Seed Germination Stage Research Articles

Hydrotime analysis of Amaranthus spp. seed germination under salinity condition

Amaranth (Amaranthus spp.) have gained interest as crop family to be grown under diverse soil conditions such as drought and heat stress. However, the presence of salinity affects crop’s germination process due to reduction in water availability for seeds to germinate. In this study, germination behaviour of Amaranthus hybridus L., Amaranthus viridis L., Amaranthus tricolor L. and Amaranthus giganticus L. under salinity condition were analysed through hydrotime model analysis. Five water potentials in NaCl solution to induce salinity condition (0, −0.3, −0.6, −0.9, and −1.2 MPa) were used in the germination tests. Differences in salinity tolerance were determined in the different species during germination. A. giganticus recorded a lower θH (40.30) and more negative Ψb(50) (−1.55) as well as higher germination rate as compared to the other species. The hydrotime modelling approach applied in this study for the analysis of amaranth species which might help to identify crop salt tolerance at seed germination stage.

Influence of Salt Stress on Growth of Spermosphere Bacterial Communities in Different Peanut (Arachis hypogaea L.) Cultivars.

Background: Exposure of seeds to high salinity can cause reduced germination and poor seedling establishment. Improving the salt tolerance of peanut (Arachis hypogaea L.) seeds during germination is an important breeding goal of the peanut industry. Bacterial communities in the spermosphere soils may be of special importance to seed germination under salt stress, whereas extant results in oilseed crop peanut are scarce. Methods: Here, bacterial communities colonizing peanut seeds with salt stress were characterized using 16S rRNA gene sequencing. Results: Peanut spermosphere was composed of four dominant genera: Bacillus, Massilia, Pseudarthrobacter, and Sphingomonas. Comparisons of bacterial community structure revealed that the beneficial bacteria (Bacillus), which can produce specific phosphatases to sequentially mineralize organic phosphorus into inorganic phosphorus, occurred in relatively higher abundance in salt-treated spermosphere soils. Further soil enzyme activity assays showed that phosphatase activity increased in salt-treated spermosphere soils, which may be associated with the shift of Bacillus. Conclusion: This study will form the foundation for future improvement of salt tolerance of peanuts at the seed germination stage via modification of the soil microbes.

Cotton roots are the major source of gossypol biosynthesis and accumulation

BackgroundGossypol is a specific secondary metabolite in Gossypium species. It not only plays a critical role in development and self-protection of cotton plants, but also can be used as important anti-cancer and male contraceptive compound. However, due to the toxicity of gossypol for human beings and monogastric animals, the consumption of cottonseeds was limited. To date, little is known about the gossypol metabolism in cotton plants.ResultsIn this study, we found that cotyledon was the primary source of gossypol at the seed germination stage. But thereafter, it was mainly originated from developing roots. Grafting between glanded and glandless cotton as well as sunflower rootstocks and cotton scion revealed that gossypol was mainly synthesized in the root systems of cotton plants. And both glanded and glandless cotton roots had the ability of gossypol biosynthesis. But the pigment glands, the main storage of gossypol, had indirect effects on gossypol biosynthesis. In vitro culture of root and rootless seedling confirmed the strong gossypol biosynthesis ability in root system and the relatively weak gossypol biosynthesis ability in other organs of the seedling. Expression profiling of the key genes involved in the gossypol biosynthetic pathway also supported the root as the major organ of gossypol biosynthesis.ConclusionsOur study provide evidence that the cotton root system is the major source of gossypol in both glanded and glandless cottons, while other organs have a relatively weak ability to synthesize gossypol. Gossypol biosynthesis is not directed related to the expression of pigment glands, but the presence of pigment glands is essential for gossypol accumulation. These findings can not only clarify the complex regulation network of gossypol metabolism, but it could also accelerate the crop breeding process with enhanced commercial values.

Genetic Mapping Combined with a Transcriptome Analysis to Screen for Candidate Genes Responsive to Abscisic Acid Treatment in Brassica napus Embryos During Seed Germination.

