Pulses and oilseeds play a crucial role in global diets and agricultural sustainability, providing both nutrition and economic stability for millions of farmers. Protein-rich legumes, such as chickpea (
Cicer arietinum), mung bean (
Vigna radiata) and pigeon pea (
Cajanus cajan), deliver essential amino acids and dietary fiber. In contrast, crops like soybean (
Glycine max), mustard (
Brassica juncea) and groundnut (
Arachis hypogaea) serve as key sources of edible oils and healthy fats
(Lithourgidis et al., 2011; Martin-Guay et al., 2018;
Nassary et al., 2020). Nevertheless, in numerous farming systems, yields are significantly below potential levels, primarily due to nutrient imbalances in the soil, decreasing fertility and stress caused by unfavorable environmental conditions
(Krishnasree et al., 2022). Micronutrients especially iron (Fe), zinc (Zn), manganese (Mn) and copper (Cu) are indispensable for processes like chlorophyll synthesis, enzymatic regulation and reproductive development in plants
(Kanwal et al., 2020; Krishnasree et al., 2022). Unfortunately, conventional fertilizer and foliar formulations often fail to deliver these nutrients effectively, particularly in alkaline or degraded soils, leading to reduced uptake efficiency and significant nutrient losses through leaching (
López-Valdez et al., 2018). This inefficiency has accelerated interest in advanced nutrient delivery technologies capable of improving availability and absorption
(Ma et al., 2018).
Agriculture has benefited from new opportunities brought about by nanotechnology, which manipulates materials at scales ranging from 1 to 100 nanometers (
Monica and Cremonini, 2009;
Kah et al., 2018). The creation of nano chelates-micronutrients attached to nanoparticles-is one exciting advancement. These particles have improved stability, increased solubility and the capacity to move nutrients across plant tissues more effectively
(Kah et al., 2018; López-Valdez et al., 2018). Nano chelates have been demonstrated to enhance improved vegetative growth, maintain stronger physiological activity and raise yield potential in a range of crops by enhancing nutrient mobility
(Marzouk et al., 2019).
Recent experimental evidence indicates that the application of targeted nano chelates can enhance productivity in both pulses and oilseeds. For example, foliar sprays that include nano-Fe and nano-Zn have been shown to improve seed composition, photosynthetic rates and vegetative growth in chickpeas and soybeans
(Kanwal et al., 2020; Marzouk et al., 2019). Mung beans treated with nano-chelated iron exhibited increased biomass, a larger leaf area index and superior grain yield compared to traditional treatments
(Kanwal et al., 2020). In mustard, the use of nano-ZnO resulted in higher oil yield and increased chlorophyll content
(Marzouk et al., 2019), whereas in groundnuts, nano-micronutrient complexes enhanced drought resilience and oil concentration
(Kah et al., 2018). The application of multi-element nano chelates across various pulse and oilseed crops has also been associated with concurrent improvements in protein content, oil yield and resistance to abiotic stresses
(Kah et al., 2018).
Despite the promising findings, the adoption of these technologies at the field scale remains limited. Significant uncertainties persist concerning the long-term interactions of nano chelates with soil ecosystems, their longevity and their cumulative impacts on the health and quality of crops
(Kah et al., 2018; Ma et al., 2018). This review consolidates recent research to evaluate the effects of nano chelates on growth performance, physiological functions, biochemical alterations and yield results in pulses and oilseeds. Furthermore, the discussion highlights essential research gaps that must be addressed to promote sustainable nutrient management strategies and mechanism of nano chelates is given in Fig 1.
Growth parameters influenced by nanochelates
Nano chelates enhance solubility, mobility and the regulated distribution of essential micronutrients because of their chelated nutritional content and incredibly small particle size. In both oilseeds (like soybean, mustard and peanut) and pulses (like chickpea, mung bean, lentil and black gram), this increased nutritional efficiency leads to notable gains in germination, vegetative growth and branching. Nano-formulations perform better than conventional fertilizers in promoting early seedling establishment, enhancing canopy growth and raising biomass production, laying a strong basis for higher yield potential (
Abdelmonem, 2020).
