Network disintegration of photosynthesis-antioxidant coordination underpins thermal vulnerability in Ochroma lagopus Swartz: A 5°C threshold triggers carbon starvation
Year: 2025
Type: article
Abstract: The present study employed Ochromalagopus Swartz seedlings to examine the effects of low-temperature stress (4 gradients: CK, 7°C, 5°C, 3°C; 12–72 h) on photosynthetic traits, antioxidant enzymes, and osmoregulatory substances. Physiological responses were analysed via cluster, correlation, and PCA.The results demonstrated a decline in chlorophyll a and total chlorophyll a+b with decreasing temperature. However, moderate low temperature (5°C) led to a transient increase in chlorophyll b and carotenoids, thereby enhancing light harvesting and antioxidant activity. Chlorophyll fluorescence parameters (Fv/Fm, Fv/Fo) indicated progressive PSII damage with stress intensity/duration. The activities of antioxidant enzymes (SOD, POD, CAT) and the levels of MDA increased. The proline concentration reached its maximum at 48 h at a temperature of 5°C.The principal component analysis (PCA) revealed that PC1 (48.1 % variance) was associated with photosynthetic pigments and photochemical efficiency, while PC2 (18.7 %) was linked to initial fluorescence and lipid peroxidation. A 5°C threshold was observed to trigger carbon starvation (for a minimum of 48 h), with 3°C inducing photosynthetic collapse. The moderation of cold conditions was found to be effective in mitigating damage, a process that was facilitated by pigment adjustment and antioxidant activation. The findings provide a physiological basis for the evaluation of cold tolerance and the management of cultivation of this tropical species.
Source: Industrial Crops and Products
Authors: Yuanxi Liu, Gang Chen, Weisong Zhu, Guanben Du, Rui Shi, Junwen Wu
Institution: Southwest Forestry University
Language: English
Subfield: Plant Science
Domain: Life Sciences
SDG: Zero hunger
Open Access status: gold
Estimated APC paid: $3,720
Award: G6933961731
OpenAlex ID: W4415604688