بررسي پاسخ هاي رشدي و تجمع پرولين در سه رقم زيتون بومي ايران به تنش خشكي

Evaluation of the growth responses and proline accumulation of three Iranian native olive cultivars under drought stress

In order to select drought resistant olive cultivars for expansion of olive orchard cultivation in arid and semi-arid region of Iran, an experiment was conducted to evaluate the morphological, biochemical and physiological responses of some rooted cutting Iranian native olive cultivars (Zard, Mary-Tarom and Roghani) under drought stress. One-year-old olive plants of mentioned cultivars were used in a factorial experiment based on randomized complete block design. Irrigation treatments were at field capacity (control), medium stress (at -0.5 MPa) and severe stress (at -1.5 MPa ). According to obtained result there were a reduction in root, shoot and leaf dry weight of all cultivars with increasing the level of stress. Decreasing of root, shoot and leaf dry weight was higher in Roghani, Zard and Mary-Tarom in comparison of control plants. Mary-Tarom had better production and distribution of dry matter under water stress than the other cultivars in compare with its control. Plant heights of Mary-Tarom and Zard cultivars under water stress showed no significant differences than control but not Roghani. In general, leaf proline content increased with increasing of water stress in all cultivars. Predawn leaf water potential in plants was exposed to medium (-0.5 MPa) and severe (-1.5 MPa) water stress decreased with increasing duration of water stress. This increasing was significant in compare with control plants. Decreasing of predawn leaf water potential of plants under severe water stress was significant among cultivars. The amount of relative water content was decreased with increasing of soil drying during the measurement period. Reduction in leaf relative water content in Roghani, Zard and Mary-Tarom was higher, respectively. We can conclude that Mary-Tarom, Zard and Roghani had better growth and adaptation to drought stress conditions, respectively.