The effect of silicon on some morpho-physiological and phytochemical traits of Purple Coneflower (Echinacea purpurea L.) under salinity stress

The most important abiotic stresses is salinity and more importantly affect plant growth and limit the plants yield capacity. Silicon is the second most abundant element in the soil and alleviates the biotic and abiotic stresses in plants. The aim of this study is to assess the effects of salt stress and silicon on the some morphological and phytochemical characteristics of purple coneflower (Echinacea purpurea L.). This study was conducted in completely randomized based factorial design with 4 levels of salinty and 4 levels of silicon and 4 replications. Application of stress in hydroponic culture medium (perlite and cocopeat) with Hoagland nutrition solution. The result showed, salinity significantly affected morphophysiological and phytochemical characteristics and silicon affected all characteristics except leaf burn percent. Also, the interactions of these two factors on each trait except shoot wet and dry weight and leaf burn percentage were significant So that the negative effects of salinity stress on growth, morpho-physiological and phytochemical traits of the plant were greatly reduced by silicon and improved the growth and increase of yield. Also, the interaction of these two factors on all traits except the wet and dry weight and leaf burn were affected and the negative effect of salinity stress, especially in the least to medium levels, on growth and morphology, and phytochemical characteristics of the plant were decreased and improved growth. So that the best salinity level in increasing biochemical factors, 25 mM NaCl and the best level for silicon, was 2.25 mM in reducing the negative effects of salinity stress.