Saffron Agronomy and Technology

Saffron Agronomy and Technology

The effect of foliar application of potassium nitrate and forchlorfenuron on carbohydrate allocation and some physiological and biochemical traits of saffron plant

Document Type : Research Paper

Authors
Nasim Rezvani 1
Majid Poorusef 2
afshin tavakoli 2
1 Ph.D. Student of Agronomy, Department of Plant Production and Genetics, Faculty of Agriculture, University of Zanjan, Zanjan, Iran.
2 Associate Prof., Department of Plant Production and Genetics, Faculty of Agriculture, University of Zanjan, Zanjan, Iran.
10.22048/jsat.2025.481279.1544
Abstract
Saffron is one of the most popular and well-known spice and medicinal plant species in the world. Limited information is available regarding the nutritional properties and allocation of phytochemicals in this plant. The aim of this study is to evaluate the impact of different concentrations of forchlorfenuron and potassium nitrate on the accumulation of carbohydrates and starch metabolism in saffron stigmas and corms. This experiment was carried out in a factorial design in a randomized complete block design at the research farm of Zanjan University. The first stage of foliar application was conducted in early February and the second stage in early March. In this study, traits such as soluble carbohydrates and starch content in stigmas and corms, the activity of the enzyme beta-amylase in stigmas and ADP-glucose pyrophosphorylase (AGP) enzyme in corms, stomatal conductance and resistance, photosynthetic rate, sub-stomatal CO₂ concentration, chlorophyll a, b and total chlorophyll, anthocyanins, and flavonoids were measured. Additionally, the percentage of nutritional elements in stigmas and corms including nitrogen and potassium was determined. Based on the results, the interactive effect of forchlorfenuron at 5 mg/L with potassium nitrate at 500 mg/L resulted in increased nitrogen and potassium in the corms, stomatal conductance, photosynthetic rate, sub-stomatal CO₂ concentration, chlorophyll a, total chlorophyll, flavonoids, and soluble carbohydrates in the stigmas. Transpiration rate and anthocyanin levels were not influenced by the treatments. Nearly all treatments, with the highest response observed with forchlorfenuron at 5 mg/L in combination with potassium nitrate at 1000 mg/L, led to an increase in starch content in the corms. The activity of the enzyme ADP-glucose pyrophosphorylase in corms continuously increased with higher levels of CPPU and KNO₃, especially reaching 49.96 µmol/min/g protein with a treatment of 5 mg CPPU and 500 mg KNO₃. This indicates an increase in starch storage in saffron stigmas under these treatments. This study reveals significant insights into the role of CPPU and potassium nitrate on growth, nutrient absorption, carbohydrate metabolism, and allocation of phytochemicals in saffron. Treatment with 5 mg/L CPPU and 500 mg/kg KNO₃ significantly improved all physiological parameters examined. This treatment resulted in increased carbohydrate storage, improved nitrogen and potassium uptake in stigmas and corms, enhanced activity of the enzyme ADP-glucose pyrophosphorylase in corms, and considerable increases in the qualitative characteristics of saffron such as safranal, crocin, and picrocrocin. The results obtained can contribute to improving the weight and quality of saffron corms to increase flower production in field conditions.
Keywords
corm weight
daughter corm
number of flowers
nutritional elements
safranal
stigma

Subjects

Abdul Jaleel, C., Manivannan, P., Sankar, B., Kishorekumar, A., Sankari, S., & Panneerselvam, R. (2007). Paclobutrazol enhances photosynthesis and ajmalicine production in Catharanthus roseus.  Process Biochemistry, 42 (11), 1566–1570. https://doi.org/10.1016/j.procbio.2007.08.006.
Aitoubahou, A., & Elotmani, M. (2022). Saffron Cultivation in Morocco. Harwood Academic Publications, Amesterdam, Poland.
Akbarian, M. M., Heidari Sharifabad, H., Noormohammadi, G., & Darvish Kojouri, F. (2020). The effect of potassium, zinc and iron foliar application on the production of saffron (Crocus sativa L.). Annals of Biological Research, 3 (12), 5651-5658. (In Persian with English Abstract). https://doi.org/10.22077/jsr.2023.6083.1206.
