Physiological efficiency during the vegetative stage of tomato crops developed from magnetically treated seeds

Abstract

The study of the effects of magnetic seed treatment (MST) has garnered significant attention from scientists due to its positive results in seed germination and seedling establishment. Few studies have comprehensively evaluated developmental parameters during the plant's vegetative stage. This study aimed to analyze tomato plants developed from magnetically treated seeds during the vegetative stage in terms of i) physiological responses, ii) growth dynamics, iii) correlation between physiological variables, and iv) the contribution of the technique compared with the performance of a highly commercial cultivar. There were 225 experimental units and three experimental groups with 75 plants each. Treatment one (T₁) included plants developed from magnetically treated low-cost seeds; control 1 (C₁) included plants developed from the same low-cost seeds without magnetic treatment (MT), and a secondary control (C₂) was included with plants developed from high-cost seeds without MT to contrast the effect of MT on a low-cost seed with the performance of a high-cost one. Each plant was measured twice a week for leaf area, stem diameter, height, number of leaves, and chlorophyll content. A longitudinal study, using a repeated-measures design over time, was complemented by a correlational cross-sectional study through principal component analysis. A longitudinal study showed that magnetic treatment continuously modified the structure and biomass accumulation of plants throughout the vegetative stage. Plant height, stem diameter, and leaf number were directly and independently correlated with time, whereas chlorophyll content and leaf area were time-dependent. The effect of MST persists and improves the physiological responses of tomato plants up to the vegetative development stage. MST changes the growth dynamics of T₁ compared to C₁. Lastly, the physiological performance of plants generated from magnetically treated low-cost seeds was superior to that of plants generated from seeds without MST, and it closely followed the trend of the highly commercial cultivar, C₂. To ensure the viability of MST as a biotechnological tool applicable to agriculture, future work should include the analysis of the subsequent phenological stages of the plants and determination of crop yield.

1. Introduction

Plant breeders, through different techniques, seek to increase efficiency of light, water, and nutrients use in plants. On the other hand, science and engineering researchers must join efforts to develop more efficient agricultural production systems for energy transformation. When considering different physical applications on plant systems as an alternative, whether mechanical, magnetic, or electromagnetic, as mentioned by De Sousa et al. [1] and Johnson and Puthur [2].The study of the effect of magnetic seed treatment (MST) has attracted the attention of scientists and is supported by multiple reviews, which not only highlight positive results on seed germination and seedling establishment but also show how plant mechanisms are modified by MST [[3], [4], [5]] in current papers [[6], [7], [8], [9]]. Although in recent years the main focus of MST has been on improving germination and planting processes, as confirmed by meta-analyses [10,11], few studies have comprehensively evaluated developmental parameters during the plant vegetative stage (Table 1). The results included these parameters only as responses to stress, thus limiting some of the implications of MST.

Table 1.

Published studies on plants generated from magnetically treated seeds and with developmental parameters measured during the vegetative stage.

Species	Doses	Variable increased	Reference
Tomato	100 mT −10 min 170 mT–3 min	Leaf area, leaf dry weight, and specific leaf area.	[12]
Tomato	50–100 and 150 mT–60 min	Leaf area, leaf number, plant height, fresh and dry mass.	[13]
Sunflower	200 mT–120 min	Leaf number and chlorophyll content	[14]
Soybean	200 mT–60 min	Leaf area, plant height, fresh and dry mass.	[15]
Barley	50 mT–120 min	Plant height, chlorophyll content.	[16]
Wheat	50 mT - 120 min	Stem diameter, leaf area, height and dry mass of plants, and chlorophyll content.	[17]

Tomato plants are one of the most cultivated plants on the planet and are commonly grown under greenhouse conditions to control the environmental conditions and water supply. This approach helps stabilize the energy supply to the system and reduces abiotic stress. Improvements in their physiology might benefit from the application of MST, where crop growth variables need to be quantified.

