Evaluating the effects of Naphthalene acetic acid (NAA) on morpho-physiological traits of valerian (Valeriana officinalis L.) in aeroponic system.

Aeroponic culture is an alternative method for optimizing growth of different plants in controlled conditions. Aeroponic systems are an efficient tool for the root studies and improving medicinal root production. In order to study the feasibility of valerian (Valeriana officinalis L.) production in aeroponic systems and assessing the effects of different NAA concentrations (0, 0.1, 0.3, and 0.5 mg/l) on some morpho-physiological traits of valerian, the current study was conducted based on a completely randomized design. The results indicated that the effects of the production system were significant for plant height, root length, number of leaves, volume of roots, and dry weight of the shoot and root. Application of NAA hormone had a significant effect on all of the studied traits and by increasing NAA concentration, leaf number, root length and volume, plant height, dry weight of root and shoot, root/shoot ratio, relative water content, and photosynthetic pigments increased significantly.