Influence of kaolin, calcium oxide, and boron trioxide sprays to reduce sunburn and enhance fruit productivity and quality in Murcott mandarin

Mosa, W., Alsakkaf, W., Sas-Paszt, L., and Ali, H. (2025). "Influence of kaolin, calcium oxide, and boron trioxide sprays to reduce sunburn and enhance fruit productivity and quality in Murcott mandarin," BioResources 20(4), 9606–9624.

Abstract

Climate change has increasingly disrupted the growth and development of many fruit crops. Among the associated challenges, sunburn caused by excessive light and solar radiation is a major physiological disorder affecting citrus and other fruit species. This study evaluated the potential of kaolin (KL), calcium oxide (CaO), and boric acid (B₂O₃) to mitigate sunburn and improve fruit set, yield, and quality in Murcott mandarin. Foliar sprays were applied at concentrations of 2000, 3000, and 4000 ppm KL, either alone or in combination with CaO and B₂O₃ at 0 CaO + 0 B₂O₃, 500 ppm CaO + 50 ppm B₂O₃, and 1000 ppm CaO + 100 ppm B₂O₃. Applications were performed four times during each season (mid-March, early July, early August, and early September) in 2023 and 2024. The results demonstrated that foliar application of KL, CaO, and B₂O₃ significantly increased fruit set, yield, and both physical and chemical quality attributes by reducing sunburn incidence across both study seasons. The most effective treatments were 4000 ppm KL + 500 ppm CaO + 50 ppm B₂O₃ and 4000 ppm KL + 1000 ppm CaO + 100 ppm B₂O₃.

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Influence of Kaolin, Calcium Oxide, and Boron Trioxide Sprays to Reduce Sunburn and Enhance Fruit Productivity and Quality in Murcott Mandarin

Walid F. A. Mosa ,^a,* Waleed A. A. Alsakkaf,^b Lidia Sas-Paszt ,^cand Hayssam M. Ali ,^b,*

DOI: 10.15376/biores.20.4.9606-9624

Keywords: Fruit quality; Kaolin; Productivity; Sunburn

Contact information: a: Plant Production Department (Horticulture-Pomology), Faculty of Agriculture, Saba Basha, Alexandria University, Alexandria 21531, Egypt; b: Department of Botany and Microbiology, College of Science, King Saud University, Riyadh– 11451, Saudi Arabia; c: The National Institute of Horticultural Research, Konstytucji 3 Maja 1/3, 96-100 Skierniewice, Poland;

* Corresponding author: walidmosa@alexu.edu.eg; hayhassan@ksu.edu.sa

INTRODUCTION

Fruit trees are highly vulnerable to environmental stresses, and the severity of these stresses has intensified in recent years due to climate change (Rachappanavar et al. 2022). Elevated temperatures impair photochemical activity and reduce light energy conversion efficiency, with excessive heat and radiation damaging the photosystems (Sun et al. 2018). Photosynthesis is particularly sensitive to high temperatures, leading to rapid declines under intense light conditions (Ahammed et al. 2018). During summer, when temperatures exceed 45 °C, sunburn damage can cause yield losses of up to 40% (Sarooghinia et al. 2020). The combined effects of strong solar radiation, high temperature, and low humidity trigger physiological disorders that markedly decrease fruit yield and quality (Kalcsits et al. 2017). Sunburn typically appears as peel discoloration and surface burns, progressing to large necrotic black patches on the fruit skin (Pareek et al. 2015).

Fertilizers and spraying of particle suspensions have emerged as promising strategies to enhance photosynthesis, improve leaf development, and promote overall plant vigor, while simultaneously reducing nutrient losses compared with conventional fertilizers. Their high efficiency not only improves yield and fruit quality but also minimizes negative environmental impacts such as soil pollution and nutrient leaching (Usman et al. 2020; Jakhar et al. 2022). Due to their small particle size and high absorption capacity, nanoparticles can improve nutrient delivery and uptake efficiency (Yadav et al. 2023).

Kaolin (KL) has been widely studied as a protective agent against abiotic stress. When applied as a foliar spray, KL forms a reflective barrier on leaves and fruits that lowers tissue temperature, mitigates solar radiation stress, reduces transpiration, and ultimately enhances fruit yield and quality (Glenn and Puterka 2010). KL reduces sunburn injury by reflecting ultraviolet and infrared radiation, without interfering with stomatal function or photosynthesis (Ergun 2012; Glenn 2012). In olive trees, KL application under water-limited conditions improved photosynthetic rates (Denaxa et al. 2012). Similarly, in mango, KL coatings alleviated high irradiance stress, decreased leaf temperature and vapor pressure deficit, and increased photosynthesis, gas exchange, fruit set, and total yield (Chamchaiyaporn et al. 2013). Other studies reported that KL improves plant growth, dry matter accumulation, and water use efficiency under stress, while reducing transpiration, tissue temperature, and leaf thickness (Segura-Monroy et al. 2015). As a natural clay mineral, KL acts as both a reflective agent and an antitranspirant, enhancing photosynthetic efficiency and stress tolerance (Ramírez-Godoy et al. 2018). It has been shown to reduce canopy temperature (Luciani et al. 2020), improve gas exchange under drought and salinity (Abdallah 2019), and alter biochemical traits such as soluble solids and anthocyanin levels in grapes (Cataldo et al. 2022; Brito et al. 2019).

Saure (2005) emphasized that calcium is crucial for membrane stability and cell integrity. It helps prevent chlorophyll degradation, improves trees’ nutritional quality by increasing chlorophyll content, leaf area, and water uptake, and enhances fruit nutrient levels. This, in turn, boosts photosynthetic efficiency, positively impacting vegetative growth and yield. Calcium, which is commonly applied as CaCl₂ or Ca(NO₃)₂, plays essential roles in plant growth, development, and stress responses. It supports photosynthesis by activating key metabolic enzymes (Akhtar et al. 2010), regulates auxin function, and promotes cell division, elongation, and pollen tube growth (Fageria 2009). In grape, calcium contributes to flowering, fruit set, cluster weight, and cell expansion (Bonomelli and Ruiz 2010). Preharvest CaCl₂ sprays reduce postharvest decay and physiological disorders (Madani et al. 2014), while enhancing antioxidant levels and secondary metabolites (Ghesmati et al. 2017; Vighi et al. 2019). Calcium strengthens the cell wall through the formation of Ca-pectate complexes, improving fruit firmness and delaying ripening (Zhang et al. 2019; Jaime-Guerrero et al. 2024). In addition, calcium regulates ethylene production, respiration, chlorophyll development, and senescence (Mounika et al. 2021). Calcium has shown promise in improving fruit yield (Gao et al. 2019), enhancing stress tolerance under salinity and drought (Nasrallah et al. 2022), and improving storage and shelf life (Zhou et al. 2018; Huang et al. 2023).

