Anatomical and morphological changes in scion of some olive grafting combinations under water deficit

Abstract

Effects of water stress deficit were studied on xylem anatomical fea- tures and some growth parameters among six olive grafting combinations; Amygdalifolia/Arbequina (Am/Ar), Amygdalifolia/Koroneiki (Am/Ko), Amygdalifolia/Zard (Am/Z), Conservallia/Koroneiki (Co/Ko), Conservallia/Zard (Co/Z) and Conservallia/Arbequina (Co/Ar) of about three-year-old olive trees (Olea europaea L.) under greenhouse conditions. To realize this, a factorial experiment was conducted in a completely randomized design (CRD). The results showed that rootstocks exhibited significant effects on scions xylem anatomical physiognomies, such as vessel lumen area (VLA) and vessel diame- ter (VD) and additionally on some growth indices including main stem length (SL), lateral shoot number (LSN) and graft union-cross sectional area (GU-CSA). Xylem anatomical characteristics including VLA, porosity, vessel frequency (VF) and VD of scions decreased when they were grafted onto Arbequina and Koroneiki rootstocks, but increased onto Zard rootstock. All growth parameters showed a decrease under drought stress, while this reduction was more pro- nounced for Zard rootstock than the other rootstocks. However, Co/Z showed the highest VF and the lowest vulnerability index (VI) and exhibited a better performance at the end of recovery.