Hypocotyl Length Research Articles

A 5.5-kb LTR-retrotransposon insertion inside phytochrome B gene (CsPHYB) results in long hypocotyl and early flowering in cucumber (Cucumis sativus L.)

The novel spontaneous long hypocotyl and early flowering (lhef) mutation in cucumber is due to a 5551-bp LTR-retrotransposon insertion in CsPHYB gene encoding PHYTOCHROME B, which plays a major role in regulating photomorphogenic hypocotyl growth and flowering. Hypocotyl length and flowering time are important for establishing high-quality seedlings in modern cucumber production, but little is known for the underlying molecular mechanisms of these two traits. In this study, a spontaneous cucumber long hypocotyl and early flowering mutant was identified and characterized. Based on multiple lines of evidence, we show that cucumber phytochrome B (CsPHYB) is the candidate gene for this mutation, and a 5551-bp LTR-retrotransposon insertion in the first exon of CsPHYB was responsible for the mutant phenotypes. Uniqueness of the mutant allele at CsPHYB was verified in 114 natural cucumber lines. Ectopic expression of the CsPHYB in Arabidopsis phyB mutant rescued the long hypocotyl and early flowering phenotype of phyB-9 mutant. The wild-type CsPHYB protein was localized on the membrane and cytoplasm under white light condition, whereas in the nucleus under red light, it is consistent with its roles as a red-light photoreceptor in Arabidopsis. However, the mutant csphyb protein was localized on the membrane and cytoplasm under both white and red-light conditions. Expression dynamics of CsPHYB and several cell elongation-related genes were positively correlated with hypocotyl elongation; the transcription levels of key positive and negative regulators for flowering time were also consistent with the anthesis dates in the mutant and wild-type plants. Yeast two hybrid and bimolecular fluorescence complementation assays identified physical interactions between CsPHYB and phytochrome interacting factor 3/4 (CsPIF3/4). These findings will provide new insights into the roles of the CsPHYB in cucumber hypocotyl growth and flowering time.

Plant growth promoting characterization of indigenous phosphate solubilizing rhizobacteria and effects on germination of some crops in Vietnam

Inorganic Phosphate Solubilizing Bacteria (PSB) are widely present in nature and have been successfully applied in fields in many countries. However, researches on indigenous PSB are still very limited in Vietnam. The objective of this study was to isolate and evaluate the growth promoting characteristics and effects on germination of seed of indigenous PSB for fertilizer production from PSB. Thirteen isolates of indigenous PSB were collected using selective isolation medium containing Ca3(PO4)2, of which eight added the ability to dissolve AlPO4 and five isolates added the ability to dissolve FePO4. Initial qualitative tests indicated that all thirteen PSB isolates were incapable of HCN and lipase production while other growth promoting activities including amylase, caseinase, cellulase, chitinase, pectinase, indole acetic acid, K solubility, Zn solubility, and N fixation varied according to PSB isolate. The collected PSB isolates had no effect on seed germination rate, root length, and hypocotyl length of plantules of soybean, rice, maize, cucumber, tomato, and chili by plate assay. This study had shown that PSB was also common in the rhizosphere of various crops in Vietnam. Therefore, isolation to enrich the indigenous PSB collection was essential for the screening of suitable PSB strains for subsequent fertilizer production.

Identification of Appropriate Light Intensity and Daytime Temperature for Cucumber (Cucumis sativus L.) Seedlings in a Plant Factory with Artificial Lighting for Use as Grafting Material

In this study, an experiment was conducted to suggest optimal daytime temperature and light intensity for cucumber scion and rootstock production in a plant factory with artificial light. Plant growth of cucumber scions and rootstocks at a day/night temperature of 26/18 °C and photosynthetic photon fluxes of 50, 120, 190, 260, 330, and 400 μmol·m−2·s−1 was investigated. Plant growth under daytime temperatures of 25/18, 26/18, 27/18, and 28/18 °C at a photosynthetic photon flux of 260 μmol·m−2·s−1 was investigated. As the photosynthetic photon flux increased, hypocotyl length was shortened in cucumber scions and rootstocks, but Dickson quality index, compactness, and Seedling Health Index were improved. As the daytime temperature increased, the hypocotyl length of cucumber scions increased, but the quality of seedlings decreased. The root growth of scions decreased as the daytime temperature increased. As for the correlation between the major growth indicators, Dickson quality index, compactness, and Seedling Health Index showed a high correlation of more than 0.8 in stem diameter, leaf, and root weight. Therefore, it is judged that it is most efficient to maintain the photosynthetic photon flux at 260 μmol·m−2·s−1 throughout the year and adjust the daytime temperature to 25 to 28 °C according to the season for farms and commercial nurseries that produce cucumber seedlings by installing plant factories with artificial light.

