Next Article in Journal
Effects of LED Irradiation and Non-Thermal Plasma Treatment on Horned Pansy During Flowering: Enhancing Yield and Functional Quality of Edible Flowers
Next Article in Special Issue
Seaweed-Derived Bio-Stimulant (Kelpak®) Enhanced the Morphophysiological, Biochemical, and Nutritional Quality of Salt-Stressed Spinach (Spinacia oleracea L.)
Previous Article in Journal
Effect of Biostimulators as Foliar Application on Eggplant “Black Beauty Cultivar” Growth, Yield and Chemical Composition in Multi-Stressed Loamy Sand Soil
Previous Article in Special Issue
Silicon Improves Soil Environment and Promotes Crop Growth under Compound Irrigation via Brackish Water and Reclaimed Water
 
 
Search for Articles:
Title / Keyword
Author / Affiliation / Email
Journal
Article Type
 
 
Advanced Search
 
Section
Special Issue
Volume
Issue
Number
Page
 
Journals
Horticulturae
Volume 10
Issue 12
10.3390/horticulturae10121273
horticulturae-logo
Submit to this Journal Review for this Journal Propose a Special Issue
► Article Menu

Article Menu

share Share announcement Help format_quote Cite question_answer Discuss in SciProfiles thumb_up
...
Endorse textsms
...
Comment
first_page
settings
Order Article Reprints
Font Type:
Arial Georgia Verdana
Font Size:
Aa Aa Aa
Line Spacing:
Column Width:
Background:
Article

Impact of Water Temperature on Seedling Quality Parameters in Lactuca sativa L., Solanum lycopersicum L., and Brassica oleracea var. gongylodes L.

by
Tilen Zamljen
* and
Ana Slatnar
Department of Agronomy, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, SI-1000 Ljubljana, Slovenia
*
Author to whom correspondence should be addressed.
Horticulturae 2024, 10(12), 1273; https://doi.org/10.3390/horticulturae10121273
Submission received: 26 August 2024 / Revised: 28 November 2024 / Accepted: 29 November 2024 / Published: 29 November 2024
(This article belongs to the Special Issue Irrigation and Water Management Strategies for Horticultural Systems)
Browse Figures
Versions Notes

Abstract

:
Heat stress represents a significant challenge to global agricultural production, with particular emphasis on air temperature stress. Despite considerable attention to this issue, limited information is available regarding the impact of irrigation water temperature on the quality of vegetable crops. In this study, kohlrabi, tomato, and lettuce were subjected to three distinct irrigation temperatures: 17 °C, 24 °C, and 34 °C. A variety of parameters were measured for the three vegetables, including seedling height, relative chlorophyll content (SPAD), mass of the green part (FW), mass of roots (FW), dry weight (DW) of the green part, DW of roots, and leaf area. The results indicated a significant decrease in oxygen (O2) content with rising water temperature, with a 20.8% reduction at 34 °C compared to 17 °C. Notably, the highest temperature of 34 °C exerted the most positive influence on the studied parameters, particularly evident in kohlrabi and tomato. This study addresses a critical knowledge gap by elucidating the impact of irrigation water temperature on the growth and development of vegetable seedlings. The findings presented here lay the groundwork for further investigations into the effects of heat stress on agricultural practices.

1. Introduction

Vegetables play a pivotal role in human nutrition, offering a plethora of minerals, vitamins, and health-promoting compounds [1]. The cultivation methods employed for different vegetables vary considerably. Some vegetables, such as carrots and beans, are directly sown, while others, including tomatoes, peppers, and kohlrabi, are predominantly grown from seedlings due to seed cost and germination conditions [2,3].
Tomatoes (Solanum lycopersicum L.) are one of the most widely consumed and produced vegetables in the world [4]. Tomatoes belong to the Solanaceae family, which includes more than 3000 species [4]. They are a rich source of lycopene, beta-carotene, flavonoids, vitamin C, and hydroxycinnamic acid derivatives. Tomatoes are mostly grown in greenhouses as they require high temperatures for normal growth and development [5]. They are produced exclusively from seedlings, as they require high temperatures and moisture for germination. By using seedlings, cultivation can commence at an earlier stage, resulting in earlier yields and a higher price per yield [6].
Kohlrabi (Brassica oleracea var. gongylodes L.) belongs to the Brassicaceae family, which includes more than 4000 species. The edible portion of kohlrabi is the enlarged stem (bulb). It contains a significant amount of vitamins, minerals, and antioxidant substances [7]. It is particularly rich in anthocyanins (purple varieties), phenolic compounds, and glucosinolates [8]. It is a cool-season, biennial vegetable harvested when the bulbs reach a diameter of 6 to 7 cm. In some cases, the bulbs are harvested for longer storage when they reach a diameter of up to 20 cm [9]. As is the case with other species belonging to the Brassicaceae family, kohlrabi is primarily cultivated as a seedling, allowing for up to two harvests per growing season [9].
Lettuce (Lactuca sativa L.) is a significant cool-season crop grown in almost every country. Lettuce is an important fresh vegetable that can be grown in greenhouses or open fields [10]. The seeds are small, and cultivation usually begins with seedlings, although certain types of lettuce are sown directly into the open field [11]. Furthermore, it is economically important, as several cultivation rotations can be carried out in one growing season [12].
Producing high-quality vegetable seedlings requires the correct selection of high-quality substrate, seed (variety), optimal fertilization, optimal temperatures, and optimal relative humidity [12]. Most seedling producers tend to focus on these parameters and neglect to consider other factors, such as the temperature of the irrigation water or the oxygen content of the water. High or low temperatures can affect nutrient uptake, chlorophyll formation, and photosynthesis [12].
While numerous studies have explored the effects of air temperature on plant growth, the influence of irrigation water temperature on vegetable seedlings remains a less-explored area. This study addresses this gap by subjecting tomato, kohlrabi, and lettuce seedlings to varying irrigation temperatures, providing valuable insights into a crucial aspect of vegetable cultivation that is often overlooked by growers. This research contributes to the practical knowledge of vegetable seedling production and its potential implications for growers seeking to optimize crop quality and yield.