Brassica napus embryos contain precursor tissues for the leaves, stem, and root, as well as the cotyledons, and these precursor tissues play key roles in seed germination, seedling survival, and subsequent seedling growth. Abscisic acid (ABA) plays a prominent role in the inhibition of seed germination. The underlying molecular mechanisms of the embryo responses to ABA stress followed by inhibited seed germination have not been reported in B. napus to date. In this study, we conducted quantitative trait locus (QTL) analysis of B. napus seed in response to ABA stress using 170 recombinant inbred lines. Furthermore, we performed transcriptome sequencing (RNA-seq) analyses by using B. napus ZS11 embryos under sterile deionized water (control) and 10 mg/L (10A), 20 mg/L (20A), and 30 mg/L (30A) ABA treatment conditions. In total, 10 QTLs were screened for explaining 2.70-6.73% of the phenotypic variation under ABA stress. In addition, 1495, 3332, and 3868 differentially expressed genes (DEGs) were identified in the "control vs 10A," "control vs 20A," and "control vs 30A" comparisons, respectively. Gene Ontology (GO) enrichment analysis indicated that DEG functions are mainly related to response to stimuli, response to oxygen-containing compounds, response to lipids, and the transport and seed dormancy processes. These DEGs mainly participated in the response to plant hormone signal transduction, starch and sucrose metabolism, cutin, suberine, and wax biosynthesis, and phenylpropanoid biosynthesis processes pathways. Our results provide a foundation for further explorations of the molecular regulatory mechanisms of B. napus embryos in response to abiotic stress during the seed germination stage.

Assessing Salicornia europaea Tolerance to Salinity at Seed Germination Stage

Salicornia europaea, a halophytic species, was investigated to assess its ability to withstand salinity during seed germination, and to identify suitable indices to interpret salt tolerance at this delicate stage. Seed germination indices (germination percentage (GP), germination energy (GE), germination value (GV), coefficient of germination velocity (CVG), germination rate index (GRI), germination peak value (GPV), mean germination time (MGT), and time to 50% germination (T50)) were calculated under increasing salinity (0, 100, 200, 300, 400, and 600 mM NaCl). Principal component analysis (PCA) was used to describe the relationships involving the variables that account for data variance. Two salinity thresholds were identified (100 and 600 mM NaCl) determining significant decreases in all the indices, except for T50 and MGT. In fact, PCA based on generated correlation circle showed significant negative correlations (r close to −1) between salt stress and GP, GE, GRI, PV, GV, and CVG, whereas no correlation was observed with T50 and MGT (r close to zero). Based on this, GP, GE, GRI, PV, GV, and CVG can be considered useful traits to assess salt tolerance during germination in S. europaea, while T50 and MGT, that were not affected by the range of salinity levels investigated, should not be used for this purpose.

Effects of interspecific interactions on seed germination between dominant species in the Yangtze River Estuary

Seed germination is the key stage of population recruitment. Competition between native and invasive species can greatly influence the seed germination and the stability of the affected populations and communities, which in turn will affect the stability of native ecosystems. In this paper, we studied the interactions between dominant species in Chongming Dongtan wetland at seed germination stage using a germination experiment. We found that both salinity and interspecific interaction significantly affected the seed germination process of dominant marsh plants, but the effects were not consistent among different species. Generally, germination rate of Scirpus mariqueter was inhibited by high salinity, whereas that of Suaeda glauca was promoted by salt. Almost all the species germinated more slowly in salt water than in fresh water. Invasive Spartina alterniflora seeds significantly promoted the germination rate of Scirpus mariqueter in salt water despite of its heavy competitive effects on this native sedge in the adult stage. Besides, the germination rate of Spartina alterniflora was significantly inhibited by Phragmites australis and Suaeda glauca seeds in salt water, whereas its germination speed was significantly inhibited by Phragmites australis in fresh water. Our study revealed the pattern of interspecific interactions in the early life stages of plants, which may improve our understanding of population and community dynamics and provide some guidance to invasive species control and wetland management.

Gradual Exposure to Salinity Improves Tolerance to Salt Stress in Rapeseed (Brassica napus L.)