Seed Germination of Three Milk Thistle (Silybum marianum (L.) Gaertn.) Populations of Greek Origin: Temperature, Duration, and Storage Conditions Effects

Milk thistle besides being a highly competitive weed is cultivated as a medicinal plant, and the seeds of which have been clinically utilized in several disorders caused in liver. The present study aims to evaluate the effect of duration and storage conditions, population, and temperature on seed germination. The experiment was conducted in Petri dishes with three replications and three factors: (a) wild populations of milk thistle (Palaionterveno, Mesopotamia, and Spata) originating from Greece, (b) duration and storage conditions (5 months at room temperature, 17 months at room temperature, and 29 months in the freezer at -18 °C), and (c) temperature (5 °C, 10 °C, 15 °C, 20 °C, 25 °C, and 30 °C). All three factors significantly affected germination percentage (GP), mean germination time (MGT), germination index (GI), radicle length (RL), and hypocotyl length (HL) and significant interactions among the treatments were noted. In specific, no seed germination was recorded at 5 °C, while the populations showed higher GP and GI at 20 °C and 25 °C after 5 months of storage. Prolonged storage negatively affected seed germination although, cold storage mitigated this effect. Moreover, higher temperatures reduced MGT and increased RL and HL with the populations reacting differently in storage and temperature regimes. The results of this study should be taken into consideration when proposing the appropriate sowing date and storage conditions of the seeds used as propagation material for crop establishment. Moreover, the effects of low temperatures such as 5 °C or 10 °C on seed germination as well as the high decline rate in germination percentage over time could be utilized in the design of integrated weed management systems thereby indicating the importance of the sowing time and the suitable crop rotation system to weed control.

Prediction Model of Pumpkin Rootstock Seedlings Based on Temperature and Light Responses

Temperature and light are the key factors that affect the quality of pumpkin rootstock seedlings’ growth process. Responses to temperature and light are an important basis for optimizing the greenhouse environment. In order to determine the quantitative effects of temperature and light on the growth and development of pumpkin (Cucurbita moschata cv. RTWM6018) rootstock seedlings, relationships between temperature, light, and pumpkin rootstock seedlings growth were established using regression analysis. The results indicated that the daily average temperature had a significant negative correlation with the development time of pumpkin rootstock seedlings, and the shoot dry weight of pumpkin rootstock seedlings increased within a certain range of the daily light integral (DLI). We established a prediction model of pumpkin rootstock seedling quality indicators (hypocotyl length, stem diameter, shoot dry weight, root dry weight, root shoot ratio, and seedling quality index) based on thermal effectiveness and photosynthetic photon flux density (TEP). The coefficient of determinations (R2) of the hypocotyl length and seedling quality index prediction models of pumpkin rootstock seedlings, based on accumulated TEP, were 0.707 and 0.834, respectively. The hypocotyl length and seedling quality index prediction models of pumpkin rootstock seedlings, based on accumulated TEP, were y1 = 0.001 x2 − 0.180 x + 13.057 and y2 = 0.008 x0.722, respectively, which could be used for predicting the growth of pumpkin rootstock seedlings grown under different temperature and light conditions.

Aqueous Extracts of Four Medicinal Plants and Their Allelopathic Effects on Germination and Seedlings: Their Morphometric Characteristics of Three Horticultural Plant Species

