Nanomaterials in Broccoli Production: Current Applications and Future Prospects

Abstract

Conventional pesticides and fertilizers are frequently linked to high resource consumption, environmental damage, and poor nutrient usage efficiency in the production of broccoli. Nanofertilizers (e.g., iron, copper, zinc oxide, and boron NMs) and pesticide nanoparticles (NPs) are examples of nanotechnology that is mainly related to broccoli production. These technologies can increase the efficiency of nutrient uptake and utilization as well as broccoli’s resistance to drought, heavy metal stress, saline and alkaline stress, and other conditions. Through accurate fertilization and dosing, nanotechnology can reduce environmental contamination and the need for traditional chemical pesticides and fertilizers. Crops with nanomaterials have higher micronutrient content and better nutritional quality. This study examines the use of nanotechnology in the production of broccoli, which could improve crop yield and quality. However, much research is still required to determine how nanomaterials affect the environment and whether or not they might be hazardous to broccoli because of their minuscule particle size and unique physical and chemical characteristics. Researchers and agricultural professionals both within and outside the field of nanobiotechnology will be able to choose the right nanoparticles for broccoli production with the help of the information presented in this paper. The use of nanotechnology can reduce production costs and support sustainable agricultural growth. Additionally, it opens up new possibilities for the future production, transportation, and storage of cruciferous vegetables.

1. Introduction

Broccoli (Brassica oleracea L. var. Italica Plenck) is a highly nutritious plant, the edible portion of which consists mainly of unopened flower buds and their young stems [1]. It is rich in ascorbic acid, vitamin B1 and B2, as well as essential minerals such as calcium and phosphorus minerals, harboring great potential to improve the quality of human dietary quality [2]. This cruciferous vegetable is particularly renowned for its high concentration of antioxidants, including glucosinolates and 3-indole methanol compounds, which contribute to strengthening the immune system, combating carcinogens, reducing the risk of stomach cancer and preventing breast and colon cancer while also supporting liver function [3]. As people’s pursuit of healthy eating grows, broccoli, a nutrient-dense vegetable, is increasingly favored by global consumers, leading to a continuous increase in its planting area and production. According to FAO data, the world’s planting area for broccoli and cauliflower (Brassica oleracea L. var. botrytis L.) was roughly 1.468 million hectares in 2020, an increase of 2.2% from the previous year. The world’s production of broccoli and cauliflower was also up 2%, at 17.457 million tons [4]. Market-oriented output is the main goal of broccoli growing. A proper increase in commercial production of broccoli can increase the income of farmers [1]. The higher nutritional and commercial value of broccoli makes it especially important to improve broccoli production more efficiently.

Many control artificial and semi-artificial control methods have been proved to stimulate the development of broccoli in a direct or indirect fashion, which is vital for successfully enhancing agricultural output and farmers’ economic returns [5]. Artificial control methods mainly include greenhouse cultivation and chemical control, where human intervention directly controls the growth environment or physiological process of broccoli. Semi-artificial methods mainly include organic fertilizer application and chemical control measures, which optimize the growth environment or physiological processes of broccoli through human-assisted means. For example, plant growth regulators including gibberellins, cytokinins, and oleuropein lactones can regulate the levels of endogenous hormones in broccoli, thus regulating the growth status of broccoli and affecting its flowering period, bud development, and overall yield and quality [6]. However, concentration and consumption have an impact on the control of plant development, and excessive use of broccoli can result in physiological problems and worse quality. Organic fertilizers can improve soil structure, increase the rate of nitrogen mineralization, improve soil properties, provide comprehensive nutrients, and promote the healthy growth of broccoli [7]. However, organic fertilizers have a slow effect and need to be applied in advance. Conventional chemical fertilizers are higher in nutrient concentrations than organic fertilizers and can significantly increase crop yields. Excessive application of traditional fertilizers leads to a large loss of nutrients and a waste of resources [8]. It also leads to a series of environmental problems, such as soil acidification, eutrophication, and increased greenhouse gas emissions [9]. Although conventional chemical fertilizers can improve crop growth, they are still needed to improve plant nutrient uptake and crop yields in the face of current environmental issues and sustainable agriculture [10]. The utilization rates of traditional fertilizers are relatively low: nitrogen (N) at 30–35%, phosphorus (P) at only 18–20%, and potassium (K) at 35–40% [11]. The comparatively low nutritional content that plants acquire from fertilizers suggests that over half of the nutrients is lost before they reach their intended location as a result of fixation, microbial breakdown, and leaching [12]. Additionally, excessive use of synthetic fertilizers lowers farmer profitability and raises production expenses [12]. The extensive use of traditional fertilizers is often accompanied by a series of negative effects such as nutrient loss, soil structure destruction, air pollution, and global warming [13]. Therefore, there is still a large gap between broccoli yield enhancement and actual agricultural production, and there is a need to develop new strategies that can sustainably enhance broccoli yield. With the development of nanotechnology and the understanding of nanomaterial–plant interactions in the past decade, the application of functional nanomaterials to enhance broccoli production will be a breakthrough attempt (Figure 1).

