Lowest Mean Germination Time Research Articles

Seed Priming and Biopriming in Two Squash Landraces (Cucurbita maxima Duchesne) from Tunisia: A Sustainable Strategy to Promote Germination and Alleviate Salt Stress.

In recent years, seed priming has gained interest, with researchers aiming to enhance seed germination and early growth, especially under abiotic stress conditions. In this study, seeds from two squash landraces (Cucurbita maxima Duchesne; i.e., Galaoui large seeds (Galaoui hereafter) and Batati green (Batati hereafter)) were subjected to different priming methods ((a) 0.3% and 0.4% KNO3 (halopriming); (b) 0.1% and 0.2% GA3 (hormopriming); (c) inoculation with Trichoderma spp. (T. harzianum, T. viride, and T. virens), Bacillus subtilis, and Pseudomonas fluorescens (biopriming) in order to promote germination parameters and seedling growth under salinity stress (0, 100, and 200 mM of NaCl). Our findings indicate the better performance of primed seeds compared to the untreated ones in terms of germination and seedling growth traits, although a varied response depending on the priming method and the landrace was observed. The highest germination percentage (GP) and the lowest mean germination time (MGT) were observed in 0.4% KNO3-primed seeds. The positive effects of 0.4% KNO3 were also depicted in all traits related to seedling growth and the seedling vigor index (SVI), indicating its effectiveness as a priming agent in squash seeds. Under salinity stress conditions, priming with 0.4% KNO3 significantly improved the germination and seedling growth traits for both landraces, while the application of 0.2% GA3 at high salinity significantly improved photosynthetic quantum yield (Fv/Fm ratio). Regarding the effects of biopriming in germination and seedling growth traits, our results indicate that T. harzianum and B. subtilis were the most effective bioagents in promoting germination and seedling growth in Galaoui and Batati seeds, respectively. In conclusion, our findings provide important information regarding the practice of using priming and biopriming agents to enhance the germination and seedling growth capacity of squash seeds, as well to mitigate the negative effects of salinity stress at the critical stages of germination and early growth.

Drought stress effects on Lathyrus seedlings: A morpho-physiological and molecular study

The experiment aimed to investigate the impact of polyethylene glycol (PEG) treatments, specifically 0% (control), 15% (PEG-I), and 20% (PEG-II), on various seed quality traits, proline content, and morpho-physiological traits at both the seed (9 days) and seedling stage (18 days) in five Lathyrus genotypes and to relate the ISSR markers based molecular characterization of these genotypes osmotic stress. The results unveiled substantial phenotypic and molecular diversity among the accessions concerning morpho-physiological and seed quality traits. Ratan variety exhibited promise as it demonstrated a higher germination percentage (G%) at 62.78±2.42% for PEG-I and 13.33±0.10% for PEG-II, along with a lower mean germination time (MGT) of 3.80±0.071 days for PEG-I and 7.33±0.16 days for PEG-II. P-24 showcased the highest seed vigour index-I (SVI-I) at 872.06±27.02 for PEG-I, whereas Nirmal recorded the highest SVI-I at 80.03±8.53 for PEG-II. Notably, Nirmal displayed the lowest proline content, expressed as μmol per gram of fresh weight (52.45±6.27 units for PEG-I and 111.37±4.75 units for PEG-II) at the seed stage. For the seedling stage, Ratan exhibited the lowest proline content, expressed as μmol per gram of fresh weight (14.18±1.09 units for PEG-I and 10.67±0.851 units for PEG-II). Prateek demonstrated higher seedling length (42.00±1.44 cm for PEG-I and 45.88±0.30 cm for PEG-II), as well as root length (14.11±0.84 cm for PEG-I and 21.29±1.59 cm). Principal component analysis (PCA) highlighted that the most influential variables contributing to the highest variability in the PCA included SVI-I, MGT, and seedling length. Molecular characterization employing ISSR markers resulted in three clusters: CI (Ratan), CII (Pusa-24 and Mahateora), and CIII (Prateek and Nirmal), based on the genetic similarity coefficient. These genotypes exhibit the potential to be recommended and utilized in breeding programs for developing drought-tolerant Lathyrus germplasm.

Morpho-Physiochemical Indices and Transcriptome Analysis Reveal the Role of Glucosinolate and Erucic Acid in Response to Drought Stress during Seed Germination of Rapeseed.

