Germination Speed Index Research Articles

Evaluation of postharvest age and dormancy-breaking methods on Echinochloa crus-galli seed germination

Barnyardgrass (Echinochloa crus-galli) is one of the most troublesome weeds in irrigated rice cultivation and has increasingly impacted rainfed crops due to the emergence of herbicide-resistant populations. Understanding its germination dynamics is crucial for developing and implementing effective management strategies. Additionally, since barnyardgrass research relies on growing plants from seeds, its dormancy characteristics are of particular interest. The present study aimed to evaluate the influence of postharvest age on barnyardgrass seed germination and the effectiveness of different dormancy-breaking methods in susceptible and herbicide-resistant populations. Germination rate (G), germination speed index (GSI), and seed viability, assessed using the topographic tetrazolium test, were measured in seed lots with four different postharvest ages: two years, one year, two months, and one day postharvest. The seeds were subjected to 15 dormancy-breaking methods, including temperature variation and the use of solutions containing H2SO4, KNO3, and GA3. Seeds that were one or two years old showed germination rates exceeding 90%, regardless of the method used. In contrast, seeds aged two months or one day postharvest only germinated when exposed to 40°C for seven days, with G values of 25.2% and 5.9%, respectively. Both herbicide-susceptible and resistant barnyardgrass populations exhibited similar dormancy levels and responses to dormancy-breaking methods. The results indicate that newly harvested seeds have high dormancy levels, and specific methods are only partially effective in overcoming barnyardgrass seed dormancy.

DESERT ROSE DIALLEL CROSSES: SEED PRODUCTION AND PHYSIOLOGY

The desert rose, known for its striking sculptural appearance and diverse flowers, holds a prominent place in the market. Despite its ornamental potential, there is limited information on the genetic variability and selection of superior genotypes and their seeds. This study aimed to assess the general (GCA) and specific (SCA) combining ability among desert rose accessions, estimate genetic parameters, and evaluate seed characteristics' correlation. Additionally, we examined the quality of seeds resulting from crosses involving five desert rose genotypes based on floral color. The evaluation included various seed-related traits such as percentage, days until harvesting, number of fruits, seeds per fruit, water content, weight of 100 seeds, seed dimensions, germination, speed of germination index (SGI) in sand, germination, and SGI in paper, seedling length, and dry seedling mass. Genotype 1 displayed positive GCA for all traits, indicating a higher number of favorable alleles for seed production. Hybrid 1X3 exhibited positive SCA estimates, suggesting significant production potential. Notably, 2X5 and 1X5 hybrids demonstrated superior seed quality. Seeds per fruit, germination in sand, seedling length, and dry seedling mass were key contributors to genetic diversity. The study revealed high heritability and positive correlations.

Effect of Plant Growth Regulators on Germination and Seedling Growth of Passiflora alata and Passiflora edulis

The yellow (Passiflora edulis) and sweet (Passiflora alata) passion fruit plants hold significant economic importance in tropical fruit cultivation, valued not only for the quality of their fruit but also for their medicinal properties. Conventional propagation through seeds faces challenges due to irregular and slow germination, affecting the time required for seedling formation and the viability and uniformity of plantations. The use of plant growth regulators has been explored as a strategy to overcome these barriers, improving both the rate and uniformity of seed germination. This study aimed to evaluate the influence of seed imbibition with plant growth regulators on the germination and subsequent growth of yellow and sweet passion fruit seedlings. Gibberellic acid (GA3) and GA4+7 combined with 6-benzyladenine (GA4+7+6BA) were applied in five different concentrations (0, 250, 500, 750, and 1000 mg L−1 a.i.). The experiments were conducted in both laboratory and greenhouse conditions, following a completely randomized design with a 2 × 5 factorial scheme. The varieties tested were ‘BRS Mel do Cerrado’ for sweet passion fruit and ‘IAC-275’ for yellow passion fruit. Quantitative parameters, such as germination percentage, germination speed index, fresh and dry biomass of roots and shoots, and enzymatic activity, were assessed. The results indicated that GA3, at higher concentrations, significantly enhanced both germination percentage and speed index in both Passiflora alata and Passiflora edulis when compared to the control. Additionally, seedlings treated with GA3 showed a marked increase in shoot and root biomass, particularly at concentrations of 500 and 750 mg L−1. Enzymatic assays revealed heightened catalase and peroxidase activities in treated seedlings, indicating improved stress tolerance. In contrast, the GA4+7+6BA treatment showed less pronounced effects on seedling growth. Overall, GA3 was more effective in enhancing germination and seedling growth in both species, suggesting its potential application in improving the propagation of passion fruit.