Days to germination and emergence
Priming seeds or applying nano-Zn, nano-Fe and multi-nutrient nano chelates at the early growth stage accelerates germination and ensures more uniform seedling establishment in pulses and oilseeds. In trials with mung bean and mustard,
Abdelmonem (2020) noted that nano-Zn priming reduced sprouting time by two to three days compared with conventional ZnSO
4.
Mallikarjuna (2021) showed that treating chickpea and soybean seeds with nano chelates enhanced amylase activity, which sped up starch breakdown, encouraged faster root and shoot emergence and improved seed vigour index values. Similarly,
Rajput et al., (2022) recorded a 15-18% improvement in germination rate in lentil after nano-Fe application, while
Jadhav et al., (2023) observed comparable gains in groundnut and black gram through the use of multi-micronutrient nano chelates.
Li et al., (2018) also reported that nanoscale nutrient delivery promoted stronger and more synchronized seedling emergence under varying field conditions.
Plant height
The enhanced absorption of micronutrients from nano-Zn and nano-Fe results in improved stem elongation, increased shoot biomass and a taller plant canopy. In their research,
Li et al., (2018) observed height increases of 20-25% in chickpea and soybean following the application of nano-Zn, while
Abdelmonem (2020) reported comparable results in mustard when foliar nano-Zn was applied during the vegetative growth phase.
Meng et al., (2018) indicated that nano-Fe promoted stem growth in lentil by stimulating both cell division and elongation in the shoot meristems.
Jashni and Aynehband (2017) discovered that mung bean and groundnut plants treated with nano chelates not only exhibited increased height but also developed stronger stems, which contributed to enhanced stress tolerance.
Rajput et al., (2022) associated this response with the activation of auxin and gibberellin pathways, which are known to regulate stem elongation and canopy structure. Additional research on groundnut and canola supports the notion that nano-calcium and foliar micronutrients further improve growth and yield under adverse soil and drought conditions (
Kalantar Ahmadi and Shoushi Dezfouli, 2019;
Liu et al., 2022).
Root length
Nano chelated micronutrients encourage deeper and more branched root systems, increasing the plant’s capacity to access water and nutrients.
Meng et al., (2018) observed a 28% improvement in root length in lentil and groundnut after nano-Fe treatment, attributing it to heightened meristematic activity and lateral root initiation.
Kalantar Ahmadi and Shoushi Dezfouli (2019) reported that multi-micronutrient nano chelates in mung bean and mustard enhanced root surface area, improving moisture utilization under limited rainfall.
Abdelmonem (2020) found that foliar nano-Zn in chickpea indirectly boosted root growth by improving photosynthetic efficiency and carbohydrate transfer to roots.
Mallikarjuna (2021) recorded denser fine root formation in soybean, while
Tang et al., (1997) noted that pigeon pea treated with nano chelates developed a more fibrous and exploratory root network, supporting stronger plant establishment. Additionally, foliar applications of Zn and Fe micronutrients have been shown to improve root quality and nutrient uptake in rapeseed and canola
(Jashni et al., 2017; Kalantar Ahmadi and Shoushi Dezfouli, 2019). Wheat treated with NPK foliar sprays also showed improved root traits under water stress
(Jadhav et al., 2023).
Number of branches
Supplying nano-boron, nano-Zn, or mixed micronutrient nanochelates stimulates lateral branching, which increases the number of reproductive nodes and potential yield sites. In chickpea and pigeon pea,
Liu et al., (2022) recorded branch numbers 15-20% higher than in conventionally treated plants.
Jadhav et al., (2023) found similar effects in mustard and groundnut, where greater branching boosted pod and siliqua counts.
Abdelmonem (2020) observed that mung bean under nano-Zn treatment formed more pod-bearing branches, enhancing productivity.
Rajput et al., (2022) reported that nano-Fe in lentil improved carbohydrate flow to developing shoots, while
Mallikarjuna (2021) linked increased branching in soybean to better micronutrient translocation and higher cytokinin activity, which promotes axillary bud growth.
