Reduced Mean Germination Time Research Articles

Effects of storage temperature and pre-treatments on seed germination of Primula mallophylla and P. sertulum (Primulaceae), two narrowly-distributed endemic species from southwest China

Primula mallophylla and P. sertulum are wild ornamental species of south-west China, but the responses of their seeds to storage have not been determined. When seeds were dry-stored for 24 months at room temperature (RT) (ca. 21°C) and at 4°C, germination increased during the first six months, but then decreased over the following 18 months. The decrease in germination was slower for seeds stored at 4°C than for those stored at RT. When seeds of these two species were dry-stored at -20°C for 24 months, germination percentage was significantly higher than that of the control seeds by the sixth month; the high germination percentages persisted at 24 months. In addition, pre-germination treatments (i.e., immersion in 100 μmol L -1 GA3 for 24 hours, cold stratification for 30 days or both) improved the final germination and reduced mean germination time of P. mallophylla seeds stored for 12 months at RT, but not those of P. sertulum. Taken together, storing seeds at -20°C is feasible and convenient for both primrose species; thus, it is possible to safely store seeds for future research and conservation.

From seed to sprout: Unveiling the potential of non-thermal plasma for optimizing cucumber growth

Background and aimsNumerous strategies for enhancing seed germination and growth have been employed over the decades. Despite these advancements, there continues to be a demand for more effective techniques, driven by the growing global population. Recently, various forms of non-thermal atmospheric pressure plasma have garnered attention as environmentally friendly, safe, and cost-effective methods to enhance the agricultural and food sectors. This study explores the remarkable impact of non-thermal plasma (NTP) treatment on cucumber (Cucumis sativus L.) seed germination. MethodsA cost-effective, custom-designed power supply operating at line frequency was used for treating seeds, with exposure times ranging from 1 to 7 min. Various germination parameters, including water contact angle measurements, mass loss, water imbibition rate, and seedling length, were evaluated to assess the impact of plasma treatment on seed germination. ResultsCucumber seeds exposed to NTP treatment for 3 min and 5 min durations showed significant germination improvements, notably a 57.9 ± 4.25 % higher final germination percentage, 14.5 ± 3.75 % reduced mean germination time, and a remarkable 90.6 ± 4.64 % increase in germination index compared to the control. These results suggest that NTP treatment enhanced seed coat permeability, triggered essential biochemical processes, and expedited water absorption and nutrient assimilation, ultimately fostering faster and more synchronized germination. ConclusionsOur findings underscore the potential of NTP as an innovative approach to improving seed germination in agricultural practices.

Nanopriming-mediated memory imprints reduce salt toxicity in wheat seedlings by modulating physiobiochemical attributes

BackgroundAround the globe, salinity is one of the serious environmental stresses which negatively affect rapid seed germination, uniform seedling establishment and plant developments restricting sustainable agricultural productivity. In recent years, the concepts of sustainable agriculture and cleaner production strategy have emphasized the introduction of greener agrochemicals using biocompatible and natural sources to maximize crop yield with minimum ecotoxicological effects. Over the last decade, the emergence of nanotechnology as a forefront of interdisciplinary science has introduced nanomaterials as fast-acting plant growth-promoting agents.ResultsHerein, we report the preparation of nanocomposite using chitosan and green tea (CS-GTE NC) as an ecofriendly nanopriming agent to elicit salt stress tolerance through priming imprints. The CS-GTE NC-primed (0.02, 0.04 and 0.06%), hydroprimed and non-primed (control) wheat seeds were germinated under normal and salt stress (150 mM NaCl) conditions. The seedlings developed from aforesaid seeds were used for physiological, biochemical and germination studies. The priming treatments increased protein contents (10–12%), photosynthetic pigments (Chl a (4–6%), Chl b (34–36%), Total Chl (7–14%) and upregulated the machinery of antioxidants (CAT (26–42%), POD (22–43%)) in wheat seedlings under stress conditions. It also reduced MDA contents (65–75%) and regulated ROS production resulting in improved membrane stability. The priming-mediated alterations in biochemical attributes resulted in improved final germination (20–22%), vigor (4–11%) and germination index (6–13%) under both conditions. It reduced mean germination time significantly, establishing the stress-insulating role of the nanocomposite. The improvement of germination parameters validated the stimulation of priming memory in composite-treated seeds.ConclusionPre-treatment of seeds with nanocomposite enables them to counter salinity at the seedling development stage by means of priming memory warranting sustainable plant growth and high crop productivity.

