Naphtalene effect on Germination and growth factors of seedlings in Helianthus annus L.

Naphthalene is one of the main polycyclic aromatic hydrocarbons that is increasing in the petrochemical industry and is on the list of toxic pollutants. These contaminations are mutagenic and have a large impact on the ecosystem of the region, gradually they are emerging to the food cycle and human societies. Thus threaten human health, plants, animals, rivers, underground water and agricultural production. Germination is the first and most important stage in plant development. In this study to evaluate the effect of naphtalene (30 & 50 mg/L) on germination, radical growth and biomass of seedlings in Helianthus annus L., an experiment was conducted. Seeds germinated in petri dishes and seven days later, those were studied. The results showed that naphthalene was not have a significant effect on germination percent. It Reduced the radicle length and also reduced the dry and fresh weight of the seedlings. Therefore, naphthalene because of its non-polar and hydrophilic structure decreases the rate of water absorption and affects the germination rate, and as a result, leads to decrease in length of the radicle and biomass of the seedlings.