2. Materials and Methods

A greenhouse experiment was conducted at the Biotechnical Faculty of Ljubljana (46°3′4″ N; 14°30′18″ E) to investigate the impact of different cultivars of vegetable seedlings. The greenhouse was a glass greenhouse (rastlinjaki Gajšek, Slovenska Bistrica, Slovenia) with an automatic ventilation and heating system. The experiment utilized the following cultivars: ‘Joliac’ lettuce (Lactuca sativa L.), ‘Toivo F1’ tomato (Solanum lycopersicum L.), and ‘Korist F1’ kohlrabi (Brassica oleracea var. gongylodes L.). Seeds were obtained from Seminis® (lettuce) and Beo (tomato and kohlrabi) and planted on 20 March 2023, in nine peat field plates with 104 holes each (with a volume of 32 mL or 32 cm3 per hole; each temperature treatment contained three field plates), with 312 tomatoes, 312 kohlrabi and 312 lettuce planted for each species altogether (104 seedlings of each species for each temperature). Three distinct treatments were implemented: (i) water temperature ranging from 17–18 °C (1st17C), (ii) water temperature ranging from 24–25 °C (2nd24C), and (iii) water temperature ranging from 33–35 °C (3rd34C).
The air temperature and relative humidity were monitored throughout the experiment using a Voltcraft DL-121TH meter. The average temperature during the experimental period was 19.0 °C ± 0.2 °C (average night temperature: 10.1 °C ± 0.1 °C, average day temperature was 28.0 °C ± 0.8 °C), with a relative humidity of 60.6% ± 2.4 °C and an average CO2 content of 402 ppm ± 1.2 ppm.
During the study, all seedlings were fertilized twice with 150 ppm of N (Poly-Feed™; 20:20:20). The irrigation was conducted every two to three days, contingent on the temperature and illumination, which influenced the rate of drying of the substrate. The seedling plates were immersed in water at an appropriate temperature and left until the substrate was saturated (approximately 10 to 15 min). The different water temperatures were applied initially when the first leaves developed, and the study concluded when the seedlings had developed three to four true leaves, approximately 1.5 months after.

2.1. Irrigation Water Temperature Establishment

The temperatures of the irrigation water were determined with hot water (heated to 65 °C in a hot water bath, which was the maximum temperature of the water bath) and with running water from the tap (temperature of 17 °C). The water was then mixed with different amounts of water based on a preliminary test so that the ranges were maintained. The model for the water temperature mixture is shown in Figure 1. For the 17 °C treatment, no hot water was added.

2.2. Measurments of Irrigation Water Parameters

The irrigation water was quantified using a portable MultiLine® WTW Multi 3630 IDS Multi-Parameter Portable Meter (Xylem Analytics, Weilheim, Germany). The pH and temperature of the water were measured with the WTW SenTix® 940 Universal IDS pH electrodes, while the oxygen concentration was determined with the WTW FDO® 925 Optical IDS Dissolved Oxygen Sensors, and the electric conductivity was assessed with the WTW TetraCon® 925 Conductivity Cell. All probes were procured from Xylem Analytics, Germany. The measurements were conducted before the water was utilized for the irrigation of the seedlings.