The global expansion of rapeseed seed quality has been focused on maintaining glucosinolate (GSL) and erucic acid (EA) contents. However, the influence of seed GSL and EA contents on the germination process under drought stress remains poorly understood. Herein, 114 rapeseed accessions were divided into four groups based on GSL and EA contents to investigate their performance during seed imbibition under drought stress. Our results revealed significant variations in seed germination-related traits, particularly with higher GSL and EA, which exhibited higher germination % (G%) and lower mean germination time (MGT) under drought stress conditions. Moreover, osmoregulation, enzymatic system and hormonal regulation were improved in high GSL and high EA (HGHE) versus low GSL and low EA (LGLE) seeds, indicating the essential protective role of GSL and EA during the germination process in response to drought stress. The transcriptional regulation mechanism for coordinating GSL-EA-related pathways in response to drought stress during seed imbibition was found to involve the differential expression of sugar metabolism-, antioxidant-, and hormone-related genes with higher enrichment in HGHE compared to LGLE seeds. GO enrichment analysis showed higher variations in transcription regulator activity and DNA-binding transcription factors, as well as ATP and microtubule motor activity in GSL-EA-related pathways. Furthermore, KEGG analysis identified cellular processes, environmental information processing, and metabolism categories, with varied gene participation between GSL, EA and GSL-EA-related pathways. For further clarification, QY7 (LGLE) seeds were primed with different concentrations of GSL and EA under drought stress conditions. The results showed that 200 μmol/L of GSL and 400 μmol/L of EA significantly improved G%, MGT, and seedling fresh weight, besides regulating stress and fatty acid responsive genes during the seed germination process under drought stress conditions. Conclusively, exogenous application of GSL and EA is considered a promising method for enhancing the drought tolerance of LGLE seeds. Furthermore, the current investigation could provide a theoretical basis of GSL and EA roles and their underlying mechanisms in stress tolerance during the germination process.

Alleviation of Seed Dormancy in Kala Zeera (Bunium Persicum) Through Chilling and Phytohormones

Kala zeera (Bunium persicum) is a high-value medicinal spice plant. The seeds and extracts are used for culinary, perfumery, flavouring food and medicinal purposes. The commercial cultivation of kala zeera is hampered due to poor seed germination and deep physiological dormancy. To break the dormancy of kala zeera, three phytohormones, gibberellic acid (100 μmol L-1), 6-benzylaminopurine (10 μmol L-1) and thidiazuron (6.3 μmol L-1) were tested individually and in combination, under two temperature levels: continuous chilling at 4°C and one week chilling at 4°C followed by incubation at room temperature. The combined application of the three phytohormones under continuous chilling (4°C) improved the germination from 11.25 to 93.25% and reduced the mean germination time 60 to 50 days. The lowest mean germination time (34.78 days) and high mean daily germination (1.57 seeds day-1) with a high coefficient of germination velocity (2.88), were found under combined application of phytohormones as compared to their individual application. The findings have implications in successful propagation and systematic cultivation of this high-value medicinal spice plant.

Impact of Hydrochloric acid on breaking seed dormancy and germination enhancement in native Alhagi graecorum Boiss ( Al-Agool ).

Despite the great importance of legumes plants, most of them have a hard and impermeable testa, which causes physical dormancy of the seeds and prevents germination even when environmental conditions are favorable. This is considered one of the major problems in successful seed germination. Alhagi graecorum plant is a wild native legume. It has a hard and impermeable testa, which causes physical dormancy of seeds, and to overcome hard coat imposed dormancy, softening the hard seed coat by soaking Hydrochloric acid ( HCl ). The present study was conducted to evaluate various duration of soaking seeds in HCL to breaking physical dormancy for A.graecorum in 10, 20, and 30 minutes. The results showed that, final germination percentage (FGP) in treated seeds significantly increased when compared with the control were 55, 62 and 68 % respectively, while in control was only 12 %. Seed germination influenced by HCL is due to its capability to break the hard seed coat that leads to water absorption and imbibition of seeds. As for the mean daily germination ( MDG ), the results revealed that, there were significance increased in seventh day of sowing in germination between the treated seeds in duration of soaking 20 and 30 min were 23 and 24 % respectively, as they were most effective in germination, while the germination in the control stopped in the fifth day of sowing at 12 %. While the mean germination time (MGT), the results indicated that the seeds soaked in acid recorded 9.66, 9.13, and 8.62 days, respectively. The minimum MGT for treated seeds was detected in 30 min., 8.62 days. The reason for the long period of the mean germination time may be due to the use of a low concentration of hydrochloric acid, so I recommend using higher concentrations of acid to obtain a lower mean germination time.

