The effect of tray cell volume and humic acid on morphological and physiological characteristics of tomato transplant (Lycopersicum esculentum Mill.)

Document Type : scientific research article


1 M.Sc. Student, Faculty of Agriculture and Natural Resources, University of Hormozgan, Bandar Abbas, Iran

2 Corresponding Author, Assistant Prof., Faculty of Agriculture and Natural Resources, University of Hormozgan, Bandar Abbas, Iran.

3 Assistant Prof., Faculty of Agriculture and Natural Resources, University of Hormozgan, Bandar Abbas, Iran.


Background and objectives: One of the main factors affecting the growth of greenhouse tomato transplant is the choose of desired cell size or volume of the tray. So that, larger cells provide more space for better transplant growth, but as the cell volume or size increases, the space required to produce the transplants increase. Therefore, it is important to determine the appropriate cell size that produces vigorous transplants. On the other hand, improved seedling growth in various vegetables such as tomatoes due to the use of humic acid has been reported by various researchers. This study was performed to investigate the effect of tray cell volume and foliar application of humic acid on morphological and physiological characteristics of tomato transplants.
Materials and Methods: A factorial experiment in a completely randomized design with three replications and two factors include tray cell volume (15, 20 and 22 cm3) and humic acid foliar application (0, 1.5, 3.5 and 5.5 g/l) was conducted in a greenhouse at the University of Hormozgan. The growing substrates were 70% coco peat and 30% perlite. Since the fourth week onwards, with the appearance of two pairs of true leaves, the seedlings were sprayed by humic acid fertilizer with concentrations 0, 1.5, 3.5, 5.5 g/l every other day for 15 days. 7 weeks after planting, seedling characteristics such as morphological and physiological traits and concentrations of leaf N, P and K were measured. At the end of the experiment, data analysis was performed using SAS software (version: 9.1). The means were compared with Duncan test at a statistical level of 5%.
Results: The results of this study showed that reducing of try cell volume decreased evaluated traits significantly so that the lowest mean of these traits was obtained in cell volume of 15 cm3. Reduction of cell volume from 22 to 15 cm3 significantly reduced the morphological traits including plant height, stem length, root fresh weight, fresh and dry weight of shoots, and leaf area by 12.7, 16.2, 21.9, 15.1, 18.8 and 18.4%, and physiological traits including Fv/Fm and PI by 10.7 and 25.7, respectively. Application of humic acid improved morphological and physiological characteristics of transplants and in most cases, the highest mean of under study traits were obtained by 5.5 g/l humic acid. With decreasing the tray cell volume from 22 to 15 cm3, the leaf nitrogen, phosphorus, and potassium concentration decreased by 15.7%, 18.9%, and 16.4%, respectively. However, foliar application of humic acid caused a significant increase in the leaf elements content, compared to the control. In general, the highest content of nitrogen (1033.91), phosphorus (224), and potassium (37534.94 mg/kg DW) were obtained with the application of humic acid in concentrations 3.5, 1.5, and 5.5 g/l. On the other hand, foliar application of humic acid improved the under study traits when compared to the control. Overall, these results indicate that humic acid could compensate for root growth restriction in trays with small cells.
Conclusion: The results of this study showed that reducing the cell volume of the tray leads to a significant reduction in physiological and morphological characteristics of tomato transplants. While the use of humic acid could improve nutrient uptake and vegetative growth of seedlings and offset the negative effects of low volume tray cell by the use of humic acid. Foliar application of humic acid improved morphological and physiological traits and absorption of nitrogen, phosphorus, and potassium. Therefore, it seems that the use of humic acid can be suggested as a strategy to produce higher quality transplants.


