By contrast, seedling emergence for seeds harvested from mother plants irrigated with mM NaCl remained high between the first and third generation. And the major factors that affecting seedling emergence rates were the seed sources from mother plant grown in 0 or mM NaCl conditions and the two types of seeds Table S1. These results indicated that the initial absence of NaCl during the growth period of the mother plant markedly inhibits seedling emergence of S.
The progeny of plants grown on low salinity sand also partially lose the high salt tolerance typical for this halophyte. However, seeds harvested from mother plants grown on sand irrigated with mM NaCl maintain high seed quality and seedling emergence regardless of their NaCl exposure. These results might also explain why the halophyte S. Figure 1 Seedling emergence rate from S.
Black seeds A ; brown seeds B. We next measured the seedling height over three generations with seeds sown under three conditions: 0, , or mM NaCl Figure 2.
High concentrations of NaCl mM inhibited plant growth as determined by seedling height relative to control conditions. By contrast, plant growth following germination of seeds harvested from mother plants exposed to mM NaCl fared much better compared with those derived from mother plants grown under control conditions.
The viability and salt tolerance of seedlings germinated from S. The main factors that influenced the seedling height were the seeds harvested from mother plant grown in 0 or mM NaCl and the two types of seeds that produced by S.
These results indicate that high salt concentrations during seed maturation promote the development of viable seed, thereby producing larger plants than seeds subjected to control conditions during maturation, especially when exposed to high salinity in subsequent generations. Figure 2 Seedlings height for plants germinated from S. Seeds from the first A ; second B ; and third C generations. To analyze the material basis of the reproductive development of S.
The formed plant of the seeds from mM NaCl displayed higher biomass with a higher plant height and branch number than that from 0 mM NaCl. To determine the effects of different mother plant growth environments on later stages of progeny plant growth of S. We then measured plant height and the diameter of the main stem Figure 3.
The growth environment experienced by the mother plants affected the growth of their progeny. Indeed, plants that had germinated from seeds harvested from mother plants exposed to mM NaCl were taller than plants that had germinated from control seeds. However, the height of plants that had germinated from seeds harvested from mother plants exposed to mM NaCl remained constant over the course of the three generations. Figure 3 Plant growth parameters of the first, second, and third generation S.
Plant height A ; stem diameter B. The diameter of the plant main stem can also reflect the growth of a plant: we therefore measured the diameter of the main stem next. The different growth environments of the mother plants did affect the main stem diameter of plants germinated from seeds from the first, second, and third generations Figure 3B.
Progeny of plants treated with mM NaCl optimum concentration had thicker stems compared to the progeny of mother plants maintained on low salt sand. As noted above for plant height, stem diameter from progeny continuously irrigated with mM NaCl did not change over the course of our experiment, and the growth condition of the mother plant was another factor that influenced the later growth stages on the progeny plants Table S2.
Individual plants that had germinated from seeds collected on mother plants grown in the presence of NaCl developed longer total branches when compared to plants derived from seeds harvested from mother plants grown under control conditions. Total branch length from the first generation progeny of mother plants grown in the presence of mM NaCl was 3 times that of first generation progeny from those of control plants and further increased to 3.
It therefore appears that irrigation of mother plants with a high concentration of NaCl may be beneficial to the growth of S. Again, total branch length of the progeny harvested from plants exposed constantly to mM NaCl remained unchanged. Figure 4 Reproductive parameters of the first, second, and third generation S.
Length of branch per plant A ; length of branch with flower per plant B ; ratio of flower branch length C. The length of flowering branches may reflect the reproductive potential of S. Plants that had germinated from seeds harvested from mother plants irrigated with mM NaCl produced flowering branches longer than plants that had germinated from seeds produced by mother plants grown under control conditions: flowering branches were 3.
The flowering branch length of plants constantly irrigated with mM NaCl showed no differences at any generation. We next calculated the ratio of flowering branch length as a proxy for the number of flowering buds per branch.
The flower bud formation in a halophyte like S. The reproductive growth of the progeny plants was mainly influenced by the growth condition of mother plant, and it was also affected by the generation Table S2.
