Investigating Different Echophysiologic and Biologic Aspects of Nettle(Urticadioica.L)1

Nettle is the native plant of Europe, Asia, North Africa and America and can be found in various parts of Iran as a wild plant. This plant belongs to Urticaceae familyand is herbaceous, flowering, and permanent with a branched stem. Its stems are straight and quadrilateral, and its leaves are covered with biting furry. In order to investigate echophysiologic and biologic aspects of nettle,the main indices (i.e., germination number, germination percent, mean germination time and coefficient of germination speed) were evaluated on the basis of cardinal, alternative and freezing temperatures in different experiments. The results showed that the best temperature for seed germination in this plant is 25˚C. Furthermore, the 15-25 alternative temperature reduced seed germination up to 74% compared to 10-14 temperature treatment. Due to the correlation between the germination features of this plant, resulting from alternating temperature treatment, the average termination time significantly changed. In fact, salt stress decreased the number of germinated seeds and germination percent respectively to 82% and 77%. Furthermore,the fourfold indices positively reacted to the freezing treatment. However,the depth of planting treatment affected only the average time and germination speed indices.