Salt tolerance of barley (Hordeum vulgare L.) cultivars at the germination stage: Analysis of the response functions

Two models, initially proposed by Van Genuchten (1983) for evaluating salinity-yield response curves at the adult stage, were applied to study the salinity response of 24 barley cultivars at the germination stage. According to the calculated salinity threshold, EC_t (the solution electrical conductivity, EC, at which germination starts to decrease), and EC₅₀ (the solution EC at which germination is reduced by 50%) parameters, both models give similar results, although model 2, a sigmoid-form curve, fits the observed data slightly better than model 1, a piecewise response function. Also, the results suggest that, for model 1, EC_t seems to be the most reliable parameter for screening barley germplasm because it clearly discriminates the relative salt-tolerance of the studied cultivars and, furthermore, it basically determines their salinity response for the 100 to 50% germination interval. On the other hand, the model 1 s parameter — percent germination decrease per unit salinity increase bove EC_t—is less relevant because of its smaller variation interval and lack of correlation with EC₅₀, indicating that the salinity response of the studied cultivars for the 50% germination value is independent of this parameter.     

Osmotic sensitivity in relation to salt sensitivity in germinating barley seeds

Abstract Cultivars of barley (Hordeum vulgare L.) were tested for germination sensitivity to progressively higher concentrations of salt, mannitol, and betaine. The three solutes were equally inhibitory at equal osmotic potential, but there was a consistent difference in osmotic sensitivity between two cultivars, CM-67 and Briggs (Briggs was the most sensitive). There was no difference between the two cultivars in salt or water uptake from salt solutions during imbibition. Brief presoaking in water did not improve salt resistance, indicating that a hydration-dependent decrease in membrane permeability is not involved in salt tolerance. The calcium content of Briggs was higher than CM-67. These results suggest that salt inhibits barley germination primarily by osmotic effects, and that salt influx during imbibition does not play a role in this inhibition. A hypothesis regarding salt effects on germination is discussed.     

大麦种子对盐的发芽响应模型

为了明确盐对种子发芽影响的渗透效应和离子效应共同作用方式以及量化种子发芽对盐的响应, 以两个大麦(Hordeum vulgare)品种‘Cask’和‘County’为研究对象, 设置4个恒定温度(5、12、20和27 ℃)、5个等渗的NaCl和聚乙二醇(PEG)浓度梯度(-0.45、-0.88、-1.32、-1.76和-2.20 MPa, 蒸馏水作对照), 做常规发芽实验。结果显示: (1)两个品种在NaCl溶液中比在等渗的PEG溶液中发芽率高且发芽速度快; (2) NaCl和PEG分别作为渗透剂计算出的水势模型参数值差异很大, 说明水势模型不能用来描述种子发芽对盐的响应; (3)大麦种子在盐溶液中的发芽速率与盐浓度成显著的负相关直线关系, 因此我们修订了水势模型, 将修订后的模型命名为盐度模型, 用来量化盐对大麦种子发芽的影响。与水势模型计算出的发芽时间相比, 盐度模型计算出的50%种子发芽时间与大麦种子实际发芽时间更接近; (4)大麦种子在等渗的NaCl和PEG溶液中发芽速率差异随着水势降低, 先增加后降低。据此我们提出盐的渗透效应和离子效应共同作用于种子发芽的3种情况: 第一种在低盐条件下, 主要是渗透效应起负作用; 第二种情况在中盐条件下, 渗透效应和离子效应共同起作用, 离子效用的正作用强于渗透效应的负作用; 第三种情况在高盐条件下, 离子效应逐渐开始起离子毒害的负作用。     

Effects of NaCl stress on seed germination and seedling development of Brassica insularis Moris (Brassicaceae)

• Brassica insularis is a protected plant that grows on both coastal and inland cliffs in the western Mediterranean Basin. The objective of this study was to test if any variability exists in the salt stress response during seed germination and seedling development in this species relative to its provenance habitat.
• Variability among three populations in the salt stress effects on seed germination and recovery under different temperatures was evaluated. The effect of nebulisation of a salt solution on seedling development was evaluated between populations growing at different distances from the sea.
• Seeds of B. insularis could germinate at NaCl concentrations up to 200 mm . Seed viability was negatively affected by salt, and recovery ability decreased with increasing temperature or salinity. Inter‐population variability was detected in salt response during the seed germination phase, as well as in seedling salt spray tolerance. The inland population seedlings had drastically decreased survival and life span and failed to survive to the end of the experiment. In contrast, at least 90% of the coastal seedlings survived, even when sprayed at the highest frequency with salt solution.
• This study allowed investigation of two natural factors, soil salinity and marine aerosols, widely present in the B. insularis habitat, and provided the first insights into ecology of this protected species and its distribution in the Mediterranean. These results might be useful in understanding the actual distributions of other species with the same ecology that experience these same abiotic parameters.