Germination of chief fire seeds cockscomb cultivar under saline stress conditions induced by sodium chloride

Cockscomb plant, Chief fire cultivar, is used as an ornamental, medicinal and non-conventional food plant (NCFP) and is cultivated from the north to the center-west of Brazil; however, these areas suffer from adverse environmental factors such as salinity stress. The objective of this study was to evaluate the seed germination performance and vigor of Celosia cristata L. var. Chief Fire seedlings exposed to salinity during the germination phase. To carry out the work, C. cristata seeds were sown in gerboxes conditioned to increasing doses of sodium chloride (NaCl), obtained by dissolving the salt in distilled water, obtaining electrical conductivities of 2.0; 4.0; 6.0 and 8.0 dS.m-1, constituting the treatments. An additional group was treated only with distilled water and was used as a control for the experiment. The experiment was conducted in a completely randomized design, with a total of five treatments and four replicates of 25 seeds. The parameters assessed were: first germination count, germination, germination speed index (GVI), mean germination time (MGT), length of aerial part and primary root. The data was submitted to analysis of variance and the means were compared using the Scott-Knott test at 5% significance. Based on the results obtained, it can be concluded that the conditions of salt stress induced by NaCl were not harmful to the germination of C. cristata, presenting itself as a species tolerant to water salinity during seed germination, since the variables analyzed showed no signs of deleterious effects as the salt concentration was increased.

Phytotoxic and Cytogenetic Assessment of Glycerol Triazole Derivatives in Model Plants and Weeds.

Weed invasion represents a challenge for farmers, who typically manage it with herbicides. However, this approach raises concerns about environmental and human health, as well as increasing resistance in these plants with continued use. Therefore, exploring alternative methods, such as heterocyclic compounds, triazoles, is essential due to their biological and environmental relevance. This study aimed to evaluate the effects of twelve 1,2,3-triazoles on the germination and early development of Lactuca sativa, Bidens pilosa, and Lolium multiflorum, as well as their impact on cell division in the cells of L. sativa. Triazole derivatives 4a, 4b, 4c, 4g, 4h, 4i, 4k, and 4l exhibited phytotoxicity, showing varying levels of inhibition in germination, germination speed index, and root growth. Chlorinated compounds were the most detrimental to lettuce development. B. pilosa was notably affected by compounds 4h, 4i, 4k, and 4l, while L. multiflorum responded most to triazoles 4c and 4l, with effectiveness comparable to that of the herbicide glyphosate. All derivatives, except 4l, exhibited aneugenic mechanisms of action, and 4a, 4b, 4c, 4e, 4f, and 4g showed clastogenic effects. This study demonstrated the potential of triazoles as effective agents against weed growth, with mechanisms that warrant further investigation for agricultural applications.

Interference of mechanical damage on the physiological performance of corn seeds

Corn (Zea mays L.) is cultivated and consumed globally due to its nutritional qualities and short production cycle. However, during harvesting, processing, transportation, and storage, seeds are susceptible to various types of damage that can compromise their productive capacity, affecting both germination and plant vigor. Therefore, this study aimed to evaluate the physiological quality of corn seeds subjected to different types of mechanical damage. The experiment was conducted at the Laboratory of Storage and Processing of Agricultural Products at the Federal University of Campina Grande, Campina Grande, Paraíba, Brazil. Corn seeds were subjected to four types of mechanical damage: hammering, cutting, abrasion, and perforation, alongside a control sample that did not undergo any mechanical damage. Each treatment (mechanical damage) consisted of 200 seeds, which were evaluated through germination tests, including first count, germination rate, germination speed index (GSI), seedling dry weight, and root length. The experiment was conducted in Completely Randomized Design. Data were subjected to Analysis of Variance, and means were compared using the Scott-Knott test (P ≤ 0.05) when necessary. Mechanical damage reduces the germination and vigor of corn seeds. Cutting-type damage affects corn seeds more severely, reducing germination by an average of 80% and impairing vigor.