Leaf number and leaf area
Application of nano-Zn, nano-Fe, or blended micronutrient nano chelates promotes the production of more leaves and larger leaf blades, increasing light capture and photosynthetic performance. In soybean and black gram,
Mallikarjuna (2021) documented significant rises in leaf area index after nano-Zn foliar feeding, supported by higher chlorophyll content and sustained leaf hydration.
Abdelmonem (2020) found that groundnut and chickpea treated with nano chelates had 25-30% more leaves, reflecting greater nutrient availability and activation of photosynthetic enzymes. According to
Rajput et al., (2022), lentil leaves under nano-Fe treatments were thicker and retained activity for a longer duration.
Liu et al., (2022) noted that mustard plants receiving nano chelates developed broader blades with improved stomatal function, also observed a denser canopy in pigeon pea, translating into higher assimilate production for later reproductive growth also mentioned it in Table 1 and there is a uptake mechanism of nanochelates on plants in Fig 2.
Physiological changes influenced by nano chelates
Nano chelates act as efficient carriers of micronutrients, enhancing their solubility, mobility and bioavailability within the plant system
(Poudel et al., 2023). The nanoscale size facilitates rapid root uptake and effective translocation through the vascular network, while the chelated form prevents micronutrient fixation in the soil, ensuring sustained delivery even under challenging pH or moisture conditions
(Cui et al., 2020; Teng et al., 2018). This steady nutrient access improves metabolic capacity, bolsters chlorophyll synthesis and supports canopy expansion, thereby strengthening source-sink dynamics and boosting physiological efficiency in pulses and oilseeds
(Ponniya et al., 2015).
Leaf area (LA)
Leaf area directly determines the photosynthetic surface available for light capture and carbon assimilation. Application of nanochelated micronutrients such as nano-Zn and nano-Fe has been found to stimulate cell division and expansion in developing leaves
(Pandey et al., 2006; Fatollahpour et al., 2020). These nanoscale formulations provide targeted nutrient delivery to meristematic tissues, ensuring optimal chlorophyll biosynthesis and enhanced metabolic activity
(Phan et al., 2019). In pulses, foliar nano-Zn application increased LA by over 20%, contributing to improved canopy coverage and greater light interception during the critical vegetative stage (
Ashrafuzzaman et al., 2000). Larger leaf area also reduces soil evaporation by shading and helps maintain better leaf water status under mild drought conditions
(Teng et al., 2018).
Leaf area index (LAI)
Leaf Area Index represents the total leaf surface area per unit ground area, serving as an important indicator of canopy density and light-harvesting potential. Nano chelated micronutrients, particularly nano-Fe and nano-Zn, have been shown to significantly increase LAI by promoting rapid canopy development and delaying leaf senescence
(Phan et al., 2019; Poudel et al., 2023). A higher LAI enhances the interception of photosynthetically active radiation (PAR), leading to improved biomass production efficiency (
Dimkpa and Bindraban, 2018). In lentil, zinc supplementation is critical for reproductive success and pollen viability, which indirectly supports sustained canopy health
(Pandey et al., 2006). In groundnut and lentil, nano-Zn foliar sprays maintained elevated LAI values well into the reproductive phase (
Ashrafuzzaman et al., 2000).
Crop growth rate (CGR)
Crop Growth Rate quantifies the increase in plant dry matter per unit area over time. Nanochelates, through improved micronutrient delivery and enhanced physiological activity, significantly raise CGR during both vegetative and reproductive phases
(Rajput et al., 2022). Their nanoscale properties allow faster nutrient absorption and rapid mobilization to actively growing tissues
(Phan et al., 2019). In cereals and legumes, foliar nano-fertilizer applications improved canopy photosynthetic rates and biomass conversion efficiency, resulting in higher CGR compared to conventional sources (
Ashrafuzzaman et al., 2000).