Boron (B) is another essential nutrient that plays critical roles in photosynthesis, stomatal conductance, carbohydrate metabolism, and reproductive development. Adequate boron supply improves photosynthetic efficiency, pollen germination, tube elongation, flowering, and fruit set (Sotiropoulos et al. 2002; Marschner 2012). Boron oxide (B₂O₃) is recognized as an essential factor in regulating the translocation of sugars and carbohydrates within plant systems. In olive (Olea europaea L.), boron deficiency markedly diminishes pollen viability, fruit set, and the normal differentiation of reproductive organs. Furthermore, insufficient boron availability compromises the mechanical stability of the leaf cuticle, frequently resulting in epidermal fissuring. Such structural impairments adversely affect stomatal functionality, thereby reducing their efficiency in the foliar uptake of nutrient solutions (Khayyat et al. 2007). Boron deficiency reduces cell division and photosynthetic activity, while affecting structural integrity of cell walls by limiting Ca–pectin binding (Ardic et al. 2009; Gupta and Solanki 2013). In various fruit crops, borax application improves fruit set, sugar transport, the metabolism of carbohydrates, nucleic acids, indole acetic acid, and phenols, seed development, and overall productivity (Xu et al. 2015; Mohammed et al. 2018; Shireen et al. 2018; Bons and Sharma 2023). It also enhances vitamin C and soluble protein content, maintains cell membrane integrity, and increases metabolic activity (Milagres et al. 2019; Xu et al. 2021; Li et al. 2023).

Given the importance of these nutrients, the present study was conducted to evaluate whether foliar application of kaolin, calcium, and boron compounds could mitigate sunburn damage in Murcott mandarin while improving fruit yield and quality.

Materials and Methods

Experimental site and applied treatments

The experiment was conducted during the 2023 and 2024 seasons on eight-year-old Murcott mandarin (Citrus reticulata) trees grafted onto Citrus volkameriana rootstock, spaced 4 × 5 m apart. The orchard was located in El-Nubaria, Beheira Governorate, Egypt, with trees grown in sandy soil under drip irrigation. Soil characteristics are presented in Table 1.

Sixty uniform trees were selected and subjected to the same cultural practices throughout both seasons. Treatments consisted of foliar sprays of kaolin (KL: 2, 3, or 4 g/L), calcium oxide (CaO: 0, 0.5, or 1 g/L), and boric acid (B₂O₃: 0, 50, or 100 mg/L), as well as an untreated control (Table 2). Sprays were applied four times each season: mid-March, early July, early August, and early September. Treatments were arranged in a randomized complete block design (RCBD) with five replicates (one tree per replicate), giving a total of 60 trees. Spray solution volume was 20 L per tree, prepared with tap water.

Fruit Set %, fruit drop %, and fruit number

At full bloom in April, the total number of flowers was recorded, and fruit set (%) was calculated (Eq. 1).

(1)

The fruit drop percentage was calculated by Eq. 2.

(2)

Fruit Yield (ton/ha)

Fruit yield (t/ha) was calculated by multiplying the average fruit weight per tree by the number of trees per hectare.

Table 1. Soil Analysis

Table 2. Weather Data during the Experimental Seasons of 2023 and 2024

Table 3. Applied Treatments

Physical fruit quality

Fruit length and diameter (cm) were measured using a digital Vernier caliper. Average fruit weight was recorded from 10 representative fruits. Fruit volume (cm³) was determined by water displacement in a 1000 mL graduated cylinder. Firmness (kg/cm²) was measured with a Magness–Taylor pressure tester. Sunburn incidence (%) was determined using Eq. 3:

(3)

Chemical fruit quality

Total soluble solids (TSS %) in the juice of fruits were measured by using a hand refractometer (ATAGO, Tokyo, Japan). Total acidity (%) was determined as citric acid/100 milliliters of fruit juice (AOAC 2005). The phenol-sulfuric acid method was used to estimate the total sugars by using 1.0 mL of sample treated with 1.0 mL of 5% phenol and 5.0 mL of concentrated H₂SO₄ and measured at 485 nm. Reduced sugars were estimated by using the 3,5-dinitro salicylic acid (DNS) method by using 2.0 mL of the sample and 1.5 mL of DNS at 80 °C for 10 min and measuring at 510 nm (Lam et al. 2021). The content of ascorbic acid was determined by titration using 2, 6-dichloro phenol indophenol (Nielsen 2017). Fruit carotene content was measured using the method of (Aquino et al. 2018) at a wavelength of 440 nm.

Nutritional Status

After harvesting the fruits in the 2023 and 2024 seasons, 40 leaves from the middle part of the shoots were collected from each tree (Arrobas et al. 2018). After washing the leaves very well with tap water, they were washed again with distilled water, dried at 70 °C until constant weight, and ground and digested using H₂SO₄ and H₂O₂until the solution became clear.

The nitrogen content was determined using the micro Kjeldahl method (Wang et al. 2016). The phosphorus content was measured using the Vanadomolybdo method (Wieczorek et al. 2022). Potassium content was determined using a flame photometer (Asch et al. 2022). Atomic absorption spectrophotometry was used to measure the content of Ca, and B.

Statistical Analysis

Data were analyzed by one-way analysis of variance (ANOVA) using CoHort Software 6.311 (Pacific Grove, CA, USA). Treatment means were compared using the least significant difference (LSD) test at the 0.05 probability level (Snedecor and Cochran 2021).

RESULTS

Fruit set percentage, fruit weight, fruit number, and overall yield were significantly improved by foliar spraying of KL in combination with calcium and boron compared with the control (Table 4; Fig. 1). The greatest increases were observed with treatment T12, followed by T11, T10, and T9, which all showed significant improvements over untreated trees in both seasons.

Table 4. Effect of the Foliar Spraying of Kaolin, CaO, and B₂O₃ on the Fruit Set %, Fruit Weight, and Number in Murcott Mandarin during 2023 and 2024

Fig. 1. The effect of the foliar spraying of KL, CaO, and B₂O₃ on the fruit yields in kg per tree and in ton per hectare in Murcott mandarin during 2023 and 2024 seasons

Fruit volume, length, and diameter were also significantly enhanced by KL + CaO + B₂O₃ applications (Table 5). Among the treatments, T12 produced the highest values, while T11 and T10 also markedly improved these parameters relative to the control.