Alsokari, S. S. (2017). Synergistic effect of kinetin and spermine on some physiological aspects of seawater-stressed    Vigna sinensis    plants. Saudi Journal of Biological Sciences, 18, 37–44. https://doi.org/10.1016/j.sjbs.2010.07.002.
Antognozzi, E., Battistelli, A., Famiani, F., Moscatello, S., Stanica, F & Tombesi, A. (2020a). Influence of CPPU on carbohydrate accumulation and metabolism in fruits of Actinidia deliciosa. Science Horticulture, 65, 37-47. https://doi.org/10.1016/0304-4238(95)00852-7.
Antognozzi, E., Famiani, F., Proietti, P., Ferranti, F., & Frenguelli, G. (2020b). Effect of CPPU (cytokinin) treatments on fruit anatomical structure and quality in Actinidia deliciosa.  Acta Horticulturae, 444, 459–465. https://doi.org/10.17660/ActaHortic.2020.444.67.
Antognozzi, E., Trainotti, L., & Dall'Aglio, E. (2010). The effect of CPPU on kiwi plants. Horticultural Science, 22 (1), 45-52. https://doi.org/10.17660/ActaHortic.1993.329.29.
Arnon, A. N. (1967). Method of extraction of chlorophyll in the plants. Agronomy Journal, 23, 112–121.
Arteca, R. N. (2020). Plant Growth Sustances Principles and Application. Translated by: Fathi, G., & smaielpour, B. Publications University of Mashhad. https://doi.org/10.1007/978-1-4757-2451-6.
Asthir, B., Kaur, A., & Basra, A. S. (1998). Do phytohormones influence the uptake and metabolism of sucrose in spikelets of wheat? Phyton - Annales Rei Botanicae, 38, 293–299. https://doi.org/10.13930/j.cnki.cjea.2011.02.018.
Ballicora, M. A., Iglesias, A. A., & Preiss, J. (2003). ADP-Glucose pyrophosphorylase: A regulatory enzyme for plant starch synthesis. Photosynthesis Research, 79 (1), 1-24. https://doi.org/10.1023/A:102584550.
Bandyopadhyay, K. K., Pradhan, S., Singh, R., Aggarwal, P., Sutradhar, A. K., & Joshi, D. K. (2021). Effect of irrigation levels and nitrogen sources on growth, yield, and input use efficiency of soybean in a sandy loam soil of a semi-arid environment. Journal of Agricultural Physics, 13 (3), 153–159. https://doi.org/10.5958/2349-4433.2021.00029.3.
Battistelli, J. P., Pedroso, M. C., Schultz, T., Jolan, B., & Amoril, J. (2010). The effect of different concentrations on the induction of apoptosis. Journal of Plant Physiology, 12 (3), 245-252. https://doi.org/10.1016/j.jplph.2010.03.010.
Behdani, M. A., Zamani, Gh., Fallahi, H. R., Sayyari Zohan, M. H., & Samadzadeh, A. (2018). Evaluation of replacement corms growth criteria of saffron in response to different organic and conventional production systems. Journal of Saffron Agriculture & Technology, 5 (2), 133-147. (In Persian with English Abstract). https://doi.org/10.22048/jsat.2016.40887.
Borzenkova, R. A., & Pozdeeva, A. A. (1998). Effect of phytohormones on starch synthesizing capacity in growing potato tubers. Russian Journal of Plant Physiology, 45, 472–480. https://doi.org/10.1007/978-1-4757-2451-6.
Borzenkova, R. A., & Borovkova, P. (2003). Developmental patterns of phytohormone content in the cortex and pith of potato tubers as related to their growth and starch content. Russian Journal of Plant Physiology, 50 (1), 119-124. https://doi.org/10.1023/A:1021957022595.
Carroll, N. V., Longley, R. W., & Roe, J. H. (1956). The determination of glycogen in liver and muscle by use of anthrone reagent. Journal of Biological Chemistry, 220, 583–593. https://doi.org/10.1016/S0021-9258(18)65284-6.
Chaji, N., Khorassani, R., Astaraei, A. R., & Lakzian, A. (2013). Effect of phosphorous and nitrogen on vegetative growth and production of daughter corms of saffron. Journal of Saffron Research, 1, 1–12. (In Persian with English Abstract). https://doi.org/10.22077/jsr.2013.352.
