Size effect of iron (III) oxide nanomaterials on the growth, and their uptake and translocation in common wheat (Triticum aestivum L.)

Abstract

Nanomaterials (NMs) have emerged in the last decades and are used in many disciplines such as industry, material sciences, biomedicine, biotechnology, bioenergy, and agriculture. The size of the NMs is a critical factor that affects NMs' integration and transfer into the biological systems. Therefore, this study aims at investigating the effect of NMs-size on i) plant growth and physiology, and ii) NMs uptake and translocation in plant tissues. For these purposes, iron (III) oxide (Fe₂O₃) NMs with varied sizes, 8-10, 20-40, and 30-50 nm, have been applied to wheat plants in a hydroponic system. Results showed that Fe₂O₃ NMs enhanced root length, plant height, biomass, and chlorophyll content of wheat. Confocal microscopy analysis indicated that Fe₂O₃ NMs cause injury in root-tip cells without a visible toxic symptom. Vibrating sample magnetometer (VSM), and inductively coupled plasma-mass spectroscopy (ICP-MS) analyses of leaf tissues revealed that all tested NMs were up taken by wheat plant and translocated to the leaves. Iron content was found to be dramatically increased in NMs-treated plant tissues, which possibly contributed to the growth enhancement. Experiments confirmed that Fe₂O₃ NMs with 20-40 nm size is much more efficient in plant growth compared to those with 8-10 and 30-50 nm size. Overall, Fe₂O₃ NMs with 20-40 nm in size could be proposed as a nano-fertilizer for agricultural applications. On the other hand, the translocation of NMs in the wheat plant requires further investigation of their effects on the end users.

Keywords: Chlorophyll; Iron oxide nanomaterials; Size effect; Translocation; Uptake; Wheat.