2.3. Plant Sampling and Plant Physiological Measurements

The seedlings were sampled at a stage of sufficient development, with at least two to three true leaves. Twenty seedlings from each species and each temperature were sampled to mitigate the edge effect. The following measurements were taken on the seedlings: seedling height (from base of the seedling to the top of the leaves), relative chlorophyll content (SPAD) (Minolta SPAD-502 chlorophyll meter, Tokyo, Japan), mass of green part (g of FW), mass of roots (g of FW), dry weight (g of DW) of green part, dry weight (g of DW) of roots (all weight measurements were carried out on a precise measuring scale Kern ALS 120-4N, Albstadt, Germany), and leaf area (LI-3050C Transparent Belt Conveyor Accessory, Bad Homburg, Germany). Fresh green parts (leaves and stems) and roots were weighed to determine fresh weight. Subsequently, the samples were dried in an oven at 65 °C for 72 h or until they reached a state of complete dryness. Following this, the samples were reweighed in order to determine their dry weight.

2.4. Statistical Analysis

The R program [13] was used for the statistical analysis of the data. The data in the tables are presented as mean ± standard error. One-way analysis of variance (ANOVA) was utilized to ascertain whether statistically significant differences existed among the parameters studied. If the analysis demonstrated differences, a multiple comparison test (Tukey’s test) was conducted (α ≤ 0.05). To evaluate the nature and strength of the linear relationships between variables, we used Pearson’s correlation test with a significance level of α < 0.05. This analysis allowed us to determine whether significant positive or negative correlations existed and quantify the strength of these associations. Given the continuous and approximately normal distribution of the variables, Pearson’s test was chosen as an appropriate measure to detect linear correlations. Additionally, a multivariate analysis of principal components (PCA) was conducted to identify the patterns of grouping in the data, indicating the extent to which the treatments (cultivar, temperature) influenced the green part FW/DW, root FW/DW, leaf area, SPAD, pH, O2, EC, and seedling height. Prior to analysis, the variables were standardized to account for differences in measurement units.

3. Results

3.1. Irrigation Water Parameters

The parameters of the irrigation water are presented in Table 1. The average temperatures were 17.3 °C for the 1st17C treatment, 24.5 °C for the 2nd24C treatment, and 34.0 °C for the 3rd34C treatment. No statistically significant differences were observed between the treatments in terms of electrical conductivity. The O2 content was the highest in the 1st17C treatment at 8.98 mg/L. In the 2nd24C treatment, the oxygen content was 8.6% lower than in the 1st17C treatment, while in the 3rd34C treatment, it was 20.8% lower. There was no variation in the pH value between the different irrigation water temperatures.

3.2. Physiological Parameters of Kohlrabi, Tomato, and Lettuce

In kohlrabi (Table 2A), the highest temperature of 34.1 °C (3rd34C) demonstrated the most favorable outcomes in terms of the green part FW, which exhibited a 28.7% and 30.7% increase compared to temperature treatments 2nd24C and 1st17C, respectively. A comparable pattern was observed for the DW values of the green part of the kohlrabi seedlings. The root fresh weight was found to be the highest in the 2nd24C and 3rd34C treatments, with a significant decrease observed at the temperature of 17.3 °C (1st17C), resulting in a 25% reduction in root fresh weight. The highest temperature of 34.1 °C (3rd34C) demonstrated the most favorable outcomes in terms of seedling height (19.2% higher than in the 1st17C and 2nd24C treatments), leaf area (25.8% higher than in the 1st17C and 2nd24C treatments), and SPAD values (6.7% higher than in the 1st17C and 2nd24C treatments).
In the tomato seedlings (Table 2B), the fresh weight (FW) of the green part was 52.8% higher in the 2nd24C treatment and 55.5% higher in the 3rd34C treatment than in the 1st17C treatment. The treatment with the highest temperature (3rd34C) demonstrated the most favorable results in terms of the dry weight (DW) of the green part, FW of the roots, and DW of the roots in comparison to treatments 1st17C and 2nd24C. The leaf area was found to be the greatest in treatments 2nd24C and 3rd34C, with a significantly lower value observed in 1st17C treatment.
Lettuce (Table 2C) exhibited the least sensitivity to changes in irrigation water temperature. At temperatures 2nd24C and 3rd34C, the highest values were observed for the green part FW, seedling height, and leaf area. The FW of the green part exhibited a 14.3% and 22.5% increase in treatments 2nd24C and 3rd34C, respectively, in comparison to the 1st17C treatment. Similarly, seedlings’ height exhibited a 10.7% and 8.6% increase in treatments 2nd24C and 3rd34C, respectively, in comparison to the 1st17C treatment. The leaf area was 28.3% and 17.8% larger in treatments 2nd24C and 3rd34C, respectively, than in the 1st17C treatment.