Chaji, N., Khorassani, R., Astaraei, A. R., & Lakzian, A. (2020). Effect of phosphorous and nitrogen on vegetative growth and production of daughter corms of saffron. Journal of Saffron Research, 1, 1–12. (In Persian with English Abstract). https://doi.org/10.22077/jsr.2013.352.
Chaurasiya, J., Verma, R. B., Ahmad, M., Adarsh, A., Kumar, R., & Pratap, T. (2016). Influence of plant growth regulators on growth, sex expression, yield and quality of Muskmelon (Cucumis melo L.). Journal of Plant Development Sciences, 22 (S), 39–43. https://doi.org/10.33545/2618060X.2024.v7.i1d.218.
De Juan, A., Moya, A., Lopez, S., Botella, O., Lopez, H., & Munoz, R. (2003). Influence of the corm size and the density of plantation in the yield and the quality of the production of corms of Crocus sativus L.  International Technology Education Association, 99, 169-180. https://doi.org/10.15835/nbha52213556.
DiCosmo, F., & Towers, G. H. N. (1984). Stress and secondary metabolism in cultured plant cells. In Timmermann, B. N., Steelink, C., & Loewus, F. A. (Eds.), Phytochemical Adaptations to Stress: Recent Advances in Phytochemistry (Vol. 18, pp. 97–175). Plenum Press, New York. https://doi.org/10.1007/978-1-4684-1206-2_5.
El-Shraiy, A. M., & Hegazi, A. M. (2010). Influence of JA and CPPU on growth, yield and α-amylase activity in potato plant (Solanum tuberosum L.). Australian Journal of Basic & Applied Sciences, 4 (2), 160–170. https://doi.org/10.13930/j.cnki.cjea.2011.02.018.
Flacher, B., & Arnold, H. (2016). The effect of CPPU on chlorophyll concentration in cucumber. Journal of Plant Physiology, 135 (2), 187-194. https://doi.org/10.1111/j.1399-3054.1990.tb05254.x.
Garrote, M. A., Robador, M. D., & Perez-Rodriguez, J. L. (2017). Analytical investigation of Mudéjar polychrome on the carpentry in the Casa de Pilatos palace in Seville using non-destructive XRF and complementary techniques.    Spectrochimica Acta Part A: Molecular & Biomolecular Spectroscopy, 173, 279–291. https://doi.org/10.1016/j.saa.2016.09.027.
Gashaw, A., Theerawitaya, C., Samphumphuang, T., Cha-um, S., & Supaibulwatana, K. (2019). CPPU elevates photosynthetic abilities, growth performances and yield traits in salt-stressed rice (Oryza sativa L. spp. indica) via free proline and sugar accumulation. Pesticide Biochemistry & Physiology, 108, 27–33. https://doi.org/10.1016/j.pestbp.2013.11.003.
Gholami, M., Kafi, M., & Khazaei, H. R. (2017). Study the relations of sink and source in saffron by means of correlation coefficients under different irrigation and fertilization levels. Saffron Agronomy & Technology, 5 (3), 195–210. (In Persian with English Abstract). https://doi.org/10.22048/jsat.2017.51480.1156.
Ghorbani Javid, M., Hosseini Fard, M., Alahdadi, I., & Soltani, E. (2022). Hormonal priming with BAP and GA3 induces improving yield and quality of saffron flower through promotion of carbohydrate accumulation in corm. Journal of Plant Growth Regulation, 41. (In Persian with English Abstract). https://doi.org/10.1007/s00344-020-10286-y.
Grossmann, K. (1990). Plant growth retardants as tools in physiological research.  Physiologia Plantarum, 78 (4), 640–648. https://doi.org/10.1111/j.1399-3054.1990.tb05254.x.
Gupta, P. K. (2000). Soil, Plant, Water and Fertilizer Analysis. Agrobios, New Delhi.
Häggman, J., & Haapala, H. (2008). The effect of 6-Benzylaminopurine on the starch metabolism of Stellaria media. Physiologia Plantarum, 24 (3), 548–551. https://doi.org/10.1111/j.1399-3054.2008.01015.x.