     

盐生植物种子萌发对环境的适应对策

盐生环境是一种严峻的胁迫环境,对植物的生长、发育、繁殖等生活史的各阶段都产生着重要的影响。盐生植物是生长在盐渍土壤上的一类天然植物区系,它们在长期的进化过程中形成了一系列适应盐生生境的特殊生存策略。一般情况下,盐生植物种子对环境的适应能力,是植物对盐生环境适应性的重要体现;而植物发育早期对盐度的适应能力又是决定物种分布和群落组成的关键因素。在对国内外相关文献进行分析归纳的基础上,从盐分对种子萌发的影响机理及植物种子萌发对盐生环境的适应对策两个方面综述了植物种子休眠萌发与盐生环境的关系。     

土壤盐分、预湿处理对Artemisia monosperma(菊科)种子传播和萌发的影响

Artemisia monosperma是分布于西奈半岛以及以色列地中海沿岸许多活动沙丘及固定沙丘上的建群种植物,在固定沙丘上,雨后的蓝细菌结皮上能产生径流水,A.monosperma的种子在径流水上漂浮并被传播到低洼处或土壤缝隙中,实验表明,有一半的种子在蒸馏水上漂浮3d,而在各种浓度的盐溶液上则能漂浮更长时间,低浓度的盐溶液对种子的萌发无影响而高浓度的盐分抑制种子的萌发,NO3^-可能是影响种子在沙质蓝细菌结皮上萌发的因素,低浓度的NO2＿促进种子萌发而高浓度则抑制。预湿处理的实验表明,在自然生境中,暴露地表或埋在浅表层的种子经受每晚的露水以及小量雨水的反复湿,春萌发力有可能通过强人作用而提高。     

Effect of environmental factors on seed germination and emergence of Lepidium vesicarium

Lepidium vesicarium is a weed species with a wide distribution in the rangelands and dry‐land farming in East Azarbaijan, Iran. The experiments were undertaken to assay the effects of light, temperature, pH, osmotic potential, NaCl concentration and burial depth on seed germination and emergence of L. vesicarium. Germination was maintained at high levels (> 80%) over a wide day/night temperature range (10/5 to 30/20°C), but a severe reduction in the germination rate of L. vesicarium was found below 20/10°C. Germination of L. vesicarium was influenced by different light/dark regimes, as the germination rate was highest at 16 h light for the all treatments (0, 8, 12, 16 and 24 h light). Germination was 92–95% over a wide range of pH (2‐10). Germination was >50% at a water potential of ?0.7 MPa and salinity of 21 dS/m, indicating that drought and salt conditions have a minimal impact on seed germination. With increasing burial depth from 0 to 2 cm, the number of days required for 50% emergence increased and no germination was observed at burial depths deeper than 3 cm. This suggests that L. vesicarium would become troublesome in the rangelands and for growers in reduced‐tillage cropping systems. The ability to emerge from shallow depths, coupled with tolerance of a wide pH range, drought and salinity at germination, should be taken into account when managing this weed species.     

Effects of neodymium magneto-priming on seed germination and salinity tolerance in tomato

Earth's biosphere is surrounded by magnetic fields that affect all living organisms. A plant's response to magnetic fields is displayed in terms of its seed's vigor, growth, and yield. Examining seed germination in such magnetic fields is the first step in the investigation of how magnetic fields might be used to enhance plant growth and maximize crop performance. In this study, salinity-sensitive Super Strain-B tomato seeds were primed with the northern and southern poles of neodymium magnets of 150, 200, and 250 mT. The magneto-primed seeds showed a significant increase in germination rate and speed, where the orientation of the magnet was identified as being crucial for germination rate and the orientation of seeds towards the magnet was shown to affect the germination speed. The primed plants exhibited enhanced growth characteristics, including longer shoots and roots, larger leaf area, more root hairs, higher water content, and more tolerance to salinity levels, up to 200 mM NaCl. All magneto-primed plants showed a significant decrease in chlorophyll content, continuous chlorophyll fluorescence yield (Ft), and quantum yield (QY). The salinity treatments decreased all chlorophyll parameters in control plants, significantly, but did not lower such parameters in magneto-primed tomatoes. The results of this study illustrate the positive effects of neodymium magnet on the growth and development of tomato plants in terms of their germination, growth, and salinity tolerance, and negatively affected the chlorophyll content in tomato leaves. © 2023 Bioelectromagnetics Society.     