Methods of breaking seed physical dormancy and germination in native species of Alhagi graecorum Boiss (Al-Agool )

Alhagi graecorum is a plant belonging to the Fabaceae family and grows as wild perennial shrubby species. Seeds of this species possess seed physical dormancy and need to be removed to enhance germination, breaking of dormancy treatments were imposed on seeds to improve germination. Treatments include scarification with sulfuric acid ( H2SO4 ) for 10, 20, 30 and40 minutes. The results showed highly significant difference between control and all the treatments of germination percentage ( GP ) was 96%, 96%, 97% and 97%, respectively, while recorded in control only 12%. As for the mean daily germination ( MDG ), the results revealed that, there was a significant differences between all treated seeds and control, which was the fastest and most effective seeds germination on the third day of sowing were 84, 89, 90, 92 % respectively, while in control was 0 %. Mean germination time (MGT) decreased in all treated seed but statistically same while significantly different from the control. The minimum time was recorded for 20 and 30 minutes was 3.14 and 3.14 days respectively. We conclude from the results obtained that, the use of concentrated sulfuric acid 98% achieved the highest GP and MDG and the lowest MGT. This is the efficient method of breaking seeds dormancy and germination for native species of Alhagi graecorum.

Water Stress Affected Seed Accumulation of Non-reducing Soluble Sugars and Germination Performance of Three Chickpea Cultivars

Background: Water stress may alter the seed chemical composition and cause changes in the concentrations of non reducing soluble sugars in seeds and germination performance of chickpea. We evaluated the effect of water stress during chickpea seed development on seed (i) accumulation of non-reducing soluble sugars, and (ii) vigour and germination. Methods: Three chickpea cultivars (Desi-K, Saina-K and ICCV-K) were subjected to two water regimes (water stress- withholding irrigation after flowering and non-stressed- irrigation at 3-day intervals throughout the crop growth) in a completely randomized design with three replications. Seed size, viability, sugars content, solute leakage, germination percentage and mean germination time were determined from seeds harvested at physiological maturity. Result: Water stress increased the raffinose seed content of Saina-K and Desi-K, decreased the raffinose seed content in ICCV-K, but had no effect on sucrose and stachyose content. Electrical conductivity (EC) increased with water stress in all cultivars, but the increase was greater in ICCV-K (57%) compared to Desi-K (18%) and Saina-K (12%). Non-stressed seeds had larger seed size, higher seed viability and germination percentage and lower EC and mean germination time than stressed seeds. Clearly, sufficient water at seed development stage is crucial for productivity of subsequent crops as it affects seed quality. However, we recommend further studies using a wide range of water stress treatments and chickpea cultivars with different seed size, seed color and seed coat texture.

Effect of acid media on seed germination performance of Swiss-chard (Beta vulgarise L.)

Objectives: An experiment was designed with the objectives of studying the effect of acidity (pH) on the seed germination performance of Swiss-chard, and to determine the optimal pH level for the highest seed germination. Methods: The study was carried out in the laboratory of the Department of Horticulture of the University of Wolkite. The treatments were different pH levels (2, 4, 6 and 7) obtained from solutions of citric acid and distilled water in different concentration mixtures. The CRD design was used with three replicates. Findings: Analysis of variance (ANOVA) showed that all recorded germination parameters (germination rate, mean germination time, germination speed and germination index) were all most significantly different (p<0.001) for different pH levels. The highest seed germination rates (85.33% and 81.33%) were recorded at pH 7 and pH 6 respectively. Similarly the highest mean germination time (13 days and 11 days) and the highest germination speed (3.88/day and 3.7/day) were recorded at pH 6 and pH 7, respectively. However, the lowest seed germination rate (4%), the lowest mean germination time (0.5 days) and the lowest seed germination speed (0.18/day) at pH 2. The highest germination index (100 and 95.42) was recorded at pH 7 and pH 6 respectively while the lowest seed germination index (4.61) was recorded at pH 2. In general pH 7 and pH 6 can give the best results to the highest germination yield of Swiss chard.

COMPARATIVE EFFECT OF SEED PRIMING AND GROWING MEDIA ON SEED GERMINATION AND SEEDLING GROWTH OF PAPAYA (CARICA PAPAYA L.)

