Scientia Horticulturae 218 (2017) 156–163 Contents lists available at ScienceDirect Scientia Horticulturae journal homepage: www.elsevier.com/locate/scihorti Mitigating the adverse effects of drought stress on the morpho-physiological traits and anti-oxidative enzyme activities of Prunus avium through -amino butyric acid drenching Taimoor Javadi ∗ , Darya Rohollahi, Naser Ghaderi, Farzad Nazari Department of Horticulture, Faculty of Agriculture, University of Kurdistan, Sanandaj, Iran a r t i c l e i n f o Article history: Received 7 December 2016 Received in revised form 5 February 2017 Accepted 10 February 2017 Keywords: Antioxidant enzymes Malondialdehyde Proline Sweet cherry Water deficit a b s t r a c t Exogenous application of certain compounds can reduce the harmful effects of water stress. This exper- iment was carried out to study the effects of -amino butyric acid (BABA) on the morpho-physiological traits and antioxidative enzyme activity in sweet cherry (Prunus avium L. cv. Takdaneh Mashhad) under water-stress conditions. Sweet-cherry saplings were exposed to three water-stress treatments (well- watered, −0.6 and −1.2 MPa based on soil water potential) and three root-applied BABA treatments (0, 0.8 and 1.6 mM). The results indicated that drought stress decreased the number of leaves, leaf area, leaf dry weight, root volume, root dry weight, total dry weight, trunk dry weight, trunk diameter increment, relative water content (RWC), membrane stability index (MSI), leaf chlorophyll and carotenoids content. It increased free proline, total soluble sugars (TSS), malondialdehyde (MDA), hydrogen peroxide (H 2 O 2 ), protein content and activity of peroxidase (POD) and ascorbate peroxidase (APX) content of leaves. Water- stress conditions with the application of BABA reduced the number of leaves, leaf dry weight, leaf area, the content of MDA and H 2 O 2 , but enhanced the trunk diameter increment, root volume, root dry weight, total dry weight, RWC, MSI, chlorophyll a, b and total chlorophyll, carotenoids, free proline and TSS, POD and APX activities in leaves compared to unprimed water-stressed plants. Application of BABA, partic- ularly at 1.6 mM, had a significant effect on some morpho-physiological and biochemical attributes and mitigated some detrimental effects of water stress. © 2017 Elsevier B.V. All rights reserved. 1. Introduction Water stress is one of the most serious environmental fac- tors limiting growth and development in higher plants. Crop plants expand a number of physiological and biochemical mech- anisms (Turner and Asseng, 2005) and initiate defenses (Chaves and Oliveira, 2004) to cope with water stress. Sweet cherry (Prunus avium L.) is an important stone fruit in the world’s temperate regions. It has the potential to suffer greatly from water deficit due to climate change in areas with limited water resources for agriculture. Plants have developed various physiological and bio- chemical mechanism to cope with water stress. Reduction in turgor pressure, the first and most sensitive response to drought stress (Taiz and Zeiger, 2006), reduces growth rate and, consequently, the plant’s ultimate size. It is the most sensitive cellular process to the ∗ Corresponding author. E-mail addresses: tjavadi@uok.ac.ir (T. Javadi), darya.rohollahi@gmail.com (D. Rohollahi), n.ghaderi@uok.ac.ir (N. Ghaderi), f.nazari433@gmail.com (F. Nazari). water stress. Water loss in plant tissues leads to growth reduc- tion, stomatal closure, reduction in photosynthesis rate (Lawlor and Cornic, 2002), protein degradation (Price and Hendry, 1991), abscisic acid increment (Davies and Zhang, 1991), reactive oxygen species enhancement (Fu and Huang, 2001) and proline accumu- lation in plants (Showler, 2002). In addition, adverse effects of drought stress on the vegetative characteristics of fruit trees have been reported (Higgs and Jones, 1990; Medeiros et al., 2012). Various physiological traits have been studied in fruit trees under drought stress, such as water status of leaf, cell membrane stability index (MSI) and photosynthesis changes. Higher relative water content (RWC) in plants means that the leaves can retain a greater amount of water under drought-stress conditions. There is a positive correlation between RWC and chlorophyll content, protein and Rubisco enzyme activity (Castrillo and Trujillo, 1994). There have also been numerous reports on fruit trees showing the nega- tive effects of drought stress: it attenuates MSI in almond (Karimi et al., 2012), RWC in Fraxinus (He et al., 2016), chlorophyll index in apple and quince rootstocks (Bolat et al., 2014) and protein con- tent in Barbados cherry leaves (Medeiros et al., 2012). Moreover, http://dx.doi.org/10.1016/j.scienta.2017.02.019 0304-4238/© 2017 Elsevier B.V. All rights reserved.