Final Germination Research Articles

The Hormonal Seed Priming in Relation to Carrot Germination

Seed priming is a pre-sowing treatment used to reduce stress effects in crops .This technique has been used to increase the germination rate of seeds mainly under unfavorable environmental condition. Crop productivity faces many problems like that unavailability of suitable condition that causes unbalanced seedling growth and poor germination. Hormones are essential to improve plant growth, development, crop yield quality and quantity. Auxin is essential hormones that improves germination of seeds and reduce stress effects. Laboratory experiment was conducted to study the effect of seed priming using different concentrations of IAA and IBA on carrot seeds (Daucus carota). In laboratory experiment, three concentrations of IAA and IBA (75 ppm, 50ppm, 25ppm) treated with distilled water with priming duration of 24 hours. Experiment was laid out in CRD with three replications. Data was collected to investigate the effect of seed priming with IAA and IBA under these condition like that (fresh weight, dry weight, speed of germination, root length, seed length, seedling length, final germination rate, mean germination time and dry matter content). Maximum fresh weight, final germination percentage, seedling length, energy of germination, speed of germination and mean germination rate was recorded IBA 75ppm. Maximum dry weight and dry matter content was observed IBA 25ppm.Maximum shoot length was recorded IBA 50ppm. Non-significant difference was recorded in root length.

Effect of seawater irrigation on germination and seedling growth of Carob tree (Ceratonia siliqua L.) from Gouraya National park (Béjaïa, Algeria)

The carob tree (Ceratonia siliqua L.) is an important component of the Mediterranean vegetation and its cultivation is important environmentally and economically. It is also an interesting leguminous species for afforestation-reforestation. In this study, carob seeds collected in a representative area of the Mediterranean basin at the national park of Gouraya (Béjaïa, Algeria), were subjected to germination tests under Mediterranean seawater (SW) irrigation of different concentrations (0, 10, 30, 50 and 100% SW) for 15-day period. Before germination tests, a 20 min pre-treatment with 96% sulphuric acid was necessary to overcome seed coat dormancy which does not permit germination. Results showed that the seeds of C. siliqua were able to germinate at different seawater concentration, except for 50% SW and 100% SW which resulted in total inhibition of germination. The maximum number of C. siliqua seed germination of 100% FGP (final germination percentage) appeared at 0% SW and 10% SW. Only 35.5% of the seeds have germinated in 30% SW. Ungerminated seeds of C. siliqua from different SW treatments showed medium germination recovery (FGPRecov) of 39.9% at 50% SW and low recovery of 18.2% at 100% SW when transferred to distilled water after 15 day-period. Seedlings length and seedling fresh and dry weight were significantly (P < 0.001) decreased with increasing SW concentrations. Seedling water content remained constant in 10% SW in comparison with the control, while it decreased very slightly in 30% SW. These findings may serve as useful information for C. siliqua habitat establishment and afforestation-reforestation programs in coastal sites and for exploiting seawater in the area.

Effect of Plant Growth Regulators on Seed Germination in Walla Patta (<em>Gyrinops walla</em>)

Walla patta (Gyrinops walla Gaertn.) belongs to family Thymelaeaceae, is a valuable endemic plant in Sri Lanka. Recently, this species has become a topic of wide interest due to its ability to produce highly valuable agarwood resin. Commercial cultivation of the species is yet to start, thus natural habitats are tremendously under pressure due to illegal harvest. The seeds of G. walla are recalcitrant and loose the viability within a shorter period of time. Due to the limited availability of information, the present study was aimed at evaluating the effect of plant growth regulators on seed germination. The experiment was conducted in a protected plant house at the Faculty of Agriculture, University of Ruhuna from September 2019 to January 2020. A completely randomized design (CRD) was used with three replicates. The influence of gibberellic acid (GA3), indole-3-acetic acid (IAA), and indol-3-butyric acid (IBA) at 800 ppm, 1000 ppm, and 1200 ppm concentrations on seed germination of the G. walla were investigated. Seeds soaked in nine different hormone solutions for 24 hours were placed in disinfected sand media and germinations were recorded daily up to 60 days. Seeds treated with water served as the control. Final germination percentage, mean germination time, mean daily germination, germination rate index and average time taken to start the germination were recorded. Hormone treatments except IBA at 1000 ppm, significantly increased (p<0.05) the seed germination, when compared with the control. GA3 at 1200 ppm showed the highest (65%) germination followed by IAA at 1000 ppm (53.33%) and 800 ppm (50%). GA3 treatments showed a significantly (p<0.05) faster germination rate than IAA and IBA. Based on the results, GA3 at 1200 ppm can be recommended to enhance the seed germination of G. walla.

