Vol. 40 No. 2 (2026):
Reviews

Heat and light induced physiological disorders in apples: Sunburn, mechanisms, and management strategies

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  • A. İkinci
A. İkinci
Harran University, Faculty of Agriculture, Department of Horticulture, Şanlıurfa, Türkiye.
DOI: https://doi.org/10.36253/ahsc-19221
Categories

Published 2026-07-27

Keywords

  • Climate change,
  • fruit surface temperature,
  • heat stress,
  • oxidative stress,
  • photoselective net,
  • sunburn
    • ...More
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How to Cite

İkinci, A. (2026). Heat and light induced physiological disorders in apples: Sunburn, mechanisms, and management strategies. Advances in Horticultural Science, 40(2), 219–234. https://doi.org/10.36253/ahsc-19221

Copyright (c) 2026 Ali İKİNCİ

Creative Commons License

This work is licensed under a Creative Commons Attribution 4.0 International License.

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Abstract

Global climate change has intensified heat and light stress in apple (Malus domestica Borkh.) orchards, markedly increasing the incidence of sunburn and related physiological disorders. Sunburn represents a complex stress response triggered when fruit surface temperature (FST) exceeds critical thresholds, leading to oxidative imbalance and structural damage. This review provides an integrated synthesis of sunburn typology - sunburn browning, sunburn necrosis, and photo-oxidative sunburn - and explores underlying cellular and biochemical mechanisms, including reactive oxygen species (ROS) accumulation, membrane peroxidation, and pigment degradation. Evidence indicates that FST values between 46-52°C are decisive in the onset of photo-oxidative injury and necrotic lesions, compromising fruit integrity and storage potential. Secondary disorders such as watercore, lenticel breakdown, and bitter pit are discussed as consequential outcomes of thermal stress. Mitigation strategies are critically evaluated, highlighting the efficacy of photoselective nets, kaolin-based particle films, and evaporative cooling, which collectively reduce sunburn incidence by up to 60%. Emerging technologies, including sensor-based early warning systems and precision agriculture tools, offer novel perspectives for proactive management. Conclusively, sustaining fruit quality under increasingly variable climatic conditions requires a multidimensional approach that integrates microclimate regulation with physiological optimization.

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