Table 5. Effect of the Foliar Spraying of Kaolin, CaO, and B₂O₃ on the Fruit Volume, Length, and Diameter in Murcott Mandarin during 2023 and 2024

Fruit juice percentage and firmness increased significantly in trees treated with KL + CaO + B₂O₃ (Table 6). Treatment T12 achieved the greatest improvement, whereas T11, T10, and T9 also produced positive effects compared with untreated trees in both seasons. In contrast, sunburn incidence was markedly reduced by T12, T11, and T10, with moderate reductions observed in T9 and T8 compared to the control.

Table 6. Effect of the Foliar Spraying of Kaolin, CaO, and B₂O₃ on Sunburn and Fruit Juice Percentages, and Fruit Firmness in Murcott Mandarin during 2023 and 2024

Chemical fruit quality also responded positively to kaolin + CaO + B₂O₃. Total soluble solids (TSS), vitamin C, and carotene content were significantly increased, with T12 again being the most effective treatment (Table 7). T11, T10, T9, and T8 also showed substantial improvements compared with untreated trees. At the same time, fruit acidity was significantly reduced by all treatments, with T12 producing the greatest reduction across both seasons.

Table 7. Effect of the Foliar Spraying of Kaolin, CaO, and B₂O₃ on Fruit Total Soluble Solids, and Acidity Percentages, Vitamin C, and Carotene in Murcott Mandarin during 2023 and 2024

Sugar fractions were strongly affected by the treatments (Table 8). T12 and T11 significantly increased total sugars, reducing sugars, and non-reducing sugars, while T10, T9, T8, and T7 also enhanced sugar content relative to the control.

Leaf mineral composition was similarly improved (Table 9). Foliar sprays of KL + calcium + boron significantly increased leaf concentrations of N, P, K, Ca, and B compared with untreated trees. T12 consistently produced the highest nutrient contents, followed by T11, T10, T9, and T8.

Table 8. Effect of the Foliar Spraying of Kaolin, CaO, and B₂O₃ on Fruit Content from the Total, Reduced, and Non-reduced Sugars in Murcott Mandarin during 2023 and 2024

Table 9. Effect of the Foliar Spraying of Kaolin, CaO, and B₂O₃ on Leaf Content from Nitrogen, Phosphorous, Potassium, Calcium, and Boron in Murcott Mandarin during 2023 and 2024

DISCUSSION

In this study, foliar application of kaolin (KL), calcium oxide (CaO), and boron trioxide (B₂O₃) significantly reduced fruit sunburn, enhanced fruit set, and improved both yield and fruit quality of Murcott mandarin trees. The combined treatment (T12) was consistently superior across both seasons, indicating a strong synergistic effect of these elements on productivity and fruit quality traits.

The positive effects of KL observed here agree with previous findings that KL enhances crop performance under heat stress. KL forms a reflective particle film that lowers fruit and leaf surface temperature, mitigates water loss, and optimizes physiological processes such as stomatal conductance and photosynthesis (Glenn and Puterka 2010; Dinis et al. 2018; Brillante et al. 2016). Studies on pear, olive, grapevine, and citrus similarly reported that KL sprays reduce sunburn, improve fruit set, and enhance both physical and biochemical quality traits (Colavita et al. 2011; Brito et al. 2018; Gullo et al. 2020; Terán et al. 2024). These benefits stem not only from reduced heat load but also from improved water use efficiency and the stimulation of primary and secondary metabolism, which contribute to higher fruit size, juice content, vitamin C, carotene, and sugar levels. Applying KL particle film promotes both primary and secondary metabolic processes in grapevines, thereby enhancing berry quality. In addition, it has been employed as a short-term strategy for mitigating climate change, as its reflective properties toward ultraviolet and infrared radiation help decrease leaf temperature and improve photosynthetic performance by alleviating photoinhibition (Conde et al. 2018). KL helps reduce water loss from transpiration and maintains a relatively open rate of stomata, thereby ameliorating the plant water content (Brito et al. 2019). KL can lower leaf temperature by up to 6.7 °C, promoting stomatal opening, which in turn boosts photosynthesis and improves plant tolerance to intense light and heat (de Abreu et al. 2022). Applying KL at concentrations of 2%, 4%, and 6% significantly improved fruit set percentage, yield, fruit weight, and firmness, while simultaneously reducing sunburn incidence in pomegranate (Al-Saif et al. 2022). Foliar KL application provides key nutrients and improves soil moisture retention, while its reflective properties lower leaf temperature and reduce water loss, collectively supporting cell division, elongation, and overall growth (Vani et al. 2023). KL alleviates environmental stress by minimizing leaf damage and abscission, protecting carotenoids, elevating proline, chlorophyll, and gas exchange, and regulating key hormones like abscisic acid, salicylic acid, indole-3-acetic acid, and jasmonic acid to strengthen stress tolerance (Terán et al. 2024). KL sprays at 3 and 6 % on apple improved tree crown and volume, increased fruit weight, fruit length, firmness, and fruit soluble solids (Faghih et al. 2021), enhanced leaf area, chlorophyll, photosynthesis, gas exchange, internal CO₂, water-use efficiency, potassium status, and kernel yield/quality, while reducing leaf temperature, fruit drop, sunburn, and cracking in Persian walnut (Gharaghani et al. 2018). Spraying KL at 3 and 6 % on ‘Tardy Nonpareil’ Almond trees improved shoot growth, prevented premature leaf abscission, water use efficiency and tree yield, reduced leaf temperature by up to 3.25 °C, and it increased the photosynthesis rate and stomata conductance, tree yield, and nut attributes, under water deficit (Gharaghani et al. 2023).

Calcium oxide application also was found to play a role in enhancing fruit quality in this study. As background, it is known that each type of calcium salt produces a different pH in distilled water, influencing its solubility. Calcium citrate has a higher solubility than calcium carbonate in water, the difference is minimal at pH 7.5. The partial pressure of CO₂ reduced the solubility of calcium carbonate at pH 7.5. Soluble calcium calculations aligned with in-vivo data on absorbed calcium. The data highlight the influence of pH and CO₂ on the solubility of calcium salts in the presence of bicarbonate secretions in the intestine (Goss et al. 2007). Marschner (2012) noted that calcium plays a key role in binding proteins and polysaccharides in the cell wall, enhancing flowering, fruit maturation, and the transport of carbohydrates from leaves to fruits.