Integrated use of bio-organic fertilizers for enhancing soil fertility–plant nutrition, germination status and initial growth of corn (Zea Mays L.)

Abstract The need for cheap and affordable alternate sources of plant nutrient inputs to boost the nutrient level of degraded arable farmlands has been a major concern for soil scientists, agronomists, and local farmers. In 2018, a greenhouse and laboratory pot experiment was carried out under control conditions for 21 weeks to evaluate the effect of plant growth-promoting rhizobacteria (Azospirillium brasilense), spent grain (SG) organic wastes from the beer industry, and chemical fertilizer (CF) on the soil fertility–plant nutrition, corn (Zea Mays L.) germination rate in calcareous soil. The treatments consisted of CK (control), SG (spent grain, 20 g kg−1 soil), Az (Azospirillium seed inoculation), CF (100% of NPK recommended fertilizers), bio-organic (Az with SG), bio-mineral (Az with CF), and organo-mineral (50% of SG +50% of CF). These treatments were arranged in a randomized complete block design and replicated three times. Results showed that after 10 and 21 weeks, SG application significantly increased soil organic carbon by 69% and 67.8%, total nitrogen (TN) by 87.66% and 85.44%, and raised available P (P) by 75.7% and 87.23%, respectively. The final germination percentage (FGP), germination index (GI), coefficient of velocity of germination (CVG) and plant height were significantly higher in the amended pots than that of the control pots after 21 days of planting. The SG with Az treatments had the highest GI, CVG, and FGP of 9.23, 0.19 day−1, and 100 %, respectively, while the least values were obtained in the CF 2.37, 0.12 day−1, and 61.6%, respectively. The highest values of N/P ratio, available Fe2＋, Zn 2 + , and Mn 2 + were 401, 20.35 mg kg−1, 7.27 mg kg−1, and 16.58 mg kg−1 respectively, as well as bio-fertilizers enhanced the dehydrogenase and urease enzymes by 1117.3 μ g TPF ml−1, and 275.4 mg NH 3 − Hg−1h−1 respectively, after 21 weeks of seed sowing. The final results among all treatments were in the order of SG > Bio-organic > Az > Organo-mineral > Bio-mineral > CF > CK. In conclusion, the application of SG and Az is recommended to improve TN and P use efficiencies, micro-nutrients uptake, plant seed germination performance of maize, and enhancement of calcareous soil properties.

Seed Viability, Seedling Growth and Yield in White Guinea Yam

The yam is an economic tuber crop utilized for food, feed, and various industrial applications. Botanical seed viability, seedling growth, and development are among factors that influence plant population dynamics, development, structure, and sustainability. However, little is known about seed viability, growth, and yield potential of seed-progenies developed using different mating designs. This study assessed seed germination, seedling growth, and yield traits in seed-progenies developed using North Carolina I (NC-1) and polycross mating designs. For this, seed germination and seedling nursery trials established using seed-progenies from different yam crosses were used. Results revealed that days to first seed germination (DAYFG), days to 50% germination (DAYSG), coefficient of velocity of germination, seed emergence speed (SES), germination index, final germination percent, and seedling vigor index significantly (p < 0.05) varied within and among NC-1 and PC-derived families. The mean days to first seed germination (DFSG) and DAYSG seed-progenies of NC-1 were significantly lower than the polycross progenies. Moreover, the seedling-progenies from the polycross produced a higher number of stems and more elongate tubers than those originated from the NC-1 mating. Progenies of family TDr1687 from a polycross mating were among the families that had the highest stem number (2.2), longest tuber (7.5 cm), and widest tuber (2.8 cm). The inter-family means of both NC-1 and polycross had a non-significant variation for mean tuber weight per plant. Our results suggest the relevance of seed germination and seedling attributes for selection of superior progenies at the early generation stage trials in yam breeding.