We next determined seed productivity in S. Plants that had germinated from seeds harvested from mother plants grown in the presence of NaCl produced more seeds than control plants for both types of S. Black seed yield was Brown seed yield was about half that of black seeds, but still well above that of control plants, reaching a yield 6. The growth condition with the mother plants of NaCl maintained the high seed productivity than those grow with no NaCl Table S3.
Seed number per plant followed the same trend, as the number of black seeds was 3. These results suggest that the presence of NaCl during plant development improved overall plant growth, resulting in higher S. Figure 5 Seed parameters of first, second, and third generation S.
Seed yield per plant A ; seed number per plant B ; mean 1,seed weight C. Consistent with a positive effect arising from exposure to high salinity, the progeny of S.
The mean-mass of 1, black seeds was 2. Interestingly, black seed weight gradually and consistently decreased in S. Brown seed weight was not affected by low salinity conditions. The prolonged relaxation of high salinity growth conditions may therefore affect S. During the seed formation and seed development processes, generation was one of the factors that affected the seed quality of S. Seed quality a collective term covering seed germination, seed size, and seedling vigor contribute to crop yield and may influence seed germination and seedling emergence at the beginning of the following generation.
Ambient temperature, light, water supply, and soil nutrient levels all constitute the growth environment experienced by the mother plant during reproduction and seed setting Roach and Wulff, These factors will affect the performance of the progeny by limiting or promoting growth of the mother plant Rengasamy, For instance, in hybrid sweet pepper Capsicum annuum L.
This offers a stark contrast to Sheepgrass Leymus chinensis , for which seed germination decreases with a rise in temperature and reduces flowering stalks Gao et al. Exposure to drought during seed setting will affect seed quality and seed yield. For example, in rapeseed Brassica napus L. Similarly, water stress imposed during the blooming stage in fennel Nigella sativa and Psyllium Plantago ovata resulted in lower seed yield Bannayan et al. Water deficit during flowering of Indian pea Lathyrus sativus L.
Furthermore, the seed germination and seedling growth were also related to the utilization of the stored materials in seeds Zhao et al. Soil salinization is a major limiting factor for economic development of agriculture and forestry, especially in arid and semi-arid regions McWilliam, The salinity of the environment in which maternal plants grow may affect the quality of the seeds they produce.
Salt-tolerant varieties of Carolina Iris Iris hexagona produce seeds that germinate better into faster-growing seedlings when mother plants are exposed to high salinity compared to seeds produced by plants grown under lower salinity Van Zandt and Mopper, In this study, seed quality of the halophyte S.
Compared with seeds produced by mother plants grown on low salinity sand, both black and brown seeds produced by mother plants irrigated with mM NaCl displayed higher seed germination percentage Figure S1 , seed vigor index Figure S4 , seedling emergence rates Figure 1 , and plant height Figure 2 , even when challenged in an environment lacking NaCl.
We had shown previously that seeds produced by mother plants grown in the presence of mM NaCl were larger and had higher protein and lipid content than seeds produced by mother plants grown on low salinity conditions Guo et al. Our results further suggest that some NaCl supplied during the course of the reproductive cycle of the halophyte S.
Our results suggest that the prolonged absence of salt during halophyte growth, especially during the reproductive stage, will severely inhibit seed development, which in turn is likely to severely limit population establishment in a low salinity environments. However, routine exposure to high NaCl may support high seed performance when mother plants grow in high salinity conditions such as mM NaCl and may provide an ecological advantage when attempting to establish or maintain a population in high salinity environments.
In addition to seed germination, seedling growth and plant growth and reproduction are also influenced by the environment experienced by the mother plants. In wild oat, the progeny produced much lighter seeds when the mother plant was infected by mycorrhizal fungi, although seed phosphorus content and seed number increased in parallel Koide and Lu, Maternal effects also affect flowering time and inflorescence number in perennial ryegrass Lolium perenne Hayward, and the height of adult plants in Aztec tobacco Jinks et al.
In the present study, the progeny of S. Therefore, one possible avenue where the maternal effect may influence plant growth is through the modulation of seed size Dolan, For example, seed size was positively associated with reproductive yield in wild radish Raphanus raphanistrum Stanton, The relationship between seed size and seed yield may also depend on the surrounding environment. The presence of mM NaCl in the irrigation solution supplied to mother plants promoted flower bud formation during the reproductive stage of S.
