Differential osmotic adjustment to iso-osmotic NaCl and PEG stress in the in vitro cultures of Sesuvium portulacastrum (
- PDF / 161,256 Bytes
- 6 Pages / 609.449 x 793.701 pts Page_size
- 46 Downloads / 184 Views
J. Crop Sci. Biotech. 2010 (December) 13 (4) : 251 ~ 256 DOI No. 10.1007/s12892-010-0008-9 RESEARCH ARTICLE
Differential Osmotic Adjustment to Iso-osmotic NaCl and PEG Stress in the in vitro Cultures of Sesuvium portulacastrum (L.) L. Vinayak Haribhau Lokhande1,2, Tukaram Dayaram Nikam1, Suprasanna Penna2* 1
Department of Botany, University of Pune, Pune 411 007 India Functional Plant Biology Section, Nuclear Agriculture & Biotechnology Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 India
2
Received: December 25, 2009 / Revised September 20, 2010 / Accepted: November 3, 2010 Ⓒ Korean Society of Crop Science and Springer 2010
Abstract The influence of iso-osmotic (-0.7 MPa) NaCl and PEG stress on growth, osmotic adjustment and antioxidant defense mechanisms was investigated in the in vitro cultures of Sesuvium portulacastrum (L.) L. The decreased relative growth rate (RGR) and water content of PEG-stressed calli in comparison to NaCl was found to be correlated with differences observed in the energy expenditure for the maintenance of osmotic balance. Osmotic adjustment in the NaCl-stressed calli favored higher accumulation of saline ions and soluble sugars, whereas PEG-stressed calli confirmed increased levels of organic osmolytes (proline, glycine betaine and soluble sugars). Permeability of Na+ ions across the membrane revealed increased relative electrolytic leakage (REL) in NaCl-stressed calli, however non-penetrating and highly viscous solution of PEG amplified the peroxidation of membrane lipids. Increased activities of superoxide dismutase and catalase displayed efficient removal of toxic reactive oxygen species in comparison to ascorbate peroxidase in the calli exposed to iso-osmotic stress. These findings suggest that differential tolerance potential to iso-osmotic NaCl and PEG stress in terms of osmotic adjustment appears to be the prime defense mechanism of Sesuvium for its survival under iso-osmotic stress conditions at the expense of reduced growth and water content. Key words: iso-osmotic stress, NaCl, osmotic adjustment, oxidative damage, PEG, Sesuvium portulacastrum
Introduction Drought and salinity are two of the most important environmental stresses which occur simultaneously in arid regions (Slama et al. 2008), thereby upsetting growth and productivity of crop plants throughout the world. Consequently, physiological and biochemical mechanisms operating under these stresses generates considerable interest (Pagter et al. 2009; Slama et al. 2007, 2008; Suriyan and Chalempol 2009). Both of these stresses have common osmotic effects that induce the plant to diminish their internal water potential to avoid desiccation. Nevertheless, salinity aggravates ionic stress other than osmotic stress; therefore physiological mechanisms that plants apply to respond to salinity or drought may differ partly on a case-by-case basis (Tonon et al. Suprasanna Penna ( ) E-mail: [email protected], [email protected]
The Korean Society of Crop Science
2004). Besides, osmotic stress effects are
Data Loading...
