title: Low-temperature conditioning induces chilling tolerance in 'Hayward' kiwifruit by enhancing antioxidant enzyme activity and regulating en-dogenous hormones levels.
abstract: BACKGROUND
  To understand the mechanisms leading to the enhanced chilling tolerance of kiwifruit by low-temperature conditioning (LTC, 12 °C for 3 days), this study investigated the effect of LTC on chilling tolerance and changes in antioxidant enzyme activities and endogenous hormones.
  
  
  RESULTS
  LTC significantly alleviated chilling injury in kiwifruit. Fruits treated with LTC maintained lower respiration and ethylene production and higher firmness. Furthermore, this treatment inhibited the accumulation of malondialdehyde, superoxide radicals and hydrogen peroxide and the increase in membrane permeability and increased the activities of superoxide dismutase, catalase, ascorbate peroxidase and peroxidase under chilling stress. The treatment also maintained higher levels of endogenous abscisic acid (ABA), indole-3-acetic acid (IAA) and zeatin riboside (ZR), lower gibberellic acid (GA3) levels and higher ABA/GA3 and ABA/IAA ratios.
  
  
  CONCLUSIONS
  The results suggested that LTC alleviated chilling injury in kiwifruit by improving antioxidant enzyme activities and maintaining higher levels of endogenous ABA, IAA and ZR, lower GA3 levels and higher ABA/GA3 and ABA/IAA ratios.
authors: College of Horticulture, Northwest A&F University, Yangling, 712100, Shaanxi, China; Department of Life Sciences, Yuncheng University, Yuncheng, 044000, Shanxi, China.
authors: Qingzhen
authors: Q
authors: Yang
authors: Zhengke
authors: Z
authors: Zhang
authors: Jingping
authors: J
authors: Rao
authors: Yuping
authors: Y
authors: Wang
authors: Zhenying
authors: Z
authors: Sun
authors: Qiushi
authors: Q
authors: Ma
authors: Xiaoqing
authors: X
authors: Dong
mesh_terms: D029042:Actinidia / Q000201:enzymology / Q000378:metabolism*; D000222:Adaptation, Physiological; D000975:Antioxidants / Q000378:metabolism*; D060387:Ascorbate Peroxidases / Q000378:metabolism; D002374:Catalase / Q000378:metabolism; D002463:Cell Membrane Permeability; D019069:Cell Respiration; D003080:Cold Temperature; D005638:Fruit / Q000201:enzymology / Q000378:metabolism*; D006244:Hardness; D006861:Hydrogen Peroxide / Q000378:metabolism; D008315:Malondialdehyde / Q000378:metabolism; D010937:Plant Growth Regulators / Q000378:metabolism*; D013482:Superoxide Dismutase / Q000378:metabolism; D013481:Superoxides / Q000378:metabolism
chemical_list: D000975:Antioxidants; D010937:Plant Growth Regulators; D013481:Superoxides; D008315:Malondialdehyde; D006861:Hydrogen Peroxide; D060387:Ascorbate Peroxidases; D002374:Catalase; D013482:Superoxide Dismutase
keywords: antioxidant enzyme; chilling tolerance; endogenous hormones; kiwifruit; low-temperature conditioning