An experiment was directed to assess the comparative effect of seed priming and growing media on seed germination and growth of papaya. Papaya seeds were primed in distilled water, 1% potassium nitrate (KNO3) for 12 hours. The un-primed seeds were taken as control. The growing medium was prepared by mixing different ratios of the canal silt, bagasse, and cocopeat. Results have shown that each experimental parameters in the current investigation was influenced by seed priming and growing media. Moreover the findings revealed that, seed priming with distilled water got the highest mean seed germination, seedling vigor index, fresh biomass of shoot and root, dry biomass of shoot, dry root weight, quality index of the seedlings, sturdiness quotient, survival % and mean germination time. While to compare means of the growing media, M2 (Canal silt + bagasse + cocopeat in 1:1:1) medium had the best results for seed germination, seedling vigor index, fresh biomass of shoot and root, dry biomass of shoot and root, quality index of the seedlings, sturdiness quotient, lowest mean germination time and leakage of the electrolytes. It’s determined from the current study that seed priming with distilled water and M2 medium contained canal silt, bagasse and cocopeat in (1:1:1) found optimal for all germination and seedling attributes of papaya.

Effect of Cutting Treatment on Seed Yield and Seed Quality of Dill

Dill, Anethum graveolens L., is grown in various regions of the world. It has been used as vegetable and medicinal plant since ancient times. Seed quality is important in dill cultivation and there is limited information on the effects of cutting treatment in this species. This research was carried out to find out the effect of cutting treatment on phenological traits, seed yield and quality of dill at Ege University, Izmir, during 2016-2018. The experiments were carried out in the randomized complete block design with three replications, comprising of cutting treatment for both spring and autumn seeding period. Significant differences were noted in the flowering period, seed yield and quality attributes with cutting treatment for both seeding period. The obtained results showed that the days from sowing to bolting initiation were increased with cutting treatment from 51 days to 65 days in spring seeding period and from 153 days to 184 days in autumn seeding period. The plant height, number of umbels per plant, seed weight per plant were lower in the cut plants in comparison to that of uncut plants for both seeding period. The uncut plants has produced significantly higher plant height (113 cm-spring seeding period; 133 cm-autumn seeding period), number of umbels/plant (8.4-spring seeding period; 10.1-autumn seeding period) and seed weight/plant (6.4 g-spring seeding period; 10.9 g-autumn seeding period). The cutting treatment decreased germination percentage by 9.27% in the spring seeding period and by 12.13% in the autumn seeding period compared to the control plant seeds. Lower mean germination time at 20/30°C (3.77 days-spring seeding period; 4.54 days-autumn seeding period) were also observed in uncut plants. Thus, it was concluded that cutting is not recommended in the vegetative stage in dill seed production as it provided lower seed yield and seed quality for both autumn and spring seed planting periods.

English

Recent interest in the cultivation and use of butterfly pea (Clitoria ternatea L.) has increased demand for its commercial production. Successful germination of seed is a critical first step to its production; however, few studies have documented factors influential to germination success. To help support commercial production efforts, the influence of substrate temperature and seed scarification technique on germination parameters were evaluated. Two scarification (nicked and soaked) and three substrate temperature treatments (21, 24 and 27°C) were imposed on C. ternatea seed. Following treatments, six germination parameters were recorded. Data showed seeds maintained at a substrate temperature of 21°C reached maximal germination (54.8%) at the longest mean germination time (2.61 d) and slowest mean germination rate (0.39 day-1). Mechanical scarification by nicking the seed coat with a razor blade prior to soaking the seed for 24 h reached maximal germination (80.95%) at the lowest mean germination time (2.06 days) and fastest mean germination rate (0.51 day-1). Optimal germination was attained when seed was scarified and soaked and then germinated in rockwool substrate maintained at a temperature (To) of 21°C. Results provide commercial growers with production technique information helpful to fast and efficient germination of C. ternatea seed. Key words: Germinability, medicinal, edible, rockwool.

Effect of Seed Priming on Germination and Seedling Parameters of Cucumber (Cucumis sativus L.) in Lamjung, Nepal.