1.Li, G., Kronzucker, H.J. and Shi, W. 2016. The response of the root apex in plant adaptation to iron heterogeneity in soil. Front. Plant Sci. 344: 1-7.
2.Peyvast, Gh. 2005. Vegetable production. Danesh Pazir Press. 346p. )In Persian (
3.Javanmardi, J. 2009. Scientific and Applied Basis for Vegetable Transplant Production. Mashhad Uni. Press, 265p. )In Persian (
4.Heber, D. 2008. Multitargeted therapy of cancer by ellagitannins. Cancer Lett.269: 2. 262-268.
5.Nair, A. and Carpenter, B. 2016. Biochar rate and transplant tray cell numberhave implications on pepper growth during transplant production. Hort. Technol. 26: 713-719.
6.Silva, V.N., Dotto, L., Hajar, A., Bittencourt, K.C. and Stella, M.R. 2017. Production of Antirrhinum majus seedlings on different substrates and containers. Cientifica. 45: 169-174.
7.Balliu, A., Sallaku, G. and Nasto, T. 2017. Nursery management practices influence the quality of vegetable seedlings. Italus Hortus. 24: 39-52.
8.Bouzo, C.A. and Favaro, J.C. 2015. Container size effect on the plant production and precocity in tomato (Solanum lycopersicum L.). Bulg. J. Agric. Sci. 21: 325-332.
9.Oagile, O., Gabolemogwe, P., Matsuane, C. and Mathowa, T. 2016. Effect of container size on the growth and development of tomato seedlings. Int. J. Curr. Microbiol. Appl. Sci. 5: 890-896.
‏10.Oh, J.H., Park, Y.G., Park, J.E. and Jeong, B.R. 2014. Effect of Cell Size on Growth and Development of Plug Seedlings of Three Indigenous Medicinal Plants. Korean J. Hort. Sci. Technol. 23: 2. 71-76.
11.Zakaria, N.I., Ismail, M.R., Awang, Y., Megat Wahab, P.E. and Berahim, Z. 2020. Effect of root restriction on the growth, photosynthesis rate, and source and sink relationship of chilli (Capsicum annuum L.) grown in soilless culture. Biomed Res. Int. 2020: 1-14.
12.Liu, F., Cao, X., Wang, H. and Liao, X. 2010. Changes of tomato powder qualities during storage. J. Powder Technol. 204: 1. 159-166.‏
13.Shopova, N. and Cholakov, D. 2014. Effect of the age and planting area of tomato (Solanum licopersicum L.) seedlings for late field production on the physiological behavior of plants. Bulg. J. Agric. Sci. 20: 173-177.
14.Poorter, H., Bühler, J., van Dusschoten, D., Climent, J. and Postma, J.A. 2012. Pot size matters: a meta-analysis of the effects of rooting volume on plant growth. Func. Plant Biol. 39: 839-850.
15.Mohamadinea, G., Hosseini Farahi, M. and Dastyaran, M. 2015. Comparisonof humic acid soil drench and foliar application on fruit set, yield and quantitative and qualitative propertiesof grape cv Askari. Agric. Comm.3: 2. 21-27.
16.Sabouri, F., Siroosmehr, A.R. and Gorgini Shabankareh, H. 2017. Effect of irrigation regimes and humic acid solution on some morphologicaland physiological characteristics ofSatureja hortensis. Iran. J. Plant Physiol. 9: 34. 13-24. (In Persian)
17.Nardi, S., Schiavon, M. and Francioso, O. 2021. Chemical structure and biological activity of humic substances define their role as plant growth promoters. Molecules. 26: 2256.
18.Zhang, J., Yin, H., Wang, H., Xu, L., Samuel, B., Chang, J., Liu, F. and Chen, H. 2019. Molecular structure-reactivity correlations of humic acid and humin fractions from a typical black soilfor hexavalent chromium reduction.Sci. Total Environ. 651: 2975-2984.
19.Canellas, L.P., Olivares, F.L., Aguiar, N.O., Jones, D.L., Nebbioso, A., Mazzei, P. and Piccolo, A. 2015. Humic and fulvic acids as biostimulants in horticulture. Sci. Hort. 196: 15-27.
20.De Hita, D., Fuentes, M., Fernández, V., Zamarreño, A.M., Olaetxea, M. and García-Mina, J.M. 2020. Discriminating the short-term action of root and foliar application of humic acids on plant growth:emerging role of jasmonic acid. Front. Plant Sci. 11: 493.
21.Osman, A.S. and Rady, M.M. 2014. Effect of Humic Acid as an Additive to Growing Media to Enhance the Production of Eggplant and Tomato Transplants. J. Hort. Sci. Biotechnol.89: 237-244.