Hayata, Y., & Niimi, Y. (1995). Synthetic cytokinin-1-(2-chloro-4-pyridyl)-3-phenylurea (CPPU) promotes fruit set and induces parthenocarpy in watermelon.  Journal of the American Society for Horticultural Science, 120, 997–1000. https://doi.org/10.21273/JASHS.120.6.997.
Heidari, Z., Basharti, H., & Maleki Farahani, S. (2014). The effect of using some chemical and biological fertilizers on quantitative and qualitative characteristics of cultivated saffron. Saffron Agricultural & Technology, 2 (3), 177–189. (In Persian with English Abstract). https://doi.org/10.22067/saff.v2i3.25880.
Hossain, A. B. M. S., Alsaif, A. M., Rudayni, H. A., Al-Hashimi, A., Aleissa, M. S., & Taha, R. M. (2023). Carbohydrate, flavonoid, anthocyanin, total phenol, chlorophyll and mineral (K+) content development of wax apple fruit as affected by CPPU and NAA using swabbing technology. Revista Brasileira de Fruticultura, 45 (5), e-798. https://doi.org/10.6084/m9.figshare.23702115.v1.
Humphery, T. (2005). Evaluation of the New Active Forchlorfenuron in the Product Sitofex 10 EC Plant Growth Regulator. Australian Pesticides and Veterinary Medicines Authority. Australia. pp, 1-30.
Jabbari, M., Khayyat, M., Fallahi, H. R., & Samadzadeh, A. (2018). Influence of saffron corm soaking in salicylic acid and potassium nitrate on vegetative and reproductive growth and its chlorophyll fluorescence indices. Journal of Saffron Agriculture & Technology, 5 (1), 21-35. (In Persian with English Abstract). https://doi.org/10.22048/jsat.2017.38893.
Kano, Y. (2005). Comparison of the effects of 4-CPA and CPPU treatment on melon cell size and sugar accumulation. Environmental Control in Biology, 43 (2), 147–154. https://doi.org/10.1016/j.jplph.2007.02.001.
Karagüzel, O., Altan, S., Doran, I., & Söğüt, Z. (2017). The effects of GA3 and additional KNO3 fertilization on flowering and quality characteristics of Gladiolus grandifloras ‘Eurovision’. In Anac, D., & Martin-PrÉvel, P. (Eds.), Improved Crop Quality by Nutrient Management (Vol. 86, pp. 589–598). Springer. https://doi.org/10.1007/978-0-585-37449-9_59.
Kim, J. G., Takami, Y., Mizugami, T., Beppu, K., Fukuda, T., & Kataoka, I. (2016). CPPU application on size and quality of hardy kiwifruit. Scientia Horticulturae, 110, 219–222. https://doi.org/10.1016/j.scienta.2006.07.001.
Kishikawa, M., Takahashi, H., & Suzuki, Y. (2014). The effect of CPPU on potato plants. Agricultural & Crop Research, 15 (4), 567-575. https://doi.org/10.1088/1755-1315/1371/4/042009.
Kumar, R., Virendra S., Kiran, D., Sharma S., & Ahuja, P. S. (2019). State of art of saffron (Crocus sativus L.) agronomy: A comprehensive review. Food Reviews International, 25 (1), 44-85. https://doi.org/10.1080/87559120802458503.
Masclaux-Daubresse, C., Daniel-Vedele, F., Dechorgnat, J., Chardon, F., Gaufichon, L., & Suzuki, A. (2010). Nitrogen uptake, assimilation and remobilization in plants: challenges for sustainable and productive agriculture. Annals of Botany, 105, 1141–1157. https://doi.org/10.1093/aob/mcq028.
McCleary, B. V., & Codd, R. (1989). Measurement of beta-amylase in cereal flours and commercial enzyme preparations.    Journal of Cereal Science, 9, 17–33. https://doi.org/10.1016/S0733-5210(89)80018-9.
McCready, R. M., Guggolz, J., Silviera, V., & Owens, H. S. (1950). Determination of starch and amylase in vegetables.    Analytical Chemistry, 22, 1156–1158. https://doi.org/10.1021/ac60045a016.
Moscatello, S., Famiani, F., Spaccino, L., Giannella, R., Antognozzi, E., & Battistelli, A. (1995). Regulation of starch synthesis in kiwifruit: The effect of CPPU.  Giornale Botanico Italiano, 129 (4), 961–962. https://doi.org/10.1080/11263509509440881.