Effect of laboratory and soil storage on fern spores germination

In the laboratory, non-chlorophyllic (orthodox) fern spores are long-lived. However, their potential longevity might not reflect ecological longevity, which determines their viability within the natural soil spore bank. Our aim was to compare ecological (in a semi-natural soil bank) and potential (storage in laboratory–suboptimal conditions) longevity and vigour of fern spores over a period of five months. We assessed these in Llavea cordifolia Lag., Pellaea ovata (Desv.) Weath., and Thelypteris ovata R.P. St. John; spores collected from a cloud forest in Hidalgo, Mexico. The spore samples were enclosed in permeable phytoplankton bags and buried in situ at 10 cm soil depth, whereas controls were stored in glass vials in the laboratory at room temperature (21.6 ± 1.8°C). After one, three, and five months, the spores of both treatments were germinated, and the final germination percentage and vigour traits (lag time, germination rate, and mean germination time) were evaluated. After five months, the spore viability of three species remained high under both storage conditions but their vigour was affected differentially. The soil-stored spores of L. cordifolia remained more vigorous and had a shorter lag and mean germination time than laboratory-stored spores. In the other two species, spore vigour declined in both storage treatments, reflecting in longer lag and mean germination time and lower germination rate. In all three species, the moist soil environment of the cloud forest maintained spore viability for over five months. However, the decline of spore vigour might be disadvantageous when competing for resources during later stages of colonization. Our study is a first experimental approach to understand the time-effect of soil storage on viability and vigour of fern spores when compared to laboratory storage. Long-term studies in different soils, climates and vegetation types are necessary to determine spore ecological longevity of different fern species.

Intra-population seed survival during burial on a mass basis

Survival during burial is dependent upon a seed's ability to resist pathogen pressure and physiological aging. Several studies support a positive interspecific relationship between seed survival in soil and seed coat thickness. Our research attempted to understand if a similar intraspecific relationship occurs in Rudbeckia mollis (Asteraceae) seeds of different mass. Seeds were collected in August 2016 and separated into light (383 ± 7 µg), intermediate (409 ± 8 µg), and heavy (447 ± 10 µg) mass classes. Pericarp thickness was measured on fresh sections of seeds from each class. Seeds were buried 25 cm deep in a non-irrigated wildflower plot and monitored for viability with a standard germination test over 24 months. Final germination percentage varied from 0 to 98% with an overall mean of 82 ± 30% among all mass classes. Germination percentage and germination rate correlated positively with soil temperature suggesting dormancy cycling that is consistent with non-deep physiological dormancy. There was no consistent relationship between the likelihood of germination and seed mass but heavy class seeds were more likely to be recovered intact following burial. Pericarp thickness ranged from 24.7–41.4 µm and there was a weak positive relationship with mass. This research suggests no short-term relationship between intra-population seed mass and viability loss during burial. However, thicker seed coats in higher mass seeds may confer greater resistance to pathogen pressure. This research is supportive of a positive intra-population relationship between survival in soil and seed coat thickness.

Germination and Seedling Growth Responses of Zygophyllum fabago, Salsola kali L. and Atriplex canescens to PEG-Induced Drought Stress

In arid and semi-arid regions, planting drought-tolerant species is the most useful strategy in the reclamation of degraded soils. In the present study, we evaluated the effect of simulated drought by polyethylene glycol (PEG-6000) on seed germination and seedling growth of three desert plants such as Atriplex canescens, Salsola kali and Zygophyllum fabago. Seeds were subjected to water stress to drought stress by PEG at five stress levels (0, −1, −4, −8, −12, −14 bars). Germination of Z. fabago was completely inhibited at an osmotic potential of −8, −10 and −12 bars and the germination of A. canescens was inhibited only at −14 bar. In contrast, S. kali responded positively to high levels of stress and our results showed the highest final germination percent (71.75, 54 and 18.25%) under three-drought stress −8, −12 and −14 bars, respectively. In addition, increasing PEG concentration adversely affected the germination rate and seedling vigor index as well as the root and shoot length of species. Under high stress levels, S. kali achieved a higher germination rate and seedling vigor index compared to Z. fabago and A. canescens. Among species, S. kali was the only one able to develop roots and shoots at −14 bar. Therefore, S. kali could be considered as a promising plant for the rehabilitation of degraded soils at risk of desertification.