Allelopathy is a biological phenomenon of synthesizing and excreting compounds that can affect the growth of various organisms, i.e., plant species. The aim of this work was to investigate the possible allelopathic influence of aqueous extracts, obtained from plant species chia (Salvia hispanica L.), black cumin (Nigella sativa L.), wormwood (Artemisia absinthium L.), and nettle (Urtica dioica L.), on the seed germination growth and morphometric characteristics of pepper (Capsicum annuum L.), spinach (Spinacia oleracea L.) and lettuce (Lactuca sativa L.) seedlings in laboratory conditions. Pepper, spinach, and lettuce seedlings were treated with aqueous extracts of chia, nettle, wormwood, and black cumin of different concentrations (2.5, 5 and 10%, respectively). The aqueous extracts were prepared according to the method developed by Norsworthy and the qualitative and quantitative analysis of phenolic compounds in aqueous extracts were performed using ultra-performance liquid chromatography electrospray ionization tandem mass spectrometry (UPLC-ESI-MS/MS). Phytochemical composition of chia aqueous extracts showed the highest content (above the 1 mg L−1) of epicatechin, quinic acid, caffeic acid, esculetin and cinnamic acid in the comparison with others from the total of 19 detected chemical compounds. In aqueous extracts of black cumin, there were six compounds detected in content above 1 mg L−1, i.e., epicatechin, quinic acid, caffeic acid, esculetin, cinnamic acid, and kaempferol. The same compounds were the most abundant in wormwood extracts, along with gallic acid. Epicatechin and esculetin were only two compounds detected in aqueous extract of nettle in concentration higher than 1 mg L−1. According to the results of this study, only the treatment of spinach seeds with chia aqueous extract in concentration of 2.5% before germination stimulates the germination of spinach seeds, and wormwood herbs and chia extracts in concentrations of 2.5 and 5% stimulate the germination of lettuce seeds and the growth of hypocotyl and radicle length of developed seedlings. The treatment of pepper and lettuce seeds with aqueous extract of nettle in concentration of 10% completely inhibited seed germination.

Mutual Effects of Zinc Concentration and Ratio of Red-Blue Light on Growth and Nutritional Quality of Flowering Chinese Cabbage Sprouts

The nutritional quality and biomass of various sprouts can be enhanced by Zn and red-blue light, especially the Brassica sprouts. However, the combined effects of this two on sprouts are rarely reported. In this study, different Zn concentrations (0, 1.74, 3.48, 10.43 and 17.39 mM) were combined with two ratios of red-blue light-emitting diodes (LEDs) (R: B = 1:2, 1R2B; R: B = 2:1, 2R1B, at 70 μmol m−2 s−1 PPFD, 14 h/10 h, light/dark) to investigate their mutual effects on the growth, mineral elements, and nutritional quality in flowering Chinese cabbage sprouts (FCCS). Fresh weight, dry weight, contents of organic Zn, soluble sugar, vitamin C, total flavonoids, total polyphenol, FRAP (ferric ion-reducing antioxidant power) and DPPH (radical inhibition percentage of 1,1-diphenyl-2-picrylhydrazyl) were significantly increased by Zn supplement (10.43 and 17.39 mM) and 2R1B, while hypocotyl length and moisture content were decreased remarkably by Zn supplement. Total glucosinolates contents in the sprouts increased dramatically under 2R1B compared with 1R2B, while photosynthetic pigments contents decreased. Heat map and principal component analysis showed that 2R1B + 17.39 mM Zn was the optimal treatment for the accumulation of biomass and health-promoting compound in FCCS, suggesting that a suitable combination of light quality and Zn supplement might be beneficial to zinc-biofortified FCCS production.

Effect of Storage Time On Seed Viability of Cocoa (theobroma cacao l.) Variety Criollo

This research activity was carried out at the Laboratory of the Faculty of Agriculture, University of Muara Bungo Sungai Binjai and on Jl. Onion bone unit 3 Rimbo Mulyo Village, Kec. Rimbo Bujang Kab. Tebo, Jambi Province. This research activity was carried out for 2 months starting from 02 March - 02 April 2022. The aim of the research was to obtain information about whether storage duration affects the viability of cocoa seeds of the Criollo variety and to obtain optimal storage duration for the viability of cacao seeds of the Criollo variety. The design used in this study used a completely randomized design (CRD) with 6 treatments and 3 replications, the treatments were: P0 : 0 MSS (Week After Storage) = 0 Days After Storage, P1:1 MSS (Week After Storage) = 7 Days After Saving, P2 : 2 MSS (Week After Saving) = 14 Days After Saving, P3 : 3 MSS (Week After Saving) = 21 Days After Saving, P4 : 4 MSS (Week After Saving) = 28 Days After Saving, P5 : 5 MSS (Week After Save) = 35 Days After Save. Parameters observed were seed moisture content after storage (%), germination rate (%), normal sprouts (%), abnormal sprouts, dead sprouts (%), hypocotyl length, root length, shoot length, as well as supporting data (determining room temperature and humidity). Data obtained from observations were analyzed statistically using variance. If there is a significant effect, then proceed with the Duncan New Multiple Range Test (DNMRT) at 5% level. The results showed that the storage time of the criollo variety cocoa seeds on the viability of cocoa seeds had a very significant effect on the moisture content of the seeds after storage, germination, normal sprouts, dead shoots, long hypocotyl root length, shoot length, and had no significant effect on sprouts. abnormal. Treatments P0, P1 and P2 at 0 MSS to 2 MSS gave good treatment of the moisture content of the seeds after the storage period on the viability of the seeds on the effect of storage duration of the criollo variety cocoa seeds.