There are no studies on tomato plants grown from magnetically treated seeds that consider growth dynamics or the correlations of implicit variables. More in-depth studies, with new experimental designs and increased statistical rigor, are needed. Therefore, the next step is to verify the responses of this technique on various parameters of the vegetative development of commercial crops. Lastly, this technique could be used to generate improvements in the vegetative development of plants, serving as a precursor to the reproductive stage. Thus, the objective of this research is to analyze tomato plants developed from magnetically treated seeds during the vegetative stage in terms of i) physiological responses, ii) growth dynamics, iii) correlations between physiological variables, and iv) the contribution of the technique compared to the performance of a highly commercial cultivar.

2. Materials and methods

The experiment was carried out between October 2022 and April 2023 in a greenhouse under semi-controlled environmental conditions at La Martinica farm, department of Caldas, Colombia (5°08′26.3"N, 75°44′31.5"W), at an altitude of 1110 MASL. Two cultivars of Solanum lycopersicum L. adapted to be grown between 600 and 2000 MASL were used, the Santa Cruz® cultivar (SCc) and Roble® hybrid (Rh). There were 225 experimental units and three experimental groups with 75 plants each. Treatment one (T₁) included SCc plants generated from magnetically treated seeds; control 1 (C₁) included SCc plants generated from seeds without magnetic treatment, and a secondary control (C₂) was included with Rh plants generated from seeds without magnetic treatment to contrast the effect of MT on a low-cost seed with the performance of a high-cost seed cultivar (Rh).

2.1. Sampling size

To calculate an appropriate correlation, the number of experimental units must be greater than or equal to five times the number of variables measured. In this study, there were 75 plants per experimental group to prevent the loss of experimental units due to anomalous data, pathogens, or insect damage. Furthermore, having 75 experimental units increased the statistical power to make inferences about the population behavior of the crop for each experimental group. All analyses were carried out with a significance of 5 %.

2.2. Germination and transplanting

The magnetic treatment (MT) and in vitro germination phases of T₁ seeds were conducted in the Magnetobiology Laboratory at Caldas de University. The treatment was performed using a non-homogeneous static magnetic field generated by a set of toroidal magnets, characterized by Ref. [18]. During the in vitro germination phase, seeds were placed in Petri dishes lined with absorbent paper moistened with distilled water. The following environmental parameters and MT conditions were selected to generate the smallest t₅₀ values: magnetic flux density (B), magnetic exposure time (t_exp), incubation temperature (T), and volume of water (V_H2O). These parameters were determined from previous germination experiments guided by a Bayesian optimization algorithm developed by the Magnetobiology Research Group. The parameters used were B = 100 mT, t_exp = 30 min, V_H2O = 12.0 mL, and T = 27.7 °C; resulting in a t₅₀ = 52.6 h. In the greenhouse, plants from the three experimental groups were combined, and C₁ and C₂ were sown simultaneously alongside the magnetically treated seeds from T₁. For the nursery phase, the seeds were sown in 128-locule trays filled with Pindstrup® peat as a substrate.

The transplantation was carried out 26 days after sowing, in 17 L pots containing 50 % soil and 50 % substrate, when plants had at least three fully opened true leaves. The soil was clay loam, with a pH of 5.6 and a cation exchange capacity of 13. To ensure independence, the 225 transplanted plants were randomly distributed in nine rows of 25 plants each, arranged at 0.4 × 1.4 m intervals. Plants were allowed to grow into two main stems, were tied to overhead wires, and were supported to reach heights of up to 2.0 m. To avoid edge effects, the experimental set-up was placed within 3 100 tomato plants. Irrigation was provided by a semi-automated drip system, delivering 700 mL ∙ d⁻¹ ∙ plant⁻¹.