Soil salinity is considered one of the most severe abiotic stresses in plants; plant acclimation to salinity could be a tool to improve salt tolerance even in a sensitive genotype. In this work we investigated the physiological mechanisms underneath the response to gradual and prolonged exposure to sodium chloride in cultivars of Brassica napus L. Fifteen days old seedlings of the cultivars Dynastie (salt tolerant) and SY Saveo (salt sensitive) were progressively exposed to increasing soil salinity conditions for 60 days. Salt exposed plants of both cultivars showed reductions of biomass, size and number of leaves. However, after 60 days the relative reduction in biomass was lower in sensitive cultivar as compared to tolerant ones. An increase of chlorophylls content was detected in both cultivars; the values of the quantum efficiency of PSII photochemistry (ΦPSII) and those of the electron transport rate (ETR) indicated that the photochemical activity was only partially reduced by NaCl treatments in both cultivars. Ascorbate peroxidase (APX) activity was higher in treated samples with respect to the controls, indicating its activation following salt exposure, and confirming its involvement in salt stress response. A gradual exposure to salt could elicit different salt stress responses, thus preserving plant vitality and conferring a certain degree of tolerance, even though the genotype was salt sensitive at the seed germination stage. An improvement of salt tolerance in B. napus could be obtained by acclimation to saline conditions.

Seed germination response of commonbean (Phaseolus vulgaris L.) genotypes to optimal and sub-optimal temperatures

Rajmash is a cool season legume crop grown during rabi season in northern India. This crop is highly sensitive to low temperature stress during seed germination and seedling establishment stage. Therefore, identification of cold tolerant genotypes is essential in rajmash breeding programme. In the present study, 37 rajmash genotypes were subjected to germination at optimal (20oC) and sub optimal (10 and 15oC) temperatures in an incubator to understand the level of variation in germination and related at low temperature. At 20oC, the 37 genotypes recorded an average value of 98.47% with a minimum value of 91.35 %; while, at 15oC an average value of 96.02% and a minimum value of 86.10% and 10oC recorded an average value of 77.13% and a minimum value of 0%. This indicated that the genotypes could tolerate cold was recorded stress upto 15oC to a considerable level while, germination was hampered greatly at 10oC. Genotypes, EC150250, EC14920 and EC14351 showed the least reduction in germination and related parameters at sub optimal temperatures, hence these were identified to be cold tolerant at seed germination stage, which however, need to be validated under field condition.

Nitrogen addition decreases seed germination in a temperate steppe.

Seed germination and seedling establishment play an important role in driving the responses of plant community structure and function to global change. Nitrogen (N) deposition is one of the driving factors of global change, which often leads to a loss in species richness in grassland ecosystems. However, how seed germination responds to N addition remains unclear. A pot incubation test was conducted in a semi‐arid grassland in the Mongolian Plateau, Northern China, to investigate the effect of N addition (0, 5, 10, 20, 40, and 80 g N/m2) on seed germination from May to October 2016. Twenty species germinated under all treatments; however, the responses of the 20 species to N addition were different. The densities of Stipa krylovii, Leymus chinensis, and Artemisia frigida, which are the dominant species in this temperate steppe, decreased significantly as the amount of N addition. Moreover, N addition significantly suppressed seedling densities of the community, perennial forbs, perennial grasses, and annuals and biennials. Furthermore, species richness of the community, perennial forbs, and annuals and biennials decreased sharply with increasing N addition level, but perennial grass species richness did not change. The Shannon–Wiener diversity index also decreased as the amount of N addition increased. Our results suggest that N enrichment plays an important role in the seed germination stage and decreases supplements of seedlings to adult plants. These findings may help explain the causes of species loss by atmospheric N deposition in grassland ecosystems.

Effects of ZnO Nanoparticles and Ethylenediamine-N,N'-Disuccinic Acid on Seed Germination of Four Different Plants.

The release of nanoparticles and biodegradable chelating agents into the environment may cause toxicological and ecotoxicological effects. The aim of this study is to determine the ecotoxic effects of zinc oxide (ZnO) nanoparticles and ethylenediamine disuccinic acid (EDDS) on most cultured four plants. The durum wheat, bread wheat, barley, and rye are exposed to 5 mL 10 mg L−1 ZnO nanoparticles and 10 mg L−1 EDDS in the seed germination stage. Results show that these different plant species have different responses to ZnO nanoparticles and EDDS. The germination percentage of bread wheat and rye decreases in the application of ZnO nanoparticles while the germination of durum wheat and barley increases as much as in radicle elongation and seedling vigor. While ZnO treatment causes a decrease in bread wheat and rye germinated rat in the range of 33–14.3%, respectively, there is no change in germination rate of these plants at EDDS treatment. In addition, EDDS treatment positively affects barley germination rate. In conclusion, it is clear that ZnO nanoparticles have more toxic effects on bread wheat and rye than EDDS, while barley is positively affected by ZnO nanoparticles and EDDS.