Calcium oxide spray enhances cell wall permeability, improving water and nutrient transport from leaves to fruits, which boosts fruit growth, maintains moisture balance between the peel and internal tissues, and preserves cell wall elasticity (Korkmaz and Askın 2015). Foliar CaCl₂ applications have been shown to improve fruit firmness, size, and storability by strengthening cell walls, maintaining water balance, and delaying senescence (Michailidis et al. 2020). The present results align with reports from pomegranate, apple, and kiwifruit where Ca sprays improved yield, fruit weight, soluble solids, and vitamin C while reducing acidity and sunburn (Ramírez-Godoy et al. 2018; Denaxa et al. 2023; Fahmy et al. 2023). The improvements in firmness and reduced sunburn incidence observed in the present study further support Ca’s protective role under environmental stress. CaCl₂ application in fruits helps maintain firmness and cell turgor, while preventing physiological disorders (Jain et al. 2019). The spraying of 100 and 200 CaCO₃ notably increased the stem thickness and plant height, which are essential for supporting the overall structure and stability of the plant, and this improvement can be attributed to Ca’s crucial role in maintaining cell wall integrity and promoting cell division and elongation (Nangare et al. 2020; Mogazy et al. 2022). Applying CaCl₂ at 1.5 and 2.0% on apple significantly improved fruit physical attributes such as fruit firmness, fruit diameter, length, weight, and size, fruit content from anthocyanin, phenols, TSS, acidity, starch content, and fiber content (Ranjbar et al. 2020). Spraying pomegranate trees cv. Wonderful with CaCl₂ at 2 and 3 % noticeably improved the fruit weight, number and fruit yield, fruit dimensions, as well as fruit content from soluble solids, and vitamin C, while it significantly reduced the fruit acidity, fruit drop percentages and fruit sunburn percentages (Fahmy et al. 2023). Calcium oxide (CaO), commonly called quicklime, is a white to grayish solid obtained by heating calcium carbonate to release carbon dioxide. At room temperature, it readily reabsorbs carbon dioxide from the air and reacts vigorously with water to form calcium hydroxide, Ca(OH)₂, releasing heat in the process—hence the term “quick,” or living, lime. This exothermic reaction has been used in portable heat sources. One of the oldest manufactured chemical products, quicklime is widely applied in construction, industrial neutralization processes, and occasionally as fertilizer, though calcium carbonate is generally preferred for agriculture. When water acts on CaO, it produces calcium hydroxide, also known as slaked lime. Only a small amount dissolves to yield limewater, while the remainder forms a suspension called milk of lime. Calcium hydroxide serves as an industrial alkali and a key ingredient in mortars, plasters, and cement. It also plays roles in the kraft paper process and in sewage treatment as a flocculant (Hanusa 2025).

Boron supplementation also contributed significantly to fruit set, retention, and overall productivity. Boron is essential for pollen germination, tube growth, sugar transport, and cell wall integrity, flower fertilization and ultimately improving the productivity (Davis et al. 2003; Bybordi and Malakouti 2006; Lewis 2019). Deficiency often results in flower drop, reduced fertilization, and lower leaf growth, root elongation, and yields (Han et al. 2008; Wang et al. 2015). The present findings agree with earlier reports by Ali et al. (2017), they noted that the external spraying of B₂O₃ at 0.2 and 0.3% improved the fruit set %, retained fruit number, fruit weight, pulp %, fruit productivity, fruit dimensions, and fruit content of chlorophyll, carotene, and vitamin C in mango and lowered the fruit drop percentage. Boron also has a vital role in cell structure and cell wall integrity (Lewis 2019) and in maintaining plasma membrane functions (Brown et al. 2002). The reduction in fruit drop from borax spraying may also be attributed to B’s indirect role in auxin synthesis, which delays the formation of the abscission layer during the early stages of fruit development, ultimately increasing the percentage of fruit retention (Gupta et al. 2022). Mosa et al. (2015) noted that the spraying of apple with B₂O₃at 0.2% markedly improved the shoot diameter, shoot length and leaf area, fruit set %, productivity, while it minimised the fruit acidity and fruit drop percentages. Spraying mandarin trees with borax at 0.04% boron remarkably improved the total flower and fruit set percentage and significantly reduced the flower and fruit drop percentages as compared to untreated trees (Ruchal et al. 2020). Sajid et al. (2024) reported that spraying B₂O₃ at 1% on three sweet cherry cultivars increased leaf area, fruit diameter, pulp %, total soluble solids, total sugars, fruit number, yield in kg, fruit set %, while it reduced the percentages of fruit drop and fruit acidity compared to untreated trees. Taken together, the combined application of KL, CaO, and B₂O₃ compounds improved both physiological efficiency and fruit quality traits in Murcott mandarin. KL primarily reduced heat and water stress, CaO enhanced cell wall strength and nutrient transport, and B₂O₃ optimized reproductive success and carbohydrate allocation. The synergistic effects of these treatments translated into higher fruit number, size, firmness, juice content, vitamin C, carotene, sugars, and leaf mineral concentrations.

These findings highlight the potential of integrated foliar sprays as an eco-friendly strategy to enhance citrus productivity and mitigate the negative impacts of abiotic stress. Further work should investigate the economic feasibility of large-scale adoption and the long-term effects of repeated applications on soil-plant interactions.

CONCLUSIONS

Foliar application of kaolin (KL) together with calcium oxide (CaO) and boron trioxide (B₂O₃) effectively mitigated the adverse effects of high temperature and solar radiation, reducing fruit sunburn and thereby increasing the proportion of marketable Murcott mandarin fruits.
The combined application of KL, CaO, and B₂O₃ compounds improved photosynthesis, fruit set, yield, and overall fruit quality.
The treatment with 4000 ppm KL + 1000 ppm CaO + 100 ppm B₂O₃ consistently produced the best results across all measured traits.

ACKNOWLEDGMENTS

The authors would like to extend their sincere appreciation to the Ongoing Research Funding Program (ORF-2025-123), King Saud University, Riyadh, Saudi Arabia.

Funding

This research was funded by Ongoing Research Funding Program (ORF-2025-123), King Saud University, Riyadh, Saudi Arabia.

Data Availability Statement

All the required data are included in the manuscript.

Conflicts of Interest

The authors declare no conflicts of interest.

REFERENCES CITED

AbdAllah, A. (2019). “Impacts of kaolin and pinoline foliar application on growth, yield and water use efficiency of tomato (Solanum lycopersicum L.) grown under water deficit: A comparative study,” J. Saudi Soc. Agric. Sci. 18(3), 256-268.

Ahammed, G. J., Xu, W., Liu, A., and Chen, S. (2018). “COMT1 silencing aggravates heat stress-induced reduction in photosynthesis by decreasing chlorophyll content, photosystem II activity, and electron transport efficiency in tomato,” Front. Plant Sci. 9, 998. DOI: 10.3389/fpls.2018.00998

Akhtar, A., Abbasi, N. A., and Hussain, A. (2010). “Effect of calcium chloride treatments on quality characteristics of loquat fruit during storage,” Pak. J. Bot. 42(1), 181-188.

