Abstract: Experiments were conducted from four aspects: The germination rate of cucumbers, root length, antioxidant system [peroxidase(POD), superoxide dismutase(SOD), catalase(CAT)], and photosynthetic characteristics of leaves(net photosynthetic rate, stomatal conductance, intercellular CO₂ concentration). Based on the physiological characteristic detection of cucumber seedlings, the effects of different concentrations of nano-iron(III) oxide (Fe₂O₃NPs) (0, 5, 10, 15, 20 mg/L) on the growth of cucumber plants were studied. The results showed that Fe₂O₃NPs had a dual concentration effect on the growth and development of cucumbers. Low concentrations(5,10 mg/L) of Fe₂O₃NPs had a certain promoting effect on the germination rate of seeds and the growth of main roots, while high concentrations(15,20 mg/L) of Fe₂O₃NPs exhibited inhibitory effects. Under low concentrations, the photosynthetic characteristics and the activity of antioxidant enzymes were enhanced, while under high concentrations, the photosynthetic characteristics and the activity of antioxidant enzymes were inhibited,accompanied by oxidative damage.

Key words: nano-iron(III) oxide(Fe₂O₃NPs), cucumber, physiological characteristics, germination rate, photosynthetic characteristics