Overexpression of a trypanothione synthetase gene from Trypanosoma cruzi, TcTrys, confers enhanced tolerance to multiple abiotic stresses in rice

Plants are frequently exposed to variable environmental stresses that adversely affect plant growth, development and agricultural production. In this study, a trypanothione synthetase gene from Trypanosoma cruzi, TcTryS, was chemically synthesized and its roles in tolerance to multiple abiotic stresses were functionally characterized by generating transgenic rice overexpressing TcTryS. Overexpression of TcTryS in rice endows transgenic plants with hypersensitivity to ABA, hyposensitivity to NaCl- and mannitol-induced osmotic stress at the seed germination stage. TcTryS overexpression results in enhanced tolerance to drought, salt, cadmium, and 2,4,6-trichlorophenol stresses in transgenic rice, simultaneously supported by improved physiological traits. The TcTryS-overexpression plants also accumulated greater amounts of proline, less malondialdehyde and more transcripts of stress-related genes than wild-type plants under drought and salt stress conditions. In addition, TcTryS might play a positive role in maintaining chlorophyll content under 2,4,6-trichlorophenol stress. Histochemical staining assay showed that TcTryS renders transgenic plants better ROS-scavenging capability. All of these results suggest that TcTryS could function as a key regulator in modulation of abiotic stress tolerance in plant, and may have applications in the engineering of economically important crops.

Evaluation of tetracycline phytotoxicity by seed germination stage and radicle elongation stage tests: A comparison of two typical methods for analysis

Biological tests with plant seeds have been adopted in many studies to investigate the phytotoxicity of pollutants to facilitate the control of risks and remain to be optimized. In this work, the experiment with a small sample size (Experiment 1) and the experiment with a large one (Experiment 2) were designed to study the effect of tetracycline (TC) on Chinese cabbage (Brassica rapa L.) at seed germination and radicle elongation stages. At the former stage, germination number data were obtained to analyze the germination energy (GE) and to judge the probability of the number of germinated seeds (Pn) by the binomial distribution model in Experiment 1. While germination time-to-number data were obtained to analyze the mean time to germination (MGT), the estimate of mean time to germination (EMGT) by survival analysis method, the time to germination for 50% of total seeds (T50) and the germination rate (GR) besides GE in Experiment 2. At the latter stage, the data of radicle length (RL) were obtained in all the experiments and the influence from the former stage on this stage was excluded in Experiment 2 but not in Experiment 1. Results showed that TC had universal adverse effects on the latter stage but not on the former stage in the experiments. Considering the availability of germination data for statistical analysis and the robustness of RL data, the methods adopted in Experiment 2 were more feasible than those in Experiment 1. In addition, Chinese cabbage seeds with medium size have the character of rapid germination compared with the commonly used crop species and can be used to shorten the experimental cycle to study the responses of seeds to pollutants to evaluate the phytotoxicity.We introduced survival analysis method to analyze the germination time-to-number data obtained in seed germination test to evaluate the phytotoxicity of tetracycline.

Spermidine promotes starch degradation to relieve the inhibitory effect of chilling on wheat seed germination

How the inhibitory effect of chilling on seed germination can be released is an important question in wheat production. In the present study, two wheat cultivars exhibiting differences in seed germination under chilling resistance were used, and their seeds were subjected to presoaking with spermidine and putrescine. The variations of polyamines and hormones and the carbohydrate in the seeds were measured under chilling stress. The objective of the present study was to investigate the effect of polyamines on wheat seed germination under chilling stress. The results indicated that spermidine could relieve the inhibitory effect of chilling stress on the seed germination of wheat, while putrescine had the opposite effect. Additionally, this specially effect of polyamines on the seed germination of wheat under chilling was related to abscisic acid and gibberellin. Spermidine significantly increased gibberellin levels in seeds and thereby promoted starch degradation in seeds. Additionally, the promotion effect of spermidine on the seed germination under chilling might be related to the increasing of abscisic acid concentration in seeds. However, external application of putrescine led to the excessively abscisic acid concentration in the wheat seeds and may by this reduced chilling resistance in seed germination stage of wheat. Taken together, these results indicated a continuous route of putrescine to spermidine synthesis that promotes chilling resistance in wheat seed germination and polyamine production, through the regulation of abscisic acid and gibberellin contents and starch degradation, to regulate wheat seed germination under chilling stress.