Azotobacter chroococcum F8/2: a multitasking bacterial strain in sugar beet biopriming

ABSTRACT This study assesses the effects of Azotobacter biopriming on the early development of sugar beet. Azotobacter chroococcum F8/2 was screened for plant growth promoting characteristics and biopriming effects were estimated through germination parameters and the structural changes of the root tissues. A. chroococcum F8/2 was characterized as a contributor to nitrogen, iron, and potassium availability, as well as a producer of auxin and 1-aminocyclopropane-1-carboxilic acid deaminase. Applied biopriming had reduced mean germination time by 34.44% and increased vigor I by 90.99% compared to control. Volatile blend comprised 47.67% ethanol, 32.01% 2-methyl-propanol, 17.32% 3-methyl-1-butanol, and a trace of 2,3-butanedione. Root micromorphological analysis of bioprimed sugar beet revealed a considerable increase in primary, secondary xylem area, and vessels size. Obtained results determine A. chroococcum F8/2 as a successful biopriming agent, and active participant in nutrient availability and hormonal status modulation affecting root vascular tissue.

Sugar beet (Beta vulgaris L.) germination indices and physiological properties affected by priming and genotype under salinity stress

Seed priming has proved to be an effective method in imparting stress tolerance to plants using natural and/or synthetic compounds to treat the seeds before germination. The present study was designed to investigate the physiological mechanism of seed priming with ZnSO4 (osmopriming) and distilled water (hydropriming) on sugar beet genotypes (‘Shokofa’, ‘Sina’, ‘Paya’, ‘Turbata’, and ‘Aria’) germination indices, seedling growth parameters, and biochemical properties under salinity stress (0, 2, 5, and 12 dS/m NaCl). A significant reduction in germination percentage (33.23%), germination rate (77.2%), chlorophyll a, b, and total contents (43.9, 31.9, and 39.9%, respectively) while, a significant increase in radical, plumule, and seedling length (57.1, 44.4, and 51.2%, respectively), seedling vigour index (48.9%), superoxide dismutase activity (61.3%), proline (54.0%) and sugar (56.3%) contents were achieved at 12 dS/m NaCl in compared to the control treatment. Seed hydropriming and osmopriming caused significant improvements in photosynthetic pigments, antioxidant enzyme activity, and proline content reflected in high germination percentage and rate as well as seedling vigour index and reduced mean germination time under salinity. ‘Paya’ and ‘Aria’ genotypes had a superiority according to the germination percentage and seedling vigour index, respectively. The hydropriming of ‘Paya’ genotype resulted in the highest germination percentage (95%) under high level of salinity (12 dS/m) which 11.84% increase compared to the control treatment. Hydropriming of ‘Sina’ seeds showed the highest chlorophyll a and total, and carotenoids under non-stress conditions (22.89, 31.65, and 2116.6 µg/g FW). Also, hydropriming by increases chlorophyll b content led to the modulation of the negative effects of high salinity stress (12 dS/m). In conclusion, different seed priming treatments in sugar beet seeds improved the salinity tolerance by physiological characteristics nonetheless hydropriming was the most effective treatment to get higher germination indices in ‘Paya’ and ‘Aria’ genotypes.

Effects of brassinosteroids and gibberellin on water uptake and performance of soya bean seeds under different temperatures

Low temperature has negative effects on seed performance and seedling growth in soya bean, reducing stand establishment. It was hypothesised, that seed treatment with plant hormones could improve seed imbibition and performance at low temperature. Therefore, the effects of 24-epibrassinolide (EBL) and gibberellic acid (GA3) on soya bean seed germination were studied. Seeds of 'CM60' and 'CM0701-24' were imbibed with 0.25 or 0.50 ppm EBL, 50 or 100 ppm GA3, or distilled water at 10, 15, 20 and 25°C. The seed imbibition patterns of the two soya bean varieties followed a similar trend. Low temperature delayed seed imbibition resulting in longer time to reach the end of phases 1 and 2 of seed germination as compared with high temperature. Soya bean seeds treated with 50 or 100 ppm GA3 showed increased germination index, shoot and root length and reduced mean germination time. Thus, 50-100 ppm GA3 could be used as a pre-soaking seed treatment to improve soya bean seed and seedling performance under low temperature.