Ali, M., Elhamahmy, M., and El-Shiekh, A. (2017). “Mango trees productivity and quality as affected by boron and putrescine,” Sci. Hortic. 216, 248-255. DOI: 10.1016/j.scienta.2017.01.026

Al-Saif, A. M., Mosa, W. F., Saleh, A. A., Ali, M. M., Sas-Paszt, L., Abada, H. S., and Abdel-Sattar, M. (2022). “Yield and fruit quality response of pomegranate (Punica granatum) to foliar spray of potassium, calcium and kaolin,” Horticulturae 8(10), article 946. DOI: 10.3390/ horticulturae8100946

AOAC International (2005). Official Methods of Analysis (18^th Ed.), Gaithersburg, MD, USA.

Aquino, C. F., Salomão, L. C. C., Pinheiro-Sant’ana, H. M., Ribeiro, S. M. R., Siqueira, D. L. D., and Cecon, P. R. (2018). “Carotenoids in the pulp and peel of bananas from 15 cultivars in two ripening stages,” Rev. Ceres 65, 217-226. DOI: 10.1590/0034-737X201865030001

Ardic, M., Sekmen, A.H., Tokur, S., Ozdemir, F., and Turkan, I. (2009). “Antioxidant responses of chickpea plants subjected to boron toxicity,” Plant Biol. 2009, 11, 328-338. DOI: 10.1111/j.1438-8677.2008.00132.x

Arrobas, M., Afonso, S., and Rodrigues, M. Â. (2018). “Diagnosing the nutritional condition of chestnut groves by soil and leaf analyses,” Sci. Hortic. 228, 113-121. DOI: 10.1016/j.scienta.2017.10.027

Asch, J., Johnson, K., Mondal, S., and Asch, F. (2022). “Comprehensive assessment of extraction methods for plant tissue samples for determining sodium and potassium via flame photometer and chloride via automated flow analysis,” J. Plant Nutr. Soil Sci. 185(2), 308-316. DOI: 10.1002/jpln.202100344.

Bonomelli, C., and Ruiz, R. (2010). “Effects of foliar and soil calcium application on yield and quality of table grape cv. ‘Thompson Seedless,” J. Plant Nutr. 33(3), 299-314. DOI: 10.1080/01904160903470364

Bons, H. K., and Sharma, A. (2023). “Impact of foliar sprays of potassium, calcium, and boron on fruit setting behavior, yield, and quality attributes in fruit crops: A review,” J. Plant Nutr. 46(13), 3232-3246. DOI: 10.1080/01904167.2023.2192242

Brillante, L., Belfiore, N., Gaiotti, F., Lovat, L., Sansone, L., Poni, S., and Tomasi, D. (2016). “Comparing kaolin and pinolene to improve sustainable grapevine production during drought,” PLoS One 11(6), article ID e0156631. DOI: 10.1371/journal.pone.0156631

Brito, C., Dinis, L.-T., Moutinho-Pereira, J., and Correia, C. (2019). “Kaolin, an emerging tool to alleviate the effects of abiotic stresses on crop performance,” Sci. Hortic. 250, 310-316. DOI:10.1016/j.scienta.2019.02.070

Brito, C., Dinis, L.-T., Silva, E., Gonçalves, A., Matos, C., Rodrigues, M. A., Moutinho-Pereira, J., Barros, A., and Correia, C. (2018). “Kaolin and salicylic acid foliar application modulate yield, quality and phytochemical composition of olive pulp and oil from rainfed trees,” Sci. Hortic. 237, 176-183. DOI:10.1016/j.scienta.2018.04.019

Brown, P. H., Bellaloui, N., Wimmer, M. A., Bassil, E. S., Ruiz, J., Hu, H., … and Römheld, V. (2002). “Boron in plant biology,” Plant Biol., 4(02), 205-223.

Bybordi, A. and Malakouti, M.J. (2006). “Effects of foliar applications of nitrogen, boron and zinc on fruit setting and quality of almonds,” Acta Hortic. 726, 2351-2358. DOI: 10.17660/ActaHortic.2006.726.56

Cataldo, E., Fucile, M., and Mattii, G. B. (2022). “Effects of kaolin and shading net on the ecophysiology and berry composition of Sauvignon Blanc grapevines,” Agriculture 12(4), article 491. DOI: 10.3390/agriculture12040491

Chamchaiyaporn, T., Jutamanee, K., Kasemsap, P., Vaithanomsat, P., and Henpitak, C. (2013). “Effects of kaolin clay coating on mango leaf gas exchange, fruit yield and quality,” Agric. Nat. Res. 47(4), 479-491. https://li01.tci-thaijo.org/index.php/anres/article/view/243088.

Colavita, G.M., Blackhall, V. and Valdez, S. (2011). “Effect of kaolin particle films on the temperature and solar injury of pear fruits,” Acta Hortic. 909, 609-615. DOI: 10.17660/ActaHortic.2011.909.73

Conde, A., Neves, A., Breia, R., Pimentel, D., Dinis, L.-T., Bernardo, S., Correia, C. M., Cunha, A., Gerós, H., and Moutinho-Pereira, J. (2018). “Kaolin particle film application stimulates photoassimilate synthesis and modifies the primary metabolome of grape leaves,” J. Plant Physiol. 223, 47-56. DOI: 10.1016/j.jplph.2018.02.004

Davis, J. M., Sanders, D. C., Nelson, P. V., Lengnick, L. and Sperry, W. J. (2003). “Boron improves growth, yield, quality, and nutrient content of tomato,” J. Am. Soc. Hortic. Sci., 128, 441-446.

de Abreu, D. P., Roda, N. D. M., de Abreu, G. P., Bernado, W. D. P., Rodrigues, W. P., Campostrini, E., and Rakocevic, M. (2022). “Kaolin film increases gas exchange parameters of coffee seedlings during transference from nursery to full sunlight,” Fron. Plant Sci. 12, article 784482. DOI:10.3389/fpls.2021.784482

Denaxa, N.-K., Roussos, P. A., Damvakaris, T., and Stournaras, V. (2012). “Comparative effects of exogenous glycine betaine, kaolin clay particles and Ambiol on photosynthesis, leaf sclerophylly indexes and heat load of olive cv. ‘Chondrolia Chalkidikis’ under drought,” Sci. Hortic. 137, 87-94. DOI: 10.1016/j.scienta.2012.01.012

