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Pelargonium zonale (L.) L'Hér. Ex Aiton) are appreciated worldwide due to their ornamental potential and versatility. The research was conducted to emphasize the evolution of morpho-decorative and qualitative traits of two geranium cultivars of high aesthetic value, namely ‘Tango Salmon’ (Montevideo) and ‘Tango Dark Red’, depending on two different fertilization, conventional-chemical fertilization, and unconventional scheme, with a homeopathic solution respectively. It is excessive repetitiveness and is not the case.) cultivar, unconventional fertilization scheme tested conducted to the best results regarding most morpho-decorative characters investigated (33.40 cm height, 21.10 leaves/plant, 34.75 flowers/inflorescence, 2.35% nitrogen, and 48.34 SPAD). For cultivar ‘Tango Dark Red’, the conventional fertilization conducted to the best results in terms of height (18.90 cm), stems/plant (5.90), leaves/plant (14.95), and flowers/inflorescence (37.55), while unconventional fertilization led to higher nitrogen accumulation (2.18%) and enhanced chlorophyll synthesis (47.08 SPAD). Between nitrogen and chlorophyll contents within geranium leaves, strong positive correlations were identified in ‘Tango Salmon’, and weak to moderate in ‘Tango Dark Red’ cultivar. Higher scores were attributed to aesthetic indicators for ‘Tango Salomon’ compared to ‘Tango Dark Red’. The unconventional fertilization of geranium cultivars is an eco-friendly solution for enhancing their morpho-decorative characteristics.


Introduction Introduction Introduction Introduction
The production of ornamental plants represents a horticultural sector in full development, which revel in appreciation within national and international profile markets. Its structure includes a wide range of products, from ornamental plants grown for leaves, to plants grown for flowers, both for cut flowers and potted, from nurseries, to greenhouse crops, etc. It is considered that the largest consumer market for ornamental plants is Europe, whereas the European countries with the largest commercial flow reported for this product category et al., 2021). In this respect, one may note that unconventional alternatives for peat replacing with compost in geranium greenhouse culture are currently proposed (Gong et al., 2018;Massa et al., 2018).
The application of homeopathic products, in accordance with the Homeopathic Pharmacopoeia guidelines established by Hahnemann in 1810 (Mukerji and Erns, 2022), contributed to introducing agroecological practices as an alternative to conventional agriculture (Andrade et al., 2011). The homeopathic approach includes the disintegration of radiation and matter, without nuclear rupture, but through the mechanical action on smaller particles and the addition of inert substances with dynamic activity (Bonato, 2008). Agricultural homeopathy, also known as the application of homeopathy in agriculture and horticulture, presents an ecologically and economically sustainable approach that has the potential to decrease the reliance on chemicals in global farming practices. The homeopathy practices contribute to enhancing internal processes in plants, thereby optimizing their growth and development. Empirical evidence in various crops has scientifically validated the capability of homeopathic products to modify the physiological response of plants, increase foliage abundance, flowering, and enhance fruit yield (Mazón-Suástegui et al., 2020). The use of the homeopathic method in plant production allows influencing the biological processes of plants, either to accelerate or to delay growth. Moreover, used as fertilizers directly promote increased production. In agriculture, homeopathic products are defined as remedies prepared from diseased tissue or disease products, but are not chemically characterized. They can be derived from products of animal, human or vegetable origin. They can be complex compounds, resulting from pathological secretions or excretions, infected tissues, or simple compounds, such as pure including corn. Additionally, other homeopathic treatments with Calcarea carbonica, Carbo vegetabilis, and Magnesia carbonica are recommended due to their potential to produce beneficial responses in plants (Mazón-Suástegui et al., 2020). Thus, testing homeopathic products in ornamental plants production as growth promoters is a challenging opportunity.
Considering all these, the current research was conducted for testing conventional and unconventional fertilization strategies for obtaining improved morpho-decorative traits in two cultivars of geraniums, 'Tango Salmon' (Montevideo) and 'Tango Dark Red' respectively, considered as very decorative.

