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

Ola, Anne ORCID: https://orcid.org/0000-0001-7271-3630; Dodd, Ian C.; Albacete, Alfonso; Xiong, Yanmei; Rasmussen, Amanda; De Diego, Nuria et Lovelock, Catherine E. (2024). Mangrove species found in contrasting environments show differing phytohormonal responses to variation in soil bulk density. Plant and Soil , vol. 500 , nº 1-2. pp. 417-430. DOI: 10.1007/s11104-024-06490-4.

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Résumé

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 (CoCl 2 ) 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.

Type de document:	Article
Mots-clés libres:	adaptation; avicennia marina; ethylene; inhibitors (AIB, CoCl2); rhizophora stylosa; roots
Centre:	Centre Eau Terre Environnement
Date de dépôt:	07 mars 2025 19:55
Dernière modification:	07 mars 2025 19:55
URI:	https://espace.inrs.ca/id/eprint/16336

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