Denaxa, N.-K., Tsafouros, A., Ntanos, E., Kosta, A., and Roussos, P. A. (2023). “Mitigation of high solar irradiance and heat stress in kiwifruit during summer via the use of alleviating products with different modes of action – Part 2. Effects on fruit quality, organoleptic, and phytochemical properties at harvest and after storage,” Agriculture 13(3), article 701. DOI: 10.3390/ agriculture13030701

Dinis, L.-T., Malheiro, A., Luzio, A., Fraga, H., Ferreira, H., Gonçalves, I., Pinto, G., Correia, C., and Moutinho-Pereira, J. (2018). “Improvement of grapevine physiology and yield under summer stress by kaolin-foliar application: Water relations, photosynthesis and oxidative damage,” Photosynthetica 56, 641-651. DOI: 10.1007/s11099-017-0714-3

Ergun, M. (2012). “Postharvest quality of ‘Galaxy’ apple fruit in response to kaolin-based particle film application,” J. Agric. Sci. Technol. 14(3), 599-607. URL: http://jast.modares.ac.ir/article-23-4511-en.html

Fahmy, E. F., El-Rhman, A., and El-Sayed, I. (2023). “Effect of hydrogel and foliar spray with potassium and calcium on the yield, fruit physical and chemical properties of Wonderful pomegranate,” Hortic. Res. J. 1(4), 107-119. DOI: 10.21608/hrj.2023.347327

Fageria, N. K. (2009). The Use of Nutrients in Crop Plants, CRC Press, Boca Raton, 2009.

Faghih, S., Zamani, Z., Fatahi, R., and Omidi, M. (2021). “Influence of kaolin application on the most important fruit and leaf characteristics of two apple cultivars under sustained deficit irrigation,” Biol. Res. 54, 1. DOI: 10.1186/s40659-020-00325-z

Gao, Q., Xiong, T., Li, X., Chen, W., and Zhu, X. (2019). “Calcium and calcium sensors in fruit development and ripening,” Sci. Hortic. 253, 412-421. DOI: 10.1016/j.scienta.2019.04.069

Goss, S. L., Lemons, K. A., Kerstetter, J. E., and Bogner, R. H. (2007). “Determination of calcium salt solubility with changes in pH and PCO₂, simulating varying gastrointestinal environments,” J. Pharm. Pharmacol. 59(11), 1485-1492. DOI. 10.1211/jpp.59.11.0004

Gharaghani, A., Javarzari, A. M., and Vahdati, K. (2018). “Kaolin particle film alleviates adverse effects of light and heat stresses and improves nut and kernel quality in Persian walnut,” Sci. Hortic. 239, 35-40. DOI: 10.1016/j.scienta.2018.05.024

Gharaghani, A., Javarzari, A. M., Rezaei, A., and Nejati, R. (2023). “Kaolin spray improves growth, physiological functions, yield, and nut quality of ‘Tardy Nonpareil’ almond under deficit irrigation regimens,” Erwerbs-Obstbau 65(4), 989-1001.

Ghesmati, M., Moradinezhad, F., and Khayyat, M. (2017). “Effects of foliar application of calcium nitrate and calcium chloride on antioxidant properties and quality of Ziziphus jujuba Mill,” Iran. J. Med. Aromat. Plants 33 (5), Pe871-Pe880, En881 ref. 45. http://ijmapr.areeo.ac.ir/article_114028_26999f47ac20a6394281c046c38edd78.pdf

Glenn, D. M. (2012). “The mechanisms of plant stress mitigation by kaolin-based particle films and applications in horticultural and agricultural crops,” HortSci. 47(6), 710-711. DOI: 10.21273/HORTSCI.47.6.710

Glenn, D. M., and Puterka, G. J. (2010). “Particle films: A new technology for agriculture,” Hortic. Rev. 31, 1-44. DOI:10.1002/9780470650882.ch1

Gullo, G., Dattola, A., Vonella, V., and Zappia, R. (2020). “Effects of two reflective materials on gas exchange, yield, and fruit quality of sweet orange tree Citrus sinensis (L.),” Osb. Eur. J. Agron. 118, article 126071. DOI: 10.1016/j.eja.2020.126071

Gupta, A., Tripathi, V. K., and Shukla, J. K. (2022). “Influence of GA₃, zinc and boron on fruit drop, yield and quality of litchi (Litchi chinensis Sonn.),” Biol. Forum-Int. J. 14(3), 1079-1083.

Gupta, U., and Solanki, H. (2013). “Impact of boron deficiency on plant growth,” Inter. J. Bioass. 2(7), 1048-1050.

Han, S., Chen, L.-S., Jiang, H.-X., Smith, B. R., Yang, L.-T., and Xie, C.-Y. (2008). “Boron deficiency decreases growth and photosynthesis and increases starch and hexoses in leaves of citrus seedlings,” J. Plant Physiol. 165(13), 1331-1341. DOI: 10.1016/j.jplph.2007.11.002

Hanusa, T. P. (2025). “Calcium,” Encyclopedia Britannica, Accessed 20 August 2025, https://www.britannica.com/science/calcium

Huang, W., Shi, Y., Yan, H., Wang, H., Wu, D., Grierson, D., and Chen, K. (2023). “The calcium-mediated homogalacturonan pectin complexation in cell walls contributes the firmness increase in loquat fruit during postharvest storage,” J. Adv. Res. 49, 47-62. DOI: 10.1016/j.jare.2022.09.009

Jaime-Guerrero, M., Álvarez-Herrera, J. G., and Fischer, G. (2024). “Effect of calcium on fruit quality: A review,” Agronomía Colombiana 42(1), 1-14. DOI: 10.15446/agron.colomb.v42n1.112026

Jain, V., Chawla, S., Choudhary, P., and Jain, S. (2019). “Post-harvest calcium chloride treatments influence fruit firmness, cell wall components and cell wall hydrolyzing enzymes of Ber (Ziziphus mauritiana Lamk.) fruits during storage,” J. Food Sci. Technol. 56, 4535-4542. DOI: 10.1007/s13197-019-03934-z

Jakhar, A. M., Aziz, I., Kaleri, A. R., Hasnain, M., Haider, G., Ma, J., and Abideen, Z. (2022). “Nano-fertilizers: A sustainable technology for improving crop nutrition and food security,” NanoImpact 27, article 100411. DOI: 10.1016/j.impact.2022. 100411

Kalcsits, L., Musacchi, S., Layne, D. R., Schmidt, T., Mupambi, G., Serra, S., Mendoza, M., Asteggiano, L., Jarolmasjed, S., and Sankaran, S. (2017). “Above and below-ground environmental changes associated with the use of photoselective protective netting to reduce sunburn in apple,” Agric. For. Meteorol. 237, 9-17. DOI: 10.1016/j.agrformet.2017.01.016

Khayyat, M., Tafazoli, E., Eshghi, S., and Rajaee, S. (2007). “Effect of nitrogen, boron, potassium and zinc sprays on yield and fruit quality of date palm,” Am. Eurasian. J. Agric. Environ. Sci. 2(3), 289-296.