Tuzluluk Stresi altında Lathyrus sativus L.'nin Çimlenme ve Büyümesini İyileştirmede, Salisilik Asit ile Tohum Priming Uygulaması

Increasing the ability of crops to maintain growth and productivity under saline conditions is of paramount importance. The effect of salicylic acid (SA) priming on germination and physiological traits of Lathyrus sativus under salinity stress was studied in a factorial experiment based on a completely randomized design. The experimental treatments composed of SA at three levels (0, 0.1, and 0.2 mM) and NaCl salinity at three levels (0, 50, and 100 mM). The effect of salinity level and SA priming was significant on all recorded factors, except from final germination percentage. As salinity level increased, all germination and physiological traits declined compared with control, whereas the mean germination time and percentage of cell death were increased. Moreover, as salinity was intensified, the Hill reaction was decreased significantly. Salinity exhibited the strongest effects at NaCl rate of 100 mM. Seed priming with SA increased germination speed index, reduced mean germination time, and increased leaf relative water content, seedling fresh and dry weight compared with plants from non-primed seeds. Seedling vigor index was increased by 23.4% in primed seeds with 0.2 mM SA. SA priming especially at 0.2 mM rate increased the Hill reaction rate and reduced percentage of cell death. SA priming could be regarded as a practical approach to improve germination traits, seedling growth, and physiological traits of Lathyrus sativus L. under salinity stress conditions.

Impact of halopriming on four wheat (Triticum aestivum L.) cultivars of balochistan under saline conditions

Priming effect of silicon sources (silica gel and sodium silicate) on the seeds of four wheat cultivars of Balochistan was studied to determine their effectiveness in increasing relative salt tolerance. The study depicts that all priming treatments of silicon sources (except sodium silicate 2%) enhanced germination and reduced mean germination time (MGT) of seeds in comparison to the control i.e. hydropriming. After germination, the young seedlings were grown in hydroponics in Hoagland’s culture solution under controlled conditions in non-saline and saline (100 mM NaCl) environments. All the growth parameters (root and shoot length, fresh and dry weights of plants and chlorophyll content of leaves) severely reduced in hydroprimed seeds under saline environments, although increased by priming seeds with silicon sources. Thus silica compounds have potential effects to break the seed dormancy and improve the growth of wheat under salinity stress.

Evaluation of structurally different benzimidazoles as priming agents, plant defence activators and growth enhancers in wheat

Priming is a valuable, facile and well-established technique used to enhance seed quality to achieve rapid germination, establishment of stress resistance and improvement of crop yields. Different natural and synthetic priming agents have been used for better crop performance and abiotic stress management. In this study, four different benzimidazoles were selected as priming agents and their comparative effects were evaluated on different biochemical attributes including total soluble protein, total oxidant status, MDA contents, antioxidant enzymes (SOD, POD) and hydrolytic enzymes (protease, estrases) compared to control. Treatments with 2-thio-1-H-benzimidazole reduced total soluble proteins and increased total oxidant status significantly but no considerable effect was observed on other parameters. Priming with 2-(4-chlorophenyl)-1-H-benzimidazole considerably increased the total oxidant status and a little improvement was observed in total soluble proteins. Seeds primed with 1-H-benzimidazole showed a noticeable decrease in the protease activity while all other priming treatments were unable to induce any detectable change compared to control. The treatment with 2-(4-methoxyphenyl)-1-H-benzimidazole induced maximum reduction in MDA contents and POD activity. Moreover, all benzimidazole priming treatments reduced mean germination time, increased germination percentage and germination rate of wheat seeds.

