Nanoparticles have broad applications in various industries, that it can be expected them find a way to enter into the environment and affected the living organism with unexpected consequences. Alumina nanoparticle is one of the most applicable nanoparticles, so in this study we assesed its effects on Lepidium draba plant. Some morphological and biochemical characteristics of the 7-day-old seedlings that were grown in Murashige and Skoog basal medium containing 0, 25, 50, 250, 500 and 1000 mg/L particles were measured in compared to the bulk form. The results revealed that nano and bulk particles lead to decreasing the seed germination rate and the root and shoot elongation, such that in the highest concentration, it was more significant by the nanoparticle. While sulforaphane contents decreased approximately the same for the nano- and bulk alumina treated seedlings, the flavonoid content increased by the increase in particles concentrations in media, but it was more significant by the nanoparticle. While the peroxidase activity significantly increases only in the presence of nanoparticle, the catalase activity significantly increased in the treated seedlings by both particles, that it was more significant by the nanoparticle. Based on the bioaccumulation data, aluminum can be absorbed by the roots and transported to the shoots from both media, but maximized by nano. Overall, it may be concluded that oxidative stress upon absorbed of these particles is responsible for decreasing more the plant growth in the presence of nanoparticles than bulk ones.