Potential of the Common Ice Plant,Mesembryanthemum crystallinumas a New High-Functional Food as Evaluated by Polyol Accumulation

Abstract

: We measured the concentration of polyols (pinitol, ononitol, and myo-inositol), which are known to have health-promoting and/or disease-preventing functions, in the common ice plant (Mesembryanthemum crystallinum L.) cultured under salt-and drought-stressed treatments. In NaCl-treated plant the concentration of pinitol/ononitol increased with increasing NaCl concentration in culture solution. The maximal concentration was 3.6 mg g -1 FW, which was found in the shoot top, followed by small side shoots (2.1 mg g -1 FW) of mature plants grown with 400 mM NaCl for 35 ds. The drought stress also accelerated the accumulation of pinitol/ ononitol. The maximal concentration was 1.2 mg g -1 FW, which was found in the shoot top of plants under the stress for 25 ds. The myo-inositol increased in salt-stressed plants at 3 ds after the start of the treatment and then decreased with the lapse of time during stress. The concentration of polyols in the ice plant was comparable to that in the other species reported to accumulate polyols at high levels. Radical scavenging activity evaluated by DPPH assay was increased two-fold by 400 mM NaCl treatment, which was twice as high as that in the leaves of lettuce (Lactuca sativa L.). These results indicated the high potential of the ice plant as a polyol-rich highfunctional food.

Ion accumulation and expression of ion homeostasis-related genes associated with halophilism, NaCl-promoted growth in a halophyte Mesembryanthemum crystallinum L.

“…Plant culture and NaCl treatment Seeds of M. crystallinum L. were surface-sterilized and sowed on germination medium as described by Agarie et al (2007). Seedlings were transferred to pots and grown in a greenhouse in Kagawa University according to the description by Agarie et al (2009). NaCl was applied to the 4-week-old plants by irrigation of nutrient solutions 'Otsuka House No.…”

“…The growth enhancement of the ice plant in salinized soils is observed at around 100-200 mM NaCl (Adams et al, 1998;Flowers, Troke & Yeo, 1977). This halophyte has been cultivated as vegetables in some countries (Agarie et al, 2009), and also used as a model system for various studies on salt tolerance (Vera-Estrella et al, 1999. However, there has been no information on the mechanisms of halophilism in this species.…”

“…In other plants, Cl − transporters, such as a plasma membrane cation/Cl − cotransporter (CCC) in Oryza sativa (OsCCC1) (Chen et al, 2016;Kong et al, 2011) and a tonoplast H + /Cl − antiporter (CLC) in Glycine max (GmCLC1) (Wei et al, 2016), are related to Cl − homeostasis. In the ice plant, proline and ononitol are accumulated in the cytoplasm as compatible solutes in response to salinity (Agarie et al, 2009;Thomas, De Armond & Bohnert, 1992;Vernon & Bohnert, 1992), and genes McP5CS and McImt1 encode enzymes delta 1-pyrroline-5-carboxylate synthase (P5CS) and myo-inositol O-methyl transferase (Imt), which catalyze synthesis of proline and ononitol, respectively (Oh et al, 2015;Vernon & Bohnert, 1992). Moreover, xyloglucan endotransglucosylase/ hydrolase (XTH) enzymes, such as a XTH of Populus euphratica poplar (PeXTH) (Han et al, 2013), play important roles in the cell wall elasticity in plants under salt stress.…”

MYB and HD-ZIP IV homologs related to trichome formation are involved in epidermal bladder cell development in the halophyteMesembryanthemum crystallinumL.

“…Mesembryanthemum crystallinum L., the common ice plant, is a leafy vegetable crop (Agarie et al, 2009) that exhibits extreme tolerance to high salinity concentrations equivalent to seawater (ca. 500 mM NaCl).…”

Content of Methylated Inositols in Familiar Edible Plants

“…Their natural and food materials, however, were restricted to common foods. On the other hand, petals of carnations 7 and ice plants 4 contain pinitol, and it was demonstrated that pinitol in the plants acts as an osmotic regulator and cryoprotectant in cells. 8 Thus, many plants are expected to contain inositols.…”