Chemical Priming with Salt and Urea Improves Germination and Seedling Growth of Black Cumin (Nigella sativa L.) under Osmotic Stress

A common problem with vegetable production in saline areas is poor crop stand, but for black cumin (Nigella sativa L.) germination data are limited and inconsistent. The effects of chemical priming with Urmia lake salt and urea solutions for 16 h at 30 °C on seed germination and seedling growth of black cumin (Nigella sativa L.) were studied under various osmotic stress levels. For a more detailed assessment of chemical priming, the effects of hydropriming for 16 h at 30 °C were also studied. A seed lot that was not exposed to any treatment, except disinfection, was used as control. Osmotic stress levels were − 2, − 4, − 6, and − 8 bar, which were achieved with polyethylene glycol 6000 (PEG 6000). Seed germination of black cumin was reduced by 16.2%, 33.8%, 50.9%, and 74.9% under osmotic potential − 2, − 4, − 6, and − 8 bar, respectively, compared with non-stressed control. Improved germination index values, reduced mean germination time, and increased coefficients of velocity of germination were observed under osmotic stress in primed seeds compared with non-primed control. Averaged over priming treatments, priming improved the final germination percentage by 10.5%, 24.3%, 45.5%, and 74.6% under osmotic potential − 2, − 4, − 6, and − 8 bar, respectively. Post-germination growth was also inhibited under low osmotic potential compared with the non-stressed control. Nevertheless, priming improved length and weight of black cumin seedlings and enhanced peroxidase and catalase activity at all osmotic potential levels compared with non-primed seeds. Higher seedling vigor indices were recorded in seedlings from primed seeds with decreasing osmotic potential levels than non-primed seeds. Urmia lake salt priming had the greatest impact on improving seed germination and vigor indices, especially under osmotic stress conditions. Although seed priming did not completely eliminate the symptoms of osmotic stress in black cumin germination, it is an efficient method to mitigate the impact of osmotic stress on germination of this species.

Seed Priming with Gibberellic Acid (GA3) Alleviates Salinity Induced Inhibition of Germination and Seedling Growth of Zea mays L., Pisum sativum Var. abyssinicum A. Braun and Lathyrus sativus L.

Low seed germination, poor seedling establishment, and less crop productivity are commonly observed problems in salt-affected soils. Genetic modification of plants for creating good varieties and selection of crop plants that have best performance on saline soils are the major accomplishments done to minimize the problem. In addition, application of Gibberellic Acid (GA3) has been reported to increase germination percentage and seedling growth performance of crop plants under salt stress. The objective of the present study was therefore to investigate the effect of GA3 on germination and early seedling growth of three important crops under saline conditions. To this effect an experiment was conducted as factorial with completely randomized design with three replicates. The factors of the experiment were salinity with four levels (0, 4, 6, 8, and 12 dS/m), hormone (GA3 at 0.2 g/L versus no GA3) and the three crops (Zea mays L., Pisums sativum Var. abyssinicum A. Braun, and Lathyrus sativus L). Consequently, priming seeds of these crops with 0.2 g/L GA3 significantly improved germination percentage, reduced mean germination time, increased shoot and root length, and total weight of the crops (P < 0.05) when the salinity level is less than 8 dS/m. However, shoots of all crops performed better than the roots.

Effects of pretreatments on seed dormancy and germination in endemic Uludağ flax (Linum olympicum Boiss.) (Linaceae)

Linum olympicum Boiss. (Linaceae) is an endemic species to Turkey, and has both medicinal and ornamental properties. In this study, we investigated the effects of GA3 and cold stratification (1 or 4 months) on the germination and mean germination time in relation to breaking dormancy in this species under darkness (20 °C) and light (20/10 °C, 12/12 h) conditions. Seeds were collected from specimens that spread on limestone or granite screes, ledges of rocky or turfy slopes, and hilltops of the alpine belt from Uludag Mt. (Bursa, Turkey, 2200–2300 m). We show that a combination of hormone and cold stratification treatments promoted seed germination under darkness and light conditions. Non-stratified seeds germinated to 73% following 1000 mg L−1 GA3 treatment and also it was 83% after 1 month cold stratification. After 4 months of cold stratification treatment, 10% and 53.3% of seeds successfully germinated after incubation in light and dark conditions, respectively. Hormone and cold stratification treatments also reduced mean germination time. Our results revealed that seeds of L. olympicum have physiological dormancy and require prolonged time for cold stratification and darkness for germination, rather than responding to the photoperiod. Germination requirements of L. olympicum have not been studied previously, and the data obtained could be used for the ex situ protection of this alpine species.

