Senna alata L., commonly known as Candle bush, belongs to the family fabaceae. It is an evergreen shrub reaching approximately 1.5 m in height; The leaves are pinnately compound, with multiple smooth, closely arranged leaflets and range in color from dark green to bluish-green, the plant produces distinctive yellow, candle-like inflorescences, which enhance its ornamental value in landscape design; The species is native to Mexico (Al-Batal, 2010). Candle bush is characterized by a relatively short and sturdy trunk with rough, fissured bark varying in color from gray to dark brown or black, the flowers develop in compact inflorescences and emit a strong fragrance that attracts pollinators, some species synthesize tannins in their leaves, resulting in a bitter taste when subjected to excessive grazing by animals, additionally, they may release volatile chemical signals that alert neighboring plants to initiate defensive responses (Al-Dab et al., 2019). Aloe vera gel is considered a natural bio stimulant rich in growth-promoting substances and is classified as an organic fertilizer containing biologically active compounds (Nephali et al., 2020). Its composition includes sugars, amino acids, fatty acids, vitamins and essential mineral elements such as Cu, Mg, K and P, as well as enzymes involved in oxidation-reduction processes (e.g., amylase and oxidase). It also contains amino acids (e.g., glycine and leucine) and vitamins B and C (Mengel and Kirkby, 1982; Yakhin et al., 2017). Furthermore, Aloe vera gel is reported to contain plant growth regulators, including auxins and gibberellins, in addition to root growth-stimulating compounds such as Salicylic acid (Al-Fatlawi et al., 2021; Surjushe et al., 2008). Previous studies have demonstrated that diluted Aloe vera gel can significantly enhance growth and yield in Salvia officinalis plants (Abbas et al., 2016). Similarly, an investigation evaluating different concentrations of Aloe vera gel (0, 1%, 30%, 60% and 100%) on the germination and growth of Moringa oleifera revealed that the 100% concentration significantly improved germination percentage (82.66%), germination index (4.99), vigor index (2230), plant height (42.11 cm) and number of branches (14.66) compared with the control treatment (Chachar et al., 2025). Moreover, it has been reported that Aloe vera gel provides essential nutrients required for spinach growth and contains biologically active compounds necessary for seed germination and seedling development of Moringa oleifera (Aamur et al., 2025). Plant Charcoal, a black and porous substance obtained by the combustion of wood that is understood to be a carbon-rich chemical transformation product, it has various forms such as wood charcoal, coal charcoal and bone charcoal and is defined as additional amendments to organic fertilizers from the decomposition of plant and animal residues (Abdl-Rhmaan and Hussein, 2026; René et al., 2024). Wood pyrolysis (The process of heating wood in an environment with limited or no oxygen) generates biochar, a key ingredient for improving soil characteristics and plant performance, it plays a role in enhancing the availability of carbon to aquatic flora, participates in processes vital for plant respiration and provides an element supply of microelements like cobalt and iron, moreover, it has been used as a biological stimulant to enhance plant growth, inhibit fungal and bacterial pathogens and cyanobacteria and boost chlorophyll content, in rose cultivation, pine wood Charcoal has been found to have significant benefits in increasing flower quality, using four concentrations (0, 25, 50 and 75%) showed that the 25%, 50% and 75% treatments were significantly higher than that of the control in electrical conductivity, carbon % and potassium + sodium concentrations in leaves, these treatments significantly increased flowering parameters (number and flower diameter) as well as vegetative growth (higher chlorophyll content), compared to the untreated control, alongside ensuring root accumulation of magnesium (Giancarlo et al., 2017). This study aims to know the role of different levels of Aloe vera gel and plant charcoal and their interaction in some vegetative and flowering characteristics of the Senna alata L. plant.

The experiment was conducted under a lath house structure in Agricultural Experiment Station affiliate the Department of Horticulture and Landscape Design, College of Agriculture, University of Kirkuk-Iraq, during the 25 January 2024-25 April 2025 growing seasons. The study utilized pots with a diameter of 30 cm and a weight of 7 kg, filled with a mixed soil medium (AL-Qadi et al., 2020), Some physical and chemical properties of the agricultural medium in which the plants were grown were measured after recycling the plastic pots (Table 1). Before planting, the soil was analyzed to determine its chemical and physical properties. Three-year-old Senna alata L. seedlings were then transplanted into the pots. One month after planting, two factors were applied: Foliar application of Aloe vera gel at four concentrations (0, 20, 40 and 80 g L^-1). The plants were sprayed twice with a 21-day interval between applications and soil amendment with Plant Charcoal at four levels (0, 10, 20 and 40 g pot^-1), so it was incorporated into the growing medium before transplanting. The experimental design included a total of 16 treatments (4 × 4 factorial arrangement) with three replications (3 × 4 × 4). The experiment was arranged according to a randomized complete block design (RCBD) and means were compared using the least significant difference (LSD) test at a 5% probability level (Al-Sahouki and Karima, 1990; Al-Fatlawi and Al-Bayati, 2021). The following traits were measured at flower color emergence.


 
• Vegetative traits: Plant height (cm), main stem diameter (mm), number of branches per plant^-1, number of leaves per plant^-1, leaf area (cm²) and chlorophyll content (%).
 
• Floral traits: Number of flowers per plant^-1, flower diameter (cm), floral stalk diameter (mm), days to flowering and flower dry weight (g).

Role of Aloe vera gel, plant charcoal and their interaction on vegetative and flowering traits of Senna alata L.
 
