Imbibition Of Seeds Research Articles

PB-12In Vivo Time-lapse Imaging of Changes in Air Space Distribution during Seed Imbibition in Lotus miyakojimae using X-ray Micro-CT

PB-12In Vivo Time-lapse Imaging of Changes in Air Space Distribution during Seed Imbibition in Lotus miyakojimae using X-ray Micro-CT

Salicylic Acid Concentrations and Its Effects on the Physiological Quality of Soybean Seeds

The objective of this study was to evaluate the physiological quality of commercial soybean seeds submitted to different concentrations of salicylic acid (SA), directly on germination paper and gerboxes for 24 hours. Seeds of cultivars NA 5909 RG and Tec Irga 6070 RR were soaked in salicylic acid solutions with concentrations of zero, 250, 500, 750, 1000, 1500, 2000, 3000, 4000 and 5000 μM. Seed imbibition occurred in two ways: (1) germination paper moistened with salicylic acid solutions; (2) imbibition of the seeds in salicylic acid solutions in gerbox boxes for 24 hours and subsequent sowing on germinated paper moistened with distilled water. On the fifth day after sowing, the number of normal seedlings (first count), length, fresh and dry mass of root and shoot were determined. It was concluded that the concentrations of SA between 250 and 750 μM can be used in soybean seeds, however, above 1000 μM may impair the parameters of physiological quality. The gerbox method for 24 hours provided the best results without the drastic reduction of the parameters in the lowest concentrations of SA.

The Effect of Ambient Temperature on Brachypodium distachyon Development.

Due to climate change, the effect of temperature on crops has become a global concern. It has been reported that minor changes in temperature can cause large decreases in crop yield. While not a crop, the model Brachypodium distachyon can help to efficiently investigate ambient temperature responses of temperate grasses, which include wheat and barley. Here, we use different accessions to explore the effect of ambient temperature on Brachypodium phenology. We recorded leaf initiation, heading time, leaf and branch number at heading, seed set time, seed weight, seed size, seed dormancy, and seed germination at different temperatures. We found that warmer temperatures promote leaf initiation so that leaf number at heading is positively correlated to temperature. Heading time is not correlated to temperature but accessions show an optimal temperature at which heading is earliest. Cool temperatures prolong seed maturation which increases seed weight. The progeny seeds of plants grown at these cool ambient temperatures show stronger dormancy, while imbibition of seeds at low temperature improves germination. Among all developmental stages, it is the duration of seed maturation that is most sensitive to temperature. The results we found reveal that temperature responses in Brachypodium are highly conserved with temperate cereals, which makes Brachypodium a good model to explore temperature responsive pathways in temperate grasses.

Interaction of functional and environmental traits on seed germination of the multipurpose tree Flacourtia indica

Flacourtia indica (Salicaceae) is a multipurpose tree native to tropical regions of Africa and India, where it is mainly used for food and medicines. Its use in reforestation is limited by poor knowledge of its seed biology and germination ecology. The aim of this study was to determine how its morphological and ecological seed traits interact with the environment and affect seed germination and seedling emergence.The results showed high germination percentages (>70%) when stones were incubated at alternating temperature regimes, regardless of the photoperiod. Lack of daily temperature fluctuation resulted in low germination, especially when the stones were incubated in the dark (<12%). Germination in a 12/12 h photoperiod at constant temperature was positively correlated with temperature, although final germination never surpassed 50%. The addition of GA3 to the substrate resulted in high final germination regardless of temperature regime or photoperiod. Stones and seeds imbibition curves suggest a lack of physical dormancy, while the presence of a fully developed spatulated embryo excluded morphological dormancy. High germination at alternating temperatures (>70%) discarded the presence of deep physiological dormancy (PD), but differences found between chipped and non-chipped seeds suggest the presence of a non-deep PD, imposed by the seed coat.Thus, difficulties in propagating this species from seeds, which have been previously reported in the literature, are probably due to initial poor seed lot quality rather than dormancy. These results suggest that F. indica seed germination is more likely to occur near the soil surface or when the tree canopy is disrupted, where daily temperature fluctuations are high and light might become available. Viable seeds not meeting germination conditions are likely to become part of the soil seed bank. Our results will help to support the effective use of F. indica seeds in reforestation and livelihoods programmes.

