Effect of various potassium nitrate levels on germination and morphological characteristics of Mentha longifolia

Nitrogen is one of the most important plant macronutrients. Nitrate accumulation in the plants via excessive use of nitrate fertilizers, sewage wastewater and etc., can affect plant growth and development and so could be a threat for human health, animals and the ecosystem. Since the Mentha longifolia is naturally growing in the margin of contaminated water, could be a candidate for nitrate phytoremediation. As the first step to evaluate phytoremediation potential of this species, effect of potassium nitrate (concentration of zero, 1, 5, 11, 15 mM) on its seed germination characteristics was studied using a completely randomized design. Then, nitrate effects on some morphological characteristics of M. longifolia which were grown in hydroponic culture, treated with different concentrations (5.5, 5.5, 5.5, 5.5 mM) of nitrate, and were evaluated. Results indicating that, potassium nitrate has a positive impact on the germination characteristics, seedling growth and morphological characteristics of this species. Thus, in the presence of high levels of nitrate can germinate and establish to be effective on nitrate absorption, assimilation and phytoremediation in the later growth stages. So it seems that M. longofolia is a good choice for phytoremediation and remove excess amounts of environmental nitrate.

Keywords:

germination index , Phytoremediation , nitrate , Mentha Longifolia