Effect of nitrogen forms on vegetative growth and flower development at hydroponically grown geraniums (Pelargonium zonale × Pelargonium peltatum)

Benedik, Lucija (author), Zamljen, Tilen (author), Osterc, Gregor (author)

Nitrogen is an essential macronutrient that greatly influences plant metabolism, growth and development. In plants, nitrogen is taken up in the form of nitrate (NO₃⁻) or ammonium (NH₄⁺), which affect plant physiology, root and shoot growth and the transition to generative phase differently. In this study we investigated the effect of nitrate and ammonium nitrogen forms on growth and development of hydroponically grown geranium plants. Rooted cuttings were cultivated in a floating hydroponic system with four treatments, differing in the nitrate-toammonium ratio in the nutrient solution. Treatment with an equal ratio of nitrate and ammonium resulted in greatest increase in shoot and root biomass, together with higher concentrations of chlorophyll a, and ammonium nitrogen in leaves. Treatment with 80:20 ratio (NO₃⁻: NH₄⁺) also had a positive effect on biomass production. Higher nitrate ratios (90%, 100%) promoted higher flowering intensity compared to the 50% nitrate treatment. These findings suggest that a proper ratio of nitrate and ammonium can positively influence growth by increasing shoot and root biomass and enhancing leaf production. The quality of hydroponically grown geraniums can be improved through the optimization of nitrogen form ratios in the nutrient solution.

• Language: English
• Keywords: hydroponics, geranium, nitrate, ammonium, growth, flowering, pigments
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: BF - Biotechnical Faculty
• Publication status: Published
• Publication version: Version of Record
• Year: 2026
• Number of pages: 7 str.
• Numbering: Vol. 365, art. 114979
• PID: 20.500.12556/RUL-184243
• UDC: 635
• ISSN on article: 0304-4238
• DOI: 10.1016/j.scienta.2026.114979
• COBISS.SI-ID: 283412227
• Publication date in RUL: 02.07.2026

Record is a part of a journal

• Title: Scientia horticulturae
• Shortened title: Sci. hortic.
• Publisher: Elsevier
• ISSN: 0304-4238
• COBISS.SI-ID: 5191687

Licences

• License: CC BY 4.0, Creative Commons Attribution 4.0 International
• Link: http://creativecommons.org/licenses/by/4.0/
• Description: This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.

Secondary language

• Language: Slovenian
• Keywords: hidroponika, okrasne rastline, pelargonije, potaknjenci, gnojenje, dušična gnojila, cvetenje, rast, pigmenti

Projects

• Funder: ARIS - Slovenian Research and Innovation Agency
• Project number: P4-0013
• Name: Hortikultura

• Funder: ARIS - Slovenian Research and Innovation Agency
• Project number: I0-0022
• Name: Mreža raziskovalnih infrastrukturnih centrov Univerze v Ljubljani (MRIC UL)