After transplantation, daily monitoring of insects and pathogens guided the management strategies. For insect pest management, the following treatments were applied: abamectin B1a + B1b (7.2 g a.i./ha), cyfluthrin (1 g a.i./1000 m³), triflumuron (124 g a.i./ha), spinetoram (90 g a.i./ha), and L. lecanii + M. anisopilae + B. thuringiensis (1·10⁸ UFC + 4·10⁸ UFC + 1·10⁸ UFC, 60 g a.i./ha). Captan (250 g a.i./ha) was used to control Botrytis cinerea. The nutritional plan was designed based on the requirements of the tomato crop and was supplied in grams per plant as follows: N (1.3); P₂O₅ (4.4); K₂O (6.1); MgO (0.3); S (0.1); CaO (1.5); B (0.1); Cu (<0.01); Fe (<0.01); Mn (<0.01); SiO₂ (1.2); Zn (0.4); Mo (<0.01). Fertilization was applied twice per week to the soil via irrigation and foliar spraying.

2.3. Plant response and environmental variables

The plant response variables included stem diameter (Φs), measured at the insertion point of the cotyledons with a digital caliper (±0.000 1 m) (Mitutoyo CD-8” CSX-B, Aurora, IL); plant height (PH), quantified with a laser distance meter (±0.001 m) (Fluke 480D, Everett, WA), measured vertically from the surface of the substrate to shoot apical meristem; and leaf area (LA), measured using the Easy Leaf Area free mobile application, version 1.02 [19]. The number of leaves (NL) per plant was determined by counting only those plants with more than three fully unfolded leaflets. Total chlorophyll content (TCC) was quantified using a portable chlorophyllometer (SPAD 502 Plus, Konica Minolta INC, Osaka, Japan) on two random leaves per plant between 11:00 a.m. and noon. All variables were measured twice a week from the fourth day after transplanting (DAT) until 28 days, which corresponded to the vegetative growth phase of tomatoes [20].

Measurements of environmental parameters were taken to determine the agroclimatic conditions in the greenhouse. Devices were placed at the center of the experimental area, 1.50 m above the ground. Relative humidity (RH) and temperature measurements were recorded with four thermohydrometers (±0.01 °C, ±0.01 %RH) (/HOBO MX2301, Onset computer corporation, Bourne, MA). The devices were configured to measure every 30 s and store the maximum, minimum, and average values every 15 min. The data from the four thermohydrometers were averaged. Growing degree days (GDD) were calculated as the difference between the mean daily air temperature and the base temperature [21]. Photosynthetically active radiation (PAR) was measured using the portable light meter (±0.001 W ∙ m⁻²) (LI-COR 250A, LI-COR, Lincoln, NE) twice a week, every hour between 6:00 a.m. and 6:00 p.m.

2.4. Statistical analysis

To identify the effects of MST and time on plant development, a longitudinal study was conducted using a repeated-measures design over time, complemented by a correlational cross-sectional study through principal component analysis (PCA). To validate the longitudinal study, the Mauchly test of the Huynh-Feldt condition for repeated measurements was applied. In cases where this condition was not met (p < 0.05), the Greenhouse-Geisser and Huynh-Feldt epsilon values were used to adjust the degrees of freedom in the ANOVA F test. Pairwise comparisons were then performed using Dunnett's test. PCA was conducted independently to identify correlations between all variables measured at different times, which were selected based on their agronomic relevance according to statistical differences. The Kaiser–Meyer–Olkin (KMO) and Bartlett's sphericity tests were applied to assess the appropriateness of factor analysis for the datasets from each selected time point. All statistical analyses were performed using XLStat 2014 software.

3. Results

The growth dynamics tomato plants, developed from magnetically treated and untreated seeds, under semi-controlled greenhouse conditions, were analyzed during the vegetative stage. A dataset was generated 225 experimental units. No plants were recorded as missing due to attacks by pathogens or insects; however, data from six plants were discarded due to the presence of anomalous values in the measured variables across the three experimental groups.

