The Role of Arbuscular Mycorrhizal Fungi on the Medicinal Plant Coriander (Coriandrum sativum L.) under Drought Stress Conditions

Arbuscular mycorrhizal fungi (AMF) are among the most important plant root symbiosis fungi, enhancing plant P uptake. To evaluate the role of arbuscular mycorrhizal fungi in enhancing the growth and P uptake of the medicinal plant coriander (Coriandrum sativum L.) under drought stress, this research was conducted in Iran in 2006. The experimental design was a split factorial with completely randomized block design in four replicates. The control and AM species, Glomus hoi, were assigned to the main plots and the combination of P fertilizer levels (including 0, 35 and 70 kg/ha of triple super phosphate) and the water stress treatments (including control treatment with irrigation interval after every 30mm evaporation and stress treatment with irrigation afetr every 60 mm evaporation from the pan) were factorially assigned to the subplots. AM and P fertilizer significantly increased the shoot yield, root colonization percent, root yield, essential oil percent, one thousand seed weight, shoot P content, root length and internode length of coriander. Means comparisons showed that the highest impacts upon those characteristics were achieved by using Glomus hoi and 70 kg/ha phosphorus application and the highest essential oil percent and root colonization percent were achieved with 35 kg/ha phosphorus application. Although the non-drought stress treatment significantly increased the growth of coriander, the highest root colonization percent, root length, and essential oil percent were achieved under the water stress treatment. It can be stated that AM is able to enhance the growth of coriander under drought stress through enhancing P uptake. This can have very important environmental implications through decreasing the amount of P fertilizer under control and drought stress conditions and also through enhancing the coriander resistance when subjected to the drought stress.