Nanotechnology increases crop yields and reduces biotic and abiotic stress factors [14]. It reduces the application of fertilizers and pesticides, thereby reducing the pollution they cause to the environment, and has therefore been widely used in agriculture. Nanotechnology mainly consists of nano-fertilizers and nano-pesticides. Nanomaterials are materials with dimensions between 1 and 100 nm that are characterized by small size, large surface area, and the ability to focus on specific biological processes [15]. Elements in nano-fertilizers are able to diffuse on the nanoscale, increasing their area of contact and reactivity with the plant root system [16]. And they are more easily absorbed and utilized by plant roots and leaves than conventional fertilizers. Nanotechnology has the potential to greatly increase agricultural output and quality through regulated and prolonged fertilization [17]. Nanotechnology is applied in plant nutrition to improve the delivery of elements that are poorly bioavailable and to enhance the efficiency of current fertilizer use by limiting the loss of mobile nutrients to the surrounding environment [18]. High reactivity and adsorption capacity nanomaterials have much promise for lowering and breaking down soil contaminants [19]. Kreslavski et al. showed that 200 and 500 mg/L iron oxide (Fe₃O₄) nanoparticles (NPs) increased leaf growth and photosynthetic rate in wheat seeds (Triticum aestivum) under saline soil conditions [20]. Ye et al. showed that 1 mg/L manganese nanoparticles (MnNPs) significantly up-regulated the expression of MnSOD by a factor of 1.8 compared to the absolute control (blank columns), which significantly increased root length and biomass of pepper [21]. Jin et al. showed that by applying nano-sized potassium silica (NKSi) and ordinary potassium silica (OKSi) to cabbage (Brassica oleracea L.), respectively, the application of nano-potassium silica cabbage was 41.1% higher in amino acids in cabbage stems than the control (CK), and it was more able to improve the quality of cabbage [22]. These results highlight how nano-fertilizers have the potential to significantly increase crop quality and output. Nano-pesticides can precisely and effectively kill harmful pests while reducing pesticide usage, thus protecting the environment [23].

Understanding the mechanisms by which nano-fertilizers work and their prospects for application in broccoli production is crucial for maximizing the potential of broccoli in agriculture. The purpose of this study is to examine the possible benefits and drawbacks of this new technology while integrating existing knowledge regarding the uses and prospects of nanoparticles in broccoli production. In light of global issues, this study aims to open up new possibilities for future broccoli production, transportation, and storage by reviewing the scientific literature and recommending the application of nanotechnology in broccoli production.

2. Main Influencing Factors in Broccoli Production

Broccoli is a plant of the cruciferous family. It is mainly used for commercial production in the form of flower buds, which are thick and soft pods [24]. Different countries and regions have different climates, and the main challenges related to broccoli growth mainly involve variety, temperature, cultivation systems, water, and use of fertilizers. When broccoli receives ample sunlight, the plants grow robustly, forming strong vegetative tissues that facilitate photosynthesis and nutrient accumulation, making the heads compact and dense with bright green color and excellent quality [25]. Broccoli has strong cold and heat tolerance, with an optimal temperature for rosette growth of 20–22 °C and a suitable temperature for flower head development of 15–18 °C. Throughout its growth period, broccoli requires substantial amounts of water, especially during vigorous leaf growth and flower head formation, when consistent moisture is essential. It is best planted in well-drained, irrigated soil that is deeply plowed, loose, fertile, and capable of retaining both water and nutrients. The ideal pH range for adaptation is 5.5–8, but 6 is the most favorable [26].

Improving the fertilization methods of broccoli has become a major determinant for enhancing commercial yields and farmers’ income. Nitrogen, phosphorus, and potassium are supplemented by applying mineral fertilizers to broccoli to increase the activity of broccoli meristematic tissue, promote broccoli leaf growth, differentiate flower buds, and promote bud formation [27]. In broccoli, nitrogen, phosphorus, potassium, and sulfur all play a variety of roles in controlling plant growth and development. For instance, the development of flower bulbs and the growth of broccoli stems and leaves are directly impacted by nitrogen, which is essential for the synthesis of proteins, nucleic acids, and chlorophyll. The supply of nitrogen helps to promote the physiological and biochemical metabolism in the body, the accumulation of sugar, and the formation of amino acids and proteins, which are conducive to the formation of flower bulbs [28]. Potassium indirectly increases vitamin C content by participating in sugar transportation to the flower bulb. Potassium regulates water balance, enzyme activity and carbohydrate transport and enhances resistance to stress (drought, disease) [29]. The formation of thioglucosides, which is vital for secondary metabolism in cruciferous plants, requires sulfur. Sulforaphane, a thioglucoside hydrolysis product, has anticancer and antioxidant properties that enhance the quality of broccoli florets [30]. Phosphorus plays a major role in broccoli flowering, fruiting, photosynthesis, and root growth [31]. In broccoli cultivation, phosphorus also controls production, quality, and disease resistance. Zinc stimulates the production of thioglucosides and zinc antioxidant enzymes (SOD) [32]. Pollen development, floral stem development, and cell wall creation are all aided by boron [33]. Broccoli accumulates vitamin C, carotenoids and antioxidants through efficient photosynthesis, and its nutritional quality is regulated by nitrogen, potassium, and sulfur [34]. Flower bulb formation is affected by temperature, light, and nutrient supply (especially phosphorus and boron), and boron deficiency tends to lead to hollow flower bulbs. Broccoli receives its nutrients from nano-fertilizers that are smaller in size and more active than regular fertilizers. It can help broccoli better absorb elements such as calcium, phosphorus, potassium, sulfur, zinc, boron, and nitrogen.