Physiological quality of green corn seeds under water stress conditions

This study aimed to evaluate the physiological quality of green corn seeds subjected to water stress. The experimental design used was completely randomized, in a 2 x 5 factorial arrangement, consisting of two corn hybrids (AG1051 and BRS3046) and five osmotic potentials (0; -0.4; -0.8; -1.2 and – 1.6 MPa) simulated with aqueous solutions of polyethylene glycol 6000 (PEG 6000), with four replications of 50 seeds per treatment, totaling 40 experimental units. The analyzed variables were: water content, germination, root protrusion, final root protrusion, germination speed index, root length and coleoptile length. There was a significant effect of the interaction between hybrid factors and osmotic potentials for all analyzed variables, except for final root protrusion, which showed an isolated effect for the two factors studied. The results obtained indicated a higher percentage of germination and initial development of green corn seedlings for green corn seeds, hybrids AG1051 and BRS3046 at the osmotic potential of 0.0 MPa. The germination and vigor of green corn seeds decrease under water stress conditions from the osmotic potential of -0.4 MPa induced by PEG 6000, inhibiting the development of normal seedlings, affecting seed viability. Hybrid AG1051 presents superior germination and vigor compared to BRS3046.

In vitro germination and seedling formation of Plantago tomentosa Lam. (Plantaginaceae): influence of concentrations of the MS medium

Plantago tomentosa Lam. (Plantaginaceae) is an herbaceous plant native to Brazil. It is widely used in folk medicine. The species has potential for use in the pharmaceutical and food industry due to its possible bioactive properties and the presence of mucilage in the seeds. The objective of this work was to investigate the influence of different concentrations of Murashige-Skoog (MS) medium on germination and seedling formation in vitro of P. tomentosa. The seeds were collected in Lajeado, disinfected, and inoculated in bottles with MS medium added to 7 g L-1 of agar and 30 g L-1 of sucrose, in four treatments: 25%, 50%, 75%, and 100% of the medium concentration. The experimental design was completely randomized, consisting of 17 replications of ten seeds for each treatment. The evaluation of germination and formed seeds was carried out every two days to determine the variables of germination percentage (GP), mean germination time (MGT), germination speed index (GSI), seedling formation percentage (SFP), mean seedling formation time (MSFT) and seedling formation speed index (SFSI). No significant difference was found between treatments for all the assessed variables. It is concluded that the use of a concentration of 25% of the MS medium is viable, as it promoted a high percentage of germination and seedling formation and in a time interval similar to that of the other concentrations, with the advantage of using fewer reagents.

Processing of Salvinia auriculata biomass by semi-solid fermentation and green mechanochemical synthesis as agricultural inputs

Currently, the biomass of various plant species is being utilized to produce high-value agricultural inputs, and the technique of green mechanochemical synthesis is employed in this process due to its relatively simple nature. This technique utilizes biomass to produce new biologically active compounds with properties such as biofertilizers, biostimulants, and bioinsecticides. In the present study, Salvinia auriculata biomass was used to obtain a valuable plant substrate and subsequently processed to be applied in vegetable crops for productivity improvement in field conditions. The Salvinia biomass was subjected to semi-solid fermentation, resulting in an organic substrate. This substrate was tested for the germination of melon (Cucumis melo L.) and watermelon (Citrullus lanatus) seeds, demonstrating excellent results when compared to commercial substrates. Comparing melon seedlings grew on different commercial substrates with Salvinia substrate, the germination index (GI), germination speed index (GSI), number of leaves (NL), aerial part length (APL), root of length (RL), aerial part fresh mass (APFM), root fresh mass (RFM), aerial part dry mass (APDM) and root dry mass (RDM) presented, respectively, an increase of 35%, 42.79%, 52%, 56.72%, 143.4%, 97%, 111.4%, 112%, 49.5% and 103%, demonstrating that Salvinia substrate is superior to the commercial substrates evaluated. Similar results were obtained for watermelon plants grew on Salvinia substrate. Subsequently, a bionanofertilizer (BNF) from fermented biomass was produced through green mechanochemical synthesis, a technique that proved to be highly efficient for nanofertilizer production. The tests demonstrated that the BNF at different doses had effects in vegetable crops after foliar application in the field. In melon plants, the productivity per plant increased by 50% after the foliar application of BNF and the productivity per hectare went from 14 Kg/ha to approximately 20 Kg/ha after 12% BNF application. Therefore, Salvinia auriculata biomass is an excellent source of organic compounds for formulating agricultural inputs.