Nafah Amal, A. S., & Hegazi Amira, E. (2010). The effect of forchlorfenuron on growth, yield, and alpha-amylase enzyme activity of saffron (Crocus sativus L.) corms, 55 and 75 days after planting. Journal of Applied Sciences Research, 6 (10), 1438-1444. https://doi.org/10.22126/ATIC.2023.8410.1072.
Naghdibadi, H., Omidi, H., Golzad, A., Torabi, H., Fotoukian, M. (2011). Change in crocin, safranal and picrocrocin content and agronomical characters of saffron (Crocus sativus L.) under biological and chemical of phosphorous fertilizers. Journal of Medicinal Plants, 10 (40), 58-68. (In Persian with English Abstract). https://doi.org/20.1001.1.2717204.2011.10.40.7.4.
Nasiri Mahallati, M., Koocheki, A. S., & Boroumand Rezazadeh, Z. (2019). Investigation of the effect of weight and storage period of coriander on the allocation of photosynthetic materials in saffron. Iranian Journal of Crop Research, 5 (1), 155-166. (In Persian with English Abstract). https://doi.org/10.22126/ATIC.2023.8410.1072.
Ogweno, O., Hu, W. H., Song, X. S., Shi, K., Mao, W. H., Zhou, Y. H., & Yu, J. Q. (2021). Photoinhibition-induced reduction in photosynthesis is alleviated by abscisic acid, cytokinin, and brassinosteroid in detached tomato leaves.    Plant Growth Regulation, 60, 175–182. https://doi.org/10.1007/s10725-009-9439-z.
Omidi, F., Naghdi Badi, H., Golzad, A., Torabi, H., & Footoukian, M.H. (2009). The effect of chemical and bio-fertilizer source of nitrogen on qualitative and quantitative yield of saffron (Crocus sativus L.). Journal of Medicinal Plants, 2 (30), 98-109. (In Persian with English Abstract). https://doi.org/20.1001.1.2717204.2009.8.30.11.4.
Page, A. L., Miller, R. H.  & Keeney, D. O. (1982). Methods of Soil Analysis. Part 2, Chemical and Microbiological Properties. American Society of Agronomy, Soil Science Society of America, Madison. https://doi.org/10.4236/oalib.1100971.
Pallotti, C., Renau-Morata, B., Cardone, L., Nebauer, S. G., Albiñana Palacios, M., Rivas-Sendra, A., Seguí-Simarro, J. M., & Molina, R. V. (2024). The understanding of saffron corm development: Insights into histological and metabolic aspects.    Plants, 13 (8), 1125. https://doi.org/10.3390/plants13081125.
Parthasarathy, V. A., Barua, A., Nagaraju, V., & Utpala Parthasarathy. (2002). Effect of cytokinins on morphological, physiological and biochemical characteristics of shoots of citrus in vitro.  Fruits, 57, 153–160. https://doi.org/10.1051/fruits:2002026.
Patil, H. G., Ravindran, C., Jayachandran, K. S., & Jaganath, S. (2006). Influence of CPPU, TDZ, and GA3 on the postharvest quality of grape (Vitis vinifera L.) cultivars 'Anab-e-Shahi' and 'Dilkush'. Acta Horticulturae, 727, 489–494. https://doi.org/10.17660/ActaHortic.2006.727.60.
Penuelas, J., Gamon, J. A., Freeden, A., Merino, J., & Field, C. (1994). Reflectance indices associated with physiological changes in N and water-limited sunflower leaves. Remote Sensing of Environment, 46, 100–118. https://doi.org/10.1016/0034-4257(94)90136-8.
Preiss, J. (2020). Biosynthesis of starch and its regulation. In P. K. Stumpf & E. E. Conn (Eds.), The Biochemistry of Plants: A Comprehensive Treatise. Academic Press. 14, 181–254. https://doi.org/10.1016/B978-0-12-450514-6.50006-3.
Raddatz, N., Deeken, R., Ache, P., Hedrich, R., & Wilmsen, T. (2020). Coordinated transport of nitrate, potassium, and sodium. Frontiers in Plant Science, 11, 247. https://doi.org/10.3389/fpls.2020.00247.