Effect of the Application of Biofertilizer Goatish as a Biostimulant on Germination Canavalia Ensiformis L.

Objective: This study aimed to evaluate the influence of different concentrations of goatish biofertilizer as an alternative biostimulant on the germination and vigor of pork bean seeds. Theoretical framework: The availability of complementary nutrients via seeds promotes germination and vigor, since they are fundamental factors for the good development of production. Therefore, the use of alternative technologies as a biostimulant promote better formation and development of the plant. Methodology: The research was carried out at the Seed Technology Laboratory of the Federal University of Paraíba. A completely randomized design was used, with treatments at different concentrations of goat biofertilizer, namely: 0% (control), 25%, 50%, 75% and 100%, where they were immersed for 10 minutes. The substrate used was Germiteste paper, where 30 jack bean seeds were distributed and stored at a temperature of 30 °C for 12 hours of light. The variables analyzed were: germination speed index, germination, primary root length, hypocotyl length, width and length of cotyledons and green and dry mass of the variables mentioned above. Results and conclusion: The application of the concentration of 50 and 75% proved to be efficient in the seed germination process and germination speed index. The 25% concentration of goat biofertilizer provided better performance in the morphological characteristics of jack bean seeds. Research implications: The main contributions of the study are in the sense of demonstrating a different methodology as an alternative biostimulant in the germination and vigor of seeds, which can contribute to researchers and family farmers in overcoming seed dormancy, as well as increasing plant growth and development. Originality/value: This study proposes to evaluate the biofertilizer as a biostimulant in the germination and vigor of jack bean seeds as an alternative for taking advantage of the organic residue.

Involvement of microRNA164 in responses to heat stress in Arabidopsis

MicroRNAs (miRNAs) are considered to be integral parts of plant stress regulatory networks. Under long-term heat stress, miR164 is induced. Conversely, its targets are repressed. Transgenic overexpressors (164OE) and mutants of MIR164 (mir164) were used to study miR164’s functions during heat responses. Target gene expression decreased in 164OE transgenic plants and increased in mir164a-4 and mir164b mutants. Under heat stress, the mir164 mutants presented heat-sensitive phenotypes, while 164OE transgenic plants showed better thermotolerance than wild-type (WT) plants. Overexpression of miR164 decreased heat-inhibition of hypocotyl lengths. Under heat stress, miR164 target genes modulated the expression of chlorophyll b reductase and chlorophyll catabolic genes, reducing the chlorophyll a/b ratio. More H2O2 accumulated in the mir164 mutants under heat stress, which may have caused oxidative damage. In addition, expression of HSPs was altered in the experimental plants compared to that of the WT. Overall, miR164 influenced target gene expression, altering development, chlorophyll a/b ratio, H2O2-caused damage, and HSPs expression under long-term heat stress. These phenomena, in turn, likely influence the thermotolerance of plants.

Germination and Seedling Growth of Sesame Cultivars under Salinity Stress

Among the most common abiotic stresses that retard the development and growth of plants is salt stress. This study examined the impact of various salt levels (NaCl and Na2SO4) on the germination behaviour of sesame cultivars. Under various simulated salt concentrations (0.05M, 0.01M, 0.15M, 0.2M, 0.25M, 0.3M, 0.35M, 0.4M, and 0.5M), the degree of salinity tolerance of two sesame cultivars, viz., GT-10 and JTS-8 were assessed. The radicle, hypocotyl length, and fresh weight measurements were made separately after 96 and 144 hours. The results revealed that germination and seedling growth drastically decreased as the salt concentration increased. In comparison to GT-10, JTS-8 exhibits greater tolerance to different NaCl concentrations and greater sensitivity to varying Na2SO4 concentrations.

Growth of tomato and cucumber seedlings under different light environments and their development after transplanting.