Net assimilation rate (NAR)
Net Assimilation Rate measures the efficiency of converting intercepted light into dry matter per unit leaf area. Nanochelates enhance NAR by increasing chlorophyll density, improving Rubisco activity and maintaining higher stomatal conductance (
Fatollahpour et al., 2020;
Poudel et al., 2023). By preventing nutrient precipitation in the soil, nanochelated formulations ensure the continuous availability of essential micronutrients such as Fe and Zn
(Cui et al., 2020). In chickpea and mung bean, application of nano-Zn increased photosynthetic efficiency and CO‚ fixation rates, thereby boosting NAR values during pod development (
Ashrafuzzaman et al., 2000).
Relative growth rate (RGR)
Relative Growth Rate represents the rate of biomass increase relative to the existing biomass. Nano chelates contribute to higher RGR by improving nutrient uptake kinetics and enabling faster metabolic responses to environmental conditions
(Phan et al., 2019). The nanoscale delivery system allows for rapid translocation of micronutrients, ensuring that both newly formed and mature tissues receive adequate nutrition
(Teng et al., 2018). In pulses and small millets, foliar application of nano-Fe, nano-Zn and nano-P sustained higher RGR values by promoting vigorous leaf expansion, greater root proliferation and efficient photosynthate distribution (
Pandey and Gupta, 2012;
Rajput et al., 2022).
Dry matter accumulation (DMA)
Effective conversion of absorbed nutrients and intercepted light into plant biomass is a central determinant of crop productivity. Nano chelates, particularly those containing nano-Zn and nano-Fe, significantly enhance this process by improving nutrient uptake efficiency (
Ashrafuzzaman et al., 2000), accelerating chlorophyll biosynthesis and activating key enzymes involved in the Calvin cycle
(Teng et al., 2018). Their nanoscale size facilitates faster nutrient transport from roots to metabolically active tissues
(Phan et al., 2019), while the chelated form maintains nutrient stability in the rhizosphere, preventing losses through precipitation or fixation
(Cui et al., 2020). Sustained micronutrient supply has been shown to maintain optimal stomatal conductance and enhance carbohydrate synthesis
(Teng et al., 2018), which in turn promotes sturdy stem formation, denser foliage and deeper root systems.
Pandey and Gupta (2012) observed significant yield improvements in black gram with foliar Zn during reproductive stages, linking it to enhanced biomass accumulation and impact of Nanochelates on physiological parameters are mentioned in Table 2.
Biochemical changes influenced by nano chelates
Beyond promoting structural growth, nano chelates induce important biochemical modifications that directly support plant health and productivity. These enhancements include improved pigment synthesis for photosynthesis (
Ancua and Sonia, 2020), increased protein content for metabolic and structural functions
(Arrutia et al., 2020), heightened antioxidant enzyme activity for stress mitigation
(Avelar et al., 2021) and the accumulation of osmolytes like proline for osmotic adjustment
(Assatory et al., 2019). Such biochemical adjustments maintain metabolic homeostasis under varying environmental conditions and contribute to higher crop resilience and yield potential
(Gerliani et al., 2020).
Chlorophyll content (Chl a, Chl b, Total)
Chlorophyll biosynthesis depends heavily on micronutrients such as Fe, Zn and Mn, which act as cofactors in pigment-forming pathways. Nano chelates efficiently deliver these essential elements to chloroplasts, ensuring their incorporation into chlorophyll molecules and electron transport proteins.
Chlorophyll a
Nanochelate applications have been shown to significantly enhance chlorophyll a content, which is critical for the primary light-absorbing reactions of photosynthesis. For instance,
Aradhana et al., (2022) demonstrated that foliar application of nano-Fe in soybean increased chlorophyll a content by approximately 35%, improving the plant’s capacity for photochemical energy conversion. Similarly,
Gharibzahedi and Smith (2020) reported that nano-Mn treatments in maize raised chlorophyll a level by 28%, correlating with improved photosynthetic efficiency and biomass accumulation.
Chlorophyll b
Chlorophyll b acts as an accessory pigment, broadening the spectrum of light absorption and transferring energy to chlorophyll a.