3. Application of Nanomaterials in Broccoli Production

In the form of nano-pesticides, fertilizers, and other products, nanotechnology can offer sustainable technological solutions for conventional farming methods [35]. Nanomaterials can be used as fertilizers to improve broccoli yield and nutrition, and excel in improving broccoli tolerance to abiotic stresses [36]. Nanotechnology can improve nutrient uptake through spraying [37]. Under conditions such as high pH, heavy metal stress, and drought, the application of nano-fertilizers can enhance plant resistance, thereby improving plant yield and quality [37]. For example, Meselhy et al. showed that nanosulfur (NS) may successfully reduce arsenic bioavailability and accumulation in rice by boosting detoxification of AsIII by influencing the gene expression activities of arsenic transport, sulfur assimilation, and glutathione production pathways. With a 40% increase in biomass and a 26% increase in seed output, respectively, the arsenic deposited in the root and shoot tissues of AsIII- and NS-applied seedlings was 32% and 11% lower than that of AsIII-applied seedlings alone when compared to the control group [38]. With a 40% increase in biomass and a 26% increase in the seed output, respectively, the arsenic deposited in the root and shoot tissues of AsIII- and NS-applied seedlings was 32% and 11% lower than that of AsIII-applied seedlings alone when compared to the control group. These results with NS application can enable growth and produce higher yields on land with significant environmental impacts and contamination [38]. This provides a rationale for the cultivation of broccoli on contaminated land with nano-fertilizers. According to Rui et al., the biomass of traditional cotton roots treated with Fe₂O₃ NPs was 30.8–41.2% greater than the control. They also discovered that Fe₂O₃ NPs enhanced cotton biomass and encouraged the formation of root hairs [39]. Numerous studies showed that the application of nanotechnology to vegetables can achieve excellent results. Wu et al. showed that 10 mg/L MgFe-layered double hydroxide nanoparticles (MgFe–LDHs) had the most significant effect on cucumber seed germination at the concentration of 10 mg/L MgFe–LDHs. MgFe–LDHs were able to adsorb on the surface of root hairs in the maturation zone of seedlings and improve the uptake of plant nutrients, such as Fe, N, K, and S, thereby increasing the accumulation of nutrient elements by seedlings [40]. According to several studies, nano-fertilizers have greater growth potential to improve broccoli yield and quality compared to conventional fertilizers.

Numerous studies have shown that nanomaterials have a favorable effect on broccoli growth and development while maximizing their beneficial effects. As a result, many nanomaterials have been developed and applied in agriculture, including nano-fertilizers and nano-pesticides (Table 1) [41]. However, at the same time, some studies have shown that nanomaterials play an inhibitory role in plant growth and development. The use of nanomaterials in broccoli production still needs to face technical and regulatory challenges. The paper’s next section provides a summary of the previous five years’ report along with a thorough analysis of the use of nano-fertilizers in broccoli production.

3.1. Nano-Fertilizers

Nano-fertilizers or nano-pesticides can release active substances at the time and place when plants need them, limiting additional fertilizers or pesticides from being converted into gas form or leaching downstream [35] (Figure 2). By focusing as the slow release of nutrients and lowering the rate of fertilizer application, nano-fertilizer increases the effectiveness of nutrient delivery [42]. The controlled release approach of nano-fertilizer can significantly increase plant nutrient absorption efficiency and decrease excessive nutrient seepage into groundwater, which can lead to eutrophication and other environmental issues, as compared to traditional fertilizers [13]. Typically, nano-fertilizers are sprayed on foliar fertilization, as opposed to soil fertilization, immediately supplementing the nutrients that plants require by being directly absorbed and used by plants, thus minimizing the loss of nutrients that the soil has fixed [43]. Abbas et al., for instance, showed how foliar spraying with nano- and chelated copper affected the development and productivity of broccoli hybrids. The study demonstrated that crop development and yield were dramatically impacted by the foliar application of nano-copper. The highest yield was 67.82 tons per hectare, with most plant nutritional and fruit growth characteristics reaching optimal levels at a nano-copper concentration of 20 mg/L [44]. The number of leaves, leaf area, leaf iron content, and overall plant yield of broccoli were all markedly increased by the combination of 50 mg/L humic acid and nano-iron treatment [45]. The results suggest that the application of nano-fertilizers made from nanomaterials to broccoli can boost fertilizer efficiency.

3.1.1. Physiological Benefits

Nano-fertilizers regulate photosynthesis in many different ways by supplementing plants with the required nutrients (Figure 3). In addition to increasing the amount of chlorophyll, they also aid in the processes of photophosphorylation and redox reactions in the electron transport chain [46]. The use of nano-fertilizers can increase the production of chlorophyll by altering the activity of enzymes involved in the biosynthesis of chlorophyll, encouraging the conversion of light energy into energy, accelerating the exchange of electrons during photosynthesis, and improving the efficiency of the photosynthetic process [47]. Nanoparticles can enhance the photosynthetic activity of chloroplasts, such as increasing the efficiency of the light reaction in the membrane of cystoid bodies and promoting the production of ATP and NADPH. Because of its antioxidant qualities, it (such as cerium dioxide) efficiently scavenges oxygen free radicals (ROS) from chloroplasts, preventing damage to the photosynthetic system II (PSII) and preserving photosynthetic stability [48]. Metal oxide nanoparticles can act as photosensitizers, absorbing light energy and generating electron–hole pairs. It can be involved in the photosynthetic electron transport system and directly participate in photosynthetic electron transfer [49]. For example, Al-Shamry et al. showed that copper nanoparticles can improve plant performance by enhancing the synthesis of chlorophyll and other pigments in broccoli, participating in photophosphorylation and redox processes in the electron transport chain. Al-Shamry et al. demonstrated that by applying 20 mg/L of copper nanoparticles (CuNPs) to the foliar surface of broccoli as compared to the control group (unfertilized), the chlorophyll content could be increased by 1.2% and unilocular weight by 1.6%. While the head carbohydrate percentage of unfertilized plants dropped to 8.50%, the treatment sprayed with copper nanoparticles at a concentration of 20 mg/L showed the greatest head carbohydrate percentage at 14.50% [44]. Sardar et al. demonstrated that foliar spraying broccoli with zinc nanoparticles might raise the amount of carotenoids, chlorophyll a, chlorophyll b, and total chlorophyll in the leaves [50]. Halshoy et al. found that the combination of 20 mg/L of titanium dioxide nanoparticles (TiO₂NPs) with 30 L/ha of organic fertilizer considerably boosted the concentration of chlorophyll b (0.40 μg/g FM), and carotenoids (0.50 μg/g FM), as compared to control plants [51]. For the foliar spraying of kale-type oilseed rape, Cheng et al. used carbon points obtained from biomass. CDs (10 mg-kg⁻¹) increased the activities of the enzymes Rubisco, Fe-oxidoreductase, and chlorophyll synthesis (30–100%), which raised the fresh biomass (80–150%) and net photosynthetic rate [52].