Furthermore, any maternal effect reaches far beyond seed development Stanton, and plays a pivotal role in the establishment of natural populations. We noticed that irrigation with high salt concentrations during plant growth all the way to seed setting produced healthy S.
We therefore tested the consequences of lack of salt exposure to the progeny harvested from mother plants irrigated with no NaCl over three consecutive generations and compared the results to those of progeny of plants continuously exposed to high salinity Table S3. Seed yield and seed number remained high for all three generations when S. Seeds harvested from S. Since high concentrations of NaCl during seed development was beneficial to the growth of the mother plants, and thus to seed quality, the absence of salt may result in the opposite effect.
Higher seed yield in high salinity conditions may rely on the induction of male reproductive organ development in S. The increased vegetative and reproductive growth processes of S.
Previous results showed that the photosynthesis in the leaves of S. When S. And the enhanced reproduction when treated with NaCl was benefited from the increased accumulation of starch in the ovules and thus increased the seed size and seed development of S.
Undoubtedly, the most fundamental material source of reproductive development is from photosynthesis products of leaves, and a very small part of photosynthesis can be carried out in the petals at early developmental stage of S. The increased photosynthetic efficiency in the leaves and flowers of S. Interestingly, the biomass and the reproduction of S. And a result of increased seed number Figure 5B and seed vigor were obtained in S.
Plant size is a strong indicator of the reproductive success. Larger plants have a relatively higher fertility or a higher vigor in their progeny Stanton, Plant height, stem diameter, and total branch length of the progeny that had germinated from seeds collected from mother plants grown in mM NaCl Figure 3 were significantly higher than those of mother plants grown under control conditions.
Reproductive parameters, including flowering branch length and the ratio of flowering branch in the progeny, were similarly higher in these plants. Our results strongly indicate that continuous exposure to high salinity promotes seedling growth and improves reproductive parameters, whereas omitting NaCl continuously negatively and gradually affects the reproductive growth process of the progeny, as measured by plant height and flowering branch length. An efficient antioxidant mechanism was present in quinoa, activated by salts during germination and early seedling growth, as shown by the activities of antioxidant enzymes.
Total antioxidant capacity was always higher under salt stress than in water. Moreover, osmotic and ionic stress factors had different degrees of influence on germination and development. Soil salinity and sodicity cause severe problems in agriculture worldwide, and salt tolerance in crops is an extremely important trait and a major focus of research.
Detrimental effects of high salinity on crops are multifaceted and affect plants in several ways: drought stress, ion toxicity, nutritional disorders, oxidative stress, alteration of metabolic processes, membrane disorganization and reduction of cell division and expansion Hasegawa et al. As a result, plant growth, development and survival are reduced Muscolo et al. Two major stresses affecting plants under salinity are osmotic and ionic stresses.
Osmotic stress, occurring immediately in the root medium on exposure to salts, can result in inhibition of water uptake, cell expansion and lateral bud development Munns and Tester Ionic stress develops when toxic ions e. In order to counteract the detrimental effects of salinity on agricultural production, extensive research on plant screening for salt tolerance has been conducted, with the aim of providing more tolerant cultivars.
However, these studies have mainly focused on conventional crops, screening criteria and investigating how plants tolerate salts Shannon and Noble ; Chen et al. Unfortunately, there are few investigations on screening of available halophytes and their responses to saline conditions Flowers et al. The seed crop quinoa is a facultative halophyte native to the Andean region of Bolivia and Peru, and a member of the Amaranthaceae: quinoa is traditionally cultivated across a range of extreme environments.
Due to its huge genetic variability, the species can be grown under unfavourable soil and climatic conditions Ruiz-Carrasco et al. Quinoa is considered a major alternative crop to meet food shortages in this century Jensen et al.
Most of the studies on the effect of salinity on seed germination of halophytes have, however, been conducted using NaCl solutions. Such investigations may not provide information on germination under field conditions, because soils contain different salts, which may collectively influence germination in different ways from their individual effects Ungar Sea salt mimics the composition of saline soil solutions and can be used to study the synergistic effect of different salts on seed germination Liu et al.
