Physiological performance of Genipa americana L. seeds primed with silicon under salt stress

ABSTRACT:

The physiological priming of seeds from native forest tree species is a promising strategy to face adverse environments. Silicon priming has shown improvements in seed coat, in addition to favoring tolerance to abiotic stresses. The aim of this work was to evaluate the physiological performance of G. americana (G. americana) seeds primed with silicon and subjected to salt stress. Two trials were carried out: in the first one, four lots of seeds were characterized and subsequently primed with silicon doses (0 mM, 2 mM, 10 mM, 60 mM), and water content and physiological performance were evaluated. In the second trial, seeds from the best lot of trial I were primed at the same doses as in the first trial and subjected to salt stress with NaCl, at osmotic potentials of -0.3; -0.6; -0.9; and -1.2 MPa (2.5; 5.0, 7.5; 10.0 dS.m־¹, respectively). For both trials, the following were evaluated: germination, first count, speed index and median germination time, in addition to seedling emergence in a greenhouse. G. americana seeds primed with distilled water and silicon are able to tolerate NaCl-induced stress, with osmotic potentials of up to -0.6 MPa. In the greenhouse, the highest seedling formation rates were observed at an osmotic potential of -0.3 MPa, while above -0.6 MPa there was a reduction in seedling emergence. Si has potential to condition G. americana seeds, improving their physiological quality and generating vigorous seedlings, suitable for reforestation in low quality soils, promoting ecological sustainability and the rational use of degraded areas.

Index terms:
reforestation; salinity; seedlings

RESUMO:

O condicionamento fisiológico de sementes de espécies florestais arbóreas nativas é uma estratégia promissora para enfrentar ambientes adversos. O condicionamento com Silício tem demonstrado melhorias no tegumento de sementes, além de favorecer a tolerância a estresses abióticos. O objetivo foi avaliar o desempenho fisiológico de sementes de G. americana (G. americana) condicionadas com silício e submetidas ao estresse salino. Dois ensaios foram conduzidos: no primeiro, quatro lotes de sementes foram caracterizados e posteriormente condicionados com doses de silício (0 mM, 2 mM, 10 mM, 60 mM), avaliando-se teor de água e desempenho fisiológico. No segundo, sementes do melhor lote do ensaio I, foram condicionadas nas mesmas doses do primeiro ensaio e submetidas ao estresse salino com NaCl, em potenciais osmóticos de -0,3, -0,6, -0,9 e -1,2 MPa (2,5; 5,0, 7,5; 10,0 dS.m־¹, respectivamente). Para ambos os ensaios, foram avaliadas a germinação, primeira contagem, índice de velocidade e tempo médio de germinação, além da emergência de plântulas em casa de vegetação. Sementes de G. americana condicionadas com água destilada e silício são capazes de tolerar o estresse induzido por NaCl, com potenciais osmóticos de até -0,6 MPa. Em casa de vegetação, os maiores índices de formação de plântulas foram observados sob o potencial osmótico de -0,3 MPa, enquanto acima de -0,6 MPa houve redução na emergência das plântulas. O Si tem potencial para o condicionamento de sementes de G. americana, melhorando sua qualidade fisiológica e gerando mudas vigorosas, adequadas para reflorestamento em solos de baixa qualidade, promovendo a sustentabilidade ecológica e o uso racional de áreas degradadas.

Termos para indexação:
reflorestamento; salinidade; mudas

INTRODUCTION

The production of seeds and seedlings of native forest species has become an urgent need, mainly due to the benefits they provide to various sectors of the economy. Among the species that are in demand, G. americana (Genipa americana L.) stands out; it belongs to the Rubiaceae family and has a high production potential in tropical regions. However, there is still a lack of knowledge when it comes to its exploration, production and use of wood, as well as the conditions for producing seedlings (Paiva et al., 2019).

Seed germination of this species is slow, with low uniformity and asynchronous (Silva et al., 2020). Another fact that affects the metabolic processes of G. americana seeds is salinity, because when they are subjected to water and salt stress they present a low germination rate (Silva et al., 2020). An alternative to accelerate and standardize the germination of G. americana seeds and mitigate environmental changes is the use of pre-sowing treatments, such as physiological priming (Morais et al., 2014). This technique is carried out in the early stages of germination, phases I and II, since it is in these stages that the necessary metabolic activities for germination begin; however, the seeds do not reach phase III. During seed priming, physical-chemical changes occur, increasing the physiological activity of the embryo and its structures, leading to greater water absorption and cell elasticity (Singh et al., 2018). Given the efficiency of these treatments in improving the physiological quality of seeds, new approaches to improve physiological priming are being explored, including the use of silicon as a potentiating agent.

