Table 1 Ameliorative effects of NMs on abiotic stress in crops

Heat

MWCNTs (10–35 nm)

Tomato (Solanum lycopersicum L.)

Upregulated the expression of various stress-related genes including HSP90

Khodakovskaya et al. [117]

CeO₂ NPs (~ 10 nm)

Maize (Zea mays L.)

Decreased production of hydrogen peroxide (H₂O₂) and upregulation of HSP70

Zhao et al. [118]

TiO₂ NPs (~ 16 nm)

Tomato (S. lycopersicum L.)

Enhanced photosynthesis, regulated energy dissipation, and induced stomatal opening

Qi et al. [119]

Ag NPs (10–20 nm)

Wheat (Triticum aestivum L.)

Protected plants against heat stress and improved plant growth significantly

Iqbal et al. [120]

Ag NPs (15–30 nm)

Wheat (T. aestivum L.)

Alleviated the harmful effects of salinity stress

Abou-Zeid and Ismail [121]

Se NPs (10–40 nm)

Tomato (S. lycopersicum L.)

Increased chlorophyll content, hydration of plants, and growth

Djanaguiraman et al. [122]

Cold

SiO₂ NPs (10–15 nm)

Wheatgrass (Agropyron elongatum L.)

Overcame seed dormancy, enhanced seed germination and seedling weight

Azimi et al. [123]

Na₂SeO₄ NPs (20–35 nm)

Tomato (S. lycopersicum L.)

Improved plant growth, chlorophyll, and leaf-relative water contents

Haghighi et al. [124]

TiO₂ NPs (~ 20 nm)

Chickpea (Cicer arietinum L.)

Enhanced expression of Rubisco- and chlorophyll-binding protein genes

Hasanpour et al. [125]

ZnO NPs (~ 30 nm)

Rice (Oryza sativa L.)

Alleviated chilling stress by regulating the chilling response transcription factors

Song et al. [126

Salinity

SiO₂ NPs (~ 20 nm)

Tomato (S. lycopersicum L.)

Alleviated the effect of salinity on fresh weight, chlorophyll, and photosynthetic rate

Haghighi and Pourkhaloee [127]

SiO₂ NPs (~ 12 nm)

Squash (Cucurbita pepo L.)

Reduced levels of malondialdehyde (MDA), H₂O₂, and electrolyte leakage

Siddiqui et al. [76]

SiO₂ NPs (~ 20 nm)

Tomato (S. lycopersicum L.)

Suppressed the effect of salinity on germination rate, root length, and fresh weight

Almutairi [128]

Chitosan NPs (~ 38 nm)

Maize (Z. mays L.)

Alleviated the harmful effects of salinity stress

Bruna et al. [129]

MWCNTs (30–100 nm)

Cabbage (Brassica oleracea L.)

Alleviated the harmful effects of salinity stress

Martinez-Ballesta et al. [130]

ZnO NPs (~ 20 nm)

Sunflower (Helianthus annuus L.)

Increased net CO₂ assimilation rate, sub-stomatal CO₂ content, and Fv/Fm ratio

Torabian et al. [131]

Fe₂O₃ NPs (~ 50 nm)

Peppermint (Mentha piperita L.)

Increased leaf dry weight, phosphorus, potassium, iron, zinc, and calcium contents

Askary et al. [132]

Fe₂O₃ NPs (~ 20 nm)

Wheat (T. aestivum L.)

Improved the growth of both root and shoot

Fathi et al. [133]

ZnO NPs (~ 20 nm)

Wheat (T. aestivum L.)

Improved the growth of both root and shoot

Fathi et al. [133]

SiO₂ NPs (~ 10 nm)

Cucumber (Cucumis sativus L.)

Increased plant germination and growth characteristics

Alsaeedi et al. [134]

SiO₂ NPs (20–30 nm)

Soybean (Glycine max L.)

Reduced oxidative damage due to expression of antioxidative enzymes

Farhangi-Abriz and Torabian [135]

Chitosan NPs (~ 25 nm)

Tomato (S. lycopersicum L.)

Alleviated the harmful effects of salinity stress

Hernandez-Hernandez et al. [136]

CeO₂ NPs (~ 8.5 nm)

Cotton (Gossypium hirsutum L.)

Modulated α-amylase activities and ROS homeostasis

Khan et al. [137]

CeO₂ NPs (~ 8 nm)

Rapeseed (Brassica napus L.)

Enabled better ability to maintain cytosolic K⁺/Na⁺ ratio

Liu et al. [138]

Drought

TiO₂ NPs (~ 20 nm)

Wheat (T. aestivum L.)

Increased growth, yield, gluten, and starch content

Jaberzadeh et al. [139]

ZnO NPs (~ 20 nm)

Soybean (G. max L.)

Increased germination percentage and rate, decrease in fresh and dry weights

Sedghi et al. [67]

Fe₂O₃ NPs (20–100 nm)

Sunflower (H. annuus L.)

Counteracted drought stress with no effect on proline and total amino acids

Martinez-Fernandez et al. [140]

TiO₂ NPs (10–25 nm)

Lin seed (Linum usitatissimum L.)

Enhanced chlorophyll and carotenoid content, decreased H₂O₂ and MDA contents

Aghdam et al. [141]

MWCNTs (20–30 nm)

Barley (Hordeum vulgare L.)

Boosted seed water absorption and increased seedling water content

Karami and Sepehri [142]

CeO₂ NPs (6–24 nm)

Soybean (G. max L.)

Enhanced growth, development, and yield

Cao et al. [143]

Fe NPs (40–53 nm)

Strawberry (Fragaria ananassa L.)

Enhanced acclimation and resistance of plants to drought

Mozafari et al. [144]

Heavy metal

Fe₃O₄ NPs (~ 20 nm)

Rice (O. sativa L.)

Reduced As transport from the root to the shoot

Huang et al.[145]

Si NPs (~ 50 nm)

Wheat (T. aestivum L.)

Alleviated Cd toxicity by reducing Cd²⁺ uptake and enhancing antioxidative capacity

Ali et al. [146]

CuO NPs (9–22 nm)

Rice (O. sativa L.)

Reduced total As by 23% and 45% in roots and shoots

Wang et al. [147]

ZnO NPs (30–40 nm)

Rice (O. sativa L.)

Improved plant growth and alleviated the toxic effects of Cd

Zhang et al. [148]

SiO₂ NPs (~ 100 nm)

Rice (O. sativa L.)

Inhibited As uptake into rice suspension cells via improving pectin synthesis

Cui et al. [149]

TiO₂ NPs (36–140 nm)

Rice (O. sativa L.)

Reduced As toxicity and reduced As bioaccumulation in rice seedlings by 40–90%

Wu et al.[150]

Au NPs (~ 40 nm)

Rice (O. sativa L.)

Suppressed Cd uptake and alleviated Cd toxicity

Jiang et al. [151]

ZnO NPs (20–40 nm)

Rice (O. sativa L.)

Modulated early growth and enhanced physio-biochemical and metabolic profiles

Li et al. [65]

ZnO NPs (20–30 nm)

Rice (O. sativa L.)

Alleviated the As toxicity and decreased the accumulation of As

Yan et al. [45, 152]