Experimental
Experiments regarding the influence of fertilization upon morpho-decorative characteristics of P. zonale plants were carried out in the greenhouse of the Horticultural Research Institute of Transylvania (ICHAT), whereas the chemical analyses were carried out in the Environmental Quality Monitoring Laboratory of the Faculty of Agriculture, both within the University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca. Experiments were organized in two successive years, 2019 and 2020 respectively, the plants being maintained in similar conditions, according to the same experimental scheme (green house temperature 18-21 °C, humidity 60-65%).

Plant material
The biological material was represented by two cultivars of P. zonale as follows: 'Tango Salmon' and 'Tango Dark Red', selected for the general appreciation of the decorative traits and their adaptability. The 'Tango Salmon' cultivar has an average height of 27 cm, slightly fragrant salmon-pink inflorescences at the ends of the stems, which appear for a long period, from late spring to early autumn ( Figure 1). The palmate-round leaves are strong, remain green, with prominent brown stripes, throughout the year. The fruit is of no ornamental importance. The mature plant does not require special care. This plant grows very well in both full sun and partial shade conditions. It requires medium humidity conditions, but does not tolerate excess water. It is not picky about soil type or soil pH. It is extremely tolerant to urban pollution.

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The cultivar 'Tango Dark Red' can grow to an average height of 20-30 cm, has dark red, slightly fragrant, large inflorescences ( Figure 1). The flowering period lasts from late spring to early autumn. Its leaves are palmate-round, strong, and remain green with prominent brown stripes throughout the year. They are sensitive, mainly to the attack of Botrytis cinarea Pers. which produce the disease called 'grey rot' and Puccinia pelagronii-zonalis Doidge which causes the disease called 'leaf rust', especially when excessive nitrogen fertilization is applied.  In each experimental year, the vegetal material was purchased (Syngenta Romania). After reception on 10 March each year, geranium cuttings with four fully grown leaves were placed in plastic pots with a capacity of 1.5 L each, and a diameter of 12 cm. Pindstrup peat was used as soil substrate.

Fertilization
Conventional fertilization was carried out with an approved product (15% N, 11% P2O5, 29% K2O, 0.12% Fe, 0.06% Mn, 0.02% B, 0.015% Cu, 0.01% Mo, 0.015% Zn 15-11-29 + Trace Elements (TE)), being considered chemical fertilization. On the other hand, a mixture of homeopathic natural products known as Schuessler Salts was used for the unconventional foliar fertilization, as an alternative solution. The product was developed by Dr. Wilhelm Heinrich Schuessler, a German physician from the 19 th century, who made a significant discovery regarding the health benefits of various mineral salts and developed a homeopathic approach to utilize these mineral salts, allowing for their assimilation by the body's cells. This approach is based on twelve fundamental remedies specifically formulated for biochemical treatments, namely: calcium fluoratum, calcium phosphate, iron phosphate, potassium chloride, potassium phosphate, potassium sulphate, magnesium phosphate, sodium chloride, sodium phosphate, sodium sulphate, silica, and calcium sulphate (Lennon and Rolfe, 2004). The salts were purchased from homeopathic pharmacies, as twelve separate liquid solutions. For applying the homeopathic treatment with Schuessler Salts, they were mixed in equal proportions previous each administration.

Trial organization
The research concerning the influence of the fertilization method (chemical and unconventional) on the morpho-decorative traits was organized as a bifactorial trial: factor 1, the geraniums' cultivar, with two graduations, 'Tango Salmon' and 'Tango Dark Red', while factor 2 was the fertilization method, with three graduations: unfertilized (control), conventional chemical fertilization, in a dose of 1-2 g/L weekly, by drip, and unconventional fertilization with the above mentioned mixture of homeopathic natural products (in a dose of 5 mL/L tap water). The foliar application was done weekly for all variants, for 12 weeks, from the moment of cuttings' plantation up to complete flowering ( Figure 2).
After 12 weeks from cuttings plantation, when plants reached maturity, the following parameters were determined: plant height (cm), number of stems, number of leaves and number of flowers/inflorescences, the concentration of nitrogen (%) and chlorophyll (SPAD), which were determined from the leaf tissue of the plants. Total nitrogen was determined by the Kjeldahl method (Șara and Odagiu, 2005). The estimation of leaf chlorophyll concentration was performed using the non-destructive method with SPAD-502 device (Konica-Minolta, Tokyo, Japan); SPAD values were determined by measuring the ratio of light transmitted through the leaf at the UV wavelength 650 nm and the infrared wavelength 940 nm. All determinations were expressed as multi-year averages, for each variant.
In view of the aesthetic assessment, three parameters were considered, namely the vegetative growth, foliage compactness, and the general aspect. They were evaluated by assigning a score from 1 to 5, with the mention that the threshold value for commercialization was considered to be the one corresponding to the score of 3 (Brentari et al., 2020) ( Figure 2).