The use of Si in Brazil became notorious after it was included as a micronutrient in fertilizer legislation, by the Ministério da Agricultura, Pecuária e Abastecimento (MAPA) (Brasil, 2004). Silicon (Si) is a metalloid that has gained attention from several plant researchers due to its beneficial effects on plant growth and development (Gaur et al., 2020). In the metabolic processes of seeds, silicone is involved in the synthesis of lignin, providing tegument resistance (Toledo et al., 2011). It improves the negative effects of salt stress, allowing for a better performance at the time of germination, and it promotes resistance to adverse conditions (Zhang et al., 2015).

Given the above, the aim of this work was to evaluate the physiological performance of G. americana seeds physiologically primed with silicon under salt stress.

MATERIAL AND METHODS

This work was carried out in the Laboratório de Fitotecnia, da Universidade Estadual de Santa Cruz (UESC), located in Ilhéus, Bahia (14°45’15’’S 39°13’59’’W). The G. americana fruits were acquired from small farmers in four locations, namely: Itajuípe (14°40’40’’S 39375°0’0’’W), Itabuna (14° 47’ 9’’S 39°16’ 48’’W), Ilhéus - urban area (14° 47’ 00’’S 39°03’00’’W) and Ilhéus - rural area (14°46′42.29′′ S 39°6′8.97′′W) from February to May 2021, forming four lots of G. americana seeds: LA, LB, LC and LD. The fruits were pulped, and the mucilage was removed by mechanical scarification, and the seeds were dried in the shade for three days. During the execution of the experiments, the lots were stored in plastic bags at 20 °C.

Seed physiological priming: the seed exposure period to silicon (Si) was determined based on water content variation during imbibition, standardized to 72 hours prior to primary root protrusion (Phase III of seed imbibition).

The first trial was carried out to evaluate the physiological performance of the lots under a completely randomized design, and the treatments consisted of seeds primed with distilled water (0 mM of Si) and seeds primed with 2 mM, 10 mM and 60 mM of Si (Hameed et al., 2021).

Preparation of the silicon solution for the physiological priming of G. americana seeds: silicon stock solution was prepared with the use of potassium silicate (K₂SiO₃) (molar weight 165.6 g.L⁻¹ and density 1.38 g.mL⁻¹). The rule of three was used to calculate 1 M of silicon, resulting in 5,897 mL of potassium silicate. A 20 M Si solution was prepared by adding 30 mL of potassium silicate and 70 mL of distilled water, totaling 100 mL. The different concentrations of silicon in the treatments (2 mM, 10 mM and 60 mM) were prepared by using the following dilution formula; $C_i\times V_i=C_f\times V_f$_, where C_i = initial concentration; V_i= initial volume; C_f = final concentration; V_f = final volume.

After defining the period of physiological priming and preparing the Si solutions, 47 g of G. americana seeds were weighed for each treatment, including the control one. The seeds were placed in beakers together with the Si solutions and kept in a BOD at 25 °C for 72 hours. After priming, the seeds were dried in the shade and subjected to the determination of water content and evaluations of physiological quality.

The seeds of the lots that were characterized, as well as the seeds that were primed with different Si doses, were subjected to the determination of water content and evaluations of quality as follows:

Water content: Two replications of 25 seeds were determined according to the oven method at 105 ± 3 °C for 24 hours; the results were expressed as a percentage (wet basis) (Brasil, 2009).

Germination test: four replications of 25 seeds per treatment were sown on paper substrate, previously moistened in water with 2,5 times the mass of dry paper, and kept at 25 °C in a germination chamber; counts were carried out 20 and 40 days later (Brasil, 2013). The evaluations were carried out in accordance with the Rules for Seed Testing (Brasil, 2009) and the results were represented as a percentage of normal seedlings.

First germination count: it was carried out in conjunction with the germination test and consisted of the percentage of normal seedlings on the twentieth day after sowing (Brasil, 2009).

Germination Speed Index (GSI): it was carried out in parallel with the germination test, with daily evaluations of the number of germinated seedlings, according to Maguire (1962).

Median Germination Time (T50): it was carried out in conjunction with the germination test to evaluate the time taken to obtain 50% of the germinated seeds, according to Farooq (2005).

