The effect of different media cultures on some growth characteristics of pot marigold (Calendula officinalis L.) plants under drought stress

Drought is one of important environmental stresses that cause decreasing of production and yield in arid and semi-arid areas. Aim of this study was using of some amendment compounds in soil to increase marigold plant (Calendula officinalis L.) resistance to drought stress. Experiments were performed in factorial according a completely randomized design with three replications. Treatment were consisted of six amendment compounds (control (only soil), 1 and 2 g/kg nano- potassium fertilizer, 30% of vase volume cocopeat, 30% of vase volume palm peat and 30% of vase volume madder plant residues) in three levels of drought stress (40, 60 and 80% of field capacity). According to the results by increasing the drought level, fresh and dry weight of flower and root significantly decreased. While peroxidase enzyme activity significantly increased. The highest fresh and dry weight of flower and root was obtained in plants were treated by madder plant residues. The lowest fresh and dry weight of flower and root in all drought levels obtained in plants were treated by palm peat. Plants were treated by palm peat in all three levels of drought did not show reproductive phase and flower. Fresh weight of flower had significant correlation by dry weight of flower, fresh and dry weight of root and phosphorus uptake. Generally, results showed that madder plant residues in compare to other treatments increased marigold resistance to drought stress and could be introduce as a suitable organic compound of media culture.