Imbibition, Germination, and Early Seedling Growth Responses of Light Purple and Yellow Seeds of Red Clover to Distilled Water, Sodium Chloride, and Nutrient Solution

The seeds of red clover are heteromorphic and two color morphs can be visually recognized, light purple and yellow, resulting from heterozygosity and recessive homozygosity at two loci. Here, we report the responses of seed imbibition, seed germination, and early seedling growth of the two morphs to distilled water, sodium chloride, and complete nutrient solution. The sensitivityof red clover seeds to treatments increased with the stage of development in what seems to be a cumulative process. No differences were found in seed imbibition between morphs or between treatments. In seedling growth, on the contrary, treatments were always effective, but differences between morphs were only observed in seeds that were treated with nutrient solution, whereas in the intermediate stage of seed germination, the effects by treatments were observed together with the appearance of differences between morphs in distilled water and in the treatment by sodium chloride solution. Simultaneously, the superior performance of the yellow morph that was found in germination, which appears to be a trait stable across cultivars of red clover seeds, turned into a superior performance of the light purple morph in seedling growth.

The Influence of H2O2 Application Methods on Melon Plants Submitted to Saline Stress

The salinity in irrigation water is one of the most important causes to decline cultivated plants yield. The H2O2 application has shown efficiency as a stimulator and activator for antioxidative defense system in plants submitted to biotic and abiotic stresses. The objective of this study was to evaluate methods for hydrogen peroxide application as a strategy to minimize the effects of saline stress on melon plants. The experiment was designed in complete randomized blocks and set in 2 &amp;times; 4 factorial scheme, consisting two levels for irrigation water salinity (S1 = 0.3 and S2 = 2.0 dS m-1) and four methods for hydrogen peroxide application (15 mM), (T1 = no peroxide application, T2= imbibition of seeds, T3 = at sowing, T4 = Foliar spraying), with five repetitions. It was evaluated the following variables at 58 days after transplanting: plant height, stem diameter, number of leaves, number of flowers, shoot dry mass, root dry mass and total dry mass. The results showed that salinity affected the growth, biomass accumulation and plant quality severely, with the highest losses promoted by the electrical conductivity of 2.0 dS m-1.

Teste de condutividade elétrica e embebição de sementes de grão-de-bico

The germination process begins with the imbibition, during the available water, which triggers a sequence of metabolic changes that culminate in the protrusion of the primary root into viable seeds. By the organization of the cell membrane system, a method that can indicate the level of seed vigor is the conductivity. The objective of this study was to evaluate and model the process of imbibition of chickpea seeds, in addition to establishing an efficient methodology for water volume, imbibition time and number of seeds in the electric conductivity test. Eight lots were used, four of the BRS Aleppo cultivar and four of the Cicero cultivar, which were submitted to the germination and vigor test for initial characterization. The electrical conductivity was conducted with 50 and 75 seed subsamples using 75 and 100 mL of deionized water, and the periods 2, 4, 8, 12, 18, 24 and 30 h were maintained at 25 °C. The experiment of electrical conductivity was in a completely randomized design with four replicates. The Peleg model was adjusted for imbibition kinetics. The most appropriate methodology was the use of 75 seeds, volume of 100 mL of water for 30 h. The Peleg model was efficient in describing the process of water absorption, although there were differences in the physiological potential of the lots.

Imbibition, Germination, and Early Seedling Growth Responses of Light Purple and Yellow Seeds of Red Clover to Distilled Water, Sodium Chloride, and Nutrient Solution

The seeds of red clover are heteromorphic and two color morphs can be visually recognized, light purple and yellow, resulting from heterozygosity and recessive homozygosity at two loci. Here, we report the responses of seed imbibition, seed germination, and early seedling growth of the two morphs to distilled water, sodium chloride, and complete nutrient solution. The sensitivity of red clover seeds to treatments increased with the stage of development in what seems to be a cumulative process. No differences were found in seed imbibition between morphs or between treatments. In seedling growth, on the contrary, treatments were always effective, but differences between morphs were only observed in seeds that were treated with nutrient solution, whereas in the intermediate stage of seed germination, the effects by treatments were observed together with the appearance of differences between morphs in distilled water and in the treatment by sodium chloride solution. Simultaneously, the superior performance of the yellow morph that was found in germination, which appears to be a trait stable across cultivars of red clover seeds, turned into a superior performance of the light purple morph in seedling growth.