Title: Enhanced salt tolerance and photosynthetic performance: Implication of ɤ-amino butyric acid application in salt-exposed lettuce (Lactuca sativa L.) plants

Gamma-Amino Butyric Acid (GABA) is a substantial component of the free amino acid pool with low concentration in plant tissues. Enhanced GABA content occurs during plant growth and developmental processes like seed germination. GABA level, basically, alters in response to many endogenous and exogenous stimuli. In the current study, GABA effects were studied on germination, photosynthetic performance and oxidative damages in salt-exposed lettuce plants. Three NaCl (0, 40 and 80 mM) and two GABA (0 and 25 μM) concentrations were applied on lettuce during two different developmental (seed germination and seedlings growth) stages. Negative effects of salinity on germination and plant growth were removed by GABA application. GABA significantly reduced mean germination time (MGT) in salt-exposed lettuce seeds. Although, salinity caused a significant decline in maximum quantum yield of photosystem II (Fv/Fm) during distinct steps of plant growth, GABA application improved Fv/Fm particularly on high salinity level. GABA decreased specific energy fluxes per reaction center (RC) for energy absorption and dissipation, while enhanced-electron transport flux in photosynthetic apparatus of lettuce plants was observed in GABA-supplemented plants. Moreover, decline in non-photochemical quenching (NPQ) and quenching coefficients (qP, qL, qN) by salt stress were recovered by GABA application. Elevated electrolyte leakage considerably decreased by GABA exposure on salt-treated plants. Although, proline level increased by NaCl treatments in a concentration dependent manner, combined application of salt with GABA caused a significant reduction in proline content. Catalase; EC 1.11.1.6 (CAT), l-ascorbate peroxidase; EC 1.11.1.11 (APX), and superoxide dismutase; EC 1.15.1.1 (SOD) activities were increased by GABA exposure in salt-supplemented plants that resulted in regulated hydrogen peroxide level. In conclusion, a multifaceted role for GABA is suggested for minimizing detrimental effects of salinity on lettuce through improvement of photosynthetic functionality and regulation of oxidative stress.

Effects of exogenous 5‐aminolevulinic acid on seed germination of alfalfa (Medicago varia Martyn.) under drought stress

AbstractMedicago varia is a very important legume forage with a high yield and good nutrient quality. It is widely cultivated in the middle‐eastern regions of China. However, drought is one of the major abiotic stresses that reduce Medicago varia growth and production. 5‐aminolevulinic acid (5‐ALA) is a physiologically active substance in plants with the potential to improve agricultural production. Exogenous application of 5‐ALA is able to increase plant resistance to multiple abiotic stresses. In this study, the effects of different concentrations of 5‐ALA (0, 5, 10, 20, 30 mg L−1) on seed germination and seedling growth of Medicago varia under drought stress was investigated. The results showed that seed germination was reduced significantly under drought stress. However, exogenous 5‐ALA significantly increased the final germination percentage (FGP) and reduced mean germination time (MGT), indicating that 5‐ALA promoted seed germination of Medicago varia under drought stress. In addition, the rate of cotyledon protruding seed coat, seedlings biomass, radicle length, chlorophyll content of cotyledon, aperture width of stomata and pore area of stomata were increased significantly and stomatal density of cotyledon was reduced significantly by 5‐ALA under drought stress. Collectively, our data suggest that 5‐ALA can be applied to promote seed germination of M. varia under drought stress.

