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Effects of green seaweed extract on Arabidopsis early development suggest roles for hormone signalling in plant responses to algal fertilizers

Ghaderiardakani, Fatemeh; Collas, Ellen; Kohn, Deborah; Tagg, Katherine; Graham, Neil S; Coates, Juliet C


Fatemeh Ghaderiardakani

Ellen Collas

Deborah Kohn

Katherine Tagg

Senior Research Fellow

Juliet C Coates


The growing population requires sustainable, environmentally-friendly crops. The plant growth enhancing properties of algal extracts have suggested their use as biofertilisers. The mechanism(s) by which algal extracts affect plant growth are unknown. We examined the effects of extracts from the common green seaweed Ulva intestinalis on germination and root development in the model land plant Arabidopsis thaliana. Ulva extract concentrations above 0.1% inhibited Arabidopsis germination and root growth. Ulva extract less than 0.1% stimulated root growth. All concentrations of Ulva extract inhibited lateral root formation.
An abscisic-acid-insensitive mutant, abi1, showed altered sensitivity to germination- and root growth-inhibition. Ethylene- and cytokinin-insensitive mutants were partly insensitive to germination-inhibition. This suggests that different mechanisms mediate each effect of Ulva extract on early Arabidopsis development and that multiple hormones contribute to germination inhibition. Elemental analysis showed that Ulva contains high levels of Aluminium ions (Al3+). Ethylene and cytokinin have been suggested to function in Al3+-mediated root growth inhibition: our data suggest that if Ulva Al3+ levels inhibit root growth, this is via a novel mechanism. We suggest algal extracts should be used cautiously as fertilisers, as the inhibitory effects on early development may outweigh any benefits if the concentration of extract is too high.


Ghaderiardakani, F., Collas, E., Kohn, D., Tagg, K., Graham, N. S., & Coates, J. C. (2019). Effects of green seaweed extract on Arabidopsis early development suggest roles for hormone signalling in plant responses to algal fertilizers. Scientific Reports, 9,

Journal Article Type Article
Acceptance Date Nov 22, 2018
Online Publication Date Feb 13, 2019
Publication Date Feb 13, 2019
Deposit Date Nov 23, 2018
Publicly Available Date Nov 23, 2018
Journal Scientific Reports
Print ISSN 2045-2322
Electronic ISSN 2045-2322
Publisher Nature Publishing Group
Peer Reviewed Peer Reviewed
Volume 9
Article Number 1983
Public URL
Publisher URL
Additional Information Received: 28 March 2018; Accepted: 22 November 2018; First Online: 13 February 2019; : The authors declare no competing interests.


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