Seed germination under osmotic stress across different wild populations of mountain rye (Secale strictum (C.Presl) C.Presl))

The selection of resilient cultivars could help stem the losses in forage production due to a changing climate. Secale strictum is a wild grass with interesting potential as a forage crop. We studied the germination requirements of six wild S. strictum populations, representative of the whole species distribution range in Italy and occurring under different osmotic conditions (0 MPa, −0.8 MPa, −1.0 MPa, −1.2 MPa, −1.4 MPa and −1.6 MPa). Our aim was to find beneficial seed and germination traits for the possible use of this species as a crop. Different accessions of domesticated Secale cereale and ×Triticosecale were used as comparison. Some populations of S. strictum were drought tolerant at germination level (final germination > 25% at −1.6 MPa). A great variability was observed among wild populations in traits that currently limit the cultivation of the species as a forage crop (seed size, germinability) and that could improve its usage, especially in arid areas (water stress tolerance, fast germination). A correlation exists between the germination rates of wild populations and the seasonality of the rainfall at their natural growing sites. These results underline the importance of choosing appropriate source lineages when selecting S. strictum populations for crop development.

EFFECT OF DIFFERENT PRE-SOWING TREATMENT ON THE EMERGENCE OF DIALIUM GUINEENSE (WILD)

The experiments were conducted in the Forestry laboratory of Kebbi State University of Science and Technology, Aliero, Kebbi State. The studies were conducted from February 2020− March 2020 to assess the most effective method of breaking seed dormancy in Dialium guineense seeds. The seeds were subjected to four (4) pre-treatment methods (sulphuric acid, hot water, cold water and mechanical scarification) with untreated seeds as control, the experiment was laid out in completely randomized design (CRD) and replicated three (3) times. Final germination percentage (FGP), germination mean time (GMT), germination index (GRI), Coefficient Velocity of Germination (CVG) and Germination rate index (GRI) were calculated and the data was subjected to the analysis of the variance (ANOVA). Seed treated with cold water for 48 hours (Trt 1) started germination at two (2) days after sowing (DAS) and ended germination at 5 DAS, control and three of the treatments (Trt 2, Trt 5& Trt 7) started germination at 3 DAS while Trt 4 and Trt 8 started at 4 and 5 DAS respectively. FGP 100% was obtained from Control and Trt 5 and they finished Germination at 9 and 21 DAS respectively. Highest GI, GRI and CVG and lowest MGT were recorded from Trt 1. The result analysis of findings at 5% level of statistics showed that there is nosignificant difference between the treatments. Similarly, no germination on seeds in Trt 3 and Trt 6. Seeds of Dialium guineense are not limited by dormancy therefore can be sown without any pre-treatment, but for large scale production of Dialium seedlings it can be treated in cold water at room temperature for 48 hours due to availability and low cost with less risks.

Stinkwort (Dittrichia graveolens) organic extracts as potential biofungicides for Fusarium poae

In the present study, we tested the antifungal activity of ethanol, methanol and acetone extracts of stinkwort against pathogenic fungus grown from ecological wheat grain, molecularly identified as Fusarium poae. Its susceptibility to the stinkworth extracts was tested in vitro with agardilution method. The results of antifungal effect of the organic stinkwort extracts showed that the growth of F. poae was significantly reduced by these extracts compared to the control and that the antifungal activity is dose-dependent. The methanol extract showed stronger inhibition than the ethanol and acetone ones at all three concentrations. All organic extracts showed a similar antifungal activity against F. poae as a broad-spectrum fungicide azoxystrobin. We tested the effects of stinkwoth extracts on the germination of radish seeds. The methanol extract delayed the germination of the radish seeds during the first 24 hours, but thereafter all three organic extracts had a comparable germination rate as the control seeds. Despite the delayed germination of the radish seeds, the methanol extract did not reduce the final germination rate and at the same time reduced the fungal infection by almost 50%. These results indicate that the methanol stinkwort extract has the potential to be used as a biofungicide in organic farming.

Seed traits of species from South Brazilian grasslands with contrasting distribution

ABSTRACT South Brazilian grasslands are among the most species-rich grasslands worldwide yet they have been suffering ongoing degradation due to land-use. Little is known about the reproductive ecology of the native species of these grasslands. Thus, our goal was to characterize seed traits and germination requirements of three native species of the tribe Tigridieae (Iridaceae, Iridoideae) due to its richness in the Pampa biome and the contrasting morphology, cytogenetics, and geographic distributions of its representatives. We tested if closely related species possess similar seed traits and whether species with wider distributions have broader germination requirements. Seed production and mass were estimated, and morphological analyses, germination experiments and viability tests were performed. Principal component analysis (PCA) was used to describe correlations between seed traits and species’ distributions. Germination was assessed using time-to-event analysis and the Cox model. All seed traits differed among the analyzed species/cytotypes. Final germination percentage (FGP) averaged 39.1 % and with overall viability of 89.9 %. Germination tests showed that seeds benefit from negative photoblasty. Species/cytotypes with wider distributions and heavier and larger seeds generally had better germination performances than narrower distributed species/cytotypes with lighter and smaller seeds.