8种盐生植物种子萌发特征与NaCl盐度的关系

耐盐植物的选育是盐渍土地生物改良的关键。通过对13个NaCl盐度梯度下,真盐生植物囊果碱蓬、盐地碱蓬、高碱蓬、盐角草、盐爪爪,泌盐植物大叶补血草、耳叶补血草、黄花补血草8种盐生植物的萌发试验,测定其种子发芽率、发芽势、发芽指数和相对盐害率等指标,研究不同NaCl盐度胁迫对其萌发特性的影响。结果表明：低盐度（50 mmol/L）能促进8种盐生植物的萌发;随着盐度的上升,盐角草、盐地碱蓬、囊果碱蓬、高碱蓬表现出较强的萌发耐盐性,发芽势和发芽指数优于其他植物;盐角草的萌发耐盐性最佳,在1000 mmol/L盐度下萌发率仍能达到54.0%。进一步通过S型生长曲线和线性模型分析得出,8种植物为对抗逆境大致分为"快速型"和"缓慢型"两种萌发策略;随盐度的升高,初始萌发时间和萌发高峰时间均不同程度的向后推迟。盐度≤200 mmol/L时,囊果碱蓬的萌发占据优势,其萌发速率大于其他植物,且差异显著;中盐度400 mmol/L左右时,盐地碱蓬和盐角草萌发最快,二者无显著差异;盐度≥600 mmol/L时,盐角草萌发速率较快,相比其他植物差异显著。泌盐植物的萌发耐盐适宜浓度和耐盐极限浓度均低于真盐生植物。8种植物均有作为氯化物为主盐渍土地区生物改良材料的潜力。     

The influence of aggregate size and drannage potential on germination of barley seeds in flooded soil

Emergence and growth of barley was severely decreased by short periods (less than 24 hours) of pre-emergence waterlogging at 20°C. The extent of damage depended on a combination of duration of waterlogging, soil water potential and aggregate size. Potentials of less than—4kPa prevented loss of plants developing in aggregates of less than 2 mm diameter after a transitory period of waterlogging although some shoot and root damage occurred. By comparison seeds growing in soil consisting of aggregates greater than 2 mm in diameter were not damaged by transitory waterlogging even when drainage only occurred at−0.8kPa. The severity of damage increased with the period of waterlogging. A criterion obtained as the product of mean size grade and water potential gave a single value (−4NM⁻¹) below which emergence was satisfactory. Waterlogging halfway through germination gave more severe damage than near sowing date or near emergence.     

Effects of NaCl salinity in vivo and in vitro on ribonuclease activity of Vigna unguiculata cotyledons during germination

Pitiuba bean [ Vigna unguiculata (L.) Walp.] seeds were sown in water or. in 0.1 M NaCl. Seedling growth and cotyledon nucleic acid mobilization were delayed by NaCl salinity. The differences in cotyledonary RNase activity between seeds sown in water and in NaCl solutions suggest that salinity delays the activation and/or de novo synthesis of the enzyme. Cotyledon extracts were subjected to gel filtration through Sephadex G-100, and RNase activity measured. Only one cotyledonary RNase appeared during germination, and salinity did not induce any change in molecular weight of the enzyme. Salinity inhibited 45% of the specific activity of the RNase on the 5th day of the experimental period. The same salt concentration (0.1 M NaCl) added in vitro inhibited only 8 % of the specific activity of the enzyme. This difference may indicate that NaCl in vivo affects mainly the de novo synthesis of the RNase.     