Nutrient Priming in Different Maize Cultivars and Evaluation of Vigour Improvement Under Controlled Conditions

Laboratory and pot experiments were conducted to study the effect of seed priming on vigourand germination characteristics of different maize cultivars during the year 2011. The seeds of four maizecultivars viz. EV 7004Q, Islamabad Gold, Rakaposhi and Sohan-3 were primed using 0% P (dry seededcontrol), 0.6% P and 1.2% P solutions of KH2PO4 for 16 h. The experiment was laid out in CompleteRandomized Design (CRD) having three replicates. All the seed priming treatments significantly improvedthe plant vigour in terms of enhanced germination percentage, reduced mean germination time (MGT),improved root, shoot lengths and dry matter production. Among the four cultivars of maize the IslamabadGold performed best followed by Sohan-3. Highest germination (94.57%) and vigour index (VI) of 431.66was observed in Islamabad Gold where 1.2% P applied compared to dry seeded control. Nutrient seedpriming may be used to improve germination vigour and crop stand establishment under field conditionsleading to good yield targets in maize under rainfed conditions.

Improving Seed Germination and Early Growth of Garden Cress (Lepidium sativum) and Basil (Ocimum basilicum) with Hydro-priming

Hydro-priming is a useful method for increasing speed and uniformity of germination in several plants, but pertinent research concerning garden cress (Lepidium sativum) and basil (Ocimum basilicum) does not exist in the literature. The effects of hydro-priming duration (0, 6, and 12 h) and temperature (15 and 25 °C) on seed germination and seedling vigour of garden cress and two varieties of basil (at priming temperature of 20 °C) were evaluated on paper and sand. With reference to garden cress, hydro-priming for 6 and 12 h at 15 °C increased uniformity of germination and reduced mean germination time. These improvements were more evident on paper. Moreover, hydro-priming for 6 and 12 h at 25 °C increased radicle length, plumule length, seedling length, and seedling vigour index on paper, but did not affect significantly those variables on sand. Overall, hydro-priming of garden cress seeds for 12 h can improve germination and early growth of this species, but germination medium can play a role due to different capacities for moisture retention. With reference to basil, hydro-priming reduced mean germination time for purple basil, but not for green basil. Also, reduced germination speed and uniformity of germination were observed for green basil on sand, but not for purple basil. Hydro-priming for 12 h increased plumule length, seedling length, and seedling vigour index for both basil varieties. Overall, hydro-priming of basil seeds for 12 h can improve germination and early growth of this species, but variety and germination medium can play a role. Data on improving germination of those species are not available in the literature and could be useful for improving plant establishment and yield of commercial plantations of garden cress and basil.

Hydrophilic polymer film coat as a micro-container of individual seed facilitates safe storage of tomato seeds

In high-value, low-volume crops like tomato, the high seed multiplication ratio and low seed rate often leads to large quantity of carry over seeds. Seeds lose viability over time, which manifests in poor crop establishment in the field. Hydrophilic polymer seed coating has been examined for better crop establishment and as a delivery system but has not been investigated as a means to maintain seed quality during storage. Hence, the present study was undertaken to investigate the use of hydrophilic polymer (Disco Clear) film coating as a tool for ensuring safe seed storage. Seed moisture kinetics under saturated atmospheric conditions revealed lower moisture adsorption and desorption pattern in hydrophilic polymer-coated seeds as compared to non-coated seeds. However, when exposed to freely available water, hydrophilic polymer facilitated faster and more controlled imbibition, which manifested in reduced mean germination time. Seeds coated with hydrophilic polymer maintained the quality over a longer storage period than non-coated seeds, irrespective of the packaging material and storage conditions. In polymer-coated seeds that were stored in paper bags under ambient room conditions, non-significant differences were observed for all the observed seed quality parameters for longer period thereby indicating its practical application as an alternative to storage under regulated environment. The presence of the hydrophilic polymer film coat acted as a physical barrier for absorption of moisture in the vapour phase and hence, under ambient conditions, the film coated seeds remained effectively protected from equilibration with fluctuating relative humidity, in a manner comparable with storage in moisture impervious containers. Considering this fact, we propose that the polymer film coat in itself acts as a micro-container for seed and thereby facilitates safe seed storage for an extended length of time.