Ramazan, A., Hafiz, I.A., Ahmad, T., & Abbasi, N.A. (2018). Effect of priming with potassium nitrate and dehusking on seed germination of gladiolus (Gladiolus alatus L.). Pakistan Journal of Botany, 42 (1), 247-258. https://doi.org/10.22126/ATIC.2023.8410.1072.
Renau-Morata, B., Nebauer, S. G., García-Carpintero, V., Cañizares, J., Minguet, E. G., de los Mozos, M., & Molina, R. V. (2021). Flower induction and development in saffron: Timing and hormone signalling pathways. Industrial Crops & Products, 164, 113370. https://doi.org/10.1016/j.indcrop.2021.113370.
Renau-Morata, B., Nebauer, S. G., Sánchez, M., & Molina, R. V. (2012). Effect of corm size, water stress and cultivation conditions on photosynthesis and biomass partitioning during the vegetative growth of saffron (Crocus sativus L.).  Industrial Crops & Products, 39, 40–46. https://doi.org/10.1016/j.indcrop.2012.01.015.
Rosin, F. M., Hart, J. K., van Onckelen, H., & Hannapel, D. J. (2003). Suppression of a vegetative MADS box gene of potato activates axillary meristem development. Plant Physiology, 131 (5), 1613–1622. https://doi.org/10.1104/pp.103.026828.
Saeed Akram, M., Ashraf, M., & Aisha Akram, N. (2009). Effectiveness of potassium sulfate in mitigating salt-induced adverse effects on different physio-biochemical attributes in sunflower (Helianthus annus L.). Journal of Flora, 204, 471-483. https://doi.org/10.1016/j.flora.2008.05.008.
Setia, N., Sangeetha, R., Setia, R. C., & Malik, C. P. (2015). Alterations in growth and yield response to foliar application of naphthyl acetic acid (NAA). Indian Journal of Plant Physiology, 36 (1), 47–52. https://doi.org/10.1007/s40502-015-0035-0.
Sharma, N., Kaur, N., & Gupta, A. K. (1998). Effect of chlorocholine chloride sprays on the carbohydrate composition and activities of sucrose metabolizing enzymes in potato (Solanum tuberosum L.).  Plant Growth Regulation, 26 (2), 97–103. https://doi.org/10.1023/A:1006087729077.
She, L. F., Xia, Y. P., Chang, L. Xiao, Y. M., Ren, Z. M. & Zhang, L. (2014). Biochemical and physiological responses of bulblets of Lycoris aurea to exogenously applied N-(2-chloro-4-pyridyl)-N1-phenylurea. The Journal of Horticultural Science & Biotechnology, 89 (5), 549-556. doi.org/10.1080/14620316.2014.11703179.
Silver, S. F., & Thompson, D. M. (2015). Measurement of photosynthesis and gas exchange in plants: Methods and applications. Photosynthesis Research, 125 (1), 1–14. https://doi.org/10.1007/s11120-015-0123-x.
Sritontip, C., Khaosumain, Y., Changjaraja, S., & Poruksa, R. (2015). Effect of potassium chlorate, potassium nitrate, sodium hypochlorite, and thiourea on off-season flowering and photosynthesis of ‘Do’ longan.    Acta Horticulturae, 665, 291–296. https://doi.org/10.17660/actahortic.2005.665.35.
Stander, O. P. J., Barry, G. H., & Cronjé, P. J. R. (2017). Fruit-load-induced starch accumulation causes leaf chlorosis in “off” ‘Nadorcott’ mandarin trees.  Scientia Horticulturae, 222, 62–68. https://doi.org/10.1016/j.scienta.2017.05.017.
Tabatabaeian, J., Hassanian Badi, S., Kadkhodaee, A. (2020). Effect of micronutrient foliar application on quantitative and qualitative traits of saffron (Crocus sativus L.). Saffron Agronomy & Technology, 8 (2), 147-163. (In Persian with English Abstract). https://doi.org/10.22048/jsat.2019.179188.1342.
Tezuka, T., Takahara, C., & Yamamoto, Y. (2012). Aspects regarding the action of CCC in hollyhock plants.  Journal of Experimental Botany, 40 (6), 689–692. https://doi.org/10.1093/jxb/40.6.689.