Osmotic and specific ion effects on the germination of Prosopis strombulifera

BACKGROUND AND AIMS: Salinity can affect germination of seeds either by creating osmotic potentials that prevent water uptake or by toxic effects of specific ions. Most studies have only used monosaline solutions, although these limit the extent to which one can interpret the results or relate them to field conditions. The aim of this work was to evaluate the germination of Prosopis strombulifera seeds under increasing salinity by using the most abundant salts in central Argentina in monosaline or bisaline iso-osmotic solutions, or in solutions of mannitol and polyethylene glycol. METHODS: Seeds were allowed to germinate under controlled conditions in a germination chamber at 30 +/- 1 degrees C and at 80 % r.h. Salinizing agents were KCl, NaCl, Na(2)SO(4), K(2)SO(4), NaCl + Na(2)SO(4) and KCl + K(2)SO(4) and osmotic agents were polyethylene glycol 6000 and mannitol. Treatments for all osmotica consisted of 0.0, -0.4, -0.8, -1.2, -1.5, -1.9 and -2.2 MPa solutions. KEY RESULTS: The percentage of germination decreased as salinity increased. SO(4)(2-) in monosaline solutions, with osmotic potentials -1.2 MPa and lower, was more inhibitory than Cl(-) at iso-osmotic concentrations. This SO(4)(2-) toxicity was alleviated in salt mixtures and was more noticeable in higher concentrations. K(+) was more inhibitory than Na(+) independently of the accompanying anion. CONCLUSIONS: Different responses to different compositions of iso-osmotic salt solutions and to both osmotic agents indicate specific ionic effects. This study demonstrates that the germination of P. strombulifera is strongly influenced by the nature of the ions in the salt solutions and their interactions. Comparative studies of Cl(-) and SO(4)(2-) effects and the interaction between SO(4)(2-) and Cl(-) in salt mixtures indicate that extrapolation of results obtained with monosaline solutions in the laboratory to field conditions can be speculative.     

Allelopathic effect of Cistus ladanifer on seed germination

1. The allelopathic effect of the exudate secreted by Cistus ladanifer leaves was tested on different plant species. Cynodon dactylon and Rumex crispus , species absent from C. ladanifer scrub (jarales), were clearly inhibited by the exudate.
2. Species present in the jarales, Medicago polymorpha and Lolium rigidum , showed no direct inhibition of germination, but the process this was delayed, and cotyledon and root size was diminished. This implies inhibition of seedling growth, and may explain the low abundance of these species inside the jarales.
3. The active constituents in the inhibition of germination are low molecular weight phenolic compounds. The flavonoids appear to exert no direct effect on germination of the species tested, but do provoke a reduction in cotyledon and root size, and could thereby inhibit subsequent seedling development.     

Differential effects of four abiotic factors on the germination of salt marsh annuals

Interspecific differences in responsiveness to temperature, photoperiod, soil salinity, and soil moisture confirm the hypothesis that abiotic factors differentially affect the germination of salt marsh plants. In growth chamber experiments, four of eight annual species responded to small differences in temperature or photoperiod. Increasing soil salinity decreased the final proportion of seeds germinating and slowed germination for each of the seven species tested. Higher soil moisture increased the proportion germinating of five species and germination speed of all seven species. Salinity and moisture interacted to affect the proportion germinating of five species and germination speed of all seven species. Although the abiotic factor with the largest effect on germination varied among species, more species responded to, and the magnitudes of the responses were larger for, soil salinity than for the other abiotic factors. These germination tests partially explained interspecific differences in the timing of germination in the field. Patterns of Hutchinsia procumbens, Lythrum hyssopifolium, Parapholis incurva, and possibly Lasthenia glabrata ssp. coulteri germination in response to a nonseasonal rainfall could be explained by their response to salinity, temperature, or photoperiod. Fine-scale differences in the timing of establishment within the typical germination window and spatial distributions along salinity and moisture gradients were not explained.     

Soil salinity delays germination and limits growth of hyphae from propagules of arbuscular mycorrhizal fungi

Colonisation of plant roots by some arbuscular mycorrhizal (AM) fungi is reduced in the presence of sodium chloride (NaCl), probably due to a direct effect of NaCl on the fungi. However, there appear to be differences between the fungi in their ability to colonise plants in the presence of NaCl. This experiment tested the hypothesis that propagules of different isolates and species of AM fungi from saline and nonsaline soils would differ in their ability to germinate and grow in the presence of NaCl in the soil solution. Spores or pieces of root colonised by a range of AM fungi were incubated between filters buried in soil to which NaCl had been added at concentrations of 0, 150 or 300 mM in the soil solution. At regular intervals, filters were removed from the soil and both the percentage of propagules which had germinated and the length of proliferating hyphae were determined. Germination of spores of AM fungi studied was delayed in the presence of NaCl, but the fungi differed in the extent to which germination was inhibited. Two isolates of Scutellospora calospora reached maximum germination in 300 mM NaCl, but neither of two isolates of Acaulospora laevis germinated in the presence of NaCl. Germination of spores of the other fungi, including some isolated from saline soil, fell between these extremes. For some fungi, the specific rate of hyphal extension was reduced by NaCl. For others, the specific rate of growth was similar in the presence of NaCl to that in the control treatment, but overall production of hyphae was reduced in the NaCl treatments because germination was reduced.     