Therefore, the work presented here was carried out to examine the effects of SW and its component salts on seed germination, seedling emergence and the antioxidative pathway of quinoa cv. Titicaca, as well as the relative importance of two components ionic and osmotic of salinity stress. Quinoa cultivars have been shown to differ in salt tolerance Bonales-Alatorre et al.
In general, varieties originating from salt-affected areas are adapted to saline conditions and hence are less affected by salinity Adolf et al. In this study, we used the Danish-bred quinoa cv. Titicaca Jacobsen et al. Quinoa production may be a viable option for farmers interested in a high-value crop with regional production and local markets in Mediterranean countries where saline water and soil salinity are major risks for the future of agricultural development. Here fresh water resources are limited, while food requirements and pressure from climate change are still growing.
The use of saline water resources may constitute a remedy for the current water scarcity. For these reasons, quinoa offers the possibility of an alternative, promising, cash crop to be cultivated in arid and semiarid environments that are prohibitive for other species and so may be able to utilize saline soils in a sustainable and productive way.
Mature seeds of the Danish-bred quinoa Chenopodium quinoa cv. Seed germination and biochemical responses were studied in the first experiment, while morphological, physiological and biochemical responses of seedlings were studied in the second experiment.
The sterilization procedure is required to eliminate saponine from seeds and to avoid contamination by microorganisms during the germination process. The entire sterilization procedure, including soaking, took 1 h and did not affect the germination process Ruiz-Carrasco et al. Seeds were placed on filter paper in 9 cm diameter Petri dishes containing 3 mL of each solution.
Seeds were considered germinated when the radicle had extended at least 2 mm. Seeds 0. The reaction mixture contained 1 mL of potassium phosphate buffer 50 mM, pH 7. Ascorbate peroxidase activity was assayed according to Nakano and Asada The reaction mixture 1. The reaction was started by the addition of H 2 O 2 and ascorbate oxidation measured at nm for 1 min. Enzyme activity was quantified using the molar extinction coefficient for ascorbate 2.
Peroxidase activity was measured on the basis of determination of guaiacol oxidation at nm for 90 s Panda et al. The reaction mixture contained 1 mL of potassium phosphate buffer 0. Superoxide dismutase activity was estimated by recording the decrease in the absorbance of superoxide nitro-blue tetrazolium complex by the enzyme Gupta et al.
The reaction mixture 3 mL contained 0. The assay was performed in duplicate for each sample. Two tubes without enzyme extract were used as a background control. The reaction was started by adding 0. The reaction was stopped by switching off the light and covering the tubes with black cloth. Tubes without enzyme developed maximum colour. A non-irradiated complete reaction mixture which did not develop colour served as the blank. The supernatants were filtered through two layers of muslin cloth and were used to determine the total antioxidant capacity by the spectrophotometric method of Prieto et al.
Aqueous extracts of the seeds were mixed in Eppendorf tubes with 1 mL of reagent solution 0. The assay was conducted in triplicate and the total antioxidant activity expressed as the absorbance of the sample at nm.
The higher the absorbance value, the higher the antioxidant activity Prasad et al. Total phenolic content was determined with the Folin—Ciocalteu reagent according to a modified procedure described by Singleton and Rossi Briefly, 0. The absorbance readings were taken at nm after incubation at room temperature for 2 h. Seeds were germinated in Petri dishes. All pots were filled with Perlite that had been equilibrated, before transplanting the germinated seeds, with one of the different salts or SW solutions at the desired concentration.
All reagents used were of the highest analytical grade and were purchased from Sigma Chemical Co. Leaf and root length were evaluated 21 days after the beginning of the stress, using six plants for each treatment. The ratio of plant material to buffer was 1 : 3. The extract was filtered through two layers of muslin and clarified by centrifugation at 15 g for 15 min.
Seedlings were harvested and root weight was recorded. Three replicated roots were analysed for each treatment. All data were analysed by one-way analysis of variance ANOVA with the salt concentration as the grouping factor. The response variables for these ANOVAs were: seed germination, seedling growth, enzyme activities, ion contents and root morphology. Since salt concentration had five levels, on all significant ANOVAs we performed Tukey's multiple comparison tests to compare all pairs of means.