Poor seed germination obstructs the early and uniform seedling emergence at the sub-optimal conditions which can be a major setback to early spring cucumber growers. Different seed priming methods ought to be efficient solutions for the problem. To standardize the best priming method, an experiment was laid out in a Completely randomized design at the Horticulture lab of IAAS, Lamjung Campus. The treatment consisted of demineralized distilled water (hydropriming), hormonal priming (GA3 100ppm and GA3 200 ppm), halopriming (NaCl 0.5% and KNO3 0.5%), and non-primed seeds as control. The seeds were soaked in the respective treatment for 24 hours and then dried to initial moisture content under shade conditions. Observation recorded significantly highest germination percentage in GA3 100ppm (19.25%) and hydro priming (19.25%). The lowest mean germination time was found in GA3 100ppm (4.19days) which was significantly at par with GA3 200ppm (4.33days) and hydro priming (4.48days). The germination energy was found highest in GA3 100ppm (39.58) followed by GA3 200ppm (33.65) and dry weight was recorded highest in hydropriming (0.0252g) followed by GA3 100ppm (0.0250g) whereas the highest root length was observed in KNO3 priming (12.955cm) which is statistically at par with hydropriming (11.42cm), GA3 200 ppm (10.872cm) and NaCl priming (10.42cm). The plumule length was observed highest in KNO3 (13.00cm) followed by NaCl (11.25cm). All primed seeds showed increased seedling vigor compared to the unprimed seeds. The study showed that applied treatment notably increased the germination characteristics and seedling stand.

Effect of seed size on germination and seedling performance during storage of bhekal (Prinsepia utilis) seeds

The present study was conducted to determine the effect of various grades of Prinsepia utilis (bhekal) seeds on germination and seedlings performance during storage. Freshly collected seeds were grouped into three sub-lots viz. large size seeds (size 10 mm or > 10 mm), medium size seeds (size < 10 mm and > 7 mm), and small size seeds (size < 7 mm) with the help of specified sieves. Seeds of all grades were sown in nursery beds as fresh and after 35 days of storage. Various grades of seeds had shown significant effect on germination percentage as fresh and after 35 days of storage. Large size seeds exhibited significantly higher germination percentage, lower mean germination time, and higher germination values as compared to medium and small size seeds. Only small size seeds significantly exhibited lower germination percentage, higher mean germination time (MGT), and lower germination values as compared to large and medium-size seeds. However, no significant difference was observed in Germination Value (GV) and germination percentage between large and medium size seeds. The large size seeds exhibited a significantly good value of seedling length, the number of leaves, collar diameter, total biomass, vigour index, sturdiness quotient, volume index and quality index as compared to medium and small size seeds.

Note on Effect of Sulfuric Acid on Breaking Seed Dormancy of Least snout Bean (Rynchosia minima L.)

Least snout bean (Rynchosia minima L.) is considered a promising rangeland legume fodder for marginal land in Sudan, but its seeds are associated with high dormancy (%). This study was carried out at the Laboratory of the Plant physiology, Department of Botany and Agricultural Biotechnology, Faculty of Agriculture, University of Khartoum to investigate the effect of sulfuric acid (H2SO4) on breaking seeds dormancy of least snout bean. The seeds were soaked in 0, 50, 70, and 100% H2SO4 concentrations for 30, 45, 60, 90 and 120 minutes. The seeds were germinated in petri dishes and incubated at room temperature for 10 days. The H2SO4 concentration and soaking period significantly (P < 0.01) increased seeds germination (%) and decreased mean germination time (MGT). The germination percentage was increased while MGT was decreased by increasing soaking period up to 60 min. The highest germination (%) and lowest MGT were obtained by soaking the seeds in 70 % H2SO4 for 60 minutes. The result would be useful for large-scale establishment of least snout bean in natural rangelands.

Transgenerational Effects of Salt Stress Imposed to Rapeseed (Brassica napus var. oleifera Del.) Plants Involve Greater Phenolic Content and Antioxidant Activity in the Edible Sprouts Obtained from Offspring Seeds.