The result showed in Table 2(A), the application of Aloe vera gel significantly influenced the vegetative growth of Senna alata L. Plants treated with 80 g L^-1 exhibited superior performance compared with the control treatment, attaining a plant height of 190.83 cm, 170.41 leaves plant^-1, a leaf area of 160.2 cm² and a chlorophyll content of 54.33%. These findings indicate a pronounced stimulatory effect of the higher Aloe vera concentration on vegetative development. With regard to the Plant Charcoal  factor, which is shown in Table 2(B) regarding, the 40 g pot^-1 treatment resulted in significant enhancements in branching and leaf development. Plants under this treatment recorded 12.30 branches plant^-1, 169.40 leaves plant^-1, a leaf area of 140 cm² and a chlorophyll percentage of 49.40%, outperforming the control. According to Table 2(C) regarding the interaction between Aloe vera gel and plant charcoal treatments demonstrated a marked synergistic effect, the combined application of 80 g L^-1 Aloe vera gel and 40 g pot^-1 plant charcoal yielded the highest values across all evaluated vegetative traits, in comparison with the control treatment. According to Table 3(A), Aloe vera gel also exerted a significant effect on flowering characteristics. The 40 g L^-1 concentration promoted earlier flowering and increased flower diameter, reaching 222 days to flowering and 9.99 mm, respectively. In contrast, the 80 g L^-1 treatment produced the highest values for number of flowers, floral stem diameter and flower fresh weight, which reached 34.19 flowers plant^-¹, 9.12 mm and 39.40 g, respectively, relative to the control. According to Table 3(B) regarding plant charcoal applications, the 10 g pot^-1 level significantly accelerated flowering by 4.21 days compared with the control. Meanwhile, the 20 g pot^-1 treatment resulted in the greatest flower fresh weight (43.81 g). The 40 g pot^-1 level significantly improved the number of flowers, flower diameter and floral stem diameter, reaching 29.40 flowers plant^-1, 10.4 cm and 9.24 mm, respectively. According to Table 3(C) significant improvements in all studied flowering parameters were observed at 20 and 80 g L^-1 Aloe vera gel when combined with 40 g pot^-1 plant charcoal, in comparison with the control treatment.




       
The significant differences observed in most vegetative and flowering traits following the application of Aloe vera gel and the organic amendment plant charcoal to candle bush can be attributed primarily to improvements in soil physicochemical properties associated with organic inputs. The incorporation of organic materials enhances nutrient availability through gradual decomposition, thereby increasing soil fertility. This process stimulates microbial activity and biomass in the rhizosphere, which in turn improves soil structure, particularly porosity and aeration. Enhanced soil porosity facilitates nutrient uptake and root development, ultimately increasing the proportion of tender vegetative tissues and promoting overall plant vigor. These findings are consistent with previous reports (Alwan et al., 2023; Sajid, 2024; Fatmi, 2023; Al-Bayati et al., 2020). This is consistent with what was found by (Chachar et al., 2025; Aamur et al., 2025 and Srikanth et al., 2017).
       
The promotive effects of Aloe vera gel may also be linked to its role in modulating endogenous phytohormones, particularly auxins and cytokinins, which regulate cell division and differentiation. In addition, gibberellins are known to stimulate both cell division and elongation by activating genes involved in DNA synthesis and chromosomal replication, thereby enhancing enzymatic activity associated with cell proliferation and expansion (Krigas et al., 2021) Such hormonal regulation contributes to structural and functional modifications at the cellular level, leading to enhanced vegetative growth, as supported by earlier findings (El-Attar and Sakr, 2022). Furthermore, Aloe vera should improve carbon assimilation and energy metabolism, thus providing the biochemical resources for cell formation. Moreover, the enhanced production of carbohydrates, proteins and starch in leaves may promote assimilate accumulation and its subsequent translocation to developing floral organs. Such increased assimilate partitioning is probably the reason for the observed positive effects on plant height, leaf number and area and ultimately flowering performance (Steenkamp and Stewart, 2007). The plant charcoal improves the microbial activity and biological mass of the soil as organic fertilizer. The addition of organic matter enhances the physical and chemical properties of soil, increases water holding capacity and improves porosity. So, these improvements increase nutrient uptake efficiency and chlorophyll synthesis, with a significant number of positive influences on flower number, flower diameter and total leaf chlorophyll content (Abdl-Rhmaan and Hussein, 2026; Alkaç et al., 2023; Al-Bayati et al., 2023). This is consistent with what was found by (Giancarlo et al., 2017; Nasar et al., 2019 and Anjali et al., 2019).

1- Treatment with Aloe vera gel at 40 g L^-1 resulted in significant differences in all studied vegetative traits except for the number of branches. Regarding flowering traits, this treatment increased flower diameter and accelerated flowering, while the highest values for the number of flowers, floral stem diameter and flower fresh  weight were observed at 80 g L^-1 compared to the control.
2- Application of Plant Charcoal at 40 g pot^-1 induced significant differences in all vegetative traits except plant height. For flowering traits, early flowering occurred at 10 g pot^-1, while 20 g pot^-1 significantly increased flower fresh weight. Furthermore, the 40 g pot^-1 level significantly enhanced the number of flowers, flower diameter and floral stem diameter compared to the control.

This study was supported by the University of Kirkuk,Callage of Agriculture.
 
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Experiment on plants, not animals.

The authors declare that there are no conflicts of interest regarding the publication of this article. No funding or sponsorship influenced the design of the study, data collection, analysis, decision to publish, or preparation of the manuscript.