3.3. Correlation and PCA Analysis of Data

A correlation analysis was conducted on the parameters under study (Table 3). The analysis revealed that the green part DW was strongly correlated with the green part FW (R2 = 0.8799), root dry weight (DW) (R2 = 0.8314), root FW (R2 = 0.8087), and leaf area (R2 = 0.7511). Furthermore, the root FW/DW and green part FW/DW were found to be correlated with each other. The leaf area exhibited a strong correlation with root FW/DW and green part FW/DW (ranging from R2 = 0.7222 to R2 = 0.8137). The correlation analysis revealed that the species (kohlrabi, tomato, and lettuce) correlated with the SPAD values (R2 = −0.6434). Furthermore, the O2 content demonstrated a strong correlation with the temperature of the irrigation water (R2 = −0.9778). Notably, the temperature of the irrigation water and oxygen levels were not found to be correlated with root fresh weight per dry weight (FW/DW), green part FW/DW, or leaf area.
The PCA analysis of all experimental data yielded three distinct groups (Figure 2). The first group included all three temperature treatments with lettuce. The variability of the data between the different irrigation temperatures for lettuce was low. Seedling height (seedling height) and relative chlorophyll content (SPAD) were low in lettuce. Lettuce exhibited an average green part and root FW or DW. The second group consisted of tomato treatments. The variability among the tomato treatments was greater than that observed for the other two vegetables. All analyzed parameters exhibited higher values in tomato seedlings compared to the other two vegetables. The third group consisted of kohlrabi treatments. As with lettuce, the variability was low.

4. Discussion

The impact of irrigation water temperature on the quality of kohlrabi, tomato, and lettuce seedlings was investigated to ascertain the optimal water temperature for each vegetable type. The multivariate statistical analysis revealed that the variability between the vegetable species with regard to the irrigation temperatures and the investigated parameters was considerable. This is mainly due to the selection of three different temperature-demanding species, with kohlrabi and lettuce requiring lower temperatures and tomato requiring higher temperatures, as reported by Welbaum [1]. In our study, the highest temperature of 34 °C demonstrated the most favorable outcomes for kohlrabi greening FW/DW, root FW/DW, leaf area, seedling height, and relative chlorophyll content (SPAD). The impact of the highest temperature on tomato seedling quality was comparable. Lettuce seedlings exhibited the least sensitivity to irrigating water temperature. The lowest water temperature of 17 °C resulted in the lowest seedling quality parameters. Temperature is a crucial factor in plant growth and development [14,15]. Each vegetable species has an optimal temperature range, and the plants themselves require different temperatures at different stages of development [16]. When plants are developing vegetatively, which is the case for seedling production, they require higher temperatures than when they reach reproductive development [14]. As reported by Wen et al. [17], several possible reasons exist for the higher FW/DW of the green part, FW/DW of the roots, leaf area, seedling height, and relative chlorophyll content (SPAD) in our seedlings due to higher temperatures.
Firstly, the results may potentially be attributed to the fact that elevated substrate temperatures result in augmented cytokinin and auxin synthesis, which in turn leads to enhanced seedling quality due to changes in the root structure [18]. Cytokinins are known to stimulate root growth in plants, as they influence cytokinesis, vascular cambium sensitivity, vascular differentiation, and root apical dominance [19]. Auxins, which are synthesized in young shoots, have been demonstrated to promote root development and induce vascular differentiation [20]. The roots of seedlings undergo three stages of root development, as reported by Siqueira et al. [21]. The first stage is the root apical meristem (RAM) emergence, the second stage is the root-foraging phase, and the third phase is the senescence stage. The highest hormonal activity is in the first two stages when the roots grow and develop [22]. These two stages are also the most important in vegetable seedling production so that the producers get high-quality seedlings.
Secondly, the higher or lower substrate temperatures caused by warmer or colder irrigation water can affect the availability of nutrients, which can strongly influence the development of vegetable seedlings [23]. As Geng et al. [24] report, especially N and P are affected by high or low air and soil temperatures. Plants that do not receive enough N grow more slowly, resulting in smaller plants with less leaf area and poorer root development [25].
Thirdly, temperature exerts a direct influence on the availability of oxygen in water [26]. The main effect of different water temperatures is to influence the percentage of dissolved oxygen, which is lowest at the highest temperature of irrigation water and highest at the lowest temperature. As reported by Wetzel and Likens [27], the oxygen content depends on the temperature, pressure, and concentration of various ions. According to Ouyang et al. [28], the dissolved oxygen content of irrigation water exerts a significant influence on the growth, photosynthetic activity, quality, and quantity of lettuce yield. However, our study did not yield conclusive evidence that the oxygen content of the irrigation water directly affects the seedlings. The treatments with higher temperatures exhibited lower oxygen levels. It is hypothesized that the difference in oxygen content of the water is so minimal that it does not affect the seedlings, particularly when the substrate is typically saturated with water and air. In their 2023 report, Kormanek et al. [29] indicate that the seedlings are primarily influenced by the air and water properties of the substrate.

