The effects of culture media on the increasing of drought stress tolerance of Osage orange tree (Maclura pomifera L.)

Osage orange tree (Maclura pomifera L.) is a native of Central America and has numerous ornamental, ecological and medicinal values. In the present study, the effects of different culture media including animal manure, vermicompost and sesame residue on the growth rate and increasing tolerance of Osage orange tree under drought stress, were investigated. This experiment was conducted as a factorial experiment based on completely randomized block design, four culture media levels including (1- soil (control), 2- 70% v/v soil + 30% v/v vermicompost, 3- 70% v/v soil + 30% v/v animal manure and 4- 80% v/v soil + 20% v/v sesame residue) and three levels of drought include 1- without stress (control) (90% allowed water depletion) 2- mild stress (55% allowed water depletion) and 3- severe stress (35% allowed water depletion) with three replicates per treatments were applied on one year old seedlings in April 2017 in field of Yazd University. According to the results, drought stress significantly decreased the height, truck diameter, fresh and dry weight of leaves of seedlings and nutrient uptake, however, activity of ascorbate peroxidase increased. Application of a modified culture media under non-stress conditions significantly increased the growth characteristics and nitrogen and phosphorus uptake. Among the used culture media, animal manure and sesame residue had the highest effects on increasing plant height, fresh and dry weight of leaves and absorption of nitrogen and phosphorus. Maximum activity of ascorbate peroxidase enzyme was obtained in agronomic soil with 30% vermicompost during severe drought stress. In general, using the culture media, especially with animal manure and sesame residue, increased the resistance of this plant to drought stress and significantly increased its growth.