3.1. Environmental conditions

Temperature controlled in the greenhouse was managed by a forced aeration system, which also regulated the RH. Fans and extractors were activated when the temperature reached 30.0 °C, at approximately 10:30 a.m. The environmental variables are shown in Fig. 1. The daily average temperature fluctuated between 21.88 °C and 26.49 °C, with an average temperature difference between day and night was 4.61 °C. During the vegetative stage, 398.01 GDD were accumulated, and since sowing, a total of 777.85 GDD were accumulated, with a daily average of 14.39 GDD and an approximate daylight accumulation of 450 h since sowing (54 d). The RH fluctuated between 62.00 % and 96.00 % (Fig. 1a), with minimum and maximum daily averages of 73.20 % and 90.25 %, respectively. The PAR inside the greenhouse, shown in Fig. 1b, was approximately 30 % lower than outside due to shade netting. The value of the compensation point (CP) for the tomato plant, according to Ref. [22], was 50 μmol ∙ m⁻² ∙ s⁻¹, which is approximately equivalent to 11.86 W ∙ m⁻².

Fig. 1.

Average environmental conditions inside the greenhouse. (a) Temperature (T, in yellow) and relative humidity (RH, in blue) are presented as a function of time over an interval of 24 h. (b) temperature (T, in yellow), and photosynthetically active radiation (PAR, in blue) are shown for a 12 h photoperiod. The value of the compensation point (CP, in cyan blue) is 11.86 W ∙ m⁻² [22]. PAR and CP intersected at 8:00 a.m. and 4:00 p.m., indicating the photosynthetic activation and inactivation thresholds, respectively (cyan blue arrows). (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)

3.2. Temporal analysis

This analysis enabled the description of the growth dynamics of tomato plants during the vegetative developmental stage. The analysis of variance with repeated measures for each response variable, considering the effects of MST and tomato materials, indicated a significant influence by MST (p < 0.05). Similarly, for all response variables, there were statistically significant effects (p < 0.05) due to the interaction between the timing of each measurement and type of plant material used. All probability values after applying the Greenhouse–Geisser and Huynh–Feldt corrections were below the significance level of 0.05. MST increased the magnitudes of all the variables compared to plants of the same variety without MT. For all response variables, the coefficients of variation percentage per experimental group were less than 30 % (Table 2), indicating high data homogeneity due to good metrological practices.

Table 2.

Values of the coefficients of variation for the variables measured.

Exp. group	LA	NL	TCC	PH	Φs
T1	24.80 %	11.78 %	8.61 %	11.28 %	10.89 %
C1	18.64 %	13.92 %	9.15 %	11.40 %	11.79 %
C2	28.16 %	17.37 %	8.12 %	9.55 %	11.55 %

3.2.1. Leaf responses

The development of the foliar components in the crop is shown in Fig. 2, where the T₁ plants exhibited an increase in both the number and size of foliar structures. In T₁, an increase in LA of up to 21 % was recorded compared to C₁. The LA of T₁ was greater than that of C₂ only at the beginning of this phase, as C₂ presented a higher growth rate, and after 14 days, the area of this exceeded the following values of the other two groups (Fig. 2a). Pairwise comparisons indicated that the LA of T₁ was higher than that of C₁ (p < 0.001) for all study periods, except for day 28. Regarding NL, T₁ showed an increase over C₁ throughout the phenological phase, while for C₂ the hybrid, the increase in structure was markedly greater (Fig. 2b) (p < 0.05). Concerning biochemical characteristics, T₁ plants presented a higher TCC compared to those from C₁ (Fig. 2c) until day 21, although there were only statistically significant differences (p < 0.05) at 14 d and 18 d. After 698 GDD, the trend of this parameter changed following day 21, as this trend is diminished, corresponding to the initiation flowering, which alters the development of the leaf structures because the assimilates and reserves are redirected toward the reproductive structures. TCC, as a parameter, was noticeably higher in the hybrid compared to the variety, however, T₁ might the trend it showed over 11 d and achieve a response similar to that of the hybrid with a greater contribution of nutrients. Table 3 presents the relationship between the GDD and DAT.

Fig. 2.

Leaf development parameters as a function of growing degree days (GDD). SCc seeds with MT (T1 in yellow); SCc seeds without MT (C₁ in blue); and Rh without MT (C₂ in cyan blue). The bars represent 95 % confidence intervals. (a) Leaf area curves (LA), (b) number of leaves (NL), and (c) total chlorophyll content (TCC). (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)

Table 3.

Equivalence between growing degree days (GDD) and days after transplanting (DAT).