Chilling imbibition improves the germination tolerance of the Andean tree Alnus acuminata to arsenic

Arsenic (As) is a toxic metalloid common in coal mining soils. We evaluated a stratification treatment of 48 h of chilling imbibition (3 °C) versus control imbibition (25 °C) in seeds of the Andean tree Alnus acuminata (Kunth). Five concentrations of As: 0, 2.5, 5.0, 7.5, and 10 mg L−1 were tested in both groups of seeds to determine whether chilling imbibition affects the germination, vigor of seedlings and tolerance to arsenic. Physiological, biochemical and morphometric traits were evaluated in germinants to establish how chilling imbibition and As modulate the early development. Growth and tolerance index were estimated in seedlings of 70 days. We found that chilling imbibition enhanced the germination tolerance to arsenic and this effect was unaltered by its concentration. The germinants accumulated arsenic and the maximum reduction of growth was around 28%, but these germinants reached the stage of seedling without negative affectations in final size or biomass. The emergence of the first leaf was delayed in germinants coming from seeds imbibed at 25 °C and exposed to As. Chilling imbibition increased the allometric relationship between size and biomass in germinants exposed to As, improving the vigor and tolerance in more than 55%. Our results suggest that accumulation of As in cotyledons, a high content of carbohydrates and proteins, the activity of SOD, POX and probably the synthesis of phytochelatins are the strategies of tolerance in germinants coming from pre-chilled seeds. This treatment becomes important for the implementation of A. acuminata in forestry programs for soils affected by coal mining.

Hydrogen peroxide signaling integrates with phytohormones during the germination of magnetoprimed tomato seeds

Seeds of tomato were magnetoprimed at 100 mT for 30 min followed by imbibition for 12 and 24 h, respectively, at 20 °C, to examine the biochemical and molecular changes involved in homeostasis of hydrogen peroxide (H2O2) and its signaling associated with hormone interactions for promoting vigor. The relative transcript profiles of genes involved in the synthesis of H2O2 like Cu-amine oxidase (AO), receptor for activated C kinase 1 (RACK1) homologue (ArcA2) and superoxide dismutase (SOD1 and SOD9) increased in magnetoprimed tomato seeds as compared to unprimed ones with a major contribution (21.7-fold) from Cu-amine oxidase. Amongst the genes involved in the scavenging of H2O2 i.e, metallothionein (MT1, MT3 and MT4), catalase (CAT1) and ascorbate peroxidase (APX1 and APX2), MT1 and MT4 exhibited 14.4- and 15.4-fold increase respectively, in the transcript abundance, in primed seeds compared to the control. We report in our study that metallothionein and RACK1 play a vital role in the reactive oxygen species mediated signal transduction pathway to enhance the speed of germination in magnetoprimed tomato seeds. Increased enzymatic activities of catalase and ascorbate peroxidase were observed at 12 h of imbibition in the magnetoprimed seeds indicating their roles in maintaining H2O2 levels in the primed seeds. The upregulation of ABA 8′-hydroxylase and GA3 oxidase1 genes eventually, lead to the decreased abscisic acid/gibberellic acid (ABA/GA3) ratio in the primed seeds, suggesting the key role of H2O2 in enhancing the germination capacity of magnetoprimed tomato seeds.

Morphology of seeds, seedlings, and young plants of Dimorphandra gardneriana Tul

Dimorphandra gardneriana Tul. is a legume, the fruits of which are used in routine extraction by the pharmaceutical industry. The objective was to study the morphological aspects of seeds, germination, seedlings, and young plants of Dimorphandra gardneriana Tul. The study was conducted at the Laboratory of Seed Analysis (LAS), Center of Agricultural Sciences, Federal University of Paraíba (CCA-UFPB), Areia - PB. The external morphological characteristics observed of the seeds were color, texture, and consistency of the teguments; seed shape; hilum and micropyle position; color and thickness of raphe and other structures present; besides internal embryo characteristics (cotyledons, hypocotyl-radicle axis, plumule, and central cylinder); and presence of the endosperm. The seed imbibition curve was determined by the weight of the seeds over a period of 90 h, evaluated every 6 h, with germination being considered as the protrusion of the primary root, or the moment when the primary root breaks the integument, and normal seedlings were evaluated on the 5th day after sowing. Most of the morphological characteristics identified in the plants and seedlings of D. gardneriana resembled those observed for other species of the same genus. The seeds of D. gardneriana Tul., were medium sized, with an average length of 11.95 mm, width of 5.33 mm, and thickness of 4.3 mm, unitegmic with a hard tegument, and impermeable to water. The process of imbibition of the seeds was initially slow and the three-phase curve of imbibition was not clear. The germination was epigeic and phanerocotiledonar and began on the 5th day after sowing.

