PJB-2018-1669
Identification of short-term Na+ secretion in salt tolerant cell line from alfalfa callus cultures selected on half-natural seawater medium
Peng Guo, Baoling Yang, Yajing Bao and Hongxu Wei
Abstract
Seawater irrigation is critical for coastal agriculture development, but key mechanism of root-ion flux in the salt-tolerance of callus-cultured plant lines in response to seawater remains to be unclear. In this study, hypocotyl-calluses of Medicago sativa L. cv. Gongnong No.2 were cultured to generate the parent line of M0, ten passages after which salt tolerant line of EMS-induced Ms1 was screened by half-natural seawater (collected from Boshi Bay in Dalian City, Northeast China). Regenerated seedlings from M0 and Ms1 were compared for their difference of salt tolerance to seawater proportions of 50%, 30%, 10%, and 0% (Control). Factors of different callus-cultured lines and seawater treatment did not have any interactive effect on shoot height (length) and Na+ accumulation, stomatal conductance (SC), foliar chlorophyll content. For both lines, seawater treatments at lower proportions of 10% and control tended to have more root length, shoot biomass, and stomatal density (SD), but less MDA and proline contents. Compared to seedlings from the M0 line, relatively higher tolerance to salt of those from the Ms1 line mainly resulted from less investment of dry-mass to root, declined SD and SC, controlled shoot Na+ accumulation, but greater chlorophyll content and membrane-protective ability. Results obtained by Non-invasive micro-test technique (NMT) indicated that in the first 1.5 min net Na+ flux in roots in the Ms1 line showed highest rate and significant extrusion pattern, while some net Na+ influx occurred in the M0 line. In conclusion, seawater irrigation has some potential to be used in the culture of coastal alfalfa development through screening salt-tolerant callus-cultured lines. Root Na+ efflux is a critical parameter determining their resistance to seawater salinity
To Cite this article:
Download
