Effect of the Seed Location on the Mother Plant and Salinity Stress on Seed Germination Characteristics of Eucalyptus comaldulensis Dehnh

The present study was conducted to evaluate the effects of these two factors as well as their interaction on seed germination of eucalyptus (E. camaldulensis). A factorial experiment based on a completely randomized design with three replications was used. Five salinity levels including 0، 50، 100، 150، 200 mM sodium chloride were tested on seed collected at top، middle and bottom of the tree. Also the electrical conductivity of leaves as well as 1000 - seed weight were measured in three different tree heights. Result showed that 1000 - seed weight and electrical conductivity of leaves were significantly different (p<0. 05) in three heights. Maximum leaves electrical conductivity and 1000 - seed weight were obtained in seeds collected from middle Crown depth. Furthermore، total seed germination percentage، speed of germination، mean daily germination، Germination index، shoot and root length، as well as seed vigor were significantly reduced (p<0. 01) with increasing the salinity stress. However، the responses were difference based on location of seeds on the mother tree. Highest mean daily germination، Germination index، speed of germination، root and shoot length and seed vigor were obtained in seeds collected from the middle Crown depth، whereas maximum seed germination percentage was related to seeds located at the lower high of the tree.