The interplay of PsABAUGT1 with other abscisic acid metabolic genes in the regulation of ABA homeostasis during the development of pea seeds and germination in the presence of H2O2

Inactivation of abscisic acid (ABA) in vitro may be catalyzed either by ABA 8′-hydroxylase (ABA8′OH) or by ABA uridine diphosphate glucosyltransferase (ABAUGT), which conjugates ABA with glucose. However, the involvement of these enzymes in the control of ABA content in vivo, especially ABAUGT, has not been fully elucidated. In pea seeds, both PsABAUGT1 and PsABA8′OH1 contribute to the reduction of ABA content during seed maturation and imbibition; however, during the first hours of imbibition, a high expression of only PsABAUGT1 was observed. Imbibition of seeds with H2O2 increased the ABA content despite the oxygen availability and altered the expression of metabolic genes. The expression of the biosynthetic gene 9-cis-epoxycarotene dioxygenase (PsNCED2) was increased, while that of PsABAUGT1 was decreased in each H2O2 experiment despite O2 availability. Under hypoxia, only seeds imbibed with H2O2 germinated, while under nonlimiting oxygen conditions, the germination rate was not altered by H2O2. Under hypoxia, the germination rate of H2O2-imbibed seeds seemed to not depend on the absolute ABA content and rather on the balance between ABA and gibberellins (GA), as H2O2 increased the expression of GA synthesis genes.Overexpression of PsABAUGT1 in Arabidopsis decreases seed ABA content, accelerates germination and reduces seed sensitivity to exogenously applied ABA, confirming the ability of PsABAUGT1 to inactivate ABA. Thus, PsABAUGT1 is a new player in the regulation of ABA content in maturating and imbibed pea seeds, both under standard conditions and in response to H2O2.

Imbibition, Germination, and Early Seedling Growth Responses of Light Purple and Yellow Seeds of Red Clover to Distilled Water, Sodium Chloride, and Nutrient Solution

The seeds of red clover are heteromorphic and two color morphs can be visually recognized, light purple and yellow, resulting from heterozygosity and recessive homozygosity at two loci. Here, we report the responses of seed imbibition, seed germination, and early seedling growth of the two morphs to distilled water, sodium chloride, and complete nutrient solution. The sensitivity of red clover seeds to treatments increased with the stage of development in what seems to be a cumulative process. No differences were found in seed imbibition between morphs or between treatments. In seedling growth, on the contrary, treatments were always effective, but differences between morphs were only observed in seeds that were treated with nutrient solution, whereas in the intermediate stage of seed germination, the effects by treatments were observed together with the appearance of differences between morphs in distilled water and in the treatment by sodium chloride solution. Simultaneously, the superior performance of the yellow morph that was found in germination, which appears to be a trait stable across cultivars of red clover seeds, turned into a superior performance of the light purple morph in seedling growth.

Physiological Quality of Common Bean Seeds Subjected to Different Concentrations of Salicylic Acid

Salicylic acid acts on several plant physiological processes. Therefore, the aim of this study was to determine if salicylic acid interferes on the physiological quality of common bean seeds soaked with different concentrations by testing two seed imbibition methodologies. Common bean seeds of the cultivars Fepagro 26 and Predileto were utilized. The seeds were soaked in solutions of salicylic acid with concentrations of zero, 250, 500, 750, 1,000, 3,000 and 5,000 &amp;mu;M. Seed imbibition occurred in two ways: (1) germination paper moistened with salicylic acid solutions, and (2) seed imbibition in salicylic acid solutions in plastic boxes for 24 hours and subsequent sowing on germination paper moistened with distilled water. The experiment was maintained in a germination incubator under 25 &amp;deg;C temperature and with constant light. The number of normal seedlings (first count), length, fresh and dry matter of seedlings were determined on the fifth day after sowing. Germination percentage was assessed nine days after sowing. The study was performed in a completely randomized design with four replicates and 50 seeds were used for each treatment. Regression analysis was performed for salicylic acid concentrations, with no comparison of cultivars and seed imbibition methods. Salicylic acid in concentrations up to 1,000 &amp;mu;M does not negatively affect the common bean seed germination of the cultivars Fepagro 26 and Predileto, using seed soaking for 24 hours and imbibition in the germination paper. Concentrations of salicylic acid up to 1,000 &amp;mu;M and seed imbibition for 24 hours do not affect the vigor (first count) of the two common bean cultivars.

