Background: Pot marigold (Calendula officinalis) and petunia (Petunia × hybrida) plants have a high ornamental value in the green space due to their attractive flowers with various colors. This is despite the fact that the region of Iran has a dry and semi-arid climate, which causes the spread of salinity in these areas. Accumulation of high concentration of salt reduces the water potential of the substrate, creates stress and limits the absorption of water and nutrients by the plant. Many researches reported the folair plant with nanochelate solutions in order to reduce the negative effects of stress on plants.
Aim: This research was carried out in order to investigate the effect of calcium, potassium and zinc nanochelate solutions on different growth and flowering characteristics of pot marigold and petunia plants under salinity stress conditions.
Methodology: The experiment was carried out as a factorial in the form of a completely randomized design with 3 replications on two ornamental plants, pot marigold and petunia, separately in soil cultivation in pots. The experimental factors included salinity stress at four levels of 1, 3, 5, and 7 ds/m and foliar spraying treatment at five levels including the control treatment, foliar spraying with calcium nanochelate, potassium nanochelate, zinc nanochelate and a combination treatment of all three nanofertilizers. The concentration of nano chelates used for each was 2 mg/l. At the end of the experiment (4 months after planting seedlings) were measured some morphological traits including shoot fresh and dry weight, leaf surface, height, number of flowers per plant and flower diameter, biochemical traits including the concentration of chlorophylls a and b and leaf carotenoids, leaf chlorophyll index , petal anthocyanin, leaf proline and the amount of calcium, magnesium, potassium, zinc, sodium and phosphorus of leaf.
Results: The results of variance analysis showed that the simple effect of salinity stress and nanoferti