GDD	458	502	557	601	657	698a	755	795
DAT	4	7	11	14	18	21a	25	28

^aIndicates the initiation of the flowering phase.

3.2.2. Stem response

The plant diameters and heights are shown in Fig. 3. The heights of T₁ plants were 9.1 % and 16.2 % higher than those C₁ and C₂, respectively (p < 0.001). There was also an increase in the Φs of T₁ plants compared to that of C₁ and C₂ plants (Fig. 3b). Between 458 and 601 GDD (4 and 14 DAT), the diameter of T₁ was 6.9 % greater than that of C₁. From the longitudinal study on the increase in PH and Φs (Fig. 3), it can be observed that, over time, there was an increase in the growth rate for the treated seeds and the controls, a similarity that we attributed to a balanced distribution of assimilates.

Fig. 3.

Stem parameters of the tomato plants as a function of growing degree days (GDD): SCc seeds with MT (T₁ in yellow), SCc seeds without MT (C₁ in blue), and Rh without MT (C₂ in cyan blue). The bars represent 95 % confidence intervals. (a) Plant height (PH), (b) stem diameter (Φs). (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)

3.3. Correlational cross-sectional study

The correlational study was conducted at 7, 14 and 25 DAT (502, 601 and 755 GDD) because these time points showed statistical relevance after the longitudinal study. For the three cases, the KMO test was 0.6, confirming that partial correlations could be explained by the newly emerging variables (main components of the factor plane). However, in all cases, according to Bartlett's sphericity test, the probability values were less than 0.001, indicating that the determined factor models were appropriate for the datasets and effectively explained the phenomenon. Additionally, the experimental groups showed differing responses depending on the material used.

The factor planes that best represent the analyzed variables as a function of two newly emerging variables are shown in Fig. 4. These factor planes could express the responses of the experimental groups based on the interdependencies of the five measured parameters. Therefore, we proposed that the principal component, F1, serves as an indicator of morphological development or plant size, while F2 indicates the capacity of the plant structure to capture photonic energy.

Fig. 4.

Factor planes involving the five quantified parameters. The yellow centroids T₁, C₁, and C₂ represent the responses of each experimental group relative to the measured and emerging variables. (a) Factor plane 7 DAT (F1 and F2: 62.32 %), (b) factor plane at 14 DAT (F1 and F2: 72.90 %), and (c) factor plane 25 DAT (F1 and F2: 66.31 %). (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)

When inspecting the three cross-sectional moments and interpreting the evolution of the variables over time through the three factorial planes, it is notable that PH, Φs, and NL presented a direct and independent correlation with time and were well represented in the principal component F1. However, TCC correlated with LA depending on the time of the study. These two variables had no interdependence with the first correlational set and were represented very well by the principal component F2. Additionally, when analyzing the projection of the yellow centroids corresponding to each of the experimental groups on the main component F1, it becomes evident that the T₁ plants exhibited positive differences in morphological development with respect to the C₁ control and C₂ secondary control. However, this trend diminished, as seen in factorial planes in Fig. 4b and c, where the position of centroid T₁ shifts slight to the left, and the distances between it and the two additional centroids decrease.

4. Discussion

The agroclimatic conditions of this study, with RH values between 60 % and 90 %, were appropriate for greenhouse tomato crops, according to the ASABE standards cited by Shamshiri et al. [20]. Regarding the thermal exposure intervals, Shamshiri et al., indicated that the optimal temperature range for the vegetative period is between 18.3 °C and 32.2 °C [20]. Similarly, Baudoin et al., indicated that the correct physiological function of tomato plants requires a thermal periodicity between 5 °C and 7 °C, with at least 500 h–550 h, over three months. In this study, the photosynthetic activity interval of the plants was approximately 8 h long, between 8:00 a.m. and 4:00 p.m. Therefore, the agroclimatic conditions to the crop were optimal, and the increase in PH and LA can suggest that the metabolic activity of plants benefited from MST, ultimately allowing us to assert that T₁ plants are more efficient in using in thermal and photonic energy use.

