Characterization of Growth, Water Relations, and Proline Accumulation in Sodium Sulfate Tolerant Callus of Brassica napus L. cv Westar (Canola)

Abstract

Unselected and sodium sulfate tolerant callus cultures of Brassica napus L. cv Westar were grown on media supplemented with mannitol, NaCl, or Na2SO4. In all cases, growth of tolerant callus, measured on a fresh weight or dry weight basis, was greater than that of unselected callus, which was also subject to necrosis on high levels of salt. Tissue water potential became more negative in both unselected and tolerant callus grown in the presence of mannitol or Na2SO4. Water potentials in unselected callus were more negative than those of the tolerant tissues; but over a range of Na2SO4 concentrations both cultures displayed osmotic adjustment, maintaining relatively constant turgor. Proline accumulation in both unselected and tolerant callus was low (15 to 20 micromoles per gram dry weight) in the absence of stress, but increased on media supplemented with mannitol, NaCI, or Na2SO4. Increases in proline concentration were approximately linear in tolerant callus, reaching a maximum of 130 to 175 micromoles per gram dry weight. In unselected callus, concentrations were higher, reaching 390 to 520 micromoles per gram dry weight. Proline accumulation was correlated with inhibition of growth, and there was a negative correlation between proline concentration and culture age for tolerant callus.There are now many reports which describe the selection of salt tolerant cell cultures (5,17,21). A practical objective of such studies is the subsequent regeneration of tolerant plants, and this has been achieved in some species (4,22,24). However, salt tolerant cell cultures are also ideal systems with which to assess the physiological effects of salt and/or water stress at the cellular level (21). Comparison to nontolerant cell cultures isolated from the same initial explants enables measurement of the capacity and range of cellular tolerance, and allows identification of mechanisms of tolerance which may be applied for more specific in vitro selection. Unfortunately, detailed studies of tolerance and adaptation in vitro have been carried out with only a few mesophytic species (5), e.g. tobacco (2,13,16,18) Quantification of Salt Tolerance. To test for salt tolerance callus pieces from both unselected and tolerant stock cultures, both initiated on the same date, were transferred to basal medium or basal medium supplemented with NaCl, Na2SO4, or mannitol. The concentration of supplements used were 55, 110, 165, 220, 275, 330, 385, and 440 mm mannitol; 27.5, 53, 79, 106, 133.5, and 159 mM NaCl, and 35, 53, 70, 105, 123, 141,

In vitroselection of salt-tolerantAilanthus altissimaSwingle

“…A similar result has been also reported in Nicotiana tabacum (Pua and Thorpe 1986;Chandler and Thorpe 1987). Cells in suspension culture derived from plants regenerated from salt-tolerant cells exhibit a higher degree of salt tolerance than wild-type cells.…”

The enhancement of drought tolerance for pigeon pea inoculated by arbuscular mycorrhizae fungi

“…P n and G s of leaves were measured out using the portable CI-301 CO 2 gas analyzer (CID Inc., Vancouver, USA). SS, Pro or MDA in leaves was quantified based on the method by Chandler and Thorpe (1987), Vasquez-Tello et al (1990) or Wen et al (2010), respectively. The RA were determined according to the description by Liu et al (2007).…”

Chemically Induced Mutants of <i>Brassica oleracea var. botrytis</i> Maintained Stable Resistance to Drought and Salt Stress after Regeneration and Micropropagation

“…In the present investigation the mechanisms leading to genotypes variation on the basis of RWC are unknown but one might be osmotic adjustment allowing uptake of water from the mannitol supplemented media. Osmotic adjustment in plants under stress has been reported in Brassica species [24,29], in sorghum [30] and in wheat [31]. Cell wall elasticity may also be the cause for variable RWC [32] and both osmotic adjustment and cell wall elasticity might have adaptive mechanisms to drought stress.…”