5. Conclusions

In this study, kohlrabi, tomato, and lettuce were subjected to three distinct temperatures of irrigation water: The temperatures were set at 17 °C, 24 °C, and 34 °C (1st17C, 2nd24C, 3rd34C respectively). The temperatures had a more pronounced effect on the green parts of the seedlings than on the roots. The findings of our investigation address a gap in the current body of knowledge, as there is a paucity of studies that have specifically examined the effects of this type of stress on kohlrabi, tomato, and lettuce seedlings. By elucidating the influence of irrigation water temperature, our findings offer invaluable insights that can be implemented in practical settings, thereby contributing to the advancement of seedling production practices on a global scale. Furthermore, they provide a foundation for further studies regarding the effect of water temperature stress on seedlings and plants.

Author Contributions

T.Z. writing, statistical analysis, and methods; A.S. reviewing of manuscript, conceptualization, and methods. All authors have read and agreed to the published version of the manuscript.

Funding

This research was funded by the Slovenian Research Agency, grant number P4-0013-0481 and The APC was funded by the program Horticulture P4-0013-0481.

Data Availability Statement

The data presented in this study are available on request from the corresponding author.

Acknowledgments

We would like to thank the Infrastructural Center IC RRC-AG (IO-0022-0481-301 001) for the usage of their infrastructure.

Conflicts of Interest

The authors declare no conflicts of interest.