The effect of phenols on respiratory enzymes in seed germination

Low molecular weight phenolic compounds were identified in two soilswith different vegetative cover, Fagus sylvatica, L. andPinus laricio, Poiret, spp. calabrica, and were tested atdifferent concentrations on seed germination of Pinuslaricio, and on respiratory and oxidative pentose phosphate pathwayenzymes involved in the first steps of seed germination. The data obtained showthat there are marked differences in the phenolic acid composition of the twoinvestigated soils. All the phenolic compounds bioassayed inhibited seedgermination and those extracted from Pinus laricio soilwere particularly inhibitory. We also found that the non-germination of seedsisstrongly correlated to the inhibition of the activities of enzymes ofglycolysisand the oxidative pentose phosphate pathway.     

Salinity and salt composition effects on seed germination and root length of four sugar beet cultivars

Salinization is one of the most important factors affecting agricultural land in the world. Salinization occurs naturally in arid and semiarid regions where evaporation is higher than rainfall. Sugar beet yield declines with an increase in salinity, but the sensitivity to salts varies with salt composition in water and sugar beet growth stage. The aim of this study was to determine the effect of water salinity levels and salt composition on germination and seedling root length of four sugar beet cultivars (PP22, IC2, PP36, and 7233). The experiments were undertaken with irrigation water with two salt compositions (NaCl alone and mixture of MgSO₄ + NaCl + Na₂SO₄ + CaCl₂) in three replicates. Thirteen salinity levels with electrical conductivity (EC) of the irrigation water ranging from 0 to 30 dS/m were applied to each cultivar in both experiments. Seed germination percentage and seedling root length growth were determined in 13 days. Statistical analysis revealed that germination and root length were significantly affected by salt composition, cultivars and salinity levels. Regardless of salt composition, seed germination and seedling root length were significantly affected by the irrigation water with EC up to 8 dS/m and 4 dS/m, respectively. Except for cultivar PP22, the adverse effect of salinity of the irrigation water on seed germination and seedling root length was higher for NaCl alone than for the salt mixture, which refers to lower salt stress in field conditions with natural salt composition. Presented at the International Conference on Bioclimatology and Natural Hazards, Poľana nad Detvou, Slovakia, 17–20 September 2007.     

Reversing the inhibitory effect of paclobutrazol on seed germination of Amaranthus paniculatus by GA3, ethephon or ACC

The germination of Amaranthus paniculatus seeds was inhibited by applying paclobutrazol, a specific inhibitor of gibberellin biosynthesis. This inhibition was markedly counteracted by gibberellin A₃ (GA₃), suggesting that endogenous gibberellins are required for germination in this species. The inhibitory effect of paclobutrazol was also overcome by ethephon (2-chloroethylphosphonic acid) or the precursor of ethylene biosynthesis, ACC (1-aminocyclopropane-l-carboxylic acid). Thus the physiological effect of gibberellin can be mimicked by ethylene released from ethephon or synthesised from exogenous ACC. It is suggested, that endogenous gibberellins are involved in germination of Amaranthus paniculatus seeds and that action of GA₃ can be substituted by ethylene.Abbreviations ACC 1-aminocyclopropane-l-carboxylic acid - AMO-1618 (2-isopropyl-5methyl-4-trimethylammoniumchloride)-phenyl-l-piperidinium-carboxylate - ancymidol -cyclopropyl--(4-methoxyphenyl)-5-pyrimidine methanol - chloromequat chloride (2-chloroethyl)trimethylammoniumchloride - ethephon 2-chloroethylphosphonic acid - GA gibberellin A₃ - paclobutrazol (2RS, 3RS)-1-(4-chlorophenyl)-4,4-dimethyl-2-(1,2,4-triazol-lyl)pentan-3-ol - Phosphon D 2,4,dichlorobenzyl-tributhylphosphoniumchloride - tetcyclacis 5,(4-chlorophenyl)-3,4,5,9,10-pentaaza-tetracyclo)5,4,1,0,Z,6,0^8,11 dodeca-3,9-diene