22.Pascual, J., Ceglie, F., Tüzel, Y.,Koller, M., Koren, A., Hitchings, R. and Tittarelli, F. 2018. Organic Substrate for Transplant Production in Organic Nurseries. A Review. Agron. Sustain. Dev. 38: 35.
23.Qin, K. and Leskovar, D.I. 2020. Humic substances improve vegetable seedling quality and post–transplant yield performance under stress conditions. Agric. 10: 254-272.
24.Olaetxea, M., Mora, V., Bacaicoa, E., Baigorri, R., Garnica, M., Fuentes, M., Zamarreño, A.M., Spíchal, L. and García-Mina, J.M. 2019. Root ABA and H+-ATPase are key players in the root- and shoot growth promoting action of humic acids. Plant Direct. 3: 1-12.
25.Zanin, L., Tomasi, N., Cesco, S., Varanini, Z. and Pinton, R. 2019. Humic substances contribute to plant iron nutrition acting as chelators andbiostimulants. Front. Plant Sci.10: 675.
26.Shen, J., Guo, M., Wang, Y., Yuan, X., Wen, Y., Song, X., Dong, S. and Guo, P. 2020. Humic acid improves the physiological and photosynthetic characteristics of millet seedlingsunder drought stress. Plant Signal. Behav. 15: 8.
27.Blanco, F.F. and Folegatti, M.V. 2003. A new method for estimating the leaf area index of cucumber and tomato plants. Hortic. Bras. 21: 666-669.
28.Bahadur, A., Lama, T.D. and Chaurasia, S.N.S. 2015. Gas exchange, chlorophyll fluorescence, biomass production, water use and yield response of tomato (Solanum lycopersicum) grown under deficit irrigation and varying nitrogen levels. Indian J. Agric. Sci. 85: 224-228.
29.Huang, P., Santos, B.M. and Whitaker, V.M. 2011. Effects of Cell Size on the Production of Containerized Strawberry Transplants in Florida (FSHS). 124: 184-187.
30.Leskovar, D.I. and Othman, Y.A. 2016. Low nitrogen fertigation promotes root development and transplant quality in globe artichoke. Hort. Sci. 51: 567-572.
31.Di Benedetto, A. and Pagani, A. 2012. Changes in dry weight accumulation in the Impatiens walleriana pot plant in response to different pre–transplantplug cell volume. Eur. J. Hort. Sci.78: 2. 76-85.
32.Kazemi, M. 2013. Vegetative and reproductive growth of tomato plants affected by calcium and humic acid. BEPLS. 2: 11. 24-29.
33.Di Benedetto, A. 2011. Root restriction and post–transplant effects for bedding pot plants. In: Aquino, J.C. (ed.). Ornamental plants: Types, cultivationand nutrition. Nova Science Publishers, Inc. NY, USA.
34.Türkmen, Ö., Dursun, A., Turan, M. and Erdinç, Ç. 2004. Calcium and Humic Acid affect Seed Germination, Growth, and Nutrient Content of Tomato (Lycopersicon esculentum L.) Seedlings under Saline Soil Conditions. Acta Agric. Sci. Biol. Soil Plant Sci.54: 168-174.
35.Lotfi, R., Kalaji, H.M., Valizadeh, G.R., Khalilvand Behrozyar, E., Hamati, A., Gharavi-Kochebagh, P. and Ghassemi, A. 2018. Effects of humic acid on photosynthetic efficiency of rapeseed plants growing under different watering conditions. Photosynthetica. 56: 962-970.
36.Fan, H., Wang, X., Sun, X., Li, Y.,Sun, X. and Zheng, C. 2014. Effects of humic acid derived from sediments on growth, photosynthesis and chloroplast ultrastructure in chrysanthemum. Sci. Hort. 177: 118-123.
37.Naseri, M., Arouiee, H. and Mohammadi, M. 2021. The Effect of Concentration and Time of Application of Humic Acid on Morpho–physiological Characteristics of Spinacia oleracea. J. Hort. Sci. 34: 4. 663-678.
38.Kazemi, M. 2014. Effect of foliar application of humic acid and calcium chloride on tomato growth. BEPLS.3: 3. 41-46.
39.Bar Tal, A. and Pressmann, E. 1996. Root restriction and potassium and calcium solution concentrations affect dry–matter production, cation uptake, and blossom–end root in greenhouse tomato. J. Am. Soc. Hort. Sci. 121: 4. 649–655.
40.Fahimi, F., Souri, M.K. and Yaghobi, F. 2016. Growth and development of greenhouse cucumber under foliar application of Biomin and Humifolin fertilizers in comparison to their soil application and NPK. J. Sci. Tech. Greenhouse Culture. 7: 1. 143-152.(In Persian)