Imbibition in plant seeds

We describe imbibition in real and artificial plant seeds, using a combination of experiments and theory. In both systems, our experiments demonstrate that liquid permeates the substrate at a rate which decreases gradually over time. Tomographic imaging of soy seeds is used to confirmed this by observation of the permeating liquid using an iodine stain. To rationalize the experimental data, we propose a model based on capillary action which predicts the temporal evolution of the radius of the wet front and the seed mass. The depth of the wetting front initially evolves as $t^{1/2}$ in accord with the Lucas-Washburn law. At later times, when the sphere is almost completely filled, the front radius scales as $(1-t/t_{\text{max}})^{1/2}$ where $t_{\text{max}}$ is the time required to complete imbibition. The data obtained on both natural and artificial seeds collapse onto a single curve that agrees well with our model, suggesting that capillary phenomena contribute to moisture uptake in soy seeds.

DA-6 promotes germination and seedling establishment from aged soybean seeds by mediating fatty acid metabolism and glycometabolism.

Soybean seeds contain higher concentrations of oil (triacylglycerol) and fatty acids than do cereal crop seeds, and the oxidation of these biomolecules during seed storage significantly shortens seed longevity and decreases germination ability. Here, we report that diethyl aminoethyl hexanoate (DA-6), a plant growth regulator, increases germination and seedling establishment from aged soybean seeds by increasing fatty acid metabolism and glycometabolism. Phenotypic analysis showed that DA-6 treatment markedly promoted germination and seedling establishment from naturally and artificially aged soybean seeds. Further analysis revealed that DA-6 increased the concentrations of soluble sugars during imbibition of aged soybean seeds. Consistently, the concentrations of several different fatty acids in DA-6-treated aged seeds were higher than those in untreated aged seeds. Subsequently, quantitative PCR analysis indicated that DA-6 induced the transcription of several key genes involved in the hydrolysis of triacylglycerol to sugars in aged soybean seeds. Furthermore, the activity of invertase in aged seeds, which catalyzes the hydrolysis of sucrose to form fructose and glucose, increased following DA-6 treatment. Taken together, DA-6 promotes germination and seedling establishment from aged soybean seeds by enhancing the hydrolysis of triacylglycerol and the conversion of fatty acids to sugars.

Evaluation of 3D/2D Imaging and Image Processing Techniques for the Monitoring of Seed Imbibition

Seed imbibition is a very important process in plant biology by which, thanks to a simple water income, a dry seed may turn into a developing organism. In natural conditions, this process occurs in the soil, e.g., with difficult access for a direct observation. Monitoring the seed imbibition with non-invasive imaging techniques is therefore an important and possibly challenging task if one tries to perform it in natural conditions. In this report, we describe a set of four different imaging techniques that enable to addressing this task either in 3D or in 2D. For each technique, the following items are proposed. A detailed experimental protocol is provided to acquire images of the imbibition process. With the illustration of real data, the significance of the physical quantities measured in terms of their relation to the income of water in the seed is presented. Complete image analysis pipelines are then proposed to extract dynamic information on the imbibition process from such monitoring experiments. A final discussion compares the advantages and current limitations of each technique in addition to elements concerning the associated throughput and cost. These are criteria especially relevant in the field of plant phenotyping where large populations of plants are imaged to produce quantitatively significative traits after image processing.

Evaluation and selection of internal reference genes from two- and six-row U.S. malting barley varieties throughout micromalting for use in RT-qPCR.