Tolerance to desiccation and freezing of Passiflora alata Curtis cv BRS Mel do Cerrado seeds and pre-germination treatments

To define the best storage conditions, it is necessary to know the physiological behavior of the seeds. The objectives of this study was to evaluate the physiological quality of seeds of Passiflora alata Curtis cultivar “BRS Mel do Cerrado” with different water contents and frozen at -20 °C. The effect of pre-germination treatments on seed performance after drying and freezing was also evaluated. Seeds dried until water content of 12.6%, 7.6%, 5.5%, 4.9%, 4.5%, 4.3%, 3.8% and undried seeds (control) with 19.2% moisture were stored at -20 ºC for 100 days. Germination and vigor tests (germination speed index, GSI) were carried out on dried seeds in the presence or absence of a growth regulator (gibberellins + cytokinins) and on frozen seeds, in the presence or absence of ascorbic acid. Seed germination after drying was high, ranging from 78% to 94%, regardless of the use of the growth regulator. Different results were observed for vigor, since greater germination speed was observed in treated seeds. The freezing did not affect germination and vigor of seeds with moisture ≤7.6%, unlikely of frozen with high moisture seeds, which did not germinate. Seeds of BRS Mel do Cerrado cultivar tolerate desiccation at low water contents and do not tolerate freezing at high moisture levels of 19.2% and 12.6%. Ascorbic acid does not increase the germination and vigor of dry and frozen seeds with differents moistures.

Assessment of Seed Germination and Growth of Seedling in Different Adenium Hybrids (Adenium arabicum) under Prayagraj Agro-climatic Conditions

The experiment was carried out during May, 2023 to April, 2024 to study the effect of seed germination and seedling growth of different Adenium hybrids in naturally ventilated polyhouse in the Department of Horticulture, SHUATS, Prayagraj. The different hybrids used in the experiment were White Zombie, Green Arabicum, Hulk, Super Dork Dork, RCN, KHZ, PBN, Godji x Red Bangle, Godji F2 and Gc x GT in completely randomized design and each hybrid was replicated thrice. The experimental results revealed that hybrid PBN reported significantly better performance in parameters like germination percentage (100%), days to 50% germination (4.4), seedling vigour index (1813.33), germination speed index (1.15), survival percentage (100%), seedling height (11.07cm), number of leaves per seedlings (16.67), leaf area (15cm2) and caudex diameter (3.93cm) which was found to be at par with hybrid RCN. Hence, hybrids PBN and RCN could be recommended for Prayagraj agro-climatic conditions.

Evaluation of Different Adenium (Adenium arabicum) Hybrids Performance for Seed Germination and Seedling Growth under Prayagraj Agro-climatic Conditions

An experiment was conducted in the Department of Horticulture, Sam Higginbottom University of Agriculture Technology And Sciences, Prayagraj, during the 2023-2024 period. The study employed Completely Randomized Design (CRD) with 10 hybrids, each replicated thrice. The hybrids tested were Godji x Nomsod, Godji x Ara Champ, Godji x Emerald Tank, Bangkla, Dynamo, Tropido, Dino King, Peth Dino, Susthaskorn, and Peth Phunlan. Among these hybrids the hybrid Godji x Ara Champ exhibited significantly better performance in several parameters, including germination percentage, days to 50% germination, seedling vigor index, seedling height, germination speed index, survival percentage, number of leaves per seedling, leaf area, caudex diameter.This hybrid's performance was found to be at par with the hybrid Dino King in terms of plant height, leaf area, caudex diameter, survival percentage. Consequently, hybrids Godji x Ara Champ and Dino King demonstrated superior performance in both germination and seedling growth under the agro-climatic conditions of Prayagraj.