References

  1. Welbaum, G. (Ed.) Vegetable Production and Practices; CAB International: Wallingforth, UK, 2015; 486p. [Google Scholar] [CrossRef]
  2. Brar, N.S.; Saini, D.K.; Kaushik, P.; Chauhan, J.; Kamboj, N.K.; Security, F. Directing for higher seed production in vegetables. Agronomy 2020, 55, 55–67. [Google Scholar]
  3. Leskovar, D.I.; Othman, Y.A. Direct Seeding and Transplanting Influence Root Dynamics, Morpho-Physiology, Yield, and Head Quality of Globe Artichoke. Plants 2021, 10, 899. [Google Scholar] [CrossRef] [PubMed]
  4. Gerszberg, A.; Hnatuszko-Konka, K.; Kowalczyk, T.; Kononowicz, A.K. Tomato (Solanum lycopersicum L.) in the service of biotechnology. Plant Cell Tissue Organ Cult. 2015, 120, 881–902. [Google Scholar] [CrossRef]
  5. Bai, Y.; Lindhout, P. Domestication and Breeding of Tomatoes: What have We Gained and What Can We Gain in the Future? Ann. Bot. 2007, 100, 1085–1094. [Google Scholar] [CrossRef]
  6. Gavrić, T.; Omerbegovic, O. Effect of transplanting and direct sowing on productive properties and earliness of sweet corn. Chil. J. Agric. Res. 2021, 81, 39–45. [Google Scholar] [CrossRef]
  7. Uddin, J.; Solaiman, A.H.M.; Hasanuzzaman, M. Plant Characters and Yield of Kohlrabi (Brassica oleraceae var. gongylodes) as Affected by Different Organic Manures. J. Hortic. Sci. Ornam. Plants 2010, 1, 1–4. [Google Scholar]
  8. Kacjan Maršić, N.; Može, K.S.; Mihelič, R.; Nečemer, M.; Hudina, M.; Jakopič, J. Nitrogen and Sulphur Fertilisation for Marketable Yields of Cabbage (Brassica oleracea L. var. Capitata), Leaf Nitrate and Glucosinolates and Nitrogen Losses Studied in a Field Experiment in Central Slovenia. Plants 2021, 10, 1304. [Google Scholar] [CrossRef]
  9. Smychkovich, A.; Hashemi, M. Yield and Nutrient Concentrations of Kohlrabi Bulbs and Leaves as Affected by Spring Transplanting Dates. Agronomy 2022, 12, 770. [Google Scholar] [CrossRef]
  10. Kumar, R.; Kaushal, S.; Shukla, Y. Variability, correlation, and path analysis studies in lettuce. Int. J. Veg. Sci. 2010, 16, 299–315. [Google Scholar] [CrossRef]
  11. Mou, B. Lettuce. In Vegetables I: Asteraceae, Brassicaceae, Chenopodicaceae, and Cucurbitaceae; Prohens, J., Nuez, F., Eds.; Springer: New York, NY, USA, 2008; pp. 75–116. [Google Scholar] [CrossRef]
  12. Majid, M.; Khan, J.N.; Ahmad Shah, Q.M.; Masoodi, K.Z.; Afroza, B.; Parvaze, S. Evaluation of hydroponic systems for the cultivation of Lettuce (Lactuca sativa L., var. Longifolia) and comparison with protected soil-based cultivation. Agric. Water Manag. 2021, 245, 106572. [Google Scholar] [CrossRef]
  13. RC Team. R: A language and environment for statistical computing. In R Foundation for Statis-517 Tical Computing; RC Team: Vienna, Austria, 2021; Available online: https://www.R-project.org/ (accessed on 13 November 2024).
  14. Hatfield, J.L.; Prueger, J.H. Temperature extremes: Effect on plant growth and development. Weather Clim. Extrem. 2015, 10, 4–10. [Google Scholar] [CrossRef]
  15. Ohtaka, K.; Yoshida, A.; Kakei, Y.; Fukui, K.; Kojima, M.; Takebayashi, Y.; Yano, K.; Imanishi, S.; Sakakibara, H. Difference Between Day and Night Temperatures Affects Stem Elongation in Tomato (Solanum lycopersicum) Seedlings via Regulation of Gibberellin and Auxin Synthesis. Difference Between Day and Night Temperatures Affects Stem Elongation in Tomato (Solanum lycopersicum) Seedlings via Regulation of Gibberellin and Auxin Synthesis. Front. Plant Sci. 2020, 11, 577235. [Google Scholar] [CrossRef]
  16. Wu, X.; Wang, Z.; Guo, L.; Liu, J.; Dhital, Y.P.; Zhu, Y.; Song, L.; Wen, Y. Timing and water temperature of drip irrigation regulate cotton growth and yield under film mulching in arid areas of Xinjiang. J. Sci. Food Agric. 2023, 103, 5754–5769. [Google Scholar] [CrossRef] [PubMed]
  17. Wen, Y.; Wu, X.; Liu, J.; Zhang, J.; Song, L.; Zhu, Y.; Li, W.; Wang, Z. Effects of drip irrigation timing and water temperature on soil conditions, cotton phenological period, and fiber quality under plastic film mulching. Agric. Water Manag. 2023, 287, 108435. [Google Scholar] [CrossRef]
  18. González-García, M.P.; Conesa, C.M.; Lozano-Enguita, A.; Baca-González, V.; Simancas, B.; Navarro-Neila, S.; Sánchez-Bermúdez, M.; Salas-González, I.; Caro, E.; Castrillo, G.; et al. Temperature changes in the root ecosystem affect plant functionality. Plant Commun. 2023, 4, 100514. [Google Scholar] [CrossRef]
  19. Arya, A.; Sharma, V.; Tyagi, P.K.; Gola, D.; Husen, A. Chapter 10—Role of cytokinins in adventitious root formation. In Environmental, Physiological and Chemical Controls of Adventitious Rooting in Cuttings; Husen, A., Ed.; Academic Press: Cambridge, MA, USA, 2022; pp. 239–249. [Google Scholar] [CrossRef]
  20. Aloni, R.; Aloni, E.; Langhans, M.; Ullrich, C.I. Role of cytokinin and auxin in shaping root architecture: Regulating vascular differentiation, lateral root initiation, root apical dominance and root gravitropism. Ann. Bot. 2006, 97, 883–893. [Google Scholar] [CrossRef]
  21. Siqueira, J.A.; Otoni, W.C.; Araújo, W.L. The hidden half comes into the spotlight: Peeking inside the black box of root developmental phases. Plant Commun. 2022, 3, 100246. [Google Scholar] [CrossRef]
  22. Li, J.; Li, D.; Liu, B.; Wang, R.; Yan, Y.; Li, G.; Wang, L.; Ma, C.; Xu, W.; Zhao, L.; et al. Effects of root restriction on phytohormone levels in different growth stages and grapevine organs. Sci. Rep. 2022, 12, 1323. [Google Scholar] [CrossRef]
  23. Razavi, B.S.; Liu, S.; Kuzyakov, Y. Hot experience for cold-adapted microorganisms: Temperature sensitivity of soil enzymes. Soil. Biol. Biochem. 2017, 105, 236–243. [Google Scholar] [CrossRef]
  24. Geng, Y.; Baumann, F.; Song, C.; Zhang, M.; Shi, Y.; Kühn, P.; Scholten, T.; He, J.S. Increasing temperature reduces the coupling between available nitrogen and phosphorus in soils of Chinese grasslands. Sci. Rep. 2017, 7, 43524. [Google Scholar] [CrossRef]
