Characterization of Heat Tolerance in Two Apple Rootstocks Using Chlorophyll Fluorescence as a Screening Method

High temperature has an adverse effect on apple production worldwide. Photosynthesis is a process especially vulnerable to heat stress, which can reduce photosynthetic efficiency, plant growth, development, and ultimately yield. Although the effects of heat stress on apples have been partially exami...

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Main Authors: Ines Mihaljević, Marija Viljevac Vuletić, Vesna Tomaš, Dominik Vuković, Zvonimir Zdunić
Format: Article
Language:English
Published: MDPI AG 2025-06-01
Series:Agronomy
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Online Access:https://www.mdpi.com/2073-4395/15/6/1442
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author Ines Mihaljević
Marija Viljevac Vuletić
Vesna Tomaš
Dominik Vuković
Zvonimir Zdunić
author_facet Ines Mihaljević
Marija Viljevac Vuletić
Vesna Tomaš
Dominik Vuković
Zvonimir Zdunić
author_sort Ines Mihaljević
collection DOAJ
description High temperature has an adverse effect on apple production worldwide. Photosynthesis is a process especially vulnerable to heat stress, which can reduce photosynthetic efficiency, plant growth, development, and ultimately yield. Although the effects of heat stress on apples have been partially examined, the photochemical reactions and heat tolerance of specific rootstocks have still not been sufficiently investigated. Identification of rootstocks with better photosynthetic performance and adaptation to heat stress enables the selection of rootstocks, which could contribute to stable yields and good fruit quality even at elevated temperatures. In this study, chlorophyll <i>a</i> fluorescence (ChlF) induction kinetics was used to investigate the heat tolerance between two apple rootstocks (M.9 and G.210). In addition, we employed lipid peroxidation measurements, hydrogen peroxide quantification, proline content, and total phenolic and flavonoid assessments. Analysis of chlorophyll fluorescence parameters and OJIP curves (different steps of the polyphasic fluorescence transient; O–J–I–P phases) revealed significant differences in their responses, with higher values of the PI<sub>ABS</sub> parameter indicating better PS II stability and overall photosynthetic efficiency in M.9 rootstock. The higher contents of chlorophyll, carotenoids, proline, and significant increase in the accumulation of phenolics, and flavonoids in this rootstock also contributed to its better adaptation to heat stress. Oxidative stress was more pronounced in G.210 through higher H<sub>2</sub>O<sub>2</sub> and MDA levels, which could point to its lower capacity to adjust to heat stress conditions. This research can provide a scientific basis for further breeding programs and growing plans due to climate change and the occurrence of extremely high temperatures.
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spelling doaj-art-5a92902f7be747db8cd97e8e6a56fcf52025-08-20T03:24:29ZengMDPI AGAgronomy2073-43952025-06-01156144210.3390/agronomy15061442Characterization of Heat Tolerance in Two Apple Rootstocks Using Chlorophyll Fluorescence as a Screening MethodInes Mihaljević0Marija Viljevac Vuletić1Vesna Tomaš2Dominik Vuković3Zvonimir Zdunić4Agricultural Institute Osijek, Južno Predgrađe 17, 31000 Osijek, CroatiaAgricultural Institute Osijek, Južno Predgrađe 17, 31000 Osijek, CroatiaAgricultural Institute Osijek, Južno Predgrađe 17, 31000 Osijek, CroatiaAgricultural Institute Osijek, Južno Predgrađe 17, 31000 Osijek, CroatiaAgricultural Institute Osijek, Južno Predgrađe 17, 31000 Osijek, CroatiaHigh temperature has an adverse effect on apple production worldwide. Photosynthesis is a process especially vulnerable to heat stress, which can reduce photosynthetic efficiency, plant growth, development, and ultimately yield. Although the effects of heat stress on apples have been partially examined, the photochemical reactions and heat tolerance of specific rootstocks have still not been sufficiently investigated. Identification of rootstocks with better photosynthetic performance and adaptation to heat stress enables the selection of rootstocks, which could contribute to stable yields and good fruit quality even at elevated temperatures. In this study, chlorophyll <i>a</i> fluorescence (ChlF) induction kinetics was used to investigate the heat tolerance between two apple rootstocks (M.9 and G.210). In addition, we employed lipid peroxidation measurements, hydrogen peroxide quantification, proline content, and total phenolic and flavonoid assessments. Analysis of chlorophyll fluorescence parameters and OJIP curves (different steps of the polyphasic fluorescence transient; O–J–I–P phases) revealed significant differences in their responses, with higher values of the PI<sub>ABS</sub> parameter indicating better PS II stability and overall photosynthetic efficiency in M.9 rootstock. The higher contents of chlorophyll, carotenoids, proline, and significant increase in the accumulation of phenolics, and flavonoids in this rootstock also contributed to its better adaptation to heat stress. Oxidative stress was more pronounced in G.210 through higher H<sub>2</sub>O<sub>2</sub> and MDA levels, which could point to its lower capacity to adjust to heat stress conditions. This research can provide a scientific basis for further breeding programs and growing plans due to climate change and the occurrence of extremely high temperatures.https://www.mdpi.com/2073-4395/15/6/1442apple rootstockchlorophyll fluorescenceheat stresspigmentsphenols
spellingShingle Ines Mihaljević
Marija Viljevac Vuletić
Vesna Tomaš
Dominik Vuković
Zvonimir Zdunić
Characterization of Heat Tolerance in Two Apple Rootstocks Using Chlorophyll Fluorescence as a Screening Method
Agronomy
apple rootstock
chlorophyll fluorescence
heat stress
pigments
phenols
title Characterization of Heat Tolerance in Two Apple Rootstocks Using Chlorophyll Fluorescence as a Screening Method
title_full Characterization of Heat Tolerance in Two Apple Rootstocks Using Chlorophyll Fluorescence as a Screening Method
title_fullStr Characterization of Heat Tolerance in Two Apple Rootstocks Using Chlorophyll Fluorescence as a Screening Method
title_full_unstemmed Characterization of Heat Tolerance in Two Apple Rootstocks Using Chlorophyll Fluorescence as a Screening Method
title_short Characterization of Heat Tolerance in Two Apple Rootstocks Using Chlorophyll Fluorescence as a Screening Method
title_sort characterization of heat tolerance in two apple rootstocks using chlorophyll fluorescence as a screening method
topic apple rootstock
chlorophyll fluorescence
heat stress
pigments
phenols
url https://www.mdpi.com/2073-4395/15/6/1442
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