Fig. 4
From: Silica nanoparticles protect rice against biotic and abiotic stresses
TEM observation of SiO2 NPs distribution in rice leaves under different concentrations through foliar treatment. Leaves of the 2-week-old rice seedlings were exposed to SiO2 NPs with spraying method treated for 1 day before observation. Red arrows point to the nanoparticles. Ep stands for epidermis. The boxes with dashed and solid lines represent the magnification of the part. A Rice leaves treated with 100 mg/L SiO2 NPs through foliar treatment. Little SiO2 NPs were observed in the inside air space with no nanoparticles accumulated around the stomata. No nanoparticles found in the cell wall and epidermis cells. B Rice leaves treated with 3000 mg/L SiO2 NPs through foliar treatment. Numerous nanoparticles accumulated around the stomata and entered into the plant not only through the stomata but also through the nearby epidermis cells. The small letter “a, b, and c” point to the SiO2 NPs entry process from outside cell wall to the inside epidermis cell and then into the air space