18 kDa. Peptide bands with molecular weight of 97 kDa and 29 kDa decreased in intensity after 48 hrs of germination in four landraces. Free amino acids content significantly (p<0.05) increased following 24 hrs germination period in all the landraces. The activity of endopeptidase increased significantly (p<0.05), reaching maximum after 96 hrs germination. Significant (p<0.05) increase in gibberellic acid level throughout germination period was also observed. Although slow degradation rate of storage proteins was observed, there was variation in the rate at which storage protein and its fractions decreased among the bambaranut landraces during germination. This variation could be utilized towards obtaining improved bambaranut genotypes with better germination characteristics.