Short-Term Liquid Nitrogen Storage of Pyrostegia venusta Embryos: Effects on Germination, Phenotypic and Biochemical Characteristics, and In Vitro Secondary Metabolite Production

In this study, short-term liquid nitrogen (LN) storage was used as a strategy to conserve Pyrostegia venusta embryos, and its effects on in vitro germination, phenotypic and biochemical characteristics, and in vitro secondary metabolite production were assessed. Embryos stored in LN for 1 and 7 days presented a higher germination rate and germination speed index compared to those of the control (non-cryostored embryos). Short-term LN storage also favored the phenotypic characteristics of seedlings. LN storage significantly affected the proteins (PTN), soluble sugar (SS) and reducing sugar (RS) contents, oxidative metabolism, and phenylalanine ammonia-lyase (PAL) activity, as well as the total phenolic compound, flavonoid, phytosterol, and alkaloid levels in seedlings regenerated from embryos cryostored for 7 days. Benzoic acid derivatives and flavonoids were observed in regenerated non-acclimatized seedlings. LN storage did not affect the survival rate or phenotypic characteristics of seedlings during acclimatization. Acclimatization promoted significant changes in PTN, SS and RS contents, oxidative metabolism, and PAL activity in seedlings from embryos cryostored for 7 days. Roots from acclimatized seedlings exhibited the highest phenolic, phytosterol, and total alkaloid levels. Differences in the chromatographic profiles of the acclimatized seedlings compared with the non-acclimatized seedlings were observed. LN storage can be an effective means of ex situ conservation of P. venusta genetic resources.

PHYSIOLOGICAL PERFORMANCE OF SEEDS OF Phaseolus vulgaris L. AS A FUNCTION OF ZINC AND PHYSIOLOGICAL MATURITY

The objective of this study was to study the physiological quality of bean treated with levels of zinc during the physiological maturation stage. The work was carried out at Fazenda Ponte da Braúna and at the Seed Analysis Laboratory of the Center for Agricultural Sciences and Engineering at the Federal University of Espírito Santo. Bean seeds of the cultivar Peanut were treated with Zn at concentrations of 0; 2.5; 5.0; 7.5 and 10 g kg-1 of seeds and sown in the field. The variables analyzed were seed moisture, 1000-seed weight, length, width and thickness of pods and seeds, germination, germination speed index, shoot length, root length, shoot and root dry matter. The experimental design used was completely randomized, in the factorial 5 x 7 (zinc doses x maturation periods), with four replications of 25 seeds. The seeds of the bean cultivar Amendoim treated with zinc at 10 g kg-1 seeds showed the highest values of pod length, thickness, and width. The seeds of the bean cultivar Amendoim showed the highest germination means and GSI after 35 days from anthesis. The treatment of seeds of the bean cultivar Amendoim with zinc does not influence the seedling characteristics. Seed treatment with zinc does not interfere with the seed maturation time of the bean cultivar Amendoim. The physiological maturation of seeds of the bean cultivar Amendoim occurs after 42 days from anthesis. The seed water content of the bean cultivar Amendoim at the stage of physiological maturation is 19%

Chemical and Mechanical Scarification as Techniques for Overcoming Dormance in Red Tent Seeds (Adenanthera pavonina L.)

Purpose: Evaluate chemical and mechanical scarification techniques, as methods for overcoming dormancy in red vine seeds. Theoretical Framework: Based on scientific articles found on search engines and books in the field of seeds, types of forest seeds, types of dormancy in forest seeds and techniques for overcoming dormancy. In order to support the explanation of how techniques for overcoming dormancy are related to the rate and time of germination of red seed seeds, and how germination time can subsequently affect the quantity of seedlings produced, as well as their initial growth. Method: The experiment was installed to test the following treatments: T0 – without scarification; T1 – mechanical scarification; T2 chemical scarification with 80% H2SO4 for half an hour; T3 – chemical scarification with 80% H2SO4 for one hour; T4 – chemical scarification with 0.4% KNO3 for half an hour; T5 – chemical scarification with 0.4% KNO3 for one hour. The design used was completely randomized, with six treatments, five replications and 20 seeds in each replication. At the end of 30 days, counting from the beginning of germination, the following variables were evaluated: germination speed index (IVG), average germination time (TMG), germination percentage (G) and germination speed index (IVG). Results and Conclusion: The most efficient methods for germinating the red tent seeds were mechanical scarification with sandpaper and immersion in 0.4% KNO3 for half an hour. However, mechanical scarification would be the most easily used and least expensive method for producing seedlings in nurseries. Research Implications: These results indicate that the mechanical scarification technique is an efficient method for overcoming the dormancy of the red tent, which is integumentary. Understanding the most efficient and effective techniques for overcoming dormancy in seeds of species that present this characteristic is important to allow, within the nursery, germination to occur quickly and uniformly. Consequently, making it possible to obtain seedlings with more uniform sizes, even though these are produced from seeds. Originality/Value: A high germination rate and uniform initial growth are important factors within the nursery, especially if it is of a commercial nature, but also for the restoration of areas, because it allows seedlings to be obtained in less time.

