Application of ZnO nanoparticles in influencing the growth rate of Cicer arietinum

In this work, ZnO nanoparticles (NPs) have been synthesised by hydrothermal method. This hydrothermally synthesised product has been characterised by powder X-ray diffraction and field emission scanning electron microscopy (FE-SEM) for the study of crystal structure and morphology/size. FE-SEM image revealed that ZnO NPs are spherical in shape with a diameter of 20-30 nm. The photoluminescence study of these NPs revealed that ZnO NPs consist of three emission peaks at 401, 482 and 524 nm. The UV emission peak at 401 nm is the band edge emission; however, the blue-green emission at 482 nm and green emission at 524 nm is related to defects. These ZnO NPs are used during the seed germination and root growth of Cicer arietinum. The effect of ZnO NPs has been observed on the seed germination and root growth of C. arietinum seeds. The effect of these ZnO NPs on the reactivity of phytohormones, especially indole acetic acid (IAA) involved in the phytostimulatory actions, is also carried out. Due to oxygen vacancies, the oxygen deficient, i.e. zinc-rich ZnO NPs increased the level of IAA in roots (sprouts), which in turn indicate the increase in the growth rate of plants as zinc is an essential nutrient for plants.