Effects of Priming with Ascorbic Acid, L-Cystein and Triacontanol on Germination of Rapeseed (Brassica napusL.)

AbstractThe germination of seed batches of two rapeseed (Brassica napusL.) hybrids (‘Hybrirock’ and ‘Factor’) were investigated in response to priming in aqueous solutions of ascorbic acid (10 mM), L-cysteine (10 mM) and triacontanol (1 μM), respectively tap water (as control treatment). Investigations were focused on seed quality parameters, such as germination percentage, mean germination time, germination index, uniformity of germination, and seedling shoot and root growth. Germinated seeds were counted every 24 hours for a period of seven days, recording the final germination percentage (FGP), mean germination time (MGT), the coefficient of velocity of germination (CVG), germination rate index (GRI), germination index (GI), uncertanty (U), and synchrony (Z). In a separate trial fresh shoot- and root length, respectively the dry weight of the shoots and roots were also determined after a 14 day period. Germination tests were performed to examine the quality of seeds in response to different priming treatments. The results demonstrated that priming improved the germination parameters of seeds of both hybrids. Furthermore, the use of ascorbic acid, L-cysteine and triacontanol also enhanced seedling growth. The results may be used to rank seed lots by vigor, and decisions can be made regarding planting potential of each seed lot.

Germination, growth, and yield of rocket populations show strong ecotypic variation under NaCl stress

Rocket (Eruca sativa L.) is an old native plant well adapted to diverse climates in Iran. It’s known for the ability to grow and produce seeds rich in protein and oil as well as edible foliage under marginal conditions and has a potential as a promising oil seed. Nonetheless, little is known about its response to salt stress. This study aimed to evaluate possible genetic diversity of local landraces of rocket in terms of salinity tolerance both in germination and whole plant level. In the first experiment, germination characteristics of seven ecotypes of rocket named based on the region of collection as Sirjan, Bardsir, Rigan, Shahdad, Abadeh, Lamerd and Darejove were assayed under increasing salinity from 0 to 18 dS/m. Increasing salinity decreased all germination indices but ecotypes significantly differ in the magnitude of response. Averaged over salinity levels and based on scoring values for final germination percentage, germination rate and seed vigor, one superior (Sirjan), one inferior (Bardsir) and one moderate (Darejove) ecotype were selected for further investigation in the second experiment in which plants were subjected to three salinity levels (1.8, 6 and 12 dS/m) in a hydroculture system and some of their biochemical, physiological and dry matter accumulation attributes were evaluated. Results showed that increasing salinity decreased grain and biological yield, relative water content, leaf chlorophyll content and leaf area but increased leaf carotenoids content, electrolyte leakage, proline and soluble sugars concentrations and shoot and root Na content. Also, in all three ecotypes activities of catalase, superoxide dismutase, guaiacole peroxidase and ascorbate peroxides increased in response to application of 6 or 12 dS/m salinity, but these alterations were not correlated with dry matter or grain production. Na shoot content, however, was closely and negatively associated with grain and biological yield and differ significantly among ecotypes. Interestingly, Bardsir, the least salt tolerant ecotype at germination, was the best in hydroculture experiment and often showed the highest values for the most growth parameters measured. These differential responses suggest a possible change in salt tolerance mechanism along with developmental stages transition.

Nutritional Characteristics and Seed Germination Improvement of the Forage Shrub Retama sphaerocarpa (L.) Boiss