Previous research has demonstrated that rapeseed sprouts obtained under salinity demonstrate greater phenolic content and antioxidant activity compared to those sprouted with distilled water. This work aimed to test the hypothesis that these effects of salinity may persist into the next generation, so that offspring seeds of plants grown under salt stress may give edible sprouts with increased phenolic content and antioxidant activity. Plants of one rapeseed cultivar were grown in pots with 0, 100 and 200 mM NaCl, isolated from each other at flowering to prevent cross-pollination. Offspring seeds harvested from each salinity treatment were then sprouted with distilled water. We performed the extraction of free and bound phenolic fractions of sprouts and, in each fraction (methanolic extract), we determined the total polyphenols (P), flavonoids, (F), and tannins (T) with Folin–Ciocalteu reagent, the phenolic acids (PAs) by ultra-high-performance liquid chromatographs (UHPLC) analysis, and the antioxidant activity with three tests (2,2-diphenyl-1-picrylhydrazyl-hydrate, DPPH; ferric reducing antioxidant power, FRAP; 2,2′-azino-bis[3-ethylbenzothiazoline-6-sulfonic acid] diammonium salt, ABTS). Individual seed weight was slightly decreased by salinity, whereas germination performance was improved, with a lower mean germination time for salted treatments. No significant differences were observed among treatments for P, F and T, except for bound P, while, in most cases, single PAs (as free, bound and total fractions) and antioxidant activity were significantly increased in salted treatments. Our results open new perspectives for the elicitation of secondary metabolites in the offspring seeds by growing parental plants under stressing conditions, imposed on purpose or naturally occurring.

Effects of Day and Night Temperature and GA<sub>3</sub> on Seed Germination of <i>Lilium callosum</i> Siebold & Zucc. and L. Leichtlin ex D.D.T. Moore

The demand for Lilium callosum Siebold and L. hansonii Leichtlin ex D.D.T. Moore has increased recently, but their chances of reaching full maturity are low, since the population in their natural habitat decreases each year. The purpose of this study was to identify the favorable day and night temperature conditions needed for the seed germination of L. callosum Siebold and L. hansonii Leichtlin ex D.D.T. Moore, as well as the appropriate GA3 concentration needed to promote the mass production of L. hansonii Leichtlin ex D.D.T. Moore. Seeds from L. callosum Siebold were harvested in Gangwon-do Dunsan-myeon Wonchang-ri (37°47'10.00N, 127°44'31.00E) on October 24, 2017. Seeds from L. hansonii Leichtlin ex D.D.T. Moore were collected in Ulleung-do Ulleung-gun Nari (37°31'27.06 N, 130°52'25.08 E) on October 2, 2017. Each treatment was replicated three times, and included 30 seeds per replication. The day and night temperatures of the cultivators were set at 15/5°C, 20/10°C, 25/15°C, and 20/20°C for the temperature experiment. The GA3 treatment experiment was conducted under the temperatures at which the germination rates were the most dominant. The germination rate of L. callosum Siebold was the highest at 95.0%, and the mean germination time was the lowest at 10.1 days at 20/20°C. The germination rate of L. hansonii Leichtlin ex D.D.T. Moore was the highest at 78.8%, and the mean germination time was the lowest at 40.1 days at 20/20°C. Based on these results, the GA3 treatment experiment of L. hansonii Leichtlin ex D.D.T. Moore was conducted at 20/20°C. The highest germination rate of 81.6% in the control group, and the lowest mean germination time was 37.1 days in the 200 mg･L-1 treatment. The optimal day and night temperature for germination of L. callosum Siebold and L. hansonii Leichtlin ex D.D.T. Moore was 20/20°C. The GA3 treatments were not effective for germination of the L. hansonii Leichtlin ex D.D.T. Moore seeds.

Use of seaweed-based biostimulant (Ascophyllum nodosum) on ornamental sunflower seed germination and seedling growth

Abstract Seaweed extracts are employed as biostimulants due to their beneficial effects on crop growth and yield. Ascophyllum nodosum seaweed extract aid to improve seedling growth and development, and decrease seedlings production costs; however, the correct concentration must be used in order to maximize the biostimulant effects. Consequently, this study aimed to analyze the effects of different concentrations of a seaweed-based (Ascophyllum nodosum) biostimulant on ornamental sunflower seed germination and seedling growth. Seeds of ornamental sunflower cv. “Sol Pleno” were sown in polyethylene trays containing commercial substrate. The treatments consisted of dairy spraying 60 mL of the solutions 0 (control), 5, 10 or 15 mL L-1 biostimulant on substrate. The experimental design was completely randomized with 4 treatments (concentrations of biostimulant) and 4 replicates (10 seeds replicate-1). The evaluated variables were percentage, index and time averages of germination, seedling height, fresh and dry mass of shoot and roots, and root system morphology (WinRhizo). The increase of the biostimulant concentration enhances seed germination and seedlings development. The concentration 15 mL L-1 biostimulant showed the best results for percentage and index of germination and the lowest mean germination time and increase plant height and fresh and dry mass of shoots in relation to the control treatment. Accordingly, 15 mL L-1 biostimulant (Ascophyllum nodosum) is recommended for ornamental sunflower “Sol Pleno” seed germination and seedlings growth.