Low-temperature tolerance and transcriptome analyses during seed germination of Anabasis aphylla

ABSTRACT This study aimed to explore differences in the low-temperature tolerance of a desert plant, Anabasis aphylla, at different seed germination stages during the fall using transcriptome sequencing to identify related genes. The survival rate of the seeds decreased with lower temperatures at different germination stages, and the tolerance of the stages in decreasing order was as follows: imbibition (I) ≈ testa rupture (II) > testa removal (III) > elongation (IV). Superoxide dismutase, peroxidase, and catalase activities and the malondialdehyde content showed a downward trend after stage II. Transcriptome sequencing of seeds, including ripe and dry dominant seeds (W1) and seeds during different germination stages [imbibition (W2), testa removal (W3), and elongation (W4)] was performed. Some genes were downregulated during seed germination, which mainly included cytochrome P450, oleosin, ethylene-responsive transcription factor, and low temperature-induced protein. This study suggests that downregulated of some genes may result in a decrease in low-temperature tolerance.

A Genome-Wide Association Study Reveals Candidate Genes Related to Salt Tolerance in Rice (Oryza sativa) at the Germination Stage.

Salt toxicity is the major factor limiting crop productivity in saline soils. In this paper, 295 accessions including a heuristic core set (137 accessions) and 158 bred varieties were re-sequenced and ~1.65 million SNPs/indels were used to perform a genome-wide association study (GWAS) of salt-tolerance-related phenotypes in rice during the germination stage. A total of 12 associated peaks distributed on seven chromosomes using a compressed mixed linear model were detected. Determined by linkage disequilibrium (LD) blocks analysis, we finally obtained a total of 79 candidate genes. By detecting the highly associated variations located inside the genic region that overlapped with the results of LD block analysis, we characterized 17 genes that may contribute to salt tolerance during the seed germination stage. At the same time, we conducted a haplotype analysis of the genes with functional variations together with phenotypic correlation and orthologous sequence analyses. Among these genes, OsMADS31, which is a MADS-box family transcription factor, had a down-regulated expression under the salt condition and it was predicted to be involved in the salt tolerance at the rice germination stage. Our study revealed some novel candidate genes and their substantial natural variations in the rice genome at the germination stage. The GWAS in rice at the germination stage would provide important resources for molecular breeding and functional analysis of the salt tolerance during rice germination.

The Application of Multi-Locus GWAS for the Detection of Salt-Tolerance Loci in Rice.

Improving the salt-tolerance of direct-seeding rice at the seed germination stage is a major goal of breeders. Efficiently identifying salt tolerance loci will help researchers develop effective rice breeding strategies. In this study, six multi-locus genome-wide association studies (GWAS) methods (mrMLM, FASTmrMLM, FASTmrEMMA, pLARmEB, pKWmEB, and ISIS EM-BLASSO) were applied to identify quantitative trait nucleotides (QTNs) for the salt tolerance traits of 478 rice accessions with 162,529 SNPs at the seed germination stage. Among the 371 QTNs detected by the six methods, 56 were identified by at least three methods. Among these 56 QTNs, 12, 6, 7, 4, 13, 12, and 12 were found to be associated with SSI-GI, SSI-VI, SSI-MGT, SSI-IR-24h, SSI-IR-48h, SSI-GR-5d, and SSI-GR-10d, respectively. Additionally, 66 candidate genes were identified in the vicinity of the 56 QTNs, and two of these genes (LOC_Os01g45760 and LOC_Os10g04860) are involved in auxin biosynthesis according to the enriched GO terms and KEGG pathways. This information will be useful for identifying the genes responsible for rice salt tolerance. A comparison of the six methods revealed that ISIS EM-BLASSO identified the most co-detected QTNs and performed best, with the smallest residual errors and highest computing speed, followed by FASTmrMLM, pLARmEB, mrMLM, pKWmEB, and FASTmrEMMA. Although multi-locus GWAS methods are superior to single-locus GWAS methods, their utility for identifying QTNs may be enhanced by adding a bin analysis to the models or by developing a hybrid method that merges the results from different methods.

Association mapping of salt tolerance traits at germination stage of rapeseed (Brassica napus L.)

