Comparative Wood Anatomy of Four Shrubs from Sarab Region

To understand the compatibility of xylem with dry climates, wood anatomy similarities and differences of four shrubs were investigated in dry and cold region of Sarab (Azarbaijan sharghi province). These shrubs were: Pteropyrum olivieri, Rosa canina, Tamarix gallica, and Rhamnus pallasii, while the wood anatomy of Pteropyrum sp. is reported for the first time, in this research. After preparing microscopic sections of mature xylem and staining them, wood anatomy of studied species were reported and compared. The results showed that Pteropyrum olivieri and Rosa canina are the most similar in terms of wood anatomy while Rhamnus pallasii and Tamarix gallica have the least similarities with each other. Those anatomical features which compensate the drought stress were different in these shrubs according to local distribution of studied species; among them was the occurrence and intensity of spiral thickenings in vessels, the presence of vascular / vasicentric tracheids, and the size and grouping of vessels. Tamarix gallica which were grown only near the lake had the least adaptation to drought in its stem while Rhamnus pallasii which could distribute in the harshest conditions were equipped with the best adaptive traits.