Summary Retama sphaerocarpa shrubs form populations that can be an important forage resource during the dry season when pasture shortages are common in certain arid and semi-arid Mediterranean basin regions. The leaves of R. sphaerocarpa were analyzed for dry matter (DM), crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF) and acid detergent lignin (ADL) contents. Leaves were also analyzed for the concentration of macro- (P, K, Ca and Mg) and microelements (Mn, Zn, Fe, and Na). According to the contents of CP, NDF, ADF and ADL in the leaves examined, this species could strike an appropriate balance between available feed ingredients for daily nutritional needs of animals. The contents of Ca, K, Na, P, Fe, Mg, and Zn in Retama sphaerocarpa shrubs were found to be high, compared to a number of other forage shrub species. Conversely, the rate of natural regeneration of this shrub in situ was estimated at 2-5%. R. sphaerocarpa seeds are affected by seed coat dormancy that prevents seed germination under natural conditions. The seed germination was assessed at a laboratory after the chemical scarification of seeds by concentrated sulphuric acid in the duration range of 0 min and 240 min. The principal component analysis of data related to the germination ability and seedling emergence showed that the best pretreatment was 120 min immersion in sulphuric acid at 25°C (± 2°C), resulting in 86% of the final germination percentage (FGP) and 14.6 cm of the seedling length (SL). According to the results obtained, this species could be considered a ruminant feed of great nutritive value when drought decreases grazing herbaceous biomass yields. These results should encourage farmers and foresters to integrate R. sphaerocarpa into their planting programs.

Response of three tossa jute (Corchorus olitorius L.) cultivars produced in Benin to salinity stress at germination and young plant stages

The response of three tossa jute cultivars Ordinaire, 5-Doigts and Acc : Sud 2 to salt stress was evaluated at germination and young plant stages. Five NaCl concentrations: 0; 30; 60; 90 and 120 mM NaCl were used. Seeds were submitted to NaCl in petri dishes and germination was checked every day during thirty days in a completely randomized design with four replicates. Four-week old plants were submitted in pots to the same five NaCl concentrations by irrigation every two days for two weeks in screen house. NaCl reduced seed germination rate in all cultivars from day 2 to day 30 and the germination index. At the end of the 30 days, salt stress reduced the final germination percentages with a significant difference among cultivars: cultivar 5-doigts was the least affected than the two other cultivars. Salt effect caused a reduction of young plant growth whatever the growth parameter considered with a significant difference among cultivars. The growth of cultivar Acc:Sud 2 was more affected by salt stress with the lowest salt tolerance index whereas that of cultivar Ordinaire was the least affected with the highest salt tolerance index. Thus, cultivar 5-Doigts appeared as the most resistant to salt stress at germination stage among the three cultivars; whereas cultivar Ordinaire followed by 5-Doigts was the most salt resistant at young plant stage.

Under pressure: maternal effects promote drought tolerance in progeny seed of Palmer amaranth (Amaranthus palmeri)

AbstractThe environmental conditions under which parental plants are reared can affect the seed characteristics of the progeny. The variation originating from such maternal effects has rarely been incorporated into models of seed germination. Here, using Palmer amaranth (Amaranthus palmeriS. Watson), we examined the effects of water stress during the growth of parental plants on the progeny seed characteristics, including weight, size, final germination, and parameters of a hydrotime germination model. We grew two populations (from California and Kansas) under continuous water-deficit or well-watered conditions. In bothA. palmeripopulations, progeny seeds originating from water-stressed plants were heavier and larger than those from well-watered plants. Plants exposed to water stress also produced seeds that were ~30% less dormant than seeds from control plants. To test whether the maternal environment affects the parameters of a hydrotime model, progeny seeds were subject to five water potentials (0, −0.2, −0.4, −0.6, and −0.8 MPa) and incubated at 20 and 30 C; germination was monitored daily. The estimated median base water potential (Ψb(50)), that is, the water potential at which 50% of seeds cannot germinate, was consistently lower for seeds from water-stressed plants than for seeds from well-watered plants. Our results showed thatA. palmeriplants experiencing drought during their growth produce seeds that are less dormant and can germinate from drier conditions—a maternal response that seems to be adaptive. These findings also call for development of germination models that incorporate the environmental conditions of both the current and past seasons to better describe the variability in germination of weed seeds.

Seed germination of selected crop and graminoid species in response to treatment with sodium chloride and oil-field brine solutions