Verlinden, S., & Garcia, J. J. (2004). Sucrose loading decreases ethylene responsiveness in carnation (Dianthus caryophyllus cv. White Sim) petals. Postharvest Biology & Technology, 31 (3), 305–312. https://doi.org/10.1016/j.postharvbio.2003.09.010.
Wang, H. Q., & Xiao, L. T. (2009). Effects of chlorocholine chloride on phytohormones and photosynthetic characteristics in potato (Solanum tuberosum L.). Journal of Plant Growth Regulation, 28 (1), 21–27. https://doi.org/10.1007/s00344-008-9069-0.
Wang, H. Q., Li, H. S., Liu, F. L., & Xiao, L. T. (2009). Chlorocholine chloride application effects on photosynthetic capacity and photo-assimilate partitioning in potato (Solanum tuberosum L.). Scientia Horticulturae, 119, 113–116. https://doi.org/10.1016/j.scienta.2008.07.019.
Wang, Q. M. (2016). Effect of CPPU on growth and endogenous phytohormonne contents of balsam pear (Momordica charantia L.) fruit. Journal of Agriculture & Life Sciences, 5, 513–517. https://doi.org/10.3390/ijms18122555.
Watanabe, H. (1989). The use of growth regulators applied to stem cuttings of lilies. Bulletin of the Nara Agricultural Experiment Station, 20, 67–71.
Wu, W., Zhang, L., Li, J., & Wang, H. (2012). A report on wheat and kiwi. Journal of Agriculture & Food Chemistry, 60 (20), 5087-5094. doi.org/10.1094/CCHEM-03-12-0042-R.
Wu, X., Zhu, Z., Li, X., & Zha, D. (2012). Effects of cytokinin on photosynthetic gas exchange, chlorophyll fluorescence parameters and antioxidative system in seedlings of eggplant (Solanum melongena L.) under salinity stress. Acta Physiologiae Plantarum, 34, 2105–2114. https://doi.org/10.1007/s11738-012-1010-2.
Yakimova, E. T., Kapchina-Toteva, V. M., Groshkoff, I., & Ivanova, G. (2021). Effect of BA and CPPU on protease and α-amylase activity of in vitro cultured explants of Rosa hybrida L. Bulgarian Journal of Plant Physiology, 26 (1–2), 39–47. https://doi.org/10.22620/bjpp.2021.26.1-2.039.
Yang, Y. G., Zhang, H. S., Li, Y. L. & Yu, J. H. (2011). Endogenous hormone content in relation to thickening of carrot fleshy root during summer season in plateau region. Chinese Journal of Eco-Agriculture, 19, 342–346. https://doi.org/10.13930/j.cnki.cjea.2011.02.018.
Zabihi, H. R., Rezaeiyan, S., & Nouri Hosseini, S. M. (2013). Investigation of the effect of different levels and sources of potassium on the yield of saffron plant. First Regional Conference on Medicinal Plants of Northern Iran, Gorgan, Agricultural Research Center & Natural Resources of Golestan.
Zeng, H., Yang, W., Lu, C., Lin, W., Zou, M., Zhang, H., & et al. (2016). Effect of CPPU on carbohydrate and endogenous hormone levels in young Macadamia fruit. PLos One, 11 (7), e0158705. https://doi.org/10.1371/journal.pone.015870.
Zhang, S., Wang, L., Ma, F., Bloomfield, K. J., Yang, J., & Atkin, O. K. (2015). Is resource allocation and grain yield of rice altered by inoculation with arbuscular mycorrhizal fungi? Journal of Plant Ecology, 8 (4), 436–448. https://doi.org/10.1093/jpe/rtu017.
Zhang, Y., Vriesekoop, F., Yuan, Q., & Liang, H. (2008). Effects of naringin on the growth of four intestinal bacteria in vitro. Journal of Applied Microbiology, 105 (5), 1573-1580. https://doi.org/10.1111/j.1365-2672.2008.03882.x.
Zongeni. T, (2007). The role of cytokinins in plant growth and development. Journal of Plant Physiology, 124 (3), 345-358. https://doi.org/10.1016/j.jplph.2007.02.001.