Nano-fertilizer can increase the biomass of broccoli by affecting the photosynthesis of broccoli and promote the growth of broccoli roots, stems, leaves, and flower buds. The development of broccoli requires the trace element boron. Numerous physiological processes, including the metabolism of nucleic acids, the creation of proteins, hormones, the control of photosynthesis, the synthesis of carbohydrates, and membrane function, depend on boron [50]. A lack of boron causes broccoli heads to be smaller, have an uneven form, and taste bitter, all of which reduce the crop’s market demand [53]. In comparison to conventional boric acid fertilizer, Abbas et al. demonstrated that broccoli sprayed with nanoboron (NBO) fertilizer enhanced leaf area, head yield, and vitamin C content in the head [54].

Although foliar application of boron nanoparticle fertilizers may not be harmful and improves crop yield, quality, and physiological parameters, it should be noted that different broccoli types may have significantly varying ideal concentrations. There have also been many studies showing that nanoparticles mixed with other fertilizers can better enhance broccoli biomass. For example, Halshoy et al. showed that the combination of 20 mg/L TiO₂NPs with 30 L/ha OF resulted in the most significant increase in broccoli root diameter (8.77 mm) and total flavonoids content (4.56 mu g QE/g FM) compared to the control plants and the single effect of TiO₂NPs with organic fertilizer (OF) [51]. Shabani et al. showed that the highest bud fresh weight of broccoli was obtained with a 50:50 ratio of nanoscale zero-valent iron with iron chelate (NI/iron chelate) and pH = 7. 0 nutrient solution. Broccoli plant growth and yield were enhanced with nanoscale zero-valent iron powder [55]. But some of the nano-fertilizers have also been demonstrated to be harmful to the growth of broccoli. Excessive nanoparticle phytotoxicity also damages the photosynthetic system, changes gene expression, impacts broccoli germination and biomass, and causes epigenetic variation in plants [56]. For instance, Xiang et al. discovered that the toxicity of nano-ZnOs is influenced by particle size and shape. At concentrations between 1 and 80 mg/L, zinc oxide nanoparticles (nano-ZnOs) dramatically reduced the growth of Chinese cabbage seedlings’ roots and stems, with the roots being more vulnerable [57]. When Chung et al. applied NiO NPs to cabbage seedlings, proline and anthocyanin expression was markedly increased, whereas chlorophyll, carotenoids, and sugars were decreased. In cabbage seedlings, the treatment of NiO NPs increased the amounts of phytochemicals (phenolic compounds and mustard oleoresins) and triggered harmful effects [58]. Since Chinese cabbage is grown in a similar way to broccoli, this could have an impact on broccoli growth [57]. Thus, various types of nano-fertilizers can increase broccoli biomass and promote photosynthesis. Nano-fertilizer types, particle sizes, and concentrations still need to be determined by actual production requirements to determine the most appropriate dosage for broccoli.

Figure 3. Effect of nano-fertilizers on photosynthesis in broccoli [59]. Reproduced with permission from Wang, Journal of Integrative Plant Biology, published by John Wiley and Sons, 2025.

Figure 3. Effect of nano-fertilizers on photosynthesis in broccoli [59]. Reproduced with permission from Wang, Journal of Integrative Plant Biology, published by John Wiley and Sons, 2025.

3.1.2. Stress Tolerance

The primary abiotic stressors that can cause crop production to decline are salinization, heavy metals, drought, high temperatures, and high oxygen stress [60]. Salt stress causes a reduction in crop biomass, chlorophyll degradation, and changes in water status, resulting in reduced broccoli yield [61]. Lead, mercury, cadmium, and other heavy metals lower the amount of chlorophyll, interfere with photosynthesis and water balance, and cause cell death from the buildup of reactive oxygen species (ROS). These effects will hinder the growth and development of broccoli and lower its biomass [62]. Numerous studies have demonstrated that nanoparticles can lessen heavy metal stress in plants [63]. Specific components in nano-fertilizers can react with heavy metal ions in the soil, reducing the risk of vegetables absorbing heavy metals. Furthermore, drought affects the development of broccoli heads, especially during the rosette and heading stages; prolonged drought can result in smaller heads and decreased quality. Insufficient soil moisture causes leaves to shrink, inhibits nutrient growth, leads to premature bud emergence, smaller head development, and premature senescence. Nano-fertilizers can improve agricultural water use efficiency, particularly during drought. The main locations for ROS generation in plant cells are intercellular connections and various organelles such mitochondria, chloroplasts, and peroxisomes [64]. Nano-fertilizers can scavenge reactive oxygen species (ROS) in the body, increase plant stress tolerance, and activate the activity of antioxidant enzymes in plants. For instance, the coexistence of reducing and oxidizing Mn²⁺ in MnSO₄NPs, along with redox-like transitions between II and T valence, gave MnSO₄ NPS the capacity to scavenge ROS. MnSO₄NPs also exhibit outstanding antioxidant-like enzyme activities [65].

Broccoli’s stress tolerance can be increased by using nano-fertilizers, which can also increase the plant’s permeability of cell membranes, water absorption and transportation capacity, antioxidant capacity, and nutrient absorption. Martinez-Ballesta et al. discovered that treating broccoli with commercial multi-walled carbon nanotubes (MWCNTs) can lessen the negative effects of strong salt stress. This is primarily because MWCNTs cause changes in the lipid composition, rigidity, and permeability of the root membrane, which improve energy utilization, increase net CO₂ assimilation, and increase water absorption by the cells. Furthermore, MWCNTs’ improved transport of water channel proteins enhances water absorption and transport, lessening the negative effects of salt stress [36]. According to studies by Vicas et al., broccoli exhibited the highest antioxidant capacity at a concentration of 100 ppm SeNPs, and broccoli may benefit more from NSePs in terms of nutrition and health [66].

