The Morpho-Physiological Reactions of Prunus Clonal Rootstocks to Drought Stress

In order to evaluate drought tolerance of four clonal rootstocks of Prunus an experiment was conducted in a completely randomized design with two factors. The first factor was four rootstocks including Cadaman, Myrobalan 29c, GF677, and GN15 and the second factor contained three levels of drought stress, including 100, 75, and 50% of field capacity. Height, leaf number and crown diameter were recorded during the treatments, whereas leaf relative water content, chlorophyll and carotenoids contents were measured at the end of the experiment. Fresh and dry weight of leaves and roots decreased for all rootstocks by applying drought stress. Leaf number of GF677 decreased under drought conditions, compared with the control, while its reduction was not significant for other rootstocks. The height of Myrobalan 29c plants was more affected by drought compared with the other rootstocks. Moreover, carotenoids decreased more for Cadaman and Myrobalan 29c rootstocks under drought stress, while GF677 and GN15 did not differ significantly from the control. The rootstocks responded to drought stress differently, so that leaf and root proline content, leaf and root soluble sugars and water-use efficiency (WUE) were higher for GF677 and GN15 compared with Cadaman or Myrobalan 29c.