GERMINATION PATTERN OF CHAMAEROPS HUMILIS SEED AFTER SHORT-TIME STORAGE

Dwarf fan palm (Chamaerops humilis) plays an important ecological role in the thermo Mediterranean vegetation stage, both in woodlands, xerophitic shrub communities and degraded ecosystems. Dwarf fan palm is typically propagated from seeds. Whereas other palm species show reduced germination after few months of seed storage, no information is available on the effects of storage time on seed germinability. We examined the germination pattern of dwarf palm seeds aged after a storage of 4, 6 or 8 months in comparison to fresh seed (control). A covariance analysis was performed to test the effect of time within seed-storage treatment. The germination patterns were significantly fitted by a S-shaped (sigmoidal) distribution function with the general equation y=β+α/(1+exp(-(x-μ)/s)). Short-time storage significantly increased both final seed germination and maximum germination rate, and reduced mean germination time in comparison to fresh seed. If considering that we did not make any seed treatment before sowing, these results may be due to an increased oxygen diffusion and water permeability through the seed hard coat during time.

EFFECT OF SOME TREATMENTS ON GLOBE ARTICHOKE SEED PRODUCTION UNDER EGYPTIAN CONDITIONS. B- Enhancement of Seed Germination by Seed Priming

Artichoke seeds germination shows variation in germination percentage and speed with non-uniform seedlings. Two labratory and nursery experiments were carried out during seasons of years 2011/2012 and 2012/2013 to investigate the enhancement role of seed priming agents on seed germination and seedling behvior of locally produced seeds of globle artichoke Cynara scolymus L (green globe CV.).Seeds were primed in 8 different priming agents (PEG 8000, KNo3, K2HPO4, Na2SO4, NaCl, MgSO4, KCl, or Mannitol.) plus the control treatment (without priming). Both germination under laboratory conditions and emergence under nursery conditions were evaluated. Germination percentage, coefficient of velocity and germination performance index were significantly increased as a result of seed priming treatments. KNO3 , PEG and mannitol were found to be the best treatments in this regard. Priming artichoke seeds in different priming agents reduced mean germination time and time required to reach 50% germination. KNO3 , PEG and mannitol significantly improved the seedling characters in terms of seedling length and seedling fresh and dry weights as well as amylase activity. However, K2HPO4 was the best treatment in activating theperoxidase enzyme. Emergence and subsequent growth of seedling in trays responded positively to seed priming and KNO3 was the suprior in enhancing emergance percentage and seedling growth in terms of seedlings height, number of leaves and dry weights of shoots and roots. It could be recomended that, priming local produced artichoke seeds in KNO3 , PEG and mannitol will enhance seed germination and subsequent seedling growth which in turn will lead to using seed as a new method for propagtion and multplication under Egyptian condition and subsequently the cultivated area with artichoke will increase.

SODIUM CHLORIDE PRIMING IMPROVES SALINITY RESPONSE OF TOMATO AT SEEDLING STAGE

We aimed to investigate whether sodium chloride seed priming and irrigation at seedling stage enhance response of 5-leaf stage tomato plants (Lycopersium esculentum Mill.) to high salt stress. Three experimental groups were as; non-primed seeds, seeds primed with 0.05M sodium chloride (NaCl), and seeds primed and irrigated with 0.05M NaCl starting from sowing to salt stress application. Sodium chloride solutions (0.1M, 0.2M, 0.4M, and 0.6M) were added to cups under pots in every 2 days for 10 days to treatment groups. Control groups were irrigated with distilled water at the same time intervals. At least two experimental setups contained at least four plants, and two samplings of leaf and root tissues were performed for analysis of each plant to evaluate changes in pigment and proline contents, lipid peroxidation and electrolyte leakage levels, and ascorbate peroxidase and catalase activity. Priming reduced mean germination time, and increased final germination percentage together with energy of germination. Increased root and hypocotyl lengths as well as increases in fresh weights supported enhanced seedling vigor. Considering growth and stress parameters such as chlorophyll content, chlorophyll to carotenoid ratios, and lipid peroxidation and electrolyte leakage were less affected in primed plants. Moreover, improvement of the accumulation of osmoregulating defense molecules, such as proline and anthocyanin, and of the inductions of the antioxidative enzyme system points out to higher adaptive response of these plants against deleterious effects of salt.