However, some studies showed that nanotechnology can also be toxic to broccoli growth. ZO NPs (50 and 100 mg/L) disturbed the equilibrium of other metals in plants due to their high zinc concentration, increasing the toxicity of multi-walled carbon nanotubes. Hong et al. demonstrated that a single 100 mg/L MWCNT attributable to oxidative damage would be hazardous to cabbage [67]. The above studies showed that nano-fertilizers can improve the resistance of broccoli, but when applying nano-fertilizer, the type, combinations of different nano fertilizers, and concentration should be considered, as well as different growth environments, so as to better exert their effects.

3.1.3. Nutritional Quality

Appropriate use of nanoparticles can increase the content of vitamin C, amino acids, and antioxidants in broccoli, improve the inorganic nutritional quality of the plant, and increase the uptake of N, K, P, S, Ca, and other important nutrients. They can also improve the plant’s economic and environmental benefits [68]. Due to its large surface area, nano-fertilizers promote the increase in enzyme activity and substance synthesis mainly through interaction with biomolecules, thus reducing oxidative stress in plants and improving the nutritional quality of crops [69]. For instance, cherry foliar spraying with 5 g/L of nano-selenium dramatically raised the fresh weight and diameter of the fruits, as well as the amounts of micronutrients and amino acids in the leaves and fruits, as compared to the control group. This was mostly because the plant’s antioxidant system was strengthened by the nano-selenium treatment, which led to a notable rise in SOD (44.3%), POD (24.3%), and CAT (95.6%) levels [70]. Water-soluble carbon nano-fertilizers with 100 mg/L Ce-CDs were the most efficient when applied to lettuce, resulting in an increase in biomass of roughly 83.3% by boosting and inducing stomatal opening and stimulating the accumulation of soluble sugars and soluble proteins [70].

The key regulatory genes of turnip thiol glycoside and sesquiterpene glycoside metabolism in cauliflower, MAM1, can be directly up-regulated by 18.75 L/ha nanocarbon. This will significantly improve the scientific and technological management of cauliflower production in China and open up a new pathway and scientific foundation for precise regulation of endogenous nutrients in cauliflower [71]. When the nano-fertilizer enters the plant, it interacts with it at both the cellular and subcellular levels. This interaction is determined by the nano-fertilizer’s properties, including its size, shape, concentration, and surface charge, as well as the age and genotype of the plant species, its physiological makeup, and other factors [72]. Nanocarbon selenium-enriched composite or blended fertilizers can significantly increase selenium levels in broccoli while keeping other nutrients stable. For example, Shams et al. showed that NBO spraying increased the leaf area, head yield, and vitamin C content in heads of broccoli [55]. The greatest effect of 40 mg/L TiO₂NPs on leaf dry matter (16.38%), total polyphenol content (39.77 μg GAE/g FM), nitrogen content (1.93%), and phosphorus content (0.35%) of broccoli was studied by Halshoy et al. In addition, broccoli nutrient and root growth, fruit characteristics, and potassium content were affected by the interaction of TiO₂NPs at 20 mg/L with organic fertilizer (OF) at 15 L/ha [51]. Sardar et al. observed that foliar sprays (Zn 0.5% and B 0.5%) boosted N content in broccoli leaves and flower bulbs. Broccoli leaves and bulbs had higher K content after being sprayed with zinc. While Zn raised the K level in broccoli bulbs, B and Zn enhanced the K content in leaves [50]. According to the aforementioned research, using the nano-fertilizer can improve broccoli’s nutrient absorption, boost its vitamin C and amino acid content, and encourage photosynthesis, which raises the vegetable’s soluble sugar content and improves its quality.

3.2. Nano-Pesticides

In addition to the nano-fertilizer having a large part in broccoli production, technologies such as nano-insecticides and nano-packaging also play an essential role in broccoli production. Broccoli attacked by pests and diseases not only consumes plant resources, but it also may spread viruses and lead to stunted growth. Pests and diseases cause significant damage to agriculture, resulting in a 20–40% reduction in crop yields, valued at up to USD 220 billion. Less than 25% of the almost 4 million tons of pesticides used annually worldwide reach the target organisms, posing a threat to both human health and the ecosystem [73]. A sustainable agricultural milestone, the application of nano-fertilizer pesticides provides a long-term substitute for conventional techniques [74] (Figure 4).

Nano-pesticides are classified in terms of composition into metal-based nano-pesticides and nano-pesticides in which NMs are used as carriers of active ingredients. Metal-based nano-pesticides are metal-based NMs (e.g., silver, copper, zinc oxide, and titanium dioxide NMs) that can be applied directly to plants and have antibacterial and antimicrobial effects [75]. Zinc nanoparticles have antimicrobial potential against a wide range of plant pathogens [76]. The toxicity mechanism of AgNPs is mostly derived from the combination of Ag⁺ produced by AgNPs with cysteine-containing proteins in the pathogen’s plasma membrane, which destroys the pathogen’s cell membrane and inhibits the growth of many pathogens. AgNPs have in vitro antifungal activity, and their application to eggplant early blight pathogens resulted in a 100% decrease in the number of the pathogens and 73% decrease in the biomass of the pathogens after 7 days [76]. Servin et al. showed that in addition to direct interactions with pathogens, metal-based NMs can alter several physiological and biochemical processes in crops to enhance crop immunity. AgNP treatment enhanced plant resistance to mosaic viruses by increasing the activity of antioxidant enzymes and total soluble protein content of the plants. Nanoparticle treatments at 50 ppm resulted in spasmolytic and inhibitory spore germination of Fusarium graminearum [77].