Selecting suitable light conditions according to the plant growth characteristics is one of the important approaches to cultivating high-quality vegetable seedlings. To determine the more favorable LED light conditions for producing high-quality tomato and cucumber seedlings in plant factories with artificial light (PFALS), the growth characteristics of tomato and cucumber seedlings under seven LED light environments (CK, B, UV-A, FR, B+UV-A, UV-A+FR, and B+FR) and the development of these seedlings after transplanting into a plastic greenhouse were investigated. The results showed that the seedling height and hypocotyl length increased in treatments with far-red light supplementation (FR, UV-A+FR, and B+FR), but decreased in the B treatment, in both varieties. The seedling index of tomato seedlings increased in the B+UV-A treatment, while that of cucumber seedlings increased in the FR treatment. After transplanting into a plastic greenhouse, tomato plants that radiated with UV-A had greater flower numbers on the 15th day after transplanting. In cucumber plants of the FR treatment, the flowering time was significantly delayed, and the female flower exhibited at a lower node position. By using a comprehensive scoring analysis of all detected indicators, light environments with UV-A and FR were more beneficial for improving the overall quality of tomato and cucumber seedlings, respectively.

Synthesis and Phytotoxic Evaluation of Isatin Derivatives Supported by 3D-QSAR Study.

Concerned about weed infestation, a major threat to food production and herbicide resistance that interferes in the mechanism of action of the main herbicides, we have synthesized eight isatin derivatives using the "Click Chemistry" approach through copper-catalyzed azide-alkyne cycloadditions (CuAAC). Sixteen isatin derivatives were evaluated for their phytotoxic activity against the seed culture of the model plants, Lactuca sativa and Allium cepa. Six of them showed phytotoxic activity similar to the positive control, trifluralin. Hypocotyl length measurement analysis in L. sativa revealed that triazole derivative 8 is more active than trifluralin. For A. cepa, root length measurement analyses revealed that 3, 10, 14, 16, and 17 were similar to the positive control trifluralin. Three-dimensional quantitative structure-activity relationship (3D-QSAR) comparative molecular field analysis (CoMFA) model construction using the acetolactate synthase (ALS) crystallographic structure displayed pki values of predicted inhibitory activity and contour maps revealing sterically bulky groups for 11, the CF3 group in ortho, and for 17, Br in ortho, favoring the inhibitory ALS activity.

The alkaloids of Lupinus mutabilis Sweet. and its use in the weed control

Allelopathy is described as the positive or negative effect that one plant causes on the growing of another, which occurs through the reléase of chemical components to the environment. The 'tarwi', Lupinus mutabilis Sweet., is a native legume from the Andean region whose seeds have a high protein content, however, these have a bitter taste due to the presence of alkaloids, metabolites that have been reported as allelochemical components, whose uses in agriculture are being investigated. Laboratory experiments were conducted to determine the effect of 5 concentrations (0, 1.55, 3.10, 4.65 and 6.20 mg mL-1) of aqueous extract of tarwi alkaloids on the germination and growth of in vitro seedlings of three species of weeds; Amaranthus dubius, Bidens pilosa and Medicago polymorpha, in which the germination percentage, radicle and hypocotyl lengths of the seedlings were evaluated. An inversely proportional relationship between the concentrations and lengths evaluated for all species was considered, having A. dubius germination and M. polymorpha seedling growth as the most affected. The most significant reduction in germination and plant growth occurred at concentrations above 4.65 mg mL-1.

Analysis of Effect of Compound Salt Stress on Seed Germination and Salt Tolerance Analysis of Pepper (Capsicum annuum L.).