Statistical analysis
From the combination of the two factors (cultivar and fertilization treatments), six experimental variants were obtained, which were placed in randomized blocks, in three repetitions, with ten plants/repetition. The results were operated and expressed as means for the entire period of the investigation, in order to note the differences among the variants.
The IBM SPSS Statistics v.20 program for Windows was used to calculate the statistical parameters of interest corresponding to descriptive statistics (mean, standard error of the mean,), and the application of Least 6 Significant Differences analysis at 5% significance threshold (LSD5%). In order to determine the intensity of the interactions between the nitrogen content and chlorophyll determined from the leaf samples, the Pearson correlation coefficients and those of determination were calculated. The Pearson parametric test was chosen because the variability values (CV%) indicated the homogeneity of data and the representativeness of the means (Merce and Merce, 2009). The significance of differences was tested using Duncan test, using the XLSTAT program.

Results Results
Results and Discussion and Discussion and Discussion and Discussion For both geranium cultivars studied, the different fertilization schemes affected the morphological traits (Tables 1 and 2). The use of unconventional fertilization scheme led to the best results of the most important morphological traits, in regard with the decorative impact, analysed for 'Tango Salmon' cultivar: plants had 33.40 cm height and 34.75 flowers/inflorescence, respectively. The number of stems was close to conventional fertilization, both significantly above the control variant (7 and 7.07 compared with 5.7 stems/plant). Even more, the lack of fertilization (control scheme) depressed the development of the above-mentioned traits compared to both fertilization schemes, even if the variability within the investigated features was not consequential (Table 1). According to the obtained results for 'Tango Salmon' cultivar, one may note that differentiated fertilization led to significant differences in plant height and number of flowers within inflorescence. Concerning the number of stems and leaves, significant differences were reported only between control and both conventional and unconventional fertilized variants (Table 1).  Ribeiro et al. (2000) obtained similar results with those obtained in the present study for 'Tango Salmon' cultivar. When solid waste compost was administered for fertilizing potted geraniums, in concentration of 10%, they obtained 16.30 leaves/plant (compared to 16.50 reported in our study in control), while with a concentration of 20%, 23.80 leaves/plant were noted (compared to 21.10 reported in our study when unconventional fertilization was applied). The administration of 40% solid waste compost conducted to 4.30 stems/plant (compared to 5.70 reported in our study in control S1), and when administered a concentration of 10%, there were 7.80 stems/plant (compared to 7.05 reported in our study when conventional scheme was applied). Corresponding to 40% solid waste compost fertilization, they reported 24.6 flowers/inflorescence (compared to 26.80 reported in our study in control), and when administered 20%, 37.70 flowers/inflorescence were obtained (compared to 37.55 reported in our study when conventional fertilization was applied).
In 'Tango Dark Red' cultivar, the use of conventional fertilization scheme led to the best results for all morphological traits (18.90 cm height, 5.90 stems/plant, 14.95 leaves/plant, and 37.55 flowers/inflorescence), while the lack of fertilization (control scheme) determined the decrease of values to above-mentioned characters. Significant differences depending on fertilization, in regard with the number of flowers/inflorescences resulted when LSD5% test was applied. For the plant height, the number of stems and 7 leaves, significant differences were reported only between control (unfertilized) and both conventional and unconventional fertilized variants (Table 2), while the number of flowers per inflorescence was superior and statistically assured for unconventional fertilization. Gong et al. (2018) reported higher values for plant height compared to both geranium varieties analysed in the hereby study, framing the trait within 39.98-61.51 cm, when waste compost and vermicompost as peat substitutes were used as growing media. Álvarez-García et al. (2019) obtained as average plant height within 23.10-26.00 cm, when fish production waste water mixed with nutrient solutions in