Oil and gas development is often associated with the production of produced water or “brine”, which is a solution of dissolved salts (NaCl ≈ 90%) exhibiting electrical conductivity (EC) upwards of 200 dS m−1. Accidental releases of brine to soils inhibit seed germination through osmotic and ionic stressors. The final germination (FG; %) of four crop species, Hordeum vulgare L. (barley), Helianthus annuus L. (sunflower), Carthamus tinctorius L. (safflower), Beta vulgaris L. (sugar beet); and four graminoid species, Pascopyrum smithii (Rydb.) Barkworth & D.R. Dewey (western wheatgrass), Elymus hoffmannii K.B. Jensen & Asay (AC Saltlander), Leymus triticoides (Buckley) Pilg. (beardless wildrye), and Elymus trachycaulus (Link) Gould ex Shinners (slender wheatgrass), were determined using sodium chloride (NaCl) and brine solutions prepared at EC levels of 0, 4, 8, 16, 24, and 32 dS m−1. No differences (p > 0.05) in FG were found between NaCl and brine solutions across graminoid species or the crop species barley, sunflower, and sugar beet. AC Saltlander had the highest FG (81.9%) at the maximum EC level (32 dS m−1), compared with 47.2% and 0.8% for western wheatgrass and beardless wildrye, respectively. Within crop species, safflower exhibited the highest germination (10%–30%) across both solutions at 32 dS m−1. Barley (0%–2.9%), sugar beet (4.9%–7.7%), and sunflower (0%–1.4%) exhibited low germination at 32 dS m−1. The implications of this experiment are that previously established NaCl tolerance indices may be used to accurately determine the FG of plant species in brine-contaminated soils and that AC Saltlander, as well as western wheatgrass, have the highest FG at 32 dS m−1, indicating these species may have the greatest potential for successfully revegetating brine-contaminated soils.

Seed Dormancy of <i>Viola mandshurica</i> and <i>V. albida</i> and Their Germination Characteristics by Seed Storage

The purpose of this study was to determine the seed dormancy types of Viola mandshurica and V. albida, and to investigate their germination characteristics during seed storage. V. mandshurica seeds were incubated at 25/15, 20/10, and 15/6°C with final germination rates of 86%, 66%, and 66%, respectively, indicating that these seeds have no physiological dormancy (PD). However, V. albida seeds were found to have PD, since germination hardly occurred during the 4-week experiment, and the final germination rate was 50% or less. When the seeds of V. albida were treated with GA3 1000 mg･L-1, the final germination rate was 100%. Moreover, the germination rate increased as the period of cold stratification for V. albida seeds increased. The germination characteristics of Viola seeds were also examined from seeds harvested in 2019. V. mandshurica seeds germinated at 25/15°C in one week, but the mean germination time decreased compared to seeds that were stored for 4 years. This shows that V. mandshurica has reduced seed viability during storage. V. albida seeds that were harvested in 2019 hardly germinated within the 4-week experiment, and the germination rate increased through cold stratification. Therefore, the seeds of V. mandshurica and V. albida do not change the seed dormancy type, but the seed viability might be affected by the type of long-term storage used.

Variations in growth and genetic properties of Zea mays L. germinants exposed to cold shock

BackgroundAbiotic stresses like low temperatures are contributory factors to the variations observed among species during plant germination, growth, and development. The present study evaluated the morphological and genetic responses of maize (Zea mays L.) seedling to cold shock induced by a one-time exposure to low temperature. Seeds were originally exposed to distilled water at room temperature for 48 h before they were completely submerged in buckets of ice for 0.5, 1.5, 3, 6, and 12 h, respectively, and then transferred into Petri dishes. The set up was left on the laboratory bench for an additional 5 days, and plant germination parameters were measured. DNA was extracted and this was followed by RAPD—polymerase chain reaction.ResultsSignificant growth impairment upon exposure to cold shock corresponding to the length of time of exposure was shown. The length of the prominent root significantly reduced upon exposure to a cold shock from 141.8 mm to as low as 91.4 mm in those plants exposed at 1.5 h. The length of the prominent leaf also significantly reduced from 100.6 mm in the control to between 62.6 and 85.5 mm in low-temperature-exposed plants (p < 0.05), notwithstanding the time of exposure. There were significant reductions in final germination percent in the low-temperature-exposed germinants (35.8–60.5%) when compared to the control (88.5%). The RAPD marker (OPA04) revealed variations in germinated maize seeds after treatment with different duration of low temperatures. The test plantlets treated for 0, 0.5, and 1.5 h have an unrecognizable complementary sequence to the primer OPA04, whereas the primer amplified regions of the genome of test plantlets treated for 3, 6, and 12 h. Primer OPA05 also presented diversity among maize seedlings stressed for various durations of cold shock.ConclusionThe existence of genetic variations in the present study has far-reaching effects on the development of maize exposed to varying degrees of cold stress. Though restricted to germination only, they are important because the development of plants begins at the germination stage. These changes may affect the characteristics of economic importance or perhaps impact on the physiology of the maize plant eventually.