Broccoli downy mildew reduces the efficiency of photosynthesis, leading to stunting of the flower bulb and yield reductions of up to 30–50% [78]. Zinc oxide nanoparticles prevented M. graminearum spores from germinating on leaves, as demonstrated by Nandhini et al. In comparison to the untreated control, the incidence of downy mildew was reduced by 35% when zinc oxide nitrogen oxides were used as a foliar spray and seed treatment. The concentration of ZnO nanoparticles resulted in plasmolysis of spores, which inhibited spore germination. At a zinc nanoparticle concentration of 150 ppm, sporulation was totally suppressed [79]. Black rot of broccoli causes blackening of the vascular bundles of the stems, internal rotting of the flower bulbs, a significant reduction in commercial value; in severe cases, the disease can result in complete crop failure [80]. Black rot of tomato was controlled using biodegradable MnO NPs. The concentration of 2.5 mg/mL of MnO NPs showed the greatest growth inhibition (86.25%). The antifungal potential of MnO NPs is suggested by the presence of alkyl halides on their surface. The antifungal potential is strongly reliant on the size and crystalline form of the NPs. The crystalline nature of NPs assists in breaking the fungal cell wall [81]. Aphids (Brevicoryne brassicae L.) suck broccoli sap, causing leaf curling and spreading viral diseases (e.g., mosaic virus) [82]. In comparison with pyrethroid commercial products (Pyrethro Vioryl, 5SC, Parapin 5SC), the application of pyrethroid nano-formulations resulted in a significant decrease in the average density (survival) of aphids, especially 1–3 days after application, which indicates an increase in efficacy by 20–40%, depending on the dose. The insecticidal effect of pyrethroid nano-formulations was significantly higher at 62% of the registered dose of the reference product against aphids. Dispersion, deposition of spray droplets on the leaf surface, and leaf adhesion were improved, resulting in increased bioavailability of the insecticide to the target insects. Furthermore, by increasing the system’s interfacial area, nano-encapsulation of water-insoluble pyrethroids in stable nanoemulsions may extend the insecticide’s shelf life and facilitate easier penetration [83].

An important development in sustainable agriculture is the use of nano-pesticides and fertilizers, which offer a long-term substitute for conventional techniques [74]. NMs can be used as vectors for insecticides, fungicides, herbicides, and silencing genes (dSRNA) to achieve precise delivery and release of active ingredients, reducing crop losses caused by agricultural pests and diseases and the environmental impact of pesticides [84]. Biocides can be delivered via nanoparticles, which have the benefits of focused distribution, controlled release, and lower environmental toxicity. Nano-pesticides come in various forms, including liposomes, polymers, and metal–organic frameworks. Polymer-based nano-pesticides may achieve precise control over the adhesion and release of pesticides on crop surfaces through their tunable microstructure [85]. Naaz et al. found that the dry silica nanoparticles killed both adults and larvae by direct application while also blocking the insect’s trachea or pores, leading to death [86]. Chen et al. showed that the application of silica nanoparticles directly to crops, resulting in a silica coating, inhibited the growth and entry of insects and larvae [87]. However, because lipid layers are soluble, liposome-based nano-pesticides may release pesticides gradually in water columns, increasing stability and persistence [88]. By combining graphene oxide (GO) with the pyrethroid pesticides bifenthrin, cypermethrin, and lambda-cyhalothrin, Gao et al. were able to improve the adsorption of pesticides on target organisms. They proposed a temperature-responsive release GO-pesticide nanocomposite. This nano-pesticide formulation is much more biologically active than individual pesticides and can adsorb on the epidermis of two-spotted spider mites and soybean leaf surfaces with highly uniform dispersion [89]. Qi et al. demonstrated that polyethyleneimine (PEI)-functionalized gold nanoparticles (PEI-AuNPs) with ROS-scavenging activity and fluorescent characteristics could be used as a siRNA delivery vehicle. The defense-regulated gene AtWRKY1 was successfully silenced by it. The silenced plants demonstrated greater resistance to Pseudomonas aeruginosa than the control plants, as seen by decreased bacterial populations, lower ROS levels, increased antioxidant enzyme activities, and enhanced chlorophyll fluorescence characteristics [90]. Environmental conditions, plant cell structure, and particle surface chemistry are some of the many variables that influence the size effect of nano-pesticides. These variables interact to influence how well nano-agrochemicals work. These considerations must be made when applying nano-pesticides to broccoli in the future. Additionally, the size effect of nano-agrochemicals in real-world application scenarios should be thoroughly examined, taking into account the variations between laboratory and field settings, long-term environmental effects, and multiscale co-exposure effects [16]. Nanotechnology-mediated pesticides provide a new approach for the pest control strategy of broccoli, but environmental safety issues must be considered to ensure the safety of nano-pesticides to animals and human body.

3.3. Nanopackaging

A large number of studies have shown that nanotechnology has been widely applied in agriculture, capable of enhancing plant nutrition and growth, improving stress resistance, and providing solutions for phytoremediation and agricultural efficiency, thereby promoting sustainable agriculture. Nanomaterials exhibit excellent properties such as high specific surface area, designability, and biodegradability [91]. These properties enable nanopackaging materials to effectively extend the freshness of broccoli. By inhibiting microbial growth, reducing oxygen permeability, and controlling humidity, nanopackaging can significantly reduce losses during storage, maintaining its freshness and nutritional value [92]. For instance, Deng et al. investigated the antibacterial film of linear low-density polyethylene (LLDPE) modified with nano-titanium dioxide (TiO₂) and basic magnesium chloride (BMH), which can preserve grape flavor, store grapes efficiently, and greatly increase the grapes’ shelf life [93]. Upadhyay et al. showed that the ethylene nanobiocomposite film impregnated with corn starch (CS) and acacia gum (GA) nanocomposite membrane on attapulgite (SP) has good mechanical properties, barrier properties and ethylene absorption properties, showing great potential in the field of broccoli active packaging [94]. Singhal et al. demonstrated that the growth of broccoli mutant bulb cabbage was enhanced by the combined action of ZnO nanorods and the fungus Piriformospora indica DSM 11827 [95]. Using a test on tiny tomatoes, Liu et al. discovered that the film containing nano-metal performed well against bacteria, and that the more nano-metal there was, the more effective it was against bacteria. Compared to traditional preservation methods, nanomaterial-based preservation technology has significant advantages, including better preservation effects, less impact on food quality, and greater environmental friendliness. As nanotechnology continues to advance, the application of nanomaterials in broccoli preservation will become more extensive and profound. In the future, we can expect more innovative nanoscale preservation technologies and products to emerge, offering more possibilities for the storage and transportation of broccoli. In summary, the application of nanomaterials in broccoli preservation technology holds broad prospects and important practical significance.