Quality assessment of soybean seeds submitted to industrial seed treatment and stored in a natural and controlled environment

Seed quality is a limiting factor in the search for high soybean yields. However, fungi and insect pests can negatively interfere with their performance, and industrial seed treatment (IST) is a tool used to minimize the attack of pathogens and pests. The treated seeds are often stored until sowing, which can lead to a reduction in their quality. This work aimed to evaluate the physical and physiological quality of soybean seeds submitted to IST, with subsequent storage in a natural and controlled environment. The experiment was conducted in a split-split-plot design in a completely randomized scheme (time x storage systems x IST) with four replications. Soybean cultivar 55I57RSF IPRO was subjected to IST with fungicide (metalaxyl-M, thiabendazole, and fludioxonil) and insecticide (thiamethoxam and cyantraniliprole), combined or not with polymer and dry powder, with subsequent storage in a controlled and natural environment. The moisture content, thousand-seed weights, germination, first germination count, germination speed index, accelerated aging, seedling length, dry matter transfer, and emergence sand test were evaluated. IST did not affect the moisture content and weight of a thousand seeds. However, storage in a controlled environment provided a greater reduction in moisture content and a smaller reduction in the weight of a thousand seeds. IST negatively affected germination, first germination count, germination speed index, and accelerated aging test. IST negatively affected plant length, except in the treatment where only insecticide was applied. The dry mass transfer was negatively affected but with less intensity in seeds subjected only to the application of insecticide or fungicide and the combination of insecticide, fungicide, and polymer. Seed emergence in the sand was negatively affected by all treatments. Regardless of the treatments, all responses evaluated showed a reduction throughout storage, with greater intensity in seeds stored in the natural environment.

Is pearl millet (Pennisetum glaucum) a good plant species for ecotoxicological tests?

Various plant species can be selected for environmental testing, including pearl millet (Pennisetum glaucum (L.) R. Br), a globally significant cereal crop. This study aims to assess millet's suitability as a species for ecotoxicological tests, examining (1) germination and initial development dynamics, (2) the minimum seed quantity for reliable sampling, (3) optimal experimental design with replication numbers, (4) suitability of positive control, and (5) the effectiveness of the protocol in evaluating toxic effects of environmental pollutants. Millet exhibited rapid and uniform germination as well as consistent initial seedling development. To establish the minimum number of seeds required for reliable experimentation, germination, and seedling growth were compared across plots containing 10, 25, and 50 seeds. Consequently, 10 seeds per plot were chosen for subsequent experiments to reduce labor and costs while maintaining reliability. To validate the selected experimental design, and to establish a positive control for assays, aluminum was used as a toxic element at concentrations ranging from 10-2 to 10-6 M. While aluminum did not affect the final percentage of germinated seeds, it did exhibit an impact on the Germination Speed Index (GSI). Significant differences in root and aerial growth, and with fresh weight, were observed. The 10-3M concentration was chosen as the positive control as the 10-2 concentration showed extreme toxicity. To assess the applicability of the established protocol in determining the toxic effects of environmental pollutants, millet roots were exposed to the toxic agents atrazine, cadmium, methyl methane sulfonate (MMS), and Spent pot liner (SPL). Millet demonstrated sensitivity and efficiency in response to these tests. In conclusion, millet proves to be an effective species for the toxicological risk assessment of environmental pollutants.