To determine the salt tolerance and physiological mechanism of pepper (Capsicum annuum L.) at the germination stage, the Hongtianhu 101 and Xinxiang 8 varieties, which have large differences in salt tolerance, are employed as the study materials. Six mixed salt concentrations of 0, 3, 5, 10, 15, and 20 g/L derived using equal molar ratios of Na2CO3, NaHCO3, NaCl, CaCl2, MgCl2, MgSO4, and Na2SO4 are used. To determine their effects, the related indexes of seed germination, seedling growth, and physiology are measured, and salt tolerance is comprehensively evaluated using membership function analysis. The results show that as the mixed salt concentration increases, the germination potential, germination index, germination rate, seed germination vigor index, root length, and root fresh weight of the two cultivars significantly decrease, whereas the relative salt rate gradually increases. The hypocotyl length and fresh weight aboveground increase first and then decrease, while the malondialdehyde (MDA), proline (Pro) content, catalase (CAT), peroxidase (POD), and superoxide dismutase (SOD) activity decrease and then increase. The germination potential, germination index, germination rate, seed germination vigor index, root length, root fresh weight, MDA and Pro content, and CAT activity of the Hongtianhu 101 seeds are higher than those of Xinxiang 8 for all salt concentrations employed here. However, hypocotyl length, fresh weight aboveground, and relative salt rate are lower in Hongtianhu 101 than in Xinxiang 8. The comprehensive evaluation of salt tolerance reveals that the total weighted values of the two membership function indexes increase first and then decrease as the mixed salt concentration increases. Compared with 5 g/L, which has the highest membership function value, the index under salt concentrations of 3 g/L, 10 g/L, and 15 g/L decreases by 4.7%-11.1%, 25.3%-28.3%, and 41.4%-45.1%, respectively. This study provides theoretical guidance for the breeding of salt-tolerant varieties of pepper and an analysis of the physiological mechanisms involved in salt tolerance and salt-tolerant cultivation.

Evaluation of Allelopathic Activity Interactions of Some Medicinal Plants Using Fractional Inhibitory Concentration and Isobologram

Allelopathy is a physiological process with an ecological concept and application. Allelopathy is the result of the production of biologically active molecules by growing plants or their remains, which may have a direct effect on the growth and development of individuals of the same species or other species after changing their shape and entering the environment. As regards, the use of natural compounds in the control of weeds and pests is a priority. In this research, the allelopathic activity of 123 specimens of medicinal and aromatic plants were investigated individually by the dish-pack method using lettuce seeds as a model. Then, the strongest inhibitory ones were selected and their allelopathic interaction effects were investigated for the first time by interacting them together. Two methods were used to evaluate allelopathic interaction effects: calculating Fractional Inhibitory Concentration (FIC) and drawing Isobologram diagrams. Lettuce hypocotyl length, root length, germination percentage, and germination rate were investigated. Pelargonium graveolens (leaf) had the greatest inhibitory effect on lettuce radicle growth (EC50 = 5.31 mg/well) and Echinophora platyloba (stem) had the greatest effect on hypocotyl growth inhibition (EC50 = 7.91 mg/well). Also, the lowest lettuce germination percentages were observed in the treatments Lavandula officinalis (flower) and Nepeta binaloudensis (leaf), respectively (23.61, 22.85%). The highest inhibitory effect by considering lettuce germination rate was detected in Salvia ceratophylla (leaf), (12.86 seed/day) and the lowest belonged to Nepeta binaloudensis (leaf) and Lavandula officinalis (flower), respectively (3.60, 3.32 seed/day). According to FIC calculations and isobolograms, two types of interaction, including synergist (Nepeta binaloudensis (leaf) with Trachyspermum ammi (fruit) and Nepeta binaloudensis (leaf) with Lavandula officinalis (flower) and antagonist (Pelargonium graveolens (leaf) with Lavandula officinalis (flower)), were observed significantly among the plants tested in this research. These interactions can be used to prepare more effective natural herbicides and decrease the use of herbicides.

Synthesis of fluorescently labeled pyrazole derivative induceing a triple response in <i>Arabidopsis</i> seedlings

A fluorescent labeled pyrazole derivative with a dansyl moiety (EH-DF) was synthesized. Design of EH-DF was carried out by using a dansyl moiety to substitute the naphthalene moiety of the parent compound (EH-1). At a concentration of 30 µM, EH-DF displayed biological activity on inducing a triple response in Arabidopsis seedlings. Compared with the non-chemical treated control, the hypocotyl length of EH-DF-treated Arabidopsis seedlings was reduced from approximately 9.2±0.7 mm to 2.4±0.2 mm. The length of the roots was reduced from 1.7±0.1 mm to 1.0±0.1 mm, and the curvature of the hook of Arabidopsis seedlings increased from 60±16 degrees to 245±35 degrees. The maxim excitation wavelength and emission wavelength of EH-DF were 350 and 535 nm, respectively. Data obtained via fluorescent microscope analysis indicated that intensive fluorescent signals of EH-DF were observed in the shoot of Arabidopsis seedlings.

Effects of Gibberellin Pre-Treatment on Seed Germination and Seedling Physiology Characteristics in Industrial Hemp under Drought Stress Condition.

