Plant responses to co-occurring heat and water deficit stress: A comparative study of tolerance mechanisms in old and modern wheat genotypes

Nagashree N. Akula*, Lamis Abdelhakim, Mikulás Knazovický, Carl-Otto Ottosen, Eva Rosenqvist

*Corresponding author for this work

Research output: Contribution to journal/Conference contribution in journal/Contribution to newspaperJournal articleResearchpeer-review


Global climate change increases the likelihood of co-occurrence of hot and dry spells with increased intensity, frequency, and duration. Studying the impact of the two stresses provide a better understanding of tolerance mechanisms in wheat, and our study was focused on revealing plant stress responses to different severities of combined stress at two phenophases in old and modern wheat genotypes. During the stem elongation and anthesis stages, plants were exposed to four treatments: control, deficit irrigation, combined heat, and deficit irrigation at 31 ◦C (HD31) and 37 ◦C (HD37). The modern genotypes were less affected by deficit irrigation at stem elongation as they maintained higher photosynthesis, stomatal conductance, and leaf cooling than old genotypes. When the HD37 stress was imposed during anthesis, the modern genotypes exhibited superior performance compared to the old, which was due to their higher photosynthetic rates resulting from improved biochemical regulation and a higher chlorophyll content. The plant responses varied during two phenophases under the combined stress exposure. Genotypes subjected to HD37 stress during stem elongation, photosynthesis was mainly controlled by stomatal regulation, whereas at anthesis it was predominated by biochemical regulation. These findings contribute to a deeper comprehension of plant tolerance mechanisms in response to different intensities of co-occurring hot and dry weather conditions
Original languageEnglish
Article number108595
JournalPlant Physiology and Biochemistry
Number of pages11
Publication statusPublished - May 2024


  • Chlorophyll fluorescence
  • Climate change stress
  • Deficit irrigation
  • Gas exchange
  • Heat
  • Spring wheat
  • Chlorophyll/metabolism
  • Genotype
  • Triticum/genetics
  • Hot Temperature
  • Dehydration
  • Water/metabolism
  • Stress, Physiological/genetics
  • Plant Stomata/physiology
  • Plant Leaves/genetics
  • Photosynthesis

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