In general, the results of this study are consistent with those of other related reports, as presented in Table 1. Regarding leaf responses, the increase in TCC observed in this study has also been reported by others [14,17]. This increase represents a biochemical adaptation, allowing the plant to enhance the transformation of available light energy into chemical energy. It is also related to the biosynthesis of carbohydrates and biomass. Therefore, an increase in this parameter suggests a modification in biochemical mechanisms. From a hormonal perspective, the increase in TCC was attributed to a higher concentration of gibberellic acid (GA₃), as reported by Selim [23]. It is plausible that hormonal modifications are related to improvements on germination parameters in magnetically treated seeds, which could persist throughout the vegetative development. Other researchers have reported increases in TCC across various species using MST, regardless of the type of photosynthetic metabolism, such as wheat [17,24], sunflowers [14], barley [16], and maize [15].

Plants developed from magnetically treated seeds showed an overall increase in LA, supported by an increase in the number and individual areas of the leaves, which also exhibited an increase in TCC. These findings are consistent with those of De Souza et al. [12], who also noted a greater capacity to collect photonic energy by plants. These three parameters enable plants to maintain a more photosynthetically active surface, throughout the entire vegetative stage. This suggests that T₁ plants have the potential to absorb a greater amount of photonic energy and possibly possess a higher capacity to transform light energy compared to C₁ plants. Additionally, the potential increase in photonic energy capture by T₁ plants leads to a higher production of photoassimilates, which contributes to the increased growth of aerial structures.

We also attribute the improvements in stem behavior in T₁ plants to an increase in the assimilates that promoted biomass accumulation in plants grown from magnetically treated seeds. We believe that the greater LA and TCC influence the increased light interception, as [25] proposed that these two factors are decisive for biomass accumulation during vegetative development. The distribution of these assimilates is related to an increase in the concentration of auxin (AIA) and GA_3, as well as enhancements in metabolic activity. Similar results have been reported for tomatoes [12,13] and other species in several reviews [3,26].

Improvements in the development of the morphological parameters resulted from increased cell division and elongation. In turn, cell elongation in tissues is related to the interaction between auxins, cytokinins (CK), and abscisic acid (ABA) [[27], [28], [29]]. The relationship between hormones is complementary because GA is required for the transport of IAA, and CK stimulates cell division in the presence of auxins [30]. Focusing specifically on the increase in NL, this process begins with the formation of primordia, which is preceded by the localized accumulation of IAA in the peripheral zone of the meristem. The formation of new leaves from primordia requires cell division in the coastal zone of the cauline apical meristem, which is promoted by signaling pathways sensitive to GAs and brassinosteroids (BR) [31,32]. Similarly, as discussed in Sections 3.3.1 and 3.3.2, an increase in PH caused by MST may occur because of the promoting action of IAA on FA biosynthesis [27].

Inspection of the development of T₁ through the longitudinal and cross-sectional analysis showed a decrease in the growth rate of four plant structural parameters after 698 GDD (21 DAT) and a decrease in the TCC. This is evident in the position of the yellow centroid of T₁, and could be explained by the onset of the flowering stage at 21 DAT. The changes observed at the beginning of this stage suggest the need of assimilates in the stem to be translocated to new structures in the reproductive phase. Plants developed from MST generated a greater amount of plant tissue, which can be related to an increase in the hormonal concentration in the plants and a potential capacity to assimilate more nutrients, as stated by Ref. [24]. Regarding the behavior associated with the main component F2, the hybrid is a plant system with a greater capacity to capture energy, although it has a smaller above-ground vegetative structure. It is also interesting to observe that as its vegetative development progresses, the plant decreases energy expenditure to synthesize chlorophyll, while increasing its contribution to developing more leaves with a greater area.