Tetrazolium: The seeds were cut longitudinally after 24 hours of imbibition and distributed in four replications of 25 seeds in Petri dishes. They were submerged in a 2-3-5 triphenyl tetrazolium solution and kept protected from light in a BOD chamber at 40 °C for 3 hours. After this period, the seeds were washed and evaluated individually, and the results were expressed as a percentage per class (Virgens et al., 2019). The classification was based on both the spatial distribution and chromatic intensity of pigmentation in the seed embryonic axis. The seeds were classified as: Viable and High vigor (TZH) seeds with a uniform carmine pink colored embryo; Viable and Low vigor (TZL) seeds with less than 50% of the embryo area colored deep red; Non-viable (TZN) more than 50% of the embryonic axis colored milky white.

Electrical conductivity: it was carried out with four replicates of 25 seeds, which were previously weighed and immersed in 75 mL of deionized water and kept in a BOD at 25 °C, for 24 hours. The conductivity reading was performed with a conductivity meter, and the results were expressed in µS.cm^-1.g^-1.

Emergence of seedlings in the greenhouse: it was carried out in commercial substrate Carolina Soil®, in plastic trays, kept in the greenhouse. Four replicates of 25 seeds per treatment were used. The counting was carried out from the emergence of the first seedling until the 40^th day. The seedlings were considered emerged when the cotyledons were above the substrate level. The results were expressed as a percentage.

For the second trial, the G. americana seeds were subjected to physiological priming with potassium silicate at doses of 2 mM, 10 mM and 60 mM and control (distilled water) for 72 h in a BOD at 25 °C. For the salt stress, NaCl was used with the following osmotic potentials: zero, -0.3; -0.6; -0.9; -1.2 MPa. Following the recommendation of the NaCl concentrations (Table 1), weighing was carried out on a precision scale until their respective values were obtained; for each salt concentration, 1000 mL of distilled water was added and then mixed in beakers to homogenize the solution.

Table 1
Sodium chlorine (NaCl) concentrations, their osmotic potentials and electrical conductivity of the saline solution (EC)

Osmotic potentials (MPa)	Concentration levels (g.L-1)	EC (µs.cm-1)
0	0	0
-0.3	4.2	8.06
-0.6	8.4	15.32
-0.9	12.6	21.59
-1.2	16.5	25.65

The seeds were placed to germinate on germitest paper, moistened with a sodium chloride solution, according to the test methodology for the characterization of the lot, with four replications of 25 seeds for each treatment. After being placed to germinate, they were stored in plastic bags and placed in a germination chamber at 25 °C, with the first evaluations taking place seven days after the experiment was set up. For the emergence test in the greenhouse, the same methodology for the preparation of the salt solution was used; the seeds were placed to germinate in trays with four replications of 25 seeds in each treatment, and were irrigated every two days with the NaCl solutions.

The data were subjected to the normality test of residuals (Shapiro-Wilk) and homoscedasticity of variance (Bartllet) at 5% probability. When there was normal distribution of residual errors and homoscedasticity, the analysis of variance and regression was carried out. The response surface methodology was employed to find maximum or minimum points of NaCl and Si that maximize the response of the variables. Package Exp.Des.pt was implemented for the analysis of variance and regression, ggplot2 to generate graphs and rsm to determine the response surface (RSM). All analyses were carried using Software R (Core Team, 2023).

RESULTS AND DISCUSSION

For the definition of the priming period, the curve of water content according to imbibing time is an essential tool to monitor the progress of this process until germination (Bewley et al., 2013). The G. americana seeds presented an initial water content of over 60%, with a slight increase in the first hours of imbibition. However, there was an increase after 18 hours, even though a plateau was not established, even with the water content reaching values close to 90% from 60 hours onwards (Figure 1). This characteristic is due to the slow germination process of the species (Silva et al., 2020), and so the period of 72 hours was established because the seeds are still between Phases I and II of imbibition (Bewley et al., 2013). Moreover, the seeds have a water content that varies between 30% and 50% at harvest, which characterizes them as recalcitrant and sensitive to desiccation (Souza et al., 2002).

Figure 1
Variation of water content in G. americana seeds in different imbibition periods.