Table 1. Some examples of nanotechnology in broccoli.

Nano Technologies	Crops	Influence	Reference
MWCNTs	broccoli	Enhanced water transport and absorption, reduced the adverse effects of salt stress	[36]
Copper nano-fertilizer	broccoli	Nano-copper applied to leaves had a major impact on crop output and growth	[44]
Humic acid and iron nano-fertilizer	broccoli	Broccoli significantly increased the number of leaves, their area, their iron content, and their overall plant production.	[45]
Zinc nano-fertilizer	broccoli	Increased the content of chlorophyll a, chlorophyll b, carotenoids and total chlorophyll in broccoli leaves	[50]
Boron nano fertilizer	broccoli	Increase the plant height, stem length and stem thickness, leaf number, leaf length and width, root fresh weight and dry weight, inflorescence number, bulb diameter, and weight of broccoli	[50]
Titanium dioxide nano fertilizer and organic fertilizer	broccoli	The content of chlorophyll b (0.40 μg/g FM) and carotenoids (0.50 μg/g FM) was increased	[51]
Nano boron fertilizer	broccoli	Increased leaf area, head yield, and vitamin C content in the head	[54]
Nanoscale zero-valent iron with iron chelate	broccoli	Increase the growth and yield of broccoli plants	[55]
NSePs	broccoli	Broccoli has the highest antioxidant capacity	[66]
Corn starch (CS) and acacia gum (GA) nanocomposite membrane	broccoli	Improving the freshness of broccoli	[94]
ZnO Nanorods and fungus	broccoli	Promote the growth of broccoli mutant broccoli	[95]

Table 1. Some examples of nanotechnology in broccoli.

Nano Technologies	Crops	Influence	Reference
MWCNTs	broccoli	Enhanced water transport and absorption, reduced the adverse effects of salt stress	[36]
Copper nano-fertilizer	broccoli	Nano-copper applied to leaves had a major impact on crop output and growth	[44]
Humic acid and iron nano-fertilizer	broccoli	Broccoli significantly increased the number of leaves, their area, their iron content, and their overall plant production.	[45]
Zinc nano-fertilizer	broccoli	Increased the content of chlorophyll a, chlorophyll b, carotenoids and total chlorophyll in broccoli leaves	[50]
Boron nano fertilizer	broccoli	Increase the plant height, stem length and stem thickness, leaf number, leaf length and width, root fresh weight and dry weight, inflorescence number, bulb diameter, and weight of broccoli	[50]
Titanium dioxide nano fertilizer and organic fertilizer	broccoli	The content of chlorophyll b (0.40 μg/g FM) and carotenoids (0.50 μg/g FM) was increased	[51]
Nano boron fertilizer	broccoli	Increased leaf area, head yield, and vitamin C content in the head	[54]
Nanoscale zero-valent iron with iron chelate	broccoli	Increase the growth and yield of broccoli plants	[55]
NSePs	broccoli	Broccoli has the highest antioxidant capacity	[66]
Corn starch (CS) and acacia gum (GA) nanocomposite membrane	broccoli	Improving the freshness of broccoli	[94]
ZnO Nanorods and fungus	broccoli	Promote the growth of broccoli mutant broccoli	[95]

3.4. Effects of Nanomaterials on Other Cruciferous Plants

The kale vegetables, which mainly include three types of cauliflower (Brassica oleracea L. var. botrytis L.), and cabbage (Brassica oleracea L.), are cultivated all over the world due to their adaptability and similar cultivation methods [96]. Nanomaterials have been shown in numerous studies to increase the development and yield of cruciferous plants. For example, Li et al. found that amaranth seed germination and growth are positively impacted by gibberellin, a photocatalytic activity seen in low concentrations of TiO₂ nanoparticles [97]. Zhao et al. examined the effects of urea, humic acid, and liquid nano-carbon biofertilizer on the root length, yield, and quality of Chinese cabbage plants that were one year old. The findings demonstrated that Chinese cabbage output could be increased and root length could be considerably increased with nano-fertilizer [98]. Liao et al. showed that 2% nano-hydroxyapatite (n-HAP) can be effective in improving slightly contaminated soil (150–300 mg/kg) with vanadium, which can reduce the pressure of soil V on cabbage [99]. According to Jin et al., cabbage treated with 300 kg·hm⁻² nanoscale potassium silica (NKSi) had an amino acid content that was 41.1% greater than the control (CK) [22]. Nevertheless, other research indicates that nanoparticles may negatively impact cruciferous plant growth. Hong et al. showed that the toxicity of cabbage caused by oxidative damage from MWCNTs alone, while the toxicity of cabbage caused by high concentrations of zinc from ZnO NPs alone [67]. When 100 mg/L of N-CDs were sprayed on lettuce, the fresh weight of the aboveground (41.70%) and underground (32.42%) sections increased noticeably. Furthermore, it may raise lettuce’s soluble protein (11.67%), soluble sugar (17.24%), and vitamin C (9.47%) contents [100].. All the above findings indicate that both spraying and spreading of nano-fertilizers can increase the growth and quality of cruciferous plants (

Table 2. Some examples of nanotechnology in cruciferous crops.

