title: Comparison of investigation methods of heat injury in grapevine (Vitis) and assessment to heat tolerance in different cultivars and species.
abstract: BACKGROUND
  In the context of global climate change, heat stress is becoming an increasingly important constraint on grapevine growth and berry quality. There is a need to breed new grape cultivars with heat tolerance and to design effective physiological defenses against heat stress. The investigation of heat injury to plants or tissues under high temperature is an important step in achieving these goals. At present, evaluation methods for heat injury include the gas exchange parameters of photosynthesis, membrane thermostability, chlorophyll content etc.; however, these methods have obvious disadvantages, such as insensitivity, inconvenience and delayed information. An effective and convenient method for investigating the heat injury of grapevine must be developed.
  
  
  RESULTS
  In this study, an investigation protocol for a critical temperature (47°C) and heat treatment time (40 min) was developed in detached grape leaves. Based on the results, we found that the OJIP test was superior to measuring electrolyte leakage or photosynthetic O₂ evolution for investigating the heat injury of three cultivars of grapevine. Heat tolerance of 47 grape species and cultivars was evaluated through investigating heat injury using the OJIP test. Moreover, the electron transport chain (donor side, acceptor side and reaction center) of PSII in photosynthesis was further investigated.
  
  
  CONCLUSIONS
  The OJIP test was a rapid, sensitive and convenient method for investigating heat injury in grapevine. An analysis of PSII function using this method indicated that the acceptor side was less sensitive to heat than was the donor side or the reaction center in grape leaves. Among the 47 taxa evaluated (cultivars, hybrids, and wild species), heat tolerance varied largely in each genotype group: most wild species and hybrids between V. labrusca and V. vinifera had relatively strong heat tolerance, but most cultivars from V. vinifera had relatively weak heat tolerance.
authors.forename: Hongguo
authors.initials: H
authors.lastname: Xu
authors.forename: Guojie
authors.initials: G
authors.lastname: Liu
authors.forename: Guotian
authors.initials: G
authors.lastname: Liu
authors.forename: Bofang
authors.initials: B
authors.lastname: Yan
authors.forename: Wei
authors.initials: W
authors.lastname: Duan
authors.affiliation: Key Laboratory of Plant Resources and Beijing Key Laboratory of Grape Science and Enology, Institute of Botany, the Chinese Academy of Sciences, Beijing 100093, People's Republic of China. ljwang@ibcas.ac.cn.
authors.forename: Lijun
authors.initials: L
authors.lastname: Wang
authors.forename: Shaohua
authors.initials: S
authors.lastname: Li
mesh_terms: D002734:Chlorophyll / Q000032:analysis; D000077194:Chlorophyll A; D004573:Electrolytes / Q000378:metabolism; D005453:Fluorescence; D006358:Hot Temperature; D010100:Oxygen / Q000378:metabolism; D010788:Photosynthesis / Q000502:physiology*; D045332:Photosystem II Protein Complex / Q000378:metabolism; D013312:Stress, Physiological; D027843:Vitis / Q000145:classification / Q000502:physiology*
chemical_list: D004573:Electrolytes; D045332:Photosystem II Protein Complex; D002734:Chlorophyll; D010100:Oxygen; D000077194:Chlorophyll A