Korkmaz, M., and Askın M. A. (2015). “Effects of calcium and boron foliar application on pomegranate (Punica granatum L.) fruit quality, yield, and seasonal changes of leaf mineral nutrition,” Acta Hortic. 1089, 413-422. DOI: 10.17660/ActaHortic.2015.1089.57

Lam, H.-H., Dinh, T.-H., and Dang-Bao, T. (2021). “Quantification of total sugars and reducing sugars of dragon fruit-derived sugar samples by UV-Vis spectrophotometric method,” IOP Conference Series: Earth and Environmental Science, IOP Publishing, 947(1), article 012041. DOI: 10.1088/1755-1315/947/1/012041.

Lewis, D. H. (2019). “Boron: The essential element for vascular plants that never was,” New Phytol. 221, 1685-1690. DOI: 10.1111/nph.15519

Li, S., Yan, L., Venuste, M., Xu, F., Shi, L., White, P. J., Wang, X., and Ding, G. (2023). “A critical review of plant adaptation to environmental boron stress: Uptake, utilization, and interplay with other abiotic and biotic factors,” Chemosphere 338, article 139474. DOI: 10.1016/j.chemosphere.2023.139474

Luciani, E., Palliotti, A., Frioni, T., Tombesi, S., Villa, F., Zadra, C., and Farinelli, D. (2020). “Kaolin treatments on Tonda Giffoni hazelnut (Corylus avellana L.) for the control of heat stress damages,” Sci. Hortic. 263, article 109097. DOI: 10.1016/j.scienta.2019.109097

Madani, B., Mohamed, M. T. M., Watkins, C. B., Kadir, J., Awang, Y., and Shojaei, T. R. (2014). “Preharvest calcium chloride sprays affect ripening of Eksotika II’papaya fruits during cold storage,” Sci. Hortic. 171, 6-13. DOI:10.1016/j.scienta.2014.03.032

Marschner, P. (2012). Mineral Nutrition of Higher Plants (3^rd Ed.), Academic Press London.

Michailidis, M., Karagiannis, E., Tanou, G., Samiotaki, M., Tsiolas, G., Sarrou, E., Stamatakis, G., Ganopoulos, I., Martens, S., Argiriou, A., and Molassiotis, A. (2020). “Novel insights into the calcium action in cherry fruit development revealed by high-throughput mapping,” Plant Mol. Biol., 104, 597-614. DOI: 10.1007/s11103-020-01063-2

Milagres, C. d. C., Maia, J. T. L. S., Ventrella, M. C., and Martinez, H. E. P. (2019). “Anatomical changes in cherry tomato plants caused by boron deficiency,” Braz. J. Bot. 42, 319-328. DOI: 10.1007/s40415-019-00537-y

Mogazy, A. M., Mohamed, H. I., and El-Mahdy, O. M. (2022). “Calcium and iron nanoparticles: A positive modulator of innate immune responses in strawberry against Botrytis cinerea,” Process Biochem. 115, 128-145. DOI: 10.1016/j.procbio.2022.02.014

Mohammed, N., Malchoul, G., and Bousissa, A. (2018). “Effect of foliar spraying with B, Zn and Fe on flowering, fruit set and physical traits of the lemon fruits (Citrus Meyeri),” SSRG Int. J. Agric. Env. Sci. 5(2), 50-57. DOI: 10.14445/23942568/IJAES-V5I2P107

Mosa, W. F. A., N. A. Abd EL-Megeed and L. S. Paszt (2015). “The effect of the foliar application of potassium, calcium, boron and humic acid on vegetative growth, fruit set, leaf mineral, yield and fruit quality of ‘Anna’ apple trees,” A. J. Exp. Agric. 8(4), 224-234.

Mounika, M., Kumar, T. S., Kumar, A. K., Joshi, V., and Sunil, N. (2021). “Studies on the effect of foliar application of calcium, potassium and silicon on quality and shelf life of sweet orange (Citrus sinensis L.) cv. Sathgudi,” J. Pharmacogn. Phytochem. 10, 1711-1713.

Nangare, D., Taware, P., Singh, Y., Kumar, P., Bal, S., Ali, S., and Pathak, H. (2020). “Dragon fruit: A potential crop for abiotic stressed areas,” Tech. Bull. 46, 24.

Nasrallah, A. K., Kheder, A. A., Kord, M. A., Fouad, A. S., El-Mogy, M. M., and Atia, M. A. (2022). “Mitigation of salinity stress effects on broad bean productivity using calcium phosphate nanoparticles application,” Horticulturae 8(1), article 75. DOI: 10.3390/ horticulturae8010075

Nielsen, S. S. (2017). “Vitamin C determination by indophenol method,” in: Food Analysis Laboratory Manual, Springer, Cham, Switzerland, pp. 143-146. DOI: 10.1007/978-3-319-44127-6_15

Pareek, S., Valero, D., and Serrano, M. (2015). “Postharvest biology and technology of pomegranate,” J. Sci. Food Agric. 95(12), 2360-2379. DOI: 10.1002/jsfa.7069

Rachappanavar, V., Padiyal, A., Sharma, J. K., and Gupta, S. K. (2022). “Plant hormone-mediated stress regulation responses in fruit crops – A review,” Sci. Hortic. 304, article 111302. DOI: 10.1016/j. scienta.2022.111302

Ramírez-Godoy, A., Puentes-Peréz, G., and Restrepo-Díaz, H. (2018). “Evaluation of the effect of foliar application of kaolin clay and calcium carbonate on populations of Diaphorina citri (Hemiptera: Liviidae) in Tahiti lime,” Crop Prot. 109, 62-71. DOI: 10.1016/j.cropro.2018.01.012

Ranjbar, S., Ramezanian, A., and Rahemi, M. (2020). “Nano-calcium and its potential to improve ‘Red Delicious’ apple fruit characteristics,” Hortic. Environ. Biot. 61, 23-30. DOI: 10.1007/s13580-019-00168-y

Ruchal, O. K., Pandeya, S. R., Regmia, R., Regmib, R., and Magrati, B. B. (2020). “Effect of foliar application of micronutrient (Zinc and Boron) in flowering and fruit setting of mandarin (Citrus reticulata Blanco) in Dailekh, Nepal,” MJSA, 4(2), 94-98.