different concentrations were used as fertilizer, while Massa et al. (2019) obtained an average plant height within 24-31 cm using green compost for peat substitution. These height intervals emphasize lower means compared to those reported in the current investigation for 'Tango Salmon' (Montevideo), 25.24-33.40 cm, but superior compared to those obtained in 'Tango Dark Red' cultivar, 15.49-18.90 cm, respectively. Concerning the foliage, Álvarez-García et al. (2019) also reported averages framing within 24.80 -30.80 leaves/plant, which emphasizes much higher values compared to those we reported in 'Tango Salmon' and 'Tango Dark Red' geranium cultivars. Schroeter-Zakrzewska et al. (2021) reported averages framing within 9.9 -18.9 leaves/plant when they used compost from post-consumer wood for P. zonale cultivation.
Superior nitrogen valorisation and intensification of chlorophyll synthesis were reported analysing 'Tango Salmon' geranium cultivar cultivated under the proposed unconventional fertilization scheme, which is confirmed by the higher nitrogen mean (2.35%), accompanied by higher chlorophyll mean (48.34 SPAD) contents, compared to means corresponding to other experimental schemes. The same evolution was also observed in 'Tango Dark Red' cultivar, with highest nitrogen (2.18%), and chlorophyll (47.08 SPAD) mean contents corresponding to unconventional fertilization scheme (Table 3).
Analysing nitrogen and chlorophyll contents in both geranium cultivars, results that different fertilization strategies led to significant differences. Concerning chlorophyll content reported in 'Tango Salmon' and nitrogen content quantified in 'Tango Dark Red', significant differences were observed between control unfertilized on one hand, and both conventional and unconventional fertilized, on the other hand. Similar results were obtained by Conversa et al. (2015) in a study conducted on 'Pinnacle Dark Red' geranium cultivar. Using unconventional fertilization (with biochar), they obtained superior mean for nitrogen accumulation in leaves compared to the mean reported when conventional fertilization was applied (1.71% versus 1.63%). Massa et al. (2018), when conducted a trial with two different compost fertilization schemes, obtained a mean nitrogen bioaccumulation in foliar apparatus framing within 2.47% -2.86%, which is slightly superior compared to the levels obtained in present research. Nevertheless, superior values concerning chlorophyll content (47.16 SPAD -65.63 SPAD) compared to those reported in our research were emphasized by Brentari et al. (2020), in an experiment conducted on hydroponic culture of P. zonale.
It is well known that there is a linear relationship of different intensity between chlorophyll and nitrogen content in plant leaves, function of species, and/or culture management (Zanin and Sambo, 2006;Papasavvas et al., 2008;Bojović and Bojović, 2009;Güiza-Castillo et al., 2020). Studies in the field emphasize that the use of SPAD-meter may be considered as a useful approach for assessing nitrogen levels from plants' leaves (Balasubramanian et al., 1999;Duttarganvi et al., 2014;Saberioon et al., 2014), which is the benefit of plant growth thereafter.
According to our study, strong simple and positive Pearson correlations were identified between nitrogen and chlorophyll contents of geranium leaves in 'Tango Salmon' cultivar, framing within R = 0.827 and R = 0.881, corresponding to control and conventionally fertilized variants ( Figures 1A-1B) respectively. According to the values of the coefficient of determination, considering nitrogen independent variable, results that in the variant of control (unfertilized), 68.30% of variance in chlorophyll content is supposed to be predicted by nitrogen content in leaves, while 31.70% cannot be explained by the dependence described by the simple Pearson correlation. In conventionally fertilized variant, 77.60% of variance in chlorophyll content can be predicted by nitrogen content in leaves ( Figures 3A-C). Wang et al. (2012b) reported coefficients of determinations of 0.861 and 0.950 in two geranium cultivars 'Horizon deep Red' and 'Horizon Tangerine' respectively, which were higher compared with those reported in the hereby research (R 2 = 0.683 -0.776), while similar values were found by Wang et al. (2012a) in 'Rocky Mountain White' (R 2 = 0.629) and 'Rocky Mountain Dark Red' (R 2 = 0.672) cultivars.
