From shade to sun : rapid phenotypic recovery but persistent metabolic legacy in apple fruit after summer pruning

Grohar, Mariana Cecilia (author), Jakopič, Jerneja (author), Pirih, Kris (author), Veberič, Robert (author)

Apple fruit can acclimate to changes in light availability, but whether fruit developing under shade can rapidly recover when suddenly exposed to full sun late in development remains unclear. Several agronomical practices aim to regulate light incidence on the fruit, thereby influencing their growth and development. Summer pruning is a good model to analyze this regulation as it includes a transition between shade and full-sun conditions. In this study, we used summer pruning as a field-scale light perturbation and analyzed the impact of summer pruning on apple fruit at both morphological and metabolic levels by comparing fruit grown under full-sun conditions, fruit grown in the shade, and fruit exposed to full-sun conditions after summer pruning. In the analysis, we included continued measurements of growth, temperature, color, and chlorophyll content before and after performing summer pruning over the last 5 weeks before harvest. Additionally, fruit and leaf dynamics of phenolic compounds was characterized in detail using HPLC/MS. Following pruning, shaded fruit rapidly converged toward sun-exposed fruit in surface temperature, color and anthocyanin accumulation, with anthocyanins reaching sun-exposed levels within six days. However, convergence was incomplete: fruit growth, total soluble solids and several phenolic traits remained intermediate. These results demonstrate that apple fruit exhibits rapid phenotypic acclimation to increased light exposure, whereas metabolic acclimation is slower and constrained by developmental history.

• Language: English
• Keywords: acclimation, phenolic compounds, HPLC/MS, temperature, light, fruit growing, ripening
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: BF - Biotechnical Faculty
• Publication status: Published
• Publication version: Version of Record
• Year: 2026
• Number of pages: 11 str.
• Numbering: art. 2111873, Vol. 240
• PID: 20.500.12556/RUL-190425
• UDC: 634
• ISSN on article: 0981-9428
• DOI: 10.1016/j.plaphy.2026.111873
• COBISS.SI-ID: 302929923
• Publication date in RUL: 28.10.2026

Record is a part of a journal

• Title: Plant physiology and biochemistry
• Shortened title: Plant physiol. biochem.
• Publisher: Gauthier-Villars, Centrale des revues
• ISSN: 0981-9428
• COBISS.SI-ID: 16873989

Licences

• License: CC BY 4.0, Creative Commons Attribution 4.0 International
• Link: http://creativecommons.org/licenses/by/4.0/
• Description: This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.

Secondary language

• Language: Slovenian
• Keywords: aklimatizacija, fenolne spojine, temperatura, svetoloba, rast plodov

Projects

• Funder: ARIS - Slovenian Research and Innovation Agency
• Project number: P4-0013
• Name: Hortikultura

• Funder: ARIS - Slovenian Research and Innovation Agency
• Project number: I0-0022
• Name: Mreža raziskovalnih infrastrukturnih centrov Univerze v Ljubljani (MRIC UL)