Reverse transcription quantitative polymerase chain reaction (RT-qPCR) is a popular method for measuring transcript abundance. The most commonly used method of interpretation is relative quantification and thus necessitates the use of normalization controls (i.e. reference genes) to standardize transcript abundance. The most popular gene targets for RT-qPCR are housekeeping genes because they are thought to maintain a static transcript level among a variety of samples. However, more recent studies have shown, several housekeeping genes are not reliably stable. This is the first study to examine the potential of several reference genes for use in RT-qPCR normalization during barley malting. The process of malting barley mechanizes the imbibition and subsequent germination of barley seeds under controlled conditions. Malt quality is controlled by many pleiotropic genes that are determined by examining the result of physiological changes the barley seed undergoes during the malting process. We compared the stability of 13 reference genes across both two-and six-row malting barleys (Conrad and Legacy, respectfully) throughout the entirety of the malting process. Initially, primer target specificity, amplification efficiency and average Ct values were determined for each of the selected primer pairs. Three statistical programs (geNorm, NormFinder, and BestKeeper) were used to rank the stability of each reference gene. Rankings were similar between the two- and six-row with the exception of BestKeeper’s ranking of glyceraldehyde-3-phosphate dehydrogenase (GAPDH). A consensus ranking among programs was determined using RefFinder. Our results show that Actin (ACT) and Heat Shock Protein 70 (HSP70) were the most stable throughout micromalting, while GAPDH and Cyclophilin (CYP) were the least stable. Two reference genes are necessary for stable transcript normalization according to geNorm and the best two reference genes (ACT and HSP70) provided a sufficient level of stability.

Sexual and asexual reproductive aspects of Leontochir ovallei, a rare and endangered geophyte of the Atacama Desert

Background“Garra de Leon” (Leontochir ovallei) is an ephemeral endangered Alstroemeriaceae species endemic to Chile. Despite many efforts to improve the conservation of this species, the stimulation of dormant seeds and the production of rhizomes under controlled conditions remain unexplored. The aims of this study were to examine the germination responses of L. ovallei seeds under different in vitro conditions and to evaluate the formation of viable rhizomes after transplantation from in vitro to ex vitro conditions.MethodsWe evaluated five in vitro seed germination treatments: (1) acid scarification, (2) acid scarification followed by imbibition of seeds in aerated water, (3) imbibition of seeds in gibberellic acid, (4) clipping of seeds with a scalpel, and (5) seeds without any treatment (control). Seedlings obtained under in vitro conditions were transplanted to ex vitro conditions following a gradual acclimation process. After eight months, the number of rhizomes per plant was counted. To test asexual multiplication, each rhizome with its respective storage organ was divided using a scalpel and then left to rest for two years before subsequent evaluation of viability. After that period, the rhizomes were re-hydrated, and the emergence of plants after three months was evaluated.ResultsSeeds exposed to treatment 2 showed the highest germination percentage (36%), followed by the seeds whose coats were clipped (14%) and seeds treated with sulphuric acid (8%). The seed germination of the control treatment was 3%. After transplantation to ex vitro conditions, we obtained 220 rhizomes, with an average of three to six rhizomes per plant. After two years of dormancy, a total of 34 rhizomes (of 220 rhizomes) reactivated growth after re-ydration, indicating that, at least, 15,5% responded positively to watering.ConclusionsWe found that the seed germination of L. ovallei was increased by strong acidic conditions, suggesting that the main type of seed dormancy in this species is physical. However, germination was further increased by aeration, indicating embryo dormancy. In addition, we were able to obtain viable rhizomes by transplanting seedlings from in vitro to ex vitro conditions, which may be helpful for the propagation and ex situ conservation of this rare geophyte of Chile and potentially other geophyte species adapted to wet-dry cycle environments.

Soil salt and NaCl have different effects on seed germination of the halophyte Suaeda salsa

AbstractSeed germination is a key life‐history stage of halophytes. Most studies on seed germination of halophytes have focused on the effects of a single salt, while little information is available on the effects of mixed salt in the natural habitat. Due to the contribution of multiple ions in saline soil, we hypothesized that the effect of mixed salt on seed germination will differ from that of a single salt and the mechanism of how germination is affected will differ as well. The effects of mixed salt and NaCl on germination, water imbibition, and ionic concentrations of seeds of Suaeda salsa (L.) Pall. were compared at various salinity levels. Germination percentage (GP) and rate (GR) decreased with increasing salinity level, regardless of salt type. There was no difference in GP or GR between mixed salt and NaCl when the salinity level was below 20 dS m−1. Above 20 dS m−1, GP and GR in NaCl were lower than those in mixed salt. At the same salinity level, Na+ concentration in seeds was higher in NaCl than that in mixed salt, but the reverse was true for Ca2+ and Mg2+ concentrations. Imbibition rate for seeds in NaCl was lower than that in mixed salt at the same salinity level. Addition of Ca2+ and Mg2+ alleviated the inhibition of NaCl on seed germination. In conclusion, our results suggest that the effects of soil salts and NaCl on seed germination are different, and using NaCl instead of soil salt might not be realistic to show the effect of saline stress on seed germination of halophytes in the natural habitat.