The germination percentage data were previously subjected to arcsine transformation but are reported in tables as untransformed values. At the lower concentrations, individual salts NaCl, CaCl 2 , KCl and MgCl 2 did not have any significant effects on the germination percentage of quinoa seeds. Conversely, dilute SW significantly lowered germination Table 1. With increasing salt concentration, the germination percentage decreased, irrespective of the treatment, except for MgCl 2. The strongest decrease was observed in SW.
Conversely, with increasing SW percentage, the MGT increased, reaching values 10 times greater than the control and of the other treatments. The strong significant inverse relationship between SW concentrations and germination indexes confirmed the detrimental effects of the SW on seed germination Table 1. Data are expressed as percentage in respect to control. Data are the means of five replicates. Calculating the relative importance of the osmotic and ionic component stresses showed that the two stressful factors made a different contribution to the deterioration of germination depending on the salts used.
The values correspond to the average of five replicates. Catalase activity increased with increasing concentration of CaCl 2 and SW. Superoxide dismutase activity decreased as the concentrations of NaCl and CaCl 2 increased. The amount of total phenols and the total antioxidant capacity of seeds varied with the salt used.
Increasing the concentrations of KCl and MgCl 2 decreased total phenols; no significant differences were instead observed with increasing the concentration of CaCl 2 with respect to control and the other treatments. Total antioxidant capacity increased in all treated seeds compared with control.
The highest antioxidant capacity was detected in the presence of SW Table 3. In seeds 3 days after sowing, the total quantity of ions increased with increasing concentration of NaCl.
A similar response was observed in the presence of SW, the only exception being at the higher concentrations mainly ungerminated seeds Fig. In the presence of KCl and CaCl 2 , the total ionic concentration gradually decreased with increasing concentrations of salts due to the increased number of non-germinated seeds Fig. Increasing the concentration of KCl caused an increase in cations and a concomitant decrease in anion percentage Fig.
Total ion content, cation and anion percentages in seeds of quinoa after 3 days of different salt treatments. No differences were observed in the presence of MgCl 2 , while with CaCl 2 a slight decline was observed with respect to the control. Cation and anion content against chloride, in seeds of quinoa treated with different salts, expressed as percentages. These findings suggest that the reduction of root mass may be the cause of the decrease in the total dry matter of the seedlings Table 5.
Investigating the root morphology showed that the total root length in all treatments was the most affected root parameter, as shown by F -ratios Table 6. Analysis of variance of the effect of different salt treatments on root morphology parameters of quinoa seedlings 21 days old.
Root morphology parameters were significantly changed by CaCl 2 and KCl compared with control but to different extents, depending on salt type Table 7. KCl, at all concentrations, significantly increased RTD and RF ratios, inducing a root system with thinner roots in comparison with control. Total cations Fig. No significant differences, in comparison to control, were observed in the presence of KCl.
Total ion content, cation and anion percentages in quinoa seedlings after 21 days of different salt treatments. Different salts caused a different distribution of cations and anions between root and shoot Fig. More cations were accumulated in shoots than in roots, decreasing in shoots when NaCl and MgCl 2 concentrations increased, while roots accumulated more anions than cations.
Seed priming is a simple, low cost and powerful biotechnological tool used to overcome the salinity problem by promoting seed germination and seedling establishment in agricultural lands [ ]. Seed are exposed to an eliciting solution for a constant period that allows partial hydration, but radicle emergence does not occur by re-drying of seed.
Seed germination occurs three distinct phases: i imbibition, ii lag phase reactivation of metabolisms and iii protrusion of the radicle through the testa. The goal of seed priming is to extend the lag phase, which allows pre-germinative physiological and biochemical processes, but prevent the seed transition towards full germination [ ]. Enhanced and uniformed germination of primed seeds occurs by reduction in the lag time of imbibition, activation of enzyme involved in seed germination, initiation of biochemical mechanisms of cell repair, increase in the RNA content and DNA replication, decrease in ROS and lipid peroxidation with increased activity of antioxidant enzymes including as superoxide dismutase, catalase, and glutathione reductase, and increase in osmotic adjustment and starch metabolism [ , ].
Several methods of seed priming have been developed in order to revive seeds under salt stress conditions. Some of these methods are hydro-priming, osmopriming, solid matrix priming, hormonal-priming, bio-priming, chemical priming, and nutripriming [ 13 ]. In recent years, many studies have been reported to exhibit the positive effects of seed priming on germination under salinity conditions in many crops Table 2.
