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Version 3.24

eHALOPH Introduction

A halophyte is a plant that completes its life cycle in a salty environment; many survive in seawater or even higher concentrations of salt. Most other plants (called glycophytes) cannot survive even one tenth the salt concentration found in seawater; this group includes virtually all our crop plants. Given the extent of salt-affected land, perhaps 6% of the world's land surface and a continued increase in the extent of agricultural land that is salt-affected, knowledge of plants that can tolerate salt provides a basis for the restoration of this land and to understanding the genetics, biochemistry and physiology of salt tolerance in plants.

A comprehensive list of halophytes was compiled by James Aronson during the 1980s: his 'HALOPH A Data Base of Salt Tolerant Plants of the World' was published in 1989 by the Office of Arid Land Studies at the University of Arizona, Tucson, Arizona . This list of 1554 species for which there is evidence that they are salt tolerant was arranged by family, genus and species and included data on salinity tolerance, together with photosynthetic pathway where known, life form, plant type, economic use and distribution [Aronson, J.A. (1989) HALOPH A Data Base of Salt Tolerant Plants of the World, Office of Arid Land Studies, University of Arizona, Tucson, Arizona, 75 pp].

The primary criterion for inclusion in HALOPH was “known or presumed tolerance to electrical conductivity measuring (or estimated to be) at least 7.8 dS m-1, during significant periods of the plant’s entire life” (Aronson 1989). Aronson wrote that this was “the maximum reported salinity tolerance of a taxon as reported in the References Cited. The unit used is the most commonly accepted one for the measurement of electrical conductivity of a saturation extract. It is for most intents and purposes equivalent to the formerly preferred term mmhos cm-1. In some cases, I have converted the terms given by an author (e.g., mg/l, mM, or meq) ECe terms for purposes of standardization. However, the reader is once again reminded that salinity tolerance is very much affected by what I have called accessory factors - season, humidity, drainage, nutrition, and the like. In addition, under field conditions, soil salinity varies significantly across a soil profile. Thus, a considerable number of difficulties arise in interpretation, and particularly, in attempted application of data of such diverse origins. Therefore I urge readers of HALOPH to go to primary sources before drawing final conclusions about a given plant's salt tolerance.

SW      This is the only non-exact term used for this field. It stands for seawater of unknown ECi, which the species is generally exposed for at least part of each day. In such cases, ECi of SW is assumed to be at least 40 dS m‑1. A high degree of seasonal and geographical variation is of course involved in seawater salinity levels.

A listing of "??" means some doubt exists as to whether this taxon really meets the criteria for inclusion in this database”


The data in HALOPH is (with permission) the basis of eHALOPH. Over the period 2002 to 2005 the printed database (Aronson 1989) was converted to an electronic format by scanning, use of text recognition software and manual editing. The files generated in Microsoft Excel were incorporated first into an Access database and then into MySQL tables. The current version retains the basic format of HALOPH with data being organised taxonomically by family, genus and species. The taxonomy has been updated to that in ‘The Plant List’: (http://www.theplantlist.org/) and from November 2018 to that in Plants of the World Online [www.plantsofhteworldonline.org]. Original data on plant type, life form, maximum salinity tolerated, photosynthetic pathway and economic uses have been supplemented with data on antioxidants, secondary metabolites, compatible solutes and habitat and whether or not there have been publications on ecotypes, germination, the presence or absence of salt glands molecular data, microbial interactions and mycorrhizal status. The geographical distribution of species provided in HALOPH was only descriptive and this field has been supplemented and enriched in eHALOPH by providing distribution maps. In eHALOPH we have added concentrations on a molar basis where these are available [note 8.0 dS / m is approximately 80 mM NaCl.

The database has been checked and compared with a list prepared by Menzel and Lieth (2003): Menzel, U and Lieth, H. (2003) HALOPHYTE database Vers. 2.0 update. In Cash Crop Helophytes, edited by Lieth, H. and Mochtchenko, M. Compact Disc. Kluwer, Dordrecht.

eHALOPH is a database of plants that show tolerance to a salt concentrations equivalent to about 80 mM NaCl or above. It includes those species defined as halophytes by Flowers and Colmer (2008) as plants that can complete their life-cycle in a salt concentration of at least 200 mM NaCl. We define euhalophytes as those plants that can complete their life-cycle in seawater concentrations of salt - around 500 mM NaCl.

In addition to the species database, eHALOPH also includes a large literature database on halophytes. This list is based on Aronson’s original references an extensive additional bibliography derived a personal bibliography generated over the last 30 years (an Endnote library; T J Flowers). The bibliography is supplemented by records imported (on a monthly basis) from a search of the Web of Science.

eHALOPH  and it bibliography is searchable and entries can be edited – see Using eHALOPH.

An earlier version of eHALOPH can also be seen in Kew's Seed Information Database (SID) http://data.kew.org/sid/about.html. Data from version 3.09 of eHALOPH is available in theTRY database (https://www.try-db.org/TryWeb/Home.php). More detail of the current version can be found in

Santos J, Al-Azzawi M, Aronson J, Flowers TJ. 2016. eHALOPH a Database of Salt-Tolerant Plants: Helping put Halophytes to Work. Plant & Cell Physiology, 57 (1): e10(1–10) (2016) doi:10.1093/pcp/pcv155.



LEGAL NOTICES — This website is protected by Copyright © The University of Sussex, 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2019, 2020, 2021, 2022. The eHALOPH database is protected by Database Right and Copyright © The University of Sussex and other contributors, 2006, 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2019, 2020, 2021, 2022. This database is based on an earlier work by James Aronson.

Contact email: halophytes@sussex.ac.uk
Credits – Tim Flowers, Joaquim Santos, Moritz Jahns, Brian Warburton, Peter Reed