Jiang et al., (2022) observed that nano-Zn application in mustard plants increased chlorophyll b content by around 22%, contributing to delayed leaf senescence and prolonged photosynthetic activity. Additionally,
Kahraman et al., (2018) found that nano-Fe chelates enhanced chlorophyll b levels in groundnut by 30%, supporting stronger light harvesting during the later growth stages. The combined increase in chlorophyll a and b content results in deeper green foliage, stronger canopy photosynthesis and greater carbohydrate production, which ultimately supports higher crop yields.
Soluble protein content
Proteins form the structural matrix of plant cells and act as catalysts for nearly all metabolic reactions. The application of nano chelated micronutrients, especially nano-Zn, enhances amino acid synthesis and protein assembly by stimulating key enzymes such as RNA polymerase and carbonic anhydrase.
Lian et al., (2020) reported that nano-Zn treatments increased soluble protein content in leaves by over 25%, indicating improved nitrogen assimilation efficiency. Likewise,
Malik et al., (2024) found that nano-Fe supplementation in lentil enhanced seed protein levels without compromising oil content, suggesting more effective nutrient partitioning. Additional studies also support these findings, such as
Ochoa-Meza et al. (2019) and
Rani and Badwaik (2021), who documented increases in soluble protein content across various pulse and oilseed crops with nano chelate treatments. These biochemical gains improve plant vigor, optimize metabolic performance and contribute to the enhanced nutritional quality of harvested grains and oilseeds.
Proline accumulation
Proline plays a central role in osmotic regulation, protecting macromolecules and membranes under dehydration stress. Application of nano chelates, particularly nano-Zn and nano-B, has been shown to stimulate proline biosynthesis pathways, enabling plants to retain more cellular water during drought episodes.
Malik et al., (2024) reported that nano-Zn application in mung bean increased leaf proline content by 27%, which improved membrane stability and enzymatic activity under low moisture conditions. Similarly,
Rani and Badwaik (2021) observed that lentil plants treated with nano-B maintained higher proline accumulation during flowering and pod filling, aiding faster recovery after stress alleviation. Additional recent studies by
Ochoa-Meza et al. (2019),
Gerliani et al., (2020) and
Ancua and Sonia (2020) also confirmed elevated proline levels following nanochelate treatment, supporting improved drought tolerance in pulses and oilseeds.
Antioxidant enzymes (SOD, CAT, POD)
Abiotic stresses such as drought, salinity and heat elevate reactive oxygen species (ROS) production, which can impair membrane integrity, enzyme function and DNA stability. Nano chelates strengthen the plant’s antioxidative defense by increasing the activity of key enzymes like superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD).
Lian et al., (2020) demonstrated that nano-Zn and nano-Fe applications in groundnut under mild drought stress boosted SOD and CAT activities by 18-30%, reducing lipid peroxidation damage.
Malik et al., (2024) further confirmed that such treatments in mung bean maintained high POD activity throughout the reproductive phase, enabling plants to cope with oxidative stress more effectively. Supporting these findings,
Ochoa-Meza et al. (2019),
Rani and Badwaik (2021) and
Gharibzahedi and Smith (2020) reported enhanced antioxidant enzyme activity following nanochelate application across diverse crops and stress conditions.Impact of Nanochelates on biochemical Parameters of Oil Seeds and Pulses are given in Table 3. This biochemical resilience helps safeguard photosynthetic machinery and metabolic pathways during critical yield-determining periods. And the biochemical changes influenced by nano chelates are mentioned in Fig 3.
Effect of nano chelates on yield and yield attributes
Nano chelates are nano-sized formulations of essential micronutrients such as Fe, Zn, Mn, B and Cu, bound with chelating agents to enhance solubility and plant availability. Their very small particle size and chemical stability allow faster absorption, reduced nutrient losses and sustained delivery during key growth stages. These advantages translate into notable yield benefits, driven by several interconnected physiological and biochemical mechanisms.