  25. Delgado-Baquerizo, M.; Maestre, F.T.; Gallardo, A.; Bowker, M.A.; Wallenstein, M.D.; Quero, J.L.; Ochoa, V.; Gozalo, B.; García-Gómez, M.; Soliveres, S.J.N. Decoupling of soil nutrient cycles as a function of aridity in global drylands. Nature 2013, 502, 672–676. [Google Scholar] [CrossRef] [PubMed]
  26. Walczyńska, A.; Sobczyk, Ł. The underestimated role of temperature-oxygen relationship in large-scale studies on size-to-temperature response. Ecol. Evol. 2017, 7, 7434–7441. [Google Scholar] [CrossRef] [PubMed]
  27. Wetzel, R.G.; Likens, G.E. Dissolved Oxygen. In Limnological Analyses; Springer: New York, NY, USA, 2000; pp. 73–84. [Google Scholar] [CrossRef]
  28. Ouyang, Z.; Tian, J.; Yan, X.; Shen, H. Effects of different concentrations of dissolved oxygen or temperatures on the growth, photosynthesis, yield and quality of lettuce. Agric. Water Manag. 2020, 228, 105896. [Google Scholar] [CrossRef]
  29. Kormanek, M.; Małek, S.; Banach, J.; Durło, G. Effect of Changing Substrate Density and Water Application Method on Substrate Physical Properties and Container-Grown Seedling Growth. Forests 2023, 14, 1490. [Google Scholar] [CrossRef]
Horticulturae 10 01273 g001
Figure 1. Test for mixing different volumes of hot water with tap water to make it easier to calculate the correct temperature ranges for the irrigation water.
Figure 1. Test for mixing different volumes of hot water with tap water to make it easier to calculate the correct temperature ranges for the irrigation water.
Horticulturae 10 01273 g001
Horticulturae 10 01273 g002
Figure 2. PCA analysis for kohlrabi, tomato, and lettuce seedlings irrigated with three different water temperatures. 1st17C: first temperature at 17 °C, 2nd24C: second temperature at 24 °C, 3rd34C: third temperature at 34 °C.
Figure 2. PCA analysis for kohlrabi, tomato, and lettuce seedlings irrigated with three different water temperatures. 1st17C: first temperature at 17 °C, 2nd24C: second temperature at 24 °C, 3rd34C: third temperature at 34 °C.
Horticulturae 10 01273 g002
Table 1. Irrigation water parameters. Data are presented as mean ± SE (n = 20). Data with different lower-case letters (a–c) are significantly different (Tukey test; p < 0.05). 1st17C: first temperature at 17 °C, 2nd24C: second temperature at 24 °C, 3rd34C: third temperature at 34 °C.
Table 1. Irrigation water parameters. Data are presented as mean ± SE (n = 20). Data with different lower-case letters (a–c) are significantly different (Tukey test; p < 0.05). 1st17C: first temperature at 17 °C, 2nd24C: second temperature at 24 °C, 3rd34C: third temperature at 34 °C.
1st17C2nd24C3rd34C
Irrigation water temperature (°C)17.30 ± 0.32 c24.50 ± 0.35 b34.08 ± 0.50 a
Electric conductivity (μS/cm)478.35 ± 2.25 a478.00 ± 2.23 a481.21 ± 2.38 a
O2 (mg/L)8.98 ± 0.06 a8.21 ± 0.08 b7.14 ± 0.06 c
pH7.43 ± 0.03 a7.44 ± 0.03 a7.44 ± 0.03 a
Table 2. Physiological parameters of kohlrabi (A), tomato (B), and lettuce (C). The data are presented as mean ± SE (n = 20). Data with different lower-case letters (a to c) are significantly different (Tukey test; p < 0.05). 1st17C: first temperature at 17 °C, 2nd24C: second temperature at 24 °C, 3rd34C: third temperature at 34 °C.
Table 2. Physiological parameters of kohlrabi (A), tomato (B), and lettuce (C). The data are presented as mean ± SE (n = 20). Data with different lower-case letters (a to c) are significantly different (Tukey test; p < 0.05). 1st17C: first temperature at 17 °C, 2nd24C: second temperature at 24 °C, 3rd34C: third temperature at 34 °C.
A Kohlrabi1st17C2nd24C3rd34C
Green part FW (mg/plant)582.04 ± 5.21 b599.06 ± 4.16 b840.52 ± 3.63 a
Green part DW (mg/plant)68.15 ± 0.08 b71.30 ± 0.05 ab87.20 ± 0.03 a
Root FW (mg/plant)169.32 ± 0.74 b212.12 ± 0.56 a200.03 ± 0.16 a
Root DW (mg/plant)19.41 ± 0.02 a17.40 ± 0.06 a19.90 ± 0.04 a
Height of seedling (cm/plant)12.95 ± 0.43 b12.86 ± 0.39 b15.34 ± 0.33 a
Leaf area (cm2/plant)14.78 ± 1.16 b15.51 ± 1.12 b20.92 ± 0.90 a
SPAD36.58 ± 0.76 b36.29 ± 0.55 b38.75 ± 0.50 a
B Tomato1st17C2nd24C3rd34C
Green part FW (mg/plant)3880.50 ± 24.47 b5930.75 ± 36.62 a6033.00 ± 23.98 a
Green part DW (mg/plant)255.80 ± 1.99 b331.70 ± 2.89 b375.15 ± 3.55 a
Root FW (mg/plant)794.06 ± 2.78 b773.02 ± 3.11 b992.36 ± 2.85 a
Root DW (mg/plant)52.76 ± 0.08 b63.12 ± 0.09 b80.55 ± 0.07 a
Height of seedling (cm/plant)18.71 ± 0.59 a21.20 ± 0.60 a24.31 ± 4.97 a
Leaf area (cm2/plant)81.36 ± 4.33 b119.38 ± 7.23 a115.61 ± 5.05 a
SPAD43.27 ± 0.48 a38.85 ± 0.46 a40.18 ± 0.54 a
C Lettuce1st17C2nd24C3rd34C
Green part FW (mg/plant)1885.50 ± 40.72 b2155.75 ± 72.74 a2309.80 ± 70.49 a
Green part DW (mg/plant)124.55 ± 2.00 a117.90 ± 1.63 a106.75 ± 1.03 a
Root FW (mg/plant)392.72 ± 3.35 a394.04 ± 2.05 a429.22 ± 3.96 a
Root DW (mg/plant)29.35 ± 0.30 a27.27 ± 0.45 a23.72 ± 0.31 a
Height of seedling (cm/plant)10.00 ± 0.18 b11.07 ± 0.22 a10.86 ± 0.21 a
Leaf area (cm2/plant)55.12 ± 1.58 b66.88 ± 2.23 a64.97 ± 2.34 a
SPAD23.55 ± 0.49 a24.94 ± 0.59 a23.49 ± 0.42 a
Table 3. Correlation analysis among the parameters studied in the experiment.
Table 3. Correlation analysis among the parameters studied in the experiment.
Green Part DWRoot DWECGreen Part FWRoot FWSeedling HeightSpeciesLeaf AreaO2pHSPADTemp.
Green part DW1.0000
Root DW0.83141.0000
EC0.0756−0.04941.0000
Green part FW0.87990.75320.00411.0000
Root FW0.80870.76660.03170.74041.0000
Seedling height0.38510.42140.00450.40900.39171.0000
Species0.14160.12770.00000.26210.26050.10651.0000
Leaf area0.75110.7222−0.04770.81370.77600.30550.42841.0000
O2−0.1692−0.1370−0.1916−0.1636−0.1187−0.15540.0000−0.10341.0000
pH0.0897−0.0356−0.17880.11510.03850.05100.0000−0.0214−0.09151.0000
SPAD0.41290.3808−0.05510.32800.26890.3927−0.64340.19690.08830.02631.0000
Temp.0.15470.14040.14850.17590.11960.18630.00000.1346−0.97780.0759−0.07811.0000
Disclaimer/Publisher’s Note: The statements, opinions and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions or products referred to in the content.

