Investigation of morphoanatomical traits associated with drought resistance in leaves of 30 varieties of olive

The olive (Olea europaea L.) tree is one of the most characteristic tree crops from the Mediterranean basin that they are frequently subjected to prolonged drought periods. Olive tree is able to tolerate the low availability of water in the soil by means of morphoanatomical and physiological adaptations. This experiment was conducted based on completely randomized design with three replications on 30 Indigenous and exotic olive cultivars in 2015. We studied leaf anatomical treats such as, stomata and trichome density, thickness of upper palisade parenchyma, length, width and size of stomata and etc. Plant materials provided from Tarom Agricultural Research Center. According to past studies, drought resistance cultivars have small stomata and light density, high trichome density, thick palisade parenchyma, small leaf area with lancelet shape. Results suggest that the cultivars such as, Amygdalia, Pichoval, Khodeiry, Verdale as well as Kayssi had lowest stomata density, Jolt, Shengeh, Kalamata, Kavi and Frantoio have smallest stomata size, Lechino, Abu-satl, Shengeh, Kayssi and Sori have highest trichome density, Koroneiki, Roghani, Shengeh, Frantoio and Coratina have thickest palisade parenchyma, Sori, viliotiky, Amygdalia, Jolt, Arbequina have lowest leaf area. According to past studies, drought resistance cultivars are Sevillana, Koroneiki, Roghani, Lechino, Amygdalia, Sori, Abu-satl, Kayssi, Zard, Konservolia and Arbequina. The based on our results, stomata and trichome density can be one of the reasons of drought resistance in Lechino, Abu-satl and Sori cultivars. In Koroneiki and Roghani cultivars and Amygdalia, Arbequina as well as Sori upper palsied parenchyma thickness and small leaf area respectively, can be reasons of drought resistance.