Plants in T₁ had slightly longer stems and wider diameters, resulting in more conductive tissues with the potential to facilitate the flow of substances to organs with greater demand. Additionally, these plants had a robust plant structure, and healthy plants with abundant foliage are better able to withstand pest attacks. Regarding photosynthetic pigments, the contrast between T₁ and C₂ plants showed an initial increase that later decreased at the end of the vegetative period. This behavior can be attributed to chlorosis, which occurs between the end of the vegetative phase and the beginning of the flowering stage in SCc plants. The observed chlorosis could be explained by a nutritional deficiency in the magnetically treated SCc, as T₁ generated more tissues but the nutritional plan was adjusted according to standard commercial requirements for the variety.

Finally, the results of this work align with other reports that applied magnetic field gradients to seeds of different species, with similar magnetic exposure doses [12,14,15]: this suggests that the modified mechanisms make plants more efficient at capturing and transforming the energy provided by the environment. This study corroborates that the impact of MST on germination extends to the vegetative stage of tomato plants. This technique could be redirected to increase crop yields, but the degree of magneto-sensitivity of each crop species must be identified and the response quantified. Results across the four phenological stages of plants will support MST as a biotechnological technique with potential application in agricultural production systems.

5. Limitations

There are compelling reasons to think that magnetic seed treatment positively "influences cellular structures, activating hormonal processes that result in increases in the number and area of leaves and stems, thereby increasing their number and size. It is recognized that there is a need to increase for more robust evaluations of specific MST and plant species where various biochemical and developmental parameters are included. Additionally, it is recommended that the leaf area be further assessed using other techniques to ensure greater confidence in the results.

6. Conclusions

The effect of magnetic seed treatment persists beyond germination and improves the physiological responses of tomato plants up to the vegetative development stage. This treatment alters the growth dynamics of the SCc variety compared to the control C₁, as evidenced by the superior development of magnetically treated SCc compared to plants grown from seeds without magnetic treatment. This could have a favorable impact on subsequent phenological stages, potentially increasing crop yield. Additionally, the physiological responses of plants developed from magnetically treated seeds tend to approach the behavior of the highly commercial cultivar, during the analyzed phenological phase. Furthermore, the correlation of the measured physiological variables showed a trend suggesting the modification of various hormonal mechanisms that favor the physiological development of plants. These correlations also indicate that, in future experiments, the measurement of certain variables could be omitted due to their high correlation.

7. Future scope

Magnetic seed treatment stimulates biochemical processes in the seed that modify physiological processes affecting the development of plants during the vegetative stage. More efforts should be directed toward clarifying these mechanisms in detail. Plants generated from magnetically treated seeds must have an adjusted nutritional plant, larger plant structures require more mineral supply and may promote the same developmental trend in subsequent phenological stages.

Based on the findings of this study, future work should include an analysis of the later physiological stages of this crop and their impact on yield. Such analyses will provide sufficient evidence to ensure the feasibility of MST and to reinforce its proposed use as a biotechnological tool applicable to agriculture.

CRediT authorship contribution statement

Javier Torres-Osorio: Writing – review & editing, Writing – original draft, Methodology, Investigation, Data curation, Conceptualization. Elisabed Villa-Carmona: Writing – original draft, Data curation. Carolina Zamorano-Montanez: Writing – review & editing, Supervision.

Data availability

Raw data associated with this study has been deposited into a publicly available repository (https://data.mendeley.com/) with accession code (https://doi.org/10.17632/7xp5zd7vgy.1)

Declaration of generative AI and AI-assisted technologies in the writing process

During the preparation of this work the authors used Chat GPT 4.0 in order to improve the grammar and language of the manuscript to enhance overall readability.

Funding

This work was supported in part by funding from the Universidad de Caldas and agreement “Proof of License of the technology -Magnetic seed treatment.” COLFOG MIP S.A.S, as well as by the Convocatoria de creación y fortalecimiento de SPIN-OFF Minciencias-Colombia, 2022.

Declaration of competing interest

The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Javier Torres-Osorio reports financial support was provided by Colombia Ministry of Science Technology and Innovation. Javier Torres-Osorio reports financial support was provided by COLFOG MIP S.A.S. Javier Torres-Osorio reports a relationship with University of Caldas that includes: employment. Carolina Zamorano-Montanez reports a relationship with University of Caldas that includes: employment. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.