Salt stress induced effects on biochemical parameters in etiolated maize leaf segments during greening

Treatment of etiolated maize leaf segments with 0-300 mM NaCl during greeningdecreased the osmotic potential of leaf sap significantly. Na+ content of the leaftissue increased significantly on supplying different concentrations of salt.Relative water content of the leaf tissue was marginally affected by the supply ofNaCl. Total protein and RNA content of the maize leaf segments graduallyincreased when treated with lower concentrations of NaCl and subsequentlydecreased at higher concentrations. Decrease in DNA content was noted withincreasing salt treatment in a concentration dependent manner. SDS-PAGE analysisof salt treated maize leaf tissue revealed appearance of one protein band (approx.73 kD) in samples incubated with 50 mM NaCl compared to control. Proteinidentification performed with the Mascot search engine in NCBI databaseindicated extensive homology of this protein with chloroplast heat shock protein70 o f Cenchrus americanu s (Prot ein sco re: 295 ), h ypo thet ical pr otei nsSEL MODR AFT_ 2678 15 o f Selagin ella moellend orffii (Prot ein sco re: 125 ),VITISV_000728 of Vitis vinifera (Protein score: 118) and SELMODRAFT_230659 ofSelaginella moellendorffii (Protein score: 51). The results revealed that the dark grownmaize leaf segments exhibit high degree of stress due to NaCl treatment, whichaffects the biochemical parameters governing the metabolic activities of the leaftissue. Further, the stress induced proteins are being synthesized in leaf tissue inresponse to salt stress.