Mangrove species found in contrasting environments show differing phytohormonal responses to variation in soil bulk density

Ola, Anne; Dodd, Ian C.; Albacete, Alfonso; Xiong, Yanmei; Rasmussen, Amanda; De Diego, Nuria; Lovelock, Catherine E.

Abstract

Background and aims: Mangrove species respond to variation in soil bulk density (BD). However, very little is known about the regulatory mechanisms that trigger these responses. Methods: Endogenous concentrations of different phytohormones were measured in the roots of two mangrove species (Avicennia marina and Rhizophora stylosa) grown in low and high BD soils. The potential involvement of ethylene in regulating plant growth responses was tested by applying the ethylene biosynthesis inhibitors cobalt chloride (CoCl2) and aminoisobutyric acid (AIB). Results: The two mangrove species responded differently to variation in soil BD. High BD decreased root growth of R. stylosa, but not A. marina. Soil BD had no effect on root phytohormone levels in R. stylosa, but loose soils increased 1-aminocyclopropane-1-carboxylic acid whilst decreasing salicylic acid and gibberellin in A. marina. Applying ethylene inhibitors enhanced R. stylosa root growth, while increasing indole-3-acetic acid but decreasing isopentenyl adenine levels. In contrast, AIB inhibited A. marina root growth, while increasing trans-zeatin levels. Ethylene inhibitors affected salicylic acid levels in both species. Conclusion: Salicylic acid is central to root growth responses to variation in BD in A. marina. Conversely, the interaction of ethylene and gibberellin drives responses in R. stylosa. Hormonal interactions involving ethylene potentially reflect the adaptations of the two species to differing conditions within the intertidal zone, with A. marina behaving like an aquatic species and R. stylosa behaving like a terrestrial species.

• Journal Article Type: Article
• Acceptance Date: Jan 9, 2024
• Online Publication Date: Feb 1, 2024
• Publication Date: Feb 1, 2024
• Deposit Date: Feb 1, 2024
• Publicly Available Date: Feb 1, 2024
• Journal: Plant and Soil
• Print ISSN: 0032-079X
• Electronic ISSN: 1573-5036
• Publisher: Springer Verlag
• Peer Reviewed: Peer Reviewed
• DOI: https://doi.org/10.1007/s11104-024-06490-4
• Keywords: Adaptation; Avicennia marina; Ethylene; Inhibitors (AIB, CoCl2); Rhizophora stylosa; Roots
• Public URL: https://nottingham-repository.worktribe.com/output/30661286
• Additional Information: Received: 15 May 2023; Accepted: 9 January 2024; First Online: 1 February 2024; : The authors declare that no funds, grants, or other support were received during the preparation of this manuscript. Further, the authors have no relevant financial or non-financial interests to disclose.; : The authors have no competing interests to declare.