Beneficial Roles of 1-MCP on Regulation of Photosynthetic Electron Transport and Energy Dissipation in Chrysanthemum Under Heat Stress
1-Methyl cyclopropene (1-MCP) is known as an ethylene antagonist, yet its mechanisms in regulating photosynthetic electron transport and energy dissipation in chrysanthemum under heat stress are not well understood. Here, the chlorophyll a fluorescence and modulated 820 nm reflection transients were...
Saved in:
| Main Authors: | , , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2025-01-01
|
| Series: | Horticulturae |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2311-7524/11/1/68 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| Summary: | 1-Methyl cyclopropene (1-MCP) is known as an ethylene antagonist, yet its mechanisms in regulating photosynthetic electron transport and energy dissipation in chrysanthemum under heat stress are not well understood. Here, the chlorophyll a fluorescence and modulated 820 nm reflection transients were analyzed in heat-tolerant and heat-sensitive chrysanthemum plants. This study demonstrates that 1-MCP pre-treatment helps maintain the net photosynthetic rate (P<sub>n</sub>) and the reaction center activity of photosystems I and II (PSI and PSII) during heat stress. Specifically, 1-MCP treatment significantly increases the fraction of active oxygen-evolving complex (OEC) centers and reduces relative variable fluorescence intensity at the J step (V<sub>J</sub>) as well as the efficiency of electron transfer at the PSI acceptor side (δ<sub>Ro</sub>). These effects mitigate damage to the photosynthetic electron transport chain. Additionally, 1-MCP-treated plants exhibit decreased quantum yield of energy dissipation (φ<sub>Do</sub>) and reduced energy flux per reaction center (DI<sub>o</sub>/RC). Overall, 1-MCP enhances light utilization efficiency and excitation energy dissipation in the PSII antennae, alleviating heat stress-induced damage to PSI and PSII structures and functions. This study not only advances our understanding of 1-MCP’s regulatory role in photosynthetic processes under heat stress but also provides a basis for using exogenous substances to improve chrysanthemum heat resistance. |
|---|---|
| ISSN: | 2311-7524 |