The effect of silver nanoparticles treatment on some physiological and biochemical responses of safflower

Silver nanoparticles are widely used in industry, medicine, biotechnology and agriculture. As a consequence, these nanoparticles are reaching the environment as waste products, which might have a negative impact on the environment, especially on plants. In this study, the effects of two concentrations (5 and 7 ppm) of silver nanoparticles on safflower (Carthamus tinctorius) were investigated in vitro. Increased germination rate in from 70% (in non treated control) up to 90% (in 7 ppm nanosilver treated seeds) was bserved. 5% higher dry weight biomas in 5 ppm nanosilver treated plants and 12% lower biomas in 7% treated ones as compared to their non-treated controls confirmed that the toxicity threshold level is between these two concentrations. Increased thickness of epidermis layer and root hairs length as well as deletion of schloranchima cells in roots under silver nanoparticle was observed in anatomical study of safflower. The results also showed a remarkable decrease in and proline content in root while induction of MDA and proline content was observed in shoot under nanosilver treatment that can be an indicator for induction of oxidative stress in shoot by treatment. Moreover, nanosilver causes induction of chlrophyll a, total chlrophyll and carotenoid contenten in safflower.