The values of initial and final water content presented a minimal variation among the lots (Figure 2A), which shows uniformity and standardization for the quality tests. Fluctuations in moisture levels alter the speed of imbibition, interfere with the initial metabolic processes and accelerate deterioration (Bewley et al., 2013). The tests for germination and first count indicate superior physiological quality in lots LA, LB, with values over 50% (Figures 2 B and C). Lot LC presented the lowest value for the germination and first count variables, both 11% (Figures 2B and C). In the emergence test of seedlings in the greenhouse (Figure 2D), lot LA presented the best performance with 73%, if compared to lots LB, LC and LD, with only 27%, 6% and 53%, respectively, of emerged seedlings.

Figure 2
A) Initial water content and Final water content B) Germination C) First Count D) Emergence (EP) of four lots of G. americana seeds primed with and without silicon in the greenhouse. Averages followed by the same letter in the bar columns do not differ from each other according to the Tukey tests (p < 0.05).

The genetic variability of the lots of G. americana seeds explains the physiological and growth differences of seedlings in the field, a common trait in non-domesticated and pioneer species such as G. americana, due to their high genetic diversity and adaptive capacity (Lowe et al., 2018). Progenies from 12 mother plants, collected in six municipalities in southern Bahia, showed variations in growth rates, indicating that the selection of seedlings with higher performance can favor success in plantations (Sousa-Santos et al., 2024). Therefore, it is essential to understand the physiological differences among the seed lots to optimize screening before seedling production.

As for viability and vigor using the tetrazolium test, in the viable and high vigor category, the seeds from lots LA, LB and LD were statistically similar when subjected to any condition of physiological priming. Furthermore, the values were higher if compared to LC, which presented 25% of seeds with high vigor (Figure 3A). Regarding the tetrazolium test in the low vigor category, the seeds of lots LA and LD did not differ statistically, presenting values above 34% and 38%, followed by LB, which differed from LC; this behavior shows that it is directly related to the differences in vigor among the lots. Regarding the evaluation of TZN, lot LC showed 50% of non-viable seeds, and lots LA and LD did not differ significantly (Figure 3A).

Figure 3
A) Tetrazolium high vigor (TZH), low vigor (TZL), non-viable (TZN), B) Electrical conductivity of G. americana seeds primed with and without silicon. Averages followed by the same letter in the bar columns do not differ from each other according to the Tukey test (p < 0.05).

The results for electrical conductivity obtained in LB showed the lowest release of electrolytes among the studied lots (Figure 3B). Seeds with lower electrical conductivity indicate greater membrane integrity, a smaller amount of ions released and little enzyme degradation (Harter and Barros, 2011). The results of LA and LD were superior, but the best results were related to the vigor tests. Lot LC, with 11.51 µS.cm^-1.g^-1 conductivity, presented a worse performance, with the highest release of ions and other compounds that show that these seeds have problems related to the integrity of the membrane systems (Figure 3B).

Based on the results of the characterization of physiological quality, the G. americana seeds from lot LA were selected. The primed seeds with different doses of silicon presented the response-dose effect; the best result obtained was at the 2 mM Si dose, while the worst response was at the 60 mM Si dose (Figures 4 and 5). For germination and first count, the dose of 2 mM Si showed itself responsive to physiological priming with a 93% rate at the end of the 40 days, being 87% for the first count at 20 DAS (Figure 4 A-B). In terms of seedling emergence in the greenhouse, the control and the treatments with silicone doses were similar, with values between 44% and 57%, except for the 60 mM Si dose, which reduced 85% in relation to the control (Figure 4C). This corroborates the results found in cotton seeds, which inhibited germination and reduced vigor and ESI when the silicon doses were increased (Zhang et al., 2015). In turn, in wheat seeds there was a linear growth when the silicon doses were increased in the germination test and first count of seedlings (Matichenkov et al., 2005). These differences in the response-dose relationship can be related to the time of priming imposition, concentration and silicon source.

Figure 4
Germination (GE); First Count (FC); - Emergence (EP) of G. americana seeds from lot LA primed with and without silicone in the greenhouse. Averages followed by the same letter in the bar columns do not differ from each other according to the Tukey test (p < 0.05).

Figure 5
Tetrazolium high vigor (TZH); Tetrazolium low vigor (TZL); Tetrazolium non-viable (TZN) of G. americana seeds from lot LA primed with and without silicon. Averages followed by the same letter in the bar columns do not differ from each other according to the Tukey test (p < 0.05).

