Growth and salt accumulation capacity of the common ice plant in the tsunami-affected soil

Abstract

Halophytes are salt-tolerant plant that grows naturally in saline areas where almost all conventional crops die due to NaCl toxicity. The common ice plant, Mesembryanthemum crystallinum L., an annual halophyte native to South Africa, tolerates high salinity levels and accumulates NaCl in a shoot at a high level. To check the availability of the ice plant for desalinization of soils, we cultured the ice plant in soils collected from 16 sites located along coastal regions in the prefectures of Miyagi and Iwate, where were attacked by the tsunami disaster in the wake of the 2011 earthquake off the Pacific coast of Tohoku on 11 March 2011. In the soils obtained from some tsunami affected areas, the growth was better than that in the non-contaminated soil. The factors associated with growth inhibition were suggested to be water ratio (an index of water content) and soil water permeability. The ice plant’s estimated biological yield ranged from 0.33 to 14.6 kg m−2, equivalent to 2.3 to 101.7 t ha−1. The sum of Na+ and Cl− was about 9.5 g in the shoot (31.8% on a dry weight basis), and the estimated total amount of these ions removed from salinized soil was 2.38 t ha−1. These results indicated that the common ice plant could be used as a crop under salinity and a tool for ameliorating NaCl from salinized soils.

Keywords

• Common ice plant
• desalinisation
• halophyte
• phytoremediation
• salinity