The present study aimed to explore the effects of exogenous gibberellins (GAs) on seed germination and subsequent seedling growth of hemp (Cannabis sativa L.) under drought stress. Seeds of two industrial hemp cultivars i.e., 'Yunma 1', (YM) and 'Bamahuoma', (BM) were treated with different concentrations of GA3 solution (0, 200, 400, 600, 800 mg/L) at 20 °C for 8 h. The effect of pre-treatment was assessed on germination characteristics and physiological indexes on subsequent exposure to drought stress using 20% (m/v) polyethylene glycol (PEG) for 7 days. The results revealed that seed germination in hemp was sensitive to drought stress, as the germination indexes (germination rate and germination potential) decreased significantly, and seedling growth (hypocotyl length and radicle length) was impeded under 20% PEG-6000 condition. GA3 pre-treatment affected germination rate, germination potential, hypocotyl length and radicle length. With increasing GA3 concentration, these indexes first increased and then decreased. For seedling physiology characteristics in hemp, GA3-pretreatment remarkedly increased the osmotic regulating substances (soluble sugar and soluble protein contents) and the activities of antioxidant enzymes (SOD, superoxide dismutase and POD, peroxidase), while sharply decreased the lipid peroxidation (malondialdehyde, MDA) in seedlings grown under PEG-6000 induced drought stress. These results suggested that seeds pre-treated with GA3 could enhance the drought tolerance of hempseeds, and the optimal effect of GA3 for seed pre-treatment of YM and BM could be obtained when the concentration of GA3 solution reached 400 mg/L and 600 mg/L, respectively.

The Effect of Immersion Time at Initial Water Temperature of 50°C and Gibberellin Concentration on Viability of Arabica Coffee Seeds (Coffea arabica L.)


 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 The coffee nursery process takes a relatively long time hence it can affect the production period of coffee plants because of it a seed treatment is needed before planting i.e. immersion with the initial water temperature and in the gibberellin solution. This research aim was to obtain the immersion time of the seeds at the initial water temperature of 50°C and the optimal gibberellins concentration to increase the viability of Arabica coffee seeds. The method used was Factorial Randomized Group Design with two factors and three replications. The first factor was the immersion time with an initial water temperature of 50°C with 4 levels, namely; 0, 10, 20, and 30 minutes. The second factor was the gibberellins concentration with 4 levels, namely; 0, 50, 100 and 150 ppm. The results showed that an increase in the immersion time of the seeds at the initial water temperature of 50°C was able to accelerate the germination rate and accelerate the time of leaves appearance. The increased of gibberellin concentration can accelerate germination rates, increase the percentage of normal sprouts, decrease the percentage of dead seeds, increase the vigor index, increase hypocotyl length, increase root length, accelerate leaf emergence and decrease the percentage of abnormal sprouts but reduce the percentage growth potential. The treatments interaction can increase the viability of Arabica coffee seeds, namely germination rate for 21.74 days, the percentage of abnormal germination by 0%, vigor index of 0.85 germinating seeds/day, and root length of 8.78 cm.

The B-box transcription factor 4 regulates seedling photomorphogenesis and flowering in tomato

Tomato (Solanum lycopersicum L.) is an important solanaceous crop worldwide. Research in the model plant species Arabidopsis revealed that B-box family transcription factors (BBXs) play key roles in plant development, however, only very few tomato BBXs have been functionally characterized. In this work, we report that the transcription factor SlBBX4 (Solyc08g006530) plays critical roles in tomato seedling photomorphogenesis. The slbbx4 frame-shift mutants showed hyposensitive response to red light, while maintained normal responses to blue, far-red light and UV-B in hypocotyl length assays. The red light-specific function in seedling photomorphogenesis is analogous to Arabidopsis BBX4 (AtBBX4). Whereas atbbx4 mutant flowered earlier than wildtype, the slbbx4 mutants showed delayed flowering, under both long-day and short-day conditions. Thus, SlBBX4 and AtBBX4 play both shared and distinct functions in plant development. The E3 ligase CONSTITUTIVELY PHOTOMORPHOGENIC1 (COP1) is known to play important functions in the regulation of seedling photomorphogenesis and flowering in Arabidopsis. SlBBX4 interacts with tomato COP1 (SlCOP1) in yeast and in planta, suggesting that SlBBX4 is likely regulated by SlCOP1. Taken together, our data suggest that SlBBX4 plays promotive roles in red light-induced photomorphogenesis and flowering, both of which are potentially beneficial in agriculture.