Soil salinization has a major effect on crop yield. Seed germination is a crucial prerequisite for the successful cultivation of rapeseed in saline soils. Limited information is available about rapeseed salt tolerance at germination stage. Here, we carried out an association mapping of salt tolerance QTLs at seed germination stage. We evaluated salt tolerance of 214 rapeseed inbred lines at germination stage, and the 60 K Brassica Infinium® SNP array was used to genotype the association panel. Finally, a total of 110 single nucleotide polymorphisms (SNPs) were associated with three salt tolerance indices and these SNPs were integrated into 44 QTLs. In addition, 56 possible candidate genes were located in or near the genomic region where the above QTLs were mapped. Thus, our results provide valuable information for understanding the genetic control of rapeseed salt tolerance at germination stage and may facilitate marker-based breeding for rapeseed salt tolerance.

Developing dual herbicide tolerant transgenic rice plants for sustainable weed management

Herbicides are important constituents of modern integrated weed management system. However, the continuous use of a single herbicide leads to the frequent evolution of resistant weeds which further challenges their management. To overcome this situation, alternating use of multiple herbicides along with conventional weed-management practices is suitable and recommended. The development of multiple herbicide-tolerant crops is still in its infancy, and only a few crops with herbicide tolerance traits have been reported and commercialized. In this study, we developed transgenic rice plants that were tolerant to both bensulfuron methyl (BM) and glufosinate herbicides. The herbicide tolerant mutant variant of rice AHAS (Acetohydroxyacid synthase) was overexpressed along with codon optimized bacterial bar gene. The developed transgenic lines showed significant tolerance to both herbicides at various stages of plant development. The selected transgenic lines displayed an increased tolerance against 100 μM BM and 30 mg/L phosphinothricin during seed germination stage. Foliar applications further confirmed the dual tolerance to 300 μM BM and 2% basta herbicides without any significant growth and yield penalties. The development of dual-herbicide-tolerant transgenic plants adds further information to the knowledge of crop herbicide tolerance for sustainable weed management in modern agricultural system.

Effect of Nano-Fertilizer on Seed Germination and First Stages of Bitter Almond Seedlings’ Growth Under Saline Conditions

This experiment was conducted to investigate the effect of nano-fertilizer on seed germination and the first stages of bitter almond growth compared to other chemical fertilizers under saline conditions. In this regard, nuts were soaked in salt solutions of NaCl as 1, 3, and 5 ds m−1 for 48 h prior to stratification. Subsequently, the seeds were sown in perlite and treated by different concentrations of urea, ammonium sulfate, and nano-fertilizer at 0, 25, 50, and 100% for each fertilizer under different saline concentrations then stratified at 6 °C for 8 weeks. The treatments were arranged in a randomized complete block design in factorial experiment with three replicates and 25 seeds for each. Germination and first stages of growth measurements were estimated. Our results revealed that pre-treating seeds of bitter almond rootstock with 50% of nano-fertilizer under saline conditions markedly increased germination measurements, stem length and diameter, elongation of secondary and primary roots/plant, and number of secondary roots/plant relative to urea and ammonium sulfate fertilizers, thus throughout its vital role in increasing the moisture content of seed which in turn increased germination percentage and rate. Additionally, all the amount of nano-fertilizer was covered by plants via slow and continuous release of fertilizer, therefore producing stronger seedlings. Hence, we can conclude to use the nano-fertilizer nanourea modified with hydroxyapatite nanoparticles as a source for N, P, and Ca nutrients under saline conditions.

Plant hormone treatments to alleviate the effects of salt stress on germination of Betula platyphylla seeds

We analyzed the germination traits (germination rate, germination potential, and germination index) of seeds from 23 half-sib families of birch (Betula platyphylla). The germination rates of the 23 families ranged from 38.57 to 76.50%. Seeds from the eight families germinating at the highest rates were then used for germination experiments under salt stress. Germination rate, germination potential, and germination index of these eight half-sib families decreased with increasing salt concentrations. The effects of four different hormones (6-benzylaminopurine, 6BA; gibberellin, GA3; naphthalene acetic acid, NAA; and melatonin) at various concentrations on the germination of seeds from the eight half-sib birch families under salt stress were investigated. Treatments with 6BA and GA3 alleviated the effects of salt stress on seed germination, whereas treatments with NAA and melatonin aggravated the effects of salt stress. The most effective treatments for alleviating the effects of salt stress on birch seed germination were 10 mg/L 6BA and 300 mg/L GA3. This study provides practical information for screening birch families for salt tolerance at the seed germination stage, and for cultivation of birch in saline environments.