Nano Technologies	Crops	Influence	Reference
NKSi	Chinese cabbage	Cabbage has a higher amino acid content	[22]
Zinc oxide nanoparticles	Chinese cabbage	Reduced the growth of the roots and seedlings of the Chinese cabbage	[57]
NiO NPs	Cabbage	Increased the amounts of phytochemicals (phenolic compounds and mustard oleoresins) and triggered harmful effects.	[58]
MWCNTs	Cabbage	Causes oxidative damage to cabbage	[67]
Ce-CDs NMs	Lettuce	Increased soluble sugar and soluble protein content	[70]
TiO2 nanoparticles	amaranth	Promote seed germination and growth	[97]
Liquid nano carbon bio-fertilizer	Chinese cabbage	Encourage cabbage root growth to boost Chinese cabbage production	[98]
n-HAP	Cabbage	Improve the resistance of plants	[99]
N-CDs	Lettuce	Raise lettuce’s soluble protein, soluble sugar, and vitamin C contents	[100]

).

3.5. Limitations and Toxicity

Nanoparticles enter plant tissues by means of soil application as well as foliar application. The nanoparticles will accumulate in the plant. This process may also depend on the nature of an NP, plant species, growth stage, and plant tissue structure [101]. The accumulation of nanoparticles in plants can interfere with their growth and development, as nanoparticles are small and at the same time highly active. When nanoparticles accumulate in plants, they block the cell wall or plasma membrane pores, thus preventing the transportation and delivery of nutrients between plant tissues [102]. In addition, too many nanoparticles lead to dysregulation of cellular molecules, affecting the physiological cycle of plant cells, metabolic reactions, and gene expression, which in turn inhibit photosynthesis in plants [103]. For example, Nair and Chung showed that Ag NPs dramatically reduced root elongation and fresh weight of root, stem, and leaf tissue in Oryza sativa L. [104]. The toxicological regulation of Ag NPs is a key mechanism of oxidative damage stimulated by excess ROS in plant cells. Mainly due to the binding of Ag with biomolecules to biomolecules, it induces apoptosis and metabolic disease toxicity mechanisms, including the role of biotransport and cytotoxicity [103]. Qian et al. showed that Ag NPs can inhibit photosynthesis by affecting Cu-binding proteins, decreasing the content of chlorophyll and carotenoids, and posing a serious threat to the cystoid lumen of the chloroplasts [105]. The accumulation of nanoparticles in plants is passed down the food chain, which in turn may pose health risks to humans as well as other organisms.

Therefore, during the use of nanotechnology in broccoli production, attention should be paid to balanced fertilization and the size as well as concentration of nanoparticles applied.

4. Discussion

The application of nanomaterials to broccoli production provides new perspectives and approaches to agricultural science research. Technologies such as nano-pesticides, nano-fertilizers, and nano-coatings can decrease the quantity of fertilizer used, increase environmental protection, and increase the efficiency of nutrient absorption and use. The application of nanomaterials in broccoli production can enhance plant resistance by supplementing required nutrients, thereby improving the crop’s nutritional quality, which is conducive to the regulation of broccoli flowering, improving the morphology and size of broccoli heads, and facilitating the commercial production of broccoli. Meanwhile, the application of nanomaterials in pesticides can precisely and effectively kill pests and reduce pollution of the environment, making them more controllable in agricultural production. Nano-coatings and nano-packaging materials can isolate broccoli from the air and extend the length of time broccoli can be preserved after harvest. The nutritional quality of harvested broccoli is better preserved with the use of nanomaterials compared to traditional materials, making them a promising option for broccoli production. Nanomaterials have also shown good results in the production of other cruciferous plants, which also provides a possibility for the application of nanomaterials in broccoli. However, at the same time, it was found in the course of the study that nanomaterials showed different effects on different varieties of broccoli due to their types, concentrations, and particle sizes, and the suitable nanomaterials to be applied should be considered comprehensively according to the local soil conditions, climate, precipitation, and other factors in the actual production. Furthermore, limited research has been conducted on the safety of nanomaterials concerning human health and the environment, and their potential toxicity to broccoli remains unknown. The practical and scalable fabrication of nanomaterials for agricultural use is still in its early stages. The following points outline potential directions for future research:

(1)

The kinds of nano-fertilizers that can boost broccoli yields can be investigated in future studies. At the moment, few kinds of nano-fertilizers have been explored, and their methods of action are still unknown. More trace nano-fertilizers should be sprayed on broccoli in the future to study their toxicity, impacts, and mechanisms of action. Further research is needed on the compatibility of nano-fertilizers with traditional fertilizers to ensure efficacy while enhancing economic benefits. Nanotechnology has to be used in conjunction with traditional water and fertilizer management practices. The determination of optimal fertilizer ratios requires further in-depth research. Ensuring the safe use of nano-fertilizers in vegetable production necessitates balanced and carefully formulated applications.

(2)

Future nanotechnology-mediated pesticides offer new strategies for pest control in broccoli, but environmental safety must be considered. The toxic mechanisms of nanoscale pesticides on plants still require further study to ensure their safety for animals and humans during production. At the same time, the use of nano-pesticides for production should be consistent with the necessity of local public policies and regulations to ensure the safe application of nanotechnology in agriculture.

(3)

At present, nanotechnology is widely used in fruit and vegetable preservation, but it is less used in broccoli preservation. In the future, more research on nanotechnology in broccoli preservation will be added. More nanomaterials should be attempted for broccoli storage in the future. In the meantime, there is still a need for research on whether it is safe to apply nanotechnology in the bioaccumulation of broccoli.

(4)

The use of nano-fertilizers in large-scale broccoli production should take into account the cost of nanotechnology as well as the acceptance of farmers and local laws and regulations. Nanotechnology still has a long way to go in large-scale broccoli cultivation.

This review details how nanomaterials can improve the yield, quality, and freshness storage of broccoli by improving physiological processes in broccoli. In the future, researchers and technicians in broccoli and cruciferous plant production can explore the effects of a wider variety of nanotechnologies on broccoli to find the optimal concentration and particle size for more efficient production.