As for TZH, the control presented the lowest percentage of seeds with high vigor if compared to the seeds primed with distilled water and with silicon at doses of 2 mM and 10 mM, showing that the priming enhanced vigor in G. americana seeds (Figure 5). Regarding TZL, the control had 46% of seeds with low vigor, a higher value if compared to the primed seeds. Concerning the TZN tetrazolium test, the percentage of the control reached 22%. For the primed seeds, the lowest values were at the 0 (distilled water) (8%), 2 mM (7%) and 10 mM (6%) doses, respectively. On the other hand, the 60 mM dose presented the highest value (16%) of non-viable seeds if compared to the other Si doses, indicating a negative effect of high doses of potassium silicate on the priming of the G. americana seeds of lot LA (Figure 5).

Silicon supplementation and seed priming with Si have been associated with positive effects on the physiological performance of plants, such as improvements in photosynthesis (Detmann et al., 2012), growth (Oliveira et al., 2024), and seed vigor (Zhang et al., 2015). However, there are also reports on negative effects with high concentrations of silicon, as it occurs in orchid species of the genera Phalaenopsis, Dendrobium (Mantovani et al., 2018) and Cymbidium (Mantovani et al., 2020), when applied via foliar application. In the case of the priming of G. americana seeds with K₂SiO₃ at 60 mM, the high concentration of silicon may have affected germination due to the increased osmoticity of the environment, making imbibition more difficult, and also due to the alkalization of the environment, which raises the pH and may harm the activity of the enzymes that are essential to the initial metabolism of seeds. This happens because when potassium silicate (K₂SiO₃) is dissolved in water, it forms silicic acid (H₄SiO₄), which is unstable in its free form and, depending on the pH and silicon concentration in the solution, may undergo polymerization (Mantovani et al., 2020).

The Si effects are even more pronounced in conditions of abiotic stress, such as salt stress, being one of the positive responses in mitigation related to the maximization of the antioxidant system (Dhiman et al., 2021). There was no significant interaction for the germination of G. americana seeds primed at doses of 2 mM, 10 mM and 60 mM, and exposed to NaCl. However, Si priming influenced germination. This priming did not promote significant differences, since it did not mitigate the osmotic effect of NaCl. For each increase of 1 dS.m־¹ in salinity, there was a 3.09% reduction in the germination rate (Figure 6). The physiological priming with distilled water provided a higher percentage of germination (84%) if compared to the factorial group (72%) (Figure 6b).

Figure 6
NaCl effect on G. americana seeds primed with silicon in the germination test. Averages followed by the same letter in the bar columns, where dose 00 and the increase in NaCl concentrations are shown, do not differ from each other according to the Tukey test (p < 0.05).

At osmotic potentials of -0.3 MPa (2.5 dS.m־¹) and -0,6 MPa (5.0 dS.m־¹), there was a delay in germination, but this did not affect total germination or the formation of normal seedlings (Figure 6A). In the control (distilled water) and at doses of 2 mM, 10 mM, 60 mM Si, there was no formation of normal seedlings at osmotic potentials -0.9 MPa (7.5 dS.m־¹) and -1.2 MPa (10.0 dS.m־¹), showing that salinity overcomes the possible mitigating effect of Si (Figure 6b). Unlike lettuce seeds, silicon application increased the percentage of germination under salt stress conditions (Lemos-Neto et al., 2018). The presence of salts, depending on the concentration, affects the water absorption capacity of the seeds, and causes a reduction in initial growth and changes in metabolism, similar to the changes caused by water stress (Taiz et al., 2017; Gomes et al., 2024).

In the evaluation of the first count of germination (Figure 7), the silicon doses did not reduce the NaCl effect (Figure 7 A, C and E). Distinct effects of NaCl and Si were observed, without the identification of maximum or minimum points. There was an indication of the joint effect of the factors (Figure 7 B), but the osmotic potential of -0.3 MPa (2.5 dS.m־¹) of NaCl was similar to the control one, since the first count was carried out at 20 DAS (Figures 7 B, D and F). This differs from the results found in wheat seeds, which showed a constant increase in germination and first count values as silicon doses increased (Matichenkov et al., 2005). However, the presence of NaCl delayed germination for the osmotic potential of -0.6 MPa (5.0 dS.m־¹).

Figure 7
Effect of Silicon concentrations (2, 10 and 60 mM) in the first count of germination. (a) linear model (y=86.17- 3.45*Silicon R²aj=0.74), (c) quadratic model (y = 78+2.62Si-0.85Si² R²aj=0.75) and (e) quadratic model (y= 67+4.52Si- 0.79Si² R²aj=0.48). Averages followed by the same letter in the bar columns, where the increase in the NaCl concentrations at Si doses are shown, do not differ from each other according to the Tukey test (p < 0.05) (b, d e f).

