Mitigation of Salt Stress-Induced Inhibition of Plantago crassifolia Reproductive Development by Supplemental Calcium or Magnesium

Abstract

In Plantago crassifolia, a moderate halophyte characteristic of borders of salt marshes in the Mediterranean region, reproductive development is more sensitive to high soil salinity than vegetative growth. To investigate the possible role of calcium and magnesium salts in the responses of this species to salt stress, adult plants were submitted over a 2-month period to treatments with 300 mM NaCl-a concentration which affects, but does not completely inhibit seed formation in P. crassifolia-either alone or combined with low concentrations of CaCl 2 (10 mM) or MgCl 2 (20 mM). The NaCl treatment did not affect plant vegetative growth and had a stimulating effect on flowering. Yet almost half the spikes produced had aborted seeds, and the effect on seed number and quality-estimated by their mean weight and germination capacity-was obviously deleterious. Addition of calcium or magnesium chloride during the saltstress treatment completely counteracted the negative effect of NaCl on the 'reproductive success' of the plants: the number, weight and germination frequency of the seeds were similar to that in the control, non-stressed plants. These results indicate that both divalent cations can suppress or mitigate the deleterious effects of salt stress. While this protective role is well established in the case of calcium, we provide here the first experimental evidence of a similar function for magnesium.

Proline and glycine betaine accumulation in two succulent halophytes under natural and experimental conditions

“…These data support and extend previous studies on the influence of salinity on the vegetative development of this species (Vicente et al 2004). Nonetheless, more recent results indicate that in older plants, salt affects mostly reproductive parameters, such as quantity and quality of flowers and seeds (Grigore et al 2012). Numerous studies have shown that salt tolerance is developmentally regulated, and the responses to salt stress of a given species may be quite diverse at different life cycle stages (Flowers et al 1986;Lauchli and Epstein 1990;Johnson et al 1992;Vicente et al 2004).…”

Salinity tolerance among a large range of bermudagrasses (Cynodon spp.) relative to other halophytic and non-halophytic perennial C4 grasses

“…Previous studies (Greenway and Munns, 1980;Grigore et al, 2012;English and Colmer, 2013) showed that supplemental Ca 2+ and Mg 2+ can mitigate the deleterious effects of salt stress. In the experiments present here, additional Ca 2+ to maintain the CAR ≥ 0.035 was provided to avoid Na + induced Ca 2+ deficiency (Kopittke and Menzies, 2005).…”

Is salinity the main ecologic factor that shapes the distribution of two endemic Mediterranean plant species of the genus Gypsophila?

“…Milestone Microwave Laboratory Systems) as detailed by Grigore et al (2012b). Quantification of Na + and K + was performed by a flame photometry Jenway PFP7, and by an atomic absorption spectrometry (Model: Varian SpectrAA 220) for the bivalent cations, at 239.9 nm for Ca 2+ and at 202.6 nm for Mg 2+ .…”

“…A high NaCl concentration in soil is one of the most restrictive environmental factors (osmotic and ionic stress), and only a small category of plants, halophytes, have adapted to survive and complete their biological cycle under such conditions. The exact definition of halophytes is ambiguous and controversial (Grigore et al 2012a, and references therein). Halophytes are generally considered to be plants that can grow and complete their life cycle in habitats with soil salinity above 200 mM NaCl (Flowers et al 1986;Flowers and Colmer 2008).…”