Sajid, M., Basit, A., Shah, S. T., Khan, A., Ullah, I., Bilal, M., … and Khan, W. (2024). “Enhancing the quality and fruit yield of sweet cherry (Prunus avium) cultivars by foliar application of boron,” Appl. Fruit Sci. 66(2), 485-494.

Sarooghinia, F., Khadivi, A., Abbasifar, A., and Khaleghi, A. (2020). “Foliar application of kaolin to reduce sunburn in ‘Red Delicious’ apple,” Erwerbs-Obstbau 62(1), article 83. DOI: 10.1007/s10341-019-00464-y

Saure, M. C. (2005). “Calcium translocation to fleshy fruit: Its mechanism and endogenous control,” Sci. Hortic. 105(1), 65-89. DOI: 10.1016/j.scienta.2004.10.003

Segura-Monroy, S., Uribe-Vallejo, A., Ramirez-Godoy, A., and Restrepo-Diaz, H. (2015). “Effect of kaolin application on growth, water use efficiency, and leaf epidermis characteristics of Physallis peruviana seedlings under two irrigation regimes,” J. Agric. Sci. Technol. 17(6), 1585-1596. URL: http://jast.modares.ac.ir/article-23-2523-en.html

Snedecor, G. C., and Cochran, W. G. (2021). Statistical Methods, 8^th Ed., Iowa State University Press, Ames, IA, USA.

Shireen, F., Nawaz, M. A., Chen, C., Zhang, Q., Zheng, Z., Sohail, H., Sun, J., Cao, H., Huang, Y., and Bie, Z. (2018). “Boron: Functions and approaches to enhance its availability in plants for sustainable agriculture,” Int. J. Mol. Sci. 19(7), article 1856. DOI: 10.3390/ijms19071856

Sotiropoulos, Th. E., Therios, I. N., Dimassi, K. N., Bosabalidis, A., and Kofidis, G. (2002). “Nutritional status, growth, CO₂ assimilation, and leaf anatomical responses in two kiwifruit species under boron toxicity,” J. Plant Nutr. 25(6), 1249-1261. DOI: 10.1081/PLN-120004386

Sun, D., Zhang, Z., and Chen, F. (2018). “Effects of light intensity, light quality, and illumination period on cell growth, TFA accumulation, and DHA production in Crypthecodinium sp. SUN,” J. Appl. Phycol. 30, 1495-1502. DOI: 10.1007/s10811-017-1379-9

Terán, F., Vives-Peris, V., López-Climent, M. F., Gómez-Cadenas, A., and Pérez-Clemente, R. M. (2024). “Palliative effects of kaolin on citrus plants under controlled stress conditions of high temperature and high light intensity,” J. Plant Growth Reg. 43(2), 486-499. DOI: 10.1007/s00344-023-11103-y

Usman, M., Farooq, M., Wakeel, A., Nawaz, A., Cheema, S. A., ur Rehman, H., Ashraf, I., and Sanaullah, M. (2020). “Nanotechnology in agriculture: Current status, challenges and future opportunities,” Sci. Total Environ. 721, article 137778. DOI: 10.1016/j.scitotenv.2020.137778

Vani, B. R. D., Ramesh, N., Manimaran, S., and Thangavel, P. (2023). “Effect of organic mulches and kaolin clay foliar spray on growth, yield attributes and yield of dry land maize (Zea mays),” Crop Res. 58(1-2), 29-33. DOI: 10.31830/2454-1761.2023.CR-868.

Vighi, I. L., Crizel, R. L., Perin, E. C., Rombaldi, C. V., and Galli, V. (2019). “Crosstalk during fruit ripening and stress response among abscisic acid, calcium-dependent protein kinase and phenylpropanoid,” Crit. Rev. Plant Sci. 38(2), 99-116. DOI:10.1080/07352689.2019.1602959

Wang, H., Pampati, N., McCormick, W. M., and Bhattacharyya, L. (2016). “Protein nitrogen determination by Kjeldahl digestion and ion chromatography,” J. Pharm. Sci. 105(6), 1851-1857. DOI: 10.1016/j.xphs.2016.03.039

Wang, N., Yang, C., Pan, Z., Liu, Y., and Peng, S. (2015). “Boron deficiency in woody plants: Various responses and tolerance mechanisms,” Front. Plant Sci. 6, article 916. DOI: 10.3389/fpls. 2015.00916

Wieczorek, D., Żyszka-Haberecht, B., Kafka, A., and Lipok, J. (2022). “Determination of phosphorus compounds in plant tissues: From colourimetry to advanced instrumental analytical chemistry,” Plant Meth. 18(1), article 22. DOI: 10.1186/s 13007-022-00854-6

Xu, W. P., Wang, L., Yang, Q., Wei, Y. H., Zhang, C. X. and Wang, S. P. (2015). “Effect of calcium and boron on the quality of kiwifruit,” Acta Hortic. 1096, 317-320. DOI: 10.17660/ActaHortic.2015. 1096.35

Xu, W., Wang, P., Yuan, L., Chen, X., and Hu, X. (2021). “Effects of application methods of boron on tomato growth, fruit quality and flavor,” Horticulturae 7(8), article 223. DOI: 10.3390/horticulturae7080223

Yadav, A., Yadav, K., and Abd-Elsalam, K. A. (2023). “Nanofertilizers: Types, delivery and advantages in agricultural sustainability,” Agrochem. 2(2), 296-336. DOI: 10.3390/agrochemicals202 0019

Zhang, L., Wang, P., Chen, F., Lai, S., Yu, H., and Yang, H. (2019). “Effects of calcium and pectin methylesterase on quality attributes and pectin morphology of jujube fruit under vacuum impregnation during storage,” Food Chem. 289, 40-48. DOI: 10.1016/j.foodchem.2019.03.008

Zhou, J., Xiao, W., Chen, X. D., Zhang, Z. J., Wen, B. B., Song, W.L., Gao, D.S., and Li, L. (2018). “Effects of spraying calcium on the postharvest storability of ‘Whangkeumbae’ pear during young fruit period,” Acta Phytophysiol. Sin. 54, 1038–1044. DOI: 10.13592/j.cnki.ppj.2018.0062

Article submitted: December 28, 2024; Peer review completed: March 30, 2025; Revised version received: August 20, 2025; Further revised version received September 7, 2025; Accepted: September 8, 2025; Published: September 12, 2025.

DOI: 10.15376/biores.20.4.9606-9624