The functions of seed priming in plant at the germination stage under salinity condition. Hydro-priming is the simplest and one of the mostly used seed priming method. Hydro-priming depends on seed soaking in pure water without chemical substances for 6—24 h and re-drying to original moisture content prior to sowing without emergence of radicle [ ]. This method is a low-cost and environmentally friendly due to no use of additional chemicals.
The uncontrolled water uptake by seeds is major disadvantage of this technique. Rapid hydration may cause leakage of essential nutrients out of the seed during germination, resulting in seed damage in some species [ ]. Osmo-priming, also known as osmotic conditioning, involves soaking seeds in aerated low water potential solution including sugar, polyethylene glycol PEG , glycerol, sorbitol, or mannitol with low water potential instead of pure water, followed by air drying before sowing.
Due to low water potential of osmotic solutions, water is absorbed slowly by dry seed, which allows gradual seed imbibition [ ]. While osmo-priming promotes activation of early phases of germination, inhibiting radicle emergence. Osmo-priming improves seed germination and enhances general crop performance under salt conditions.
Water potential of osmotic agent is critical factor since main purpose is to restrict oxidative damage caused by ROS by inhibiting excess water from entering [ ]. In hormonal priming, seed imbibition occurs in the presence of plan hormones such as GA3, ethylene, auxins, and salicylic acid, which can gave effect on seed metabolism. Chemical priming is a promising seed priming technique to enhance germination under high salinity stress.
Seeds were pre-treated with different chemical solutions used as priming agents. Chemical agents includes a wide range of both natural and synthetic compounds such as antioxidants ascorbic acid, glutathione, tocopherol, and melatonin , sodium hydrosulfide, polyamines hydrogen peroxide, sodium nitroprusside, urea, selenium, chitosan, fungicide, etc. Biopriming involves seed imbibition together with particular bacteria or fungi.
These microorganisms are able to create endophytic connections with the plant. As other priming method, this treatment increases rate and uniformity of germination under salt conditions, as well as protects seeds against the soil and seed-borne pathogens [ ].
The most frequently used biopriming species are Bacillus spp. Seed priming efficiency is influence by many factors and strongly depends on treated plant species and chosen priming technique. Physical and chemical factors including osmotica and water potential, priming agent, duration, temperature, presence or absence of light, aeration, and seed condition also influence priming success and determine germination rate and time, seedling vigor, and further plant development [ 13 , ].
Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution 3. Help us write another book on this subject and reach those readers. Login to your personal dashboard for more detailed statistics on your publications. Edited by Shah Fahad. By Haifa Abdulaziz S. Alhaithloul, Abdelghafar M. Abu-Elsaoud and Mona H.
We are IntechOpen, the world's leading publisher of Open Access books. Built by scientists, for scientists. Our readership spans scientists, professors, researchers, librarians, and students, as well as business professionals. Downloaded: Abstract Salinity is the major environmental stress source that restricts on agricultural productivity and sustainability in arid and semiarid regions by a reduction in the germination rate and a delay in the initiation of germination and subsequent seedling establishment.
Keywords salinity germination glycophyte halophyte seed priming plant hormones. Introduction Seed dormancy and germination are distinct physiological processes, and the transition from dormancy to germination is not only a critical developmental step in the life cycle of higher plants but also determines the failure or success of the subsequent seedling establishment and plant growth [ 1 ].
Table 1. Maximum salt tolerance of halophytes and glycophytes at the germination stage. Chamran Priming with 0. GA3 enhanced germination percentage from Ncir Soaking with 0. Jinyou 1 Priming with 0. Table 2. More Print chapter. How to cite and reference Link to this chapter Copy to clipboard. Available from:. Over 21, IntechOpen readers like this topic Help us write another book on this subject and reach those readers Suggest a book topic Books open for submissions.
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Access personal reporting. More About Us. Salicornia herbacea. Suaeda aralocapsica. Limonium vulgare. Sarcocornia perennis. Haloxylon ammodendron. Kochia scoparia. Kochia prostrata. Haloxylon salicornicum. Prosopis juliflora. Limonium mansanetianum.
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