Photoinhibition and photosynthetic regulation in fluctuating light under compound stresses of drought and heat

Under the background of global climate change, crop leaves usually experience fluctuating light (FL) under compound stresses of drought and heat in the field. However, photoinhibition and photosynthetic regulation in FL under these compound stresses are little known. To elucidate this, we measured g...

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Bibliographic Details
Published inPhysiologia plantarum Vol. 176; no. 3
Main Authors Wang, Xiao‐Qian, Zeng, Zhi‐Lan, Li, Yi‐Yun, Huang, Wei
Format Journal Article
LanguageEnglish
Published Oxford, UK Blackwell Publishing Ltd 01.05.2024
Wiley Subscription Services, Inc
Subjects
Climate change
Drought
Electrochromism
Gas exchange
Global climate
Heat
Heat stress
Heat tolerance
Photoinhibition
Photorespiration
Photosynthesis
Photosystem I
Photosystem II
Redox properties
Solanum lycopersicum
Tomatoes
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Summary:Under the background of global climate change, crop leaves usually experience fluctuating light (FL) under compound stresses of drought and heat in the field. However, photoinhibition and photosynthetic regulation in FL under these compound stresses are little known. To elucidate this, we measured gas exchange, chlorophyll fluorescence, P700 redox state and electrochromic shift signals for tomato (Solanum lycopersicum) leaves exposed to FL under individual and compound stresses of moderate drought and heat stresses. After treatment with short‐term FL, photosystem I (PSI) activity decreased slightly in all treatments. By comparison, photosystem II (PSII) activity was reduced slightly under individual stress but largely decreased by 46% under compound stresses. Therefore, PSI is more tolerant than PSII when exposed to FL under compound stresses of drought and heat. Under compound stresses, PSII photoinhibition largely downregulated linear electron flow and photorespiration became a major electron sink downstream. Concomitantly, cyclic electron flow (CEF) was highly enhanced to help the building up of trans‐thylakoid proton gradient. This study highlights the importance of PSII activity and CEF in crop tolerance under future compound climate extremes such as drought and heat.
ISSN:0031-9317
1399-3054
DOI:10.1111/ppl.14406