Breaking the Dormancy of Some Varieties of Papaya (Carica Papaya L.) Soaking KNO3 Solution

Dormancy is a state of stopping growth experienced by plants. This research aimed to determine the concentration of KNO3 solution in breaking dormancy in several papaya varieties. The research method used in this research was a completely randomized design (RAL) Factorial with 2 treatment factors. The first factor is variety (V), consisting of V1 = Callina, V2 = California, and V3 = Local. The second factor is the concentration of the KNO3 (K) solution consisting of: K0 = Control, K1 = 10%, K2 = 20% and K3 = 30%. The variables observed were growth synchrony and germination speed index. Data analysis uses analysis of variance. The variables observed were growth synchrony and germination speed index. An analysis of variance was used to test the effect of treatment. To test mean differences between treatments, honest significant difference tests, regression, and correlation were carried out at a test level of 5%. The research results showed that seed variety had a significant effect on growth synchrony and germination speed index. The concentration of KNO3 solution has a significant effect on growth synchrony and germination speed index. The interaction between the variety and concentration of KNO3 solution had no significant effect on all observed parameters.

Production of Seedlings of Corymbia citriodora Inoculated with Endophytic Bacteria

This study aimed to evaluate the effect of inoculants of endophytic bacteria producing indoleacetic acid (IAA) on the physiological quality of seeds and the production of seedlings of Corymbia citriodora (Hook.) KD Hill & LAS Johnson. In the physiological quality test of the seeds, the treatments used were individual inoculation with Priestia megaterium, Exiguobacterium sibiricum, Pantoea vagans strain 45URP4-1, and Bacillus sp.; joint effect of the four strains (mix); inoculation only with the carrier (cassava starch and activated charcoal); carrier with 1.0 μg mL−1 of IAA; and non-inoculated control without IAA and without a carrier. In the production of seedlings in a greenhouse, the treatments were the same, except for the mix, which was replaced by P. vagans strain 7URP1-6 (Pvs7), as inoculation with the mix increased the number of abnormal seedlings. In the physiological quality test of seeds, seeds inoculated with the bacteria individually did not have the physiological quality impaired and the carrier created a microenvironment around the seeds, benefiting germination percentage, germination speed index, average germination time, and average germination speed. In the greenhouse, seedlings inoculated with Pvs7, P. megaterium and E. sibiricum were taller, with a larger stem diameter and dry mass of shoot, roots, and total. Seeds inoculated with E. sibiricum had higher averages for height, chlorophyll b content, and shoot and total dry mass, as well as a greater ability to colonize the rhizosphere and roots of C. citriodora, resulting in the production of higher-quality seedlings. Inoculation of seeds of C. citriodora with endophytic bacteria proved to be a promising alternative for plant development.

Seed morphometry and NaCl and sucrose effect on germination rates and phytochemicals in sotol (Dasylirion acrotrichum) from the Chihuahua state, Mexico

In Mexico, “sotoles” (Dasylirion spp.) are used to elaborate the “sotol” liquor, handicraft making, and construction materials. These activities have enhanced the probability that sotol populations could decline because plants are extracted directly from their native ecosystems, given no commercial sotol plant species exist. Furthermore, from an ecological point of view, this genus has also been little studied regarding its seed morphology and germination process. The objective of this study was to characterize the morphometry of the D. acrotrichum seeds and to evaluate the effect of different concentrations of NaCl (30, 60, and 90 mM) and sucrose (30, 60, and 90 mM) on seed germination rates, seedling morphology, and the phytochemical content in the seedling leaves under in vitro conditions from plants grown in the Chihuahua State. The exogenous NaCl and sucrose treatments influenced the germination speed index, mean germination time, and mean germination speed. The NaCl treatment impacted the total weight, root weight, and leaf length of seedlings, the content of chlorophyll a, sugar, and phenolics, and the antioxidant activity determined by FRAP. Besides, the sucrose treatment affected the seedling length, the content of chlorophyll a, chlorophyll b, total chlorophyll, and sugars, and the antioxidant activity determined by FRAP and DPPH. These results could provide the guidelines to generate better afforestation programs in the areas affected by the overexploitation of the Dasylirion spp. and new information about the capacity of these species for developing under these types of stress in the natural environment.