Agathokleous E, Feng Z, Peñuelas J. Chlorophyll hormesis: Are chlorophylls major components of stress biology in higher plants?
THE SCIENCE OF THE TOTAL ENVIRONMENT 2020;
726:138637. [PMID:
32330746 DOI:
10.1016/j.scitotenv.2020.138637]
[Citation(s) in RCA: 99] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2020] [Revised: 04/09/2020] [Accepted: 04/09/2020] [Indexed: 06/11/2023]
Abstract
High oxidative stress inhibits the synthesis and accumulation of chlorophylls, the pigments that absorb and use light. We collated evidence from a diverse array of studies demonstrating that chlorophyll concentration increases in response to low-level stress and decreases in response to high-level stress. These observations were from 33 species, >20 stress-inducing agents, 43 experimental setups and 177 dose responses, suggesting generality. Data meta-analysis indicated that the maximum stimulatory response did not differ significantly among species and agents. The stimulatory response maximized within a defined time window (median = 150-160% of the control response), after which it decreased but remained elevated (median = 120-130% of control response). The common stimulation of chlorophylls by low-level stress indicates that chlorophylls are major components of stress biology, with their increased concentration at low-level stress suggestive of their requirement for normal functioning and health. Increased chlorophyll concentration in response to low-level stress may equip systems with an enhanced capacity for defense against high-level (health-threatening) challenges within defined time windows, such as pollution or herbivores. These developments have wide-ranging implications in ecophysiology, biotic interactions and evolution.
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