Unlike the previous detailed geranium cultivar, in 'Tango Dark Red' moderate and weak simple positive Pearson correlations were identified between nitrogen and chlorophyll, which framed within R = 0.202 -0.445, corresponding to unconventionally fertilized and control variants. Considering nitrogen independent variable, results that in control unfertilized 19.80% of variance in chlorophyll content was predicted by nitrogen content in leaves, while in unconventionally fertilized variant, only 4.10% of variance in chlorophyll content was predicted by nitrogen content in leaves ( Figures 3D-1F). The correlations emphasized by the current research are weaker compared to those reported by Dunnet et al. (2015), who identified correlated 9 relationships between nitrogen and chlorophyll contents between 0.402-0.962, function of N fertilization rate in Pelargonium × hortorum L.H. Bailet planted in pots.
The aesthetic assessment emphasizes no significant differences (Duncan test, p>0.05%) between scores corresponding to conventional and unconventional fertilization, whereas when compared to control (unfertilized), the differences were significant (Duncan test, p<0.05%) for both geranium cultivars (Table 4).  Legend: The data are presented as mean values and standard error of the mean (mean ± S.E.). Different letters between means within different fertilization scheme denote significant differences (LSD test, p<0.05; F-Fisher coefficient).
No significant differences (Duncan test, p>0.05%) between aesthetic scores were attributed to the investigated geranium varieties cultivated according to different fertilization schemes (Figure 4).   Figure 4. Figure 4. The comparative aesthetic assessment of geranium cultivars depending on different fertilization schemes; aesthetic scores were used (scale 0-7) C-control; CF-conventional fertilization; UF-unconventional fertilization; the same letter between cultivars denotes not significant differences (Duncan test, p>0.05) All aesthetic indicators valuable for commercialization, whatever fertilization scheme, received within the hereby investigation higher scores for 'Tango Salomon' compared to 'Tango Dark Red' geranium cultivar. In unfertilized plants of both geranium cultivars investigated, lower scores were reported, compared to those noted when fertilization schemes were applied. Nevertheless, the positive influence of both fertilization schemes on general aesthetic value of plants is worth considering. In the meantime, the results emphasize a more appropriate influence of the unconventional fertilization. Brentari et al. (2020) reported arithmetic means between the scores of the aesthetic indicators function of cultivation system, framing within 3.30-4.27, when P. zonale plants were cultivated in three low-tech soil-less systems. Their interval of results was narrower compared to those reported in the current study in both analysed geranium varieties, 3.3-4.6 in 'Tango Salmon', and 3.1-4.4 in 'Tango Dark Red', respectively. If for geranium cultivars cultivated in current study higher maximum average score was reported, to 'Tango Dark Red' variety corresponds a lower arithmetic mean of 3.1 compared to that reported by Brentari et al. (2020), of 3.3, respectively. Thus, it can be said that ecological impact, cost correlation and the ease of supply or use of fertilization scheme can be taken into consideration for a sustainable cultivation of geraniums.

Conclusions Conclusions Conclusions Conclusions
The morpho-decorative characters of 'Tango Salomon' and 'Tango Dark Red' geranium varieties analysed differ significantly depending on the fertilization scheme applied. The unconventional fertilization approach conducted to better results concerning nitrogen assimilation, chlorophyll synthesis, and aesthetic traits in both geranium cultivars. The plants' height, number of stems/plants, leaves/plant, and flowers/inflorescence were all advantaged when using the unconventional fertilization scheme in 'Tango Salomon' geranium variety, while in 'Tango Dark Red' variety when conventional scheme was applied. 'Tango Salomon' variety was defined by better performances in terms of the majority of investigated traits, except the number of flowers/inflorescences. Better nitrogen valorisation and chlorophyll yield, strongly correlated, characterized 'Tango Salomon' geranium cultivar. The results emphasized in the hereby study is in accordance with those resulted from other research performed on different geranium varieties. According to the research, the use of unconventional solutions for fertilizing geranium has noticeable performances and represents a good option for replacing the conventional approach. Ethical approval Ethical approval Ethical approval Ethical approval (for researches involving animals or humans) Not applicable.