Share and Cite

MDPI and ACS Style

Zamljen, T.; Slatnar, A. Impact of Water Temperature on Seedling Quality Parameters in Lactuca sativa L., Solanum lycopersicum L., and Brassica oleracea var. gongylodes L. Horticulturae 2024, 10, 1273. https://doi.org/10.3390/horticulturae10121273

AMA Style

Zamljen T, Slatnar A. Impact of Water Temperature on Seedling Quality Parameters in Lactuca sativa L., Solanum lycopersicum L., and Brassica oleracea var. gongylodes L. Horticulturae. 2024; 10(12):1273. https://doi.org/10.3390/horticulturae10121273

Chicago/Turabian Style

Zamljen, Tilen, and Ana Slatnar. 2024. "Impact of Water Temperature on Seedling Quality Parameters in Lactuca sativa L., Solanum lycopersicum L., and Brassica oleracea var. gongylodes L." Horticulturae 10, no. 12: 1273. https://doi.org/10.3390/horticulturae10121273

APA Style

Zamljen, T., & Slatnar, A. (2024). Impact of Water Temperature on Seedling Quality Parameters in Lactuca sativa L., Solanum lycopersicum L., and Brassica oleracea var. gongylodes L. Horticulturae, 10(12), 1273. https://doi.org/10.3390/horticulturae10121273

Note that from the first issue of 2016, this journal uses article numbers instead of page numbers. See further details here.

Article Metrics

Back to TopTop