Salinity induced changes in cell membrane stability, protein and RNA contents
Seedlings of sugar beet (Beta vulgarus L.) were used at salinity levels of 0 (control), 4.7, 9.4 and 14.1 dS m-1 to determine the effect of salt on vegetative growth, relative water content, cell membrane stability, protein and RNA contents in sand culture experiment. Fresh and dry weights of plants, shoots and roots decreased significantly with increasing salt concentration. Salinity significantly reduced leaf area and relative water content while cell membrane injury increased with increasing salt concentration. Leaf protein content decreased significantly and sodium dodecyl sulphate-polyacrylamide gel electrophresis (SDS-PAGE) analysis showed significant change in protein profiles in salt treated samples, which suggests that NaCl altered protein pattern. Salinity induced RNA degradation with increasing salt level. Cell membrane stability exhibited negative correlation with fresh and dry weight, leaf area, leaf water content and total protein content. There was also a significant positive correlation between cell membrane injury and RNA degradation.
Key words: Salt stress, membrane injury, growth, RWC, protein activity, RNA, Beta vulgarus L.