title: Influence of rootstock on drought response in young 'Gale Gala' apple (Malus domestica Borkh.) trees.
abstract: BACKGROUND
  Drought is a major environmental stress limiting plant growth, productivity, and survival worldwide. Rootstocks are widely used to enhance plants resistance to drought stresses. This study determined influence of rootstock on drought responses in 1-year-old 'Gale Gala' apple trees grafted onto Malus sieversii or M. hupehensis.
  
  
  RESULTS
  Choice of rootstock resulted in differential response to drought stress. Specifically, M. sieversii caused less drought-induced reduction in relative growth rate, biomass accumulation, leaf area, leaf chlorophyll content, relative water content, photosynthesis rate and maximum chlorophyll fluorescence yield but greater increase in whole-plant water use efficiency compared to M. hupehensis. Secondly, compared with M. hupehensis, M. sieversii caused less drought-induced accumulation of reactive oxygen species but more increase in activities of antioxidant enzymes. In addition, xylem sap abscisic acid concentration was greater in trees grafted onto M. hupehensis than in those grafted onto M. sieversii under drought stress.
  
  
  CONCLUSIONS
  'Gale Gala' trees' response to drought stress was associated with the rootstock's genotype onto which it was grafted. Trees with M. sieversii as rootstock are more drought resistant than trees with M. hupehensis as rootstock, which suggests that M. sieversii can be widely used as rootstock in arid and semi-arid regions.
authors.affiliation: College of Horticulture, Northwest A&F University, State Key Laboratory of Crop Stress Biology in Arid Areas, Yangling, Shaanxi 712100, China.
authors.forename: Bing-hua
authors.initials: BH
authors.lastname: Liu
authors.forename: Liang
authors.initials: L
authors.lastname: Cheng
authors.forename: Feng-wang
authors.initials: FW
authors.lastname: Ma
authors.forename: Dong
authors.initials: D
authors.lastname: Liang
authors.forename: Yang-jun
authors.initials: YJ
authors.lastname: Zou
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism; D000222:Adaptation, Physiological / Q000235:genetics*; D000975:Antioxidants / Q000378:metabolism; D018533:Biomass; D002734:Chlorophyll / Q000737:chemistry / Q000378:metabolism; D055864:Droughts; D005453:Fluorescence; D027845:Malus / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D010788:Photosynthesis / Q000235:genetics; D018515:Plant Leaves / Q000033:anatomy & histology / Q000378:metabolism; D018517:Plant Roots; D017382:Reactive Oxygen Species / Q000378:metabolism; D013045:Species Specificity; D013312:Stress, Physiological / Q000235:genetics*; D014197:Trees; D014867:Water / Q000502:physiology; D052584:Xylem / Q000378:metabolism
chemical_list: D000975:Antioxidants; D017382:Reactive Oxygen Species; D014867:Water; D002734:Chlorophyll; D000040:Abscisic Acid