Table 1 Mode of nanoparticle application influences phytotoxicity and their physiological function

Silver nanoparticles (AgNPs)

 AgNPs

5 and 10 mg/L

Seed priming

Improved Water Intake, Seed Germination and starch Metabolism

Elevated ROS and H₂O₂

Normal

[28]

 AgNPs

100 and 1000 mg/L

Seed priming

Decreased the germination and growth of rice seedlings

–

Normal

[36]

 AgNPs

60 mg/L

Seed priming

Improved agro-morphological parameters, biochemical parameters, and enzymatic activities

–

Normal

[36]

 AgNPs

150 mg/L

Soil

Increase of antioxidants, lipid peroxidation, and reduced contents of chlorophyll, carotenoids, total carbohydrate, and total soluble proteins

Accumulation of AgNPs in root > leaf > stem

Normal

[36]

 AgNPs

200 mg/L

Vegetative growth stage

Increase of antioxidants, lipid peroxidation, and reduced contents of chlorophyll, carotenoids, total carbohydrate, and total soluble proteins

Accumulation of AgNPs in root > leaf > stem

Normal

[37]

 AgNPs

10 and 15 mg/L

Seed priming and foliar application

Higher germination rate, increased chlorophyll contents, increased stomatal conductance, and higher seedling masses

Reduced diseased condition in seeds

Thermal stress

[38]

Gold nanoparticles (AuNPs)

 AuNPs

500–1000 µM and 5–11 mg/L

Soil

Increased the seed germination and vegetative growth

–

Normal

[44]

 AuNPs

5–11 mg/L

Soil

Increased seed germination rate

–

Normal

[44]

 AuNPs

5 to 15 ppm

Seed priming

Enhanced germination of naturally aged seeds, improved overall growth

–

Normal

[38]

 AuNPs

10, 25, 50 and 100 mg/L

Foliar spray

10 ppm increased the number of leaves per plant and seed yield and 25 ppm increased total sugar content

–

Normal

[45]

 AuNPs

20 µg/mL

Seed priming

Defense mechanism by improving plant growth and photosynthesis

–

Cold stress

[45]

 AuNPs

0.1–10 mg/L

Size dependent (15, 30 and 40 nm)

Increase in chromosomal aberrations and decrease in mitotic index

–

Normal

[47]

 AuNPs

10 mg/L

Size dependent (10 nm)

Decreased biomass and root length

–

Normal

[48]

 AuNPs

22–25 nm

Hydroponic or soil mixing methods

-

Dose-dependent DNA damage

Normal

[49]

 AuNPs

3.5 nm

Spherical-shaped AuNPs

Transporting in size-dependent mechanisms and translocating to cells and tissues

Exhibited leaf necrosis

Normal

[50]

Zinc nanoparticles (ZnONPs)

 ZnONPs

500 mg/mL

Soil

Improving the growth, chlorophyll contents, Zn contents

Reducing oxidative stress and cadmium (Cd) contents

Cd stress

[51]

 ZnONPs

200 mg/mL

Foliar spray

Improving the growth, chlorophyll contents, Zn contents

Reducing oxidative stress and cadmium (Cd) contents

Cd stress

[51]

 ZnONPs

1600 mg/L

Seed priming

Alfalfa was reduced to 40%, and tomato seeds by 20%, but increased cucumber seed germination

–

Normal

[53]

 ZnONPs

100 mg/L

Seed

Increased germination rate

–

Normal

[54]

 ZnONPs

1000 mg/L

Foliar application

Positive effect on plant height, stem diameter, chlorophyll content, fruit yield and biomass production

–

Normal

[51, 55,56,57]

 ZnONPs

2000 mg/L

Foliar application

Negative effect on plant height, stem diameter, chlorophyll content, fruit yield and biomass production

Increase antioxidant activity

Normal

[51, 55,56,57]

 ZnONPs

60 mg/L

Seed Priming

Maintain redox homeostasis by decreasing ROS generation; Increase antioxidant enzyme activities (SOD, peroxidase) and Low levels of Zn cannot elevate ROS due to poor activation of antioxidant machinery under stress conditions

Preventing cells from ROS attack under salt stress conditions

Salt stress

[58, 59]

 ZnONPs

90 mg/L

Soil

Triggered localization of ZnONPs in vacuoles and chloroplasts; Reversed abnormal modifications to chloroplast, mitochondria, and cell wall

Stimulated antioxidant enzymes, enhanced osmolyte contents; No phytotoxicity observed under heat stress for alfalfa plants

Heat stress

[58, 59]

 ZnONPs

100 mg/L

Foliar application

Improved drought-associated detrimental effects and growth-promoting effect

–

Normal and drought

[58, 59]

 ZnONPs

400 mg/L

Foliar application

Increased oxidative stress

–

Normal

[60]

 ZnONPs

400 mg/L

Foliar Application with Silicon Modification

Improved stability, hydrophilicity, and salt tolerance

–

Normal

[60]

 ZnONPs

500 mg/L

Soil mixture

Increased Zn in roots; Root elongation; Translocation of Zn to aerial parts

Increased H₂O₂ accumulation in leaves; Reduced antioxidant enzymes (CAT, APX)

Normal

[61]

Copper nanoparticles (CuNPs)

 CuNPs

4.44 mg/L

seed priming

Improved plant biomass in normal and drought conditions

–

Normal and drought

[61]

 CuNPs

250 mg/L

Seed priming

Increased bioactive components (vitamin C, lycopene, total phenols, flavonoids), antioxidant enzyme accumulation (CAT, SOD)

–

Normal and drought

[62]

 Cu

0–20 mg/L

Hydroponic Culture

Reduced root length in lettuce and alfalfa; Translocation of nCu observed in dose-dependent manner

Alfalfa more sensitive to nCu compared to lettuce

Normal

[71]

 nCu

10 and 20 mg/L

Hydroponic Culture

Reduced water content, root length, dry biomass; Modified defense-related metabolites

–

Normal

[6, 70]

 Cu@CuO and nCuSO₄.5H₂O

10 and 20 mg/L

Hydroponic Culture

Reduced water content, root length, dry biomass; Modified defense-related metabolites

–

Normal

[6, 70]

 nCu(OH)₂-b

1050 mg/L to 2100 mg/L

Foliar spray

Increased leaf biomass; Changes in metabolites indicating defensive response

–

Normal

[71]

 nCu/Kg

200–800 mg/mL

Soil

Increased Cu accumulation in roots; Detrimental effects in stem, leaves, and fruits

–

Normal

[71]

 nCu(OH)₂-b

10 mg/L

Soil

Arrested photosynthesis, stunted growth in Clarika unguiculata

High light levels and limited soil conditions

Normal

[71]