Differential Effects of Na+, Mg2+, K+, Ca2+ and Osmotic Stress on the Wild Type and the NaCl-Tolerant Mutants stl1 and stl2 of Ceratopteris richardii

Authors

Dale L. Vogelien, Kennesaw State UniversityFollow
Leslie G. Hickok, University of Tennessee - Knoxville
Thomas R. Warne, University of Tennessee - Knoxville

Department

Molecular and Cellular Biology

Document Type

Article

Publication Date

1-1996

Abstract

In order to identify physiological components that contribute to salinity tolerance, we compared the effects of Na⁺, Mg²⁺ and K⁺ salts (NaCl, Na₂SO₄, MgCl₂, MgSO₄, KCl and K₂SO₄), Ca²⁺ (CaSO₄), mannitol and melibiose on the wild type and the single-gene NaCI-tolerant mutants stll and stl2 of Ceratopteris richardii. Compared with gametophytic growth of the wild type, stl2 showed a low level of tolerance that was restricted to Na⁺ salts and osmotic stress. stl2 exhibited high tolerance to both Na⁺ and Mg²⁺ salts, as well as to osmotic stress. In response to short-term exposure (3 d) to NaCl, accumulation of K⁺ and Na⁺ was similar in the wild type and stll. In contrast, stl2 accumulated higher levels of K⁺ and lower levels of Na⁺. Ca²⁺ supplementation (1-0 mol m^-3) ameliorated growth inhibition by Na⁺ and Mg²⁺ stress in wild type and stll, but not in stl2. In addition, under Na⁺ stress (175 mol m^-3) wild-type, stll and stl2 gametophytes maintained higher tissue levels of K⁺ and lower levels of Na⁺ when supplemented with Ca²⁺ (1-0 mol m^-3). stl2 gametophytes were extremely sensitive to K⁺ supplementation. Growth of stl2 was greater than or equal to that of the wild type at trace concentrations of K⁺ hut decreased substantially with increasing K⁺ concentration. Supplementation with K⁺ from 0 to 1-85 mol m^-3 alleviated some of tbe inhibition by 75 mol m^-3 NaCl in tbe wild type and in stll. In stl2, growth at 75 mol m^-3 NaCl was similar at 0 and 1-85 mol m^-3 K⁺ supplementation. Although K⁺ supplementation above 1-85 mol m^-3 did not alleviate inhibition of growth by Na⁺ in any genotype, stl2 maintained greater relative tolerance to NaCl at all K⁺ concentrations tested.

Journal Title

Plant, Cell & Environment

Journal ISSN

0140-7791

Volume

19

Issue

1

First Page

17

Last Page

23

Digital Object Identifier (DOI)

10.1111/j.1365-3040.1996.tb00222.x