In the response surface model, there was no quadratic or interaction adjustment, and the variables were not significant. In this context, NaCl and Si were second order terms. The Si concentrations did not reduce the NaCl effect (Figure 8), that is, the use of potassium silicate in the priming of G. americana seeds did not cause a significant effect when they were exposed to salinity. The stationary point of the adjusted model is at maximum values (0.83 of NaCl and 35.83 mM of Si). However, in wheat seeds treated with Si for 6 h, there was a significant increase in the germination rate, plant growth and harvest yield, if compared to the untreated seeds (Hameed et al., 2013).

Figure 8
Response surface of the Silicon and NaCl effect in the first count of germination (stationary points 0.83 dS.m^1- NaCl and 35.83 mM Si).

In the evaluation of the median time for 50% germination (T50), there was no significant Si interaction, but there were differences when the seeds were exposed to NaCl (Figure 9A). T50 increased linearly with the increase of the concentrations of sodium chloride (Figure 8B), with an increase of 0.27 per cent for each dS.m־¹ of NaCl added. The lowest percentages for T50 were observed at the control dose of 0 dS.m־¹ (Figure 8B). The increase of salt concentrations also affected T50 at osmotic potentials of -0.9 (7.5 dS.m־¹) and -1.2 MPa (10.0 dS.m־¹); at these potentials, in addition to inhibiting germination, abnormal seedlings were formed. The increase in osmotic potential, especially NaCl, may inhibit germination depending on the tolerance level of the species (Carvalho et al., 2020).

Figure 9
NaCl effect on T50 of G. americana seeds primed with silicon. NaCl effect on T50 (a). The data were appropriately adjusted according to the linear model (y= 1.47+ 0.26NaCl, R²aj= 0.97).(b) Averages followed by the same letter in the bar columns, where dose 00 and the increase in the NaCl concentrations are shown, do not differ from each other according to the Tukey test (p < 0.05).

There was no interactive effect of Si and/or NaCl for seedling emergence in the greenhouse (Figure 10). Dose 0 (distilled water) and doses 2 mM and 10 mM of silicon did not show significant differences in the number of seedlings emerged without NaCl. At every addition of Si doses, there was a reduction of 0.48%; however, seeds primed with silicon subjected to the potential of -0.3 MPa (2.5 dS.m־¹) showed better results in all treatments, reaching an average of 50%. There was a gradual reduction in treatments with silicon and salt concentrations, from osmotic potentials of -0.9 MPa (7.5 dS.m־¹) and -1.2 MPa (10.0 dS.m־¹) onwards.

Figure 10
Effect of Silicon and NaCl on seedling emergence of G. americana in a greenhouse assay. a) Quadratic model (NaCl: y = 34+9.21NaCl 1.27NaCl₂ R²aj= 0.27), c) linear model (Silicon: y= 47.05-0.48Si R²aj= 0.37) (b) and (d) average values followed by the same letter in the bar columns do not differ from each other according to the Tukey test (p < 0.05).

The physiological priming of G. americana seeds with silicon can be a viable option to mitigate the deleterious effects of the environment; however, new studies should be carried out, as in conditions of salinity in the environment, the salt levels found in the soil or substrate should be checked for the formation of seedlings. It is worth pointing out that, at the osmotic potential of -0,3 MPa, seedlings were formed in the greenhouse. With these results, it is possible to create protocols for the physiological priming of G. americana seeds with higher doses of silicon.

CONCLUSIONS

The priming with 2 mM of silicon (Si) is efficient to mitigate the impacts of moderate salt stress on seeds, promoting significant improvements in physiological quality. On the other hand, higher doses (60 mM) showed deleterious effects. Si is capable of partially alleviating the effects of salt stress at osmotic potentials of up to -0.6 MPa, even though the benefits in the initial development of seedlings are limited. Si has the potential to improve physiological quality, generating vigorous seedlings, appropriate for reforestation in low-quality soils, promoting ecological sustainability and the rational use of degraded areas.

ACKNOWLEDGMENTS

This study was partly funded by the Coordenation for the Improvement of Higher Education Personnel - Brazil (CAPES) - Financial Code 001.

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Edited by

• Editor:
  Heloisa Oliveira dos Santos

Publication Dates

• Publication in this collection
  02 May 2025
• Date of issue
  2025

History

• Received
  01 July 2024
• Accepted
  27 Jan 2025