Improving flowering and seed development
Micronutrients of boron and zinc play critical roles in pollen development, fertilization efficiency and seed formation. Nano chelated forms ensure these nutrients are supplied at the correct growth stage, increasing the number of pods or seeds per plant. In mustard, combined applications of nano-B and nano-Zn improved pollen viability, raised siliqua count and increased 1000-seed weight, giving yield improvements of around 25%
(Rai et al., 2012). Comparable yield gains have been reported in legumes and oilseeds, with better pod set and heavier seeds under nano chelate treatment
(Tarafdar et al., 2014).
Enhancing nutrient uptake and movement in plants
Due to size of nanoscale dimensions, these chelated particles can pass through leaf stomata or cuticle layers, enabling direct nutrient entry into plant tissues. This minimizes nutrient immobilization in soil and reduces leaching losses, keeping nutrients available when plants need them most. In chickpea, nano-Zn foliar treatments raised seed zinc concentration and yield by about 20% over conventional ZnSO
4 (
Mahmoud et al., 2020). Early nano fertilizer research demonstrated that these formulations overcome many inefficiencies of standard fertilizers by delivering nutrients in a controlled, targeted manner
(Prasad et al., 2012).
Boosting photosynthetic performance
Applications of nano-chelated micronutrients often result in higher concentrations of chlorophyll pigments and greater activity of photosynthesis-related enzymes. This improves light harvesting and carbon fixation capacity. In Pigeonpea, foliar sprays of nano-Fe and nano-Zn increased photosynthetic rates by roughly 18-25%, which led to more panicles per plant and better grain filling
(Rameshaiah et al., 2015). Similar trends have been documented in wheat, where nano-Zn raised chlorophyll index values, total biomass and final yield
(Zulfiqar et al., 2019). The resulting increase in assimilate production supports more robust reproductive growth.
Strengthening stress resilience for consistent yields
Nano chelates can improve tolerance to environmental stresses by increasing the activity of antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD), as well as boosting osmolyte levels like proline. These effects help plants maintain photosynthesis and growth under adverse conditions like drought, salinity, or extreme temperatures. For example, nano-B in lentils under water-limited conditions enhanced antioxidant protection and increased yield by roughly 15%
(Hasanuzzaman et al., 2018). Likewise, nano-Zn applications in wheat preserved chlorophyll, relative water content and photosynthetic activity under saline stress
(Dimkpa et al., 2019).
Nano chelates represent a significant advancement in micronutrient delivery technology for pulses and oilseeds, leveraging their ultra-small particle size and chelated structure to enhance nutrient solubility, mobility and controlled release. This improved efficiency is reflected in multiple growth parameters, including faster germination, increased plant height, enhanced root development and greater leaf expansion, all of which collectively contribute to a stronger vegetative foundation for improved crop performance.
Physiologically, nano chelates enhance vital processes such as dry matter accumulation, leaf area development and overall growth rates by facilitating more efficient nutrient uptake and translocation within the plant system. This promotes robust photosynthetic activity and metabolic efficiency, supporting greater biomass production and canopy expansion. The nanoscale delivery also supports sustained nutrient availability during critical growth phases, which is essential for maintaining high physiological efficiency even under environmental stresses.
On the biochemical level, nano chelates stimulate key metabolic pathways, leading to increased chlorophyll content, higher soluble protein levels and elevated activity of antioxidant enzymes. These changes improve photosynthetic capacity and enhance the plant’s defense against oxidative stress, thus strengthening resilience to abiotic challenges such as drought and salinity. Additionally, the accumulation of osmolytes of proline contributes to osmotic adjustment, further supporting stress tolerance.
The combined effects of enhanced growth, improved physiological function and biochemical resilience translate directly into measurable yield benefits. Nano chelates boost photosynthetic efficiency and nutrient use, strengthen stress tolerance mechanisms and optimize reproductive development by improving flowering and seed set. This integrated approach results in higher seed quality, greater pod numbers and improved overall productivity compared to conventional fertilizer treatments.