Practical methods for rapid seed germination from seed coat-imposed dormancy of Prunus yedoensis

The seeds of Prunus yedoensis have slow and poor germination when intact (with endocarp). Cold and/or warm stratification, washing, and scarification with liquid nitrogen and sulfuric acid, in combination with or without gibberellic acid (GA3) application, were investigated as facilitators for rapid and high germination. No germination was observed without GA3 in any treatment for intact seeds. GA3 treatment for one day significantly shortens the mean germination time (MGT) and improves seed germination percentage. Immersion in liquid nitrogen followed by GA3 treatment, GA3 application to intact seeds and seed coat removed seeds significantly enhanced the germination and MGT to 63 ± 7.6% (8.6 weeks), 71 ± 5.0% (4.7 weeks), and 93 ± 5.1% (0.8 weeks), compared to untreated seeds or stratified seeds (0%) chilled for six months. Depending on the GA3 application method, results could be different in intact seeds. GA3 application with vigorous shaking accomplished higher germination and lower MGT (71 ± 5.0%, 4.7 weeks) than gentle shaking incubation (33 ± 6.0%, 10.4 weeks). The germination inhibitor(s) were located in the seed coat because seed coat extract inhibited germination in decoated seeds. Therefore, coat removal alleviates the inability to promote germination and it has the same beneficial effect as does the application of GA3. According to the results, it suggest that the effective application of GA3 on intact seeds or seed coat removal could overcome seed dormancy in P. yedoensis.

Geographical variation in breaking the seed dormancy of Persian cumin (Carum carvi L.) ecotypes and their physiological responses to salinity and drought stresses

Seed germination is a critical stage in the life of crops. The laboratory experiments were conducted to determine whether the severity of seed dormancy in Persian cumin ecotypes and their response to salinity and drought stresses could be influenced the parent plant habitat. Seeds of three Persian cumin ecotypes (Alamut, Khabar, and Tandoureh) were collected from three protected areas in Iran. For each ecotype in seed dormancy-breaking study, the treatments included control, the prechilling of seeds for 20, 40, and 60 days at 5 °C and 10% relative humidity and the inundating of them into 0.72, 1.44, and 2.88 mmol GA3 L−1 for 24 h. In the response to salinity and drought stresses study, two experiments were arranged separately as a completely randomized factorial design to investigate the effect of salinity and drought stress. In the 1st experiment, the prechilled seeds of three Persian cumin ecotypes were subjected to four salinity stress levels (0, 2, 4, and 6 dS m−1). In the 2nd experiment, those were subjected to four drought stress levels (0, −0.2, −0.4 and −0.6 MPa). All three ecotypes of Persian cumin had a deep dormancy. The ecotype of Alamut which has been harvested from a cool climate had a deeper seed dormancy than other ecotypes which have been harvested from a relatively warm climate. In all ecotypes, the highest germination rate and the lowest mean germination time were found where their seeds were prechilled for 60 days. The highest response to prechilling was observed in Alamut ecotype. The salinity and drought stresses resulted in a reduction in the rate and a delay in the speed of seed germination in three ecotypes of Persian cumin. The highest sensitive to salinity and drought stresses was observed in Alamut ecotype which its seed was obtained from where soil pH and EC are low. Here, habitat-correlated variation in Persian cumin seed germination response and stress tolerance was demonstrated.

Solid Matrix Priming Treatment with O2 Enhanced Quality of Leek Seed Lots

This study aims to determine the effect of solid matrix priming (SMP) treatment with an air composition of O2, N2, air, vacuum on four leek (Allium ampeloprasum L.) seed lots of various ages, in terms of enhancing germination, mean germination time, electrical conductivity of solute leakage and catalase activity. Untreated seeds were used as control. Solid matrix priming at a seed: vermiculite: water ratio of 2.5:1.25:3.75 (w/w/w) was applied at 20 °C for 24 hours in the dark. Solid matrix priming with O2 was found to give the highest germination, lowest mean germination time, lowest electrical conductivity (reduced solute leakage) and the highest catalase activity among all treatments and lots. SMP treatment with air provided positive response, while N2 and vacuum treatments were found to be less effective. The advantages of solid matrix priming were more pronounced in lower quality lot than in the higher quality ones. The results indicated that oxygen enrichment in SMP may enhance leek seed quality.