Short-Time Hypoxia and Post Aeration Alter Relative Membrane Permeability and Total Protein in Root and Leave of Sunflower Cultivars

Abstract

Aims: There are varieties of factors that results into hypoxia in plant’s root zone. Hypoxia causes oxidative stress and lipid peroxidation, which seriously affect plant growth. In this experiment, effects of hypoxia and post aeration on root and shoot dry weight, relative membrane permeability (RMP) and total protein (TP) of roots and leaves were evaluated. Study Design: Department of Biology (Plant Science Division), University of Isfahan and University of Arak in Iran, between September 2010 and April 2012. Methodology: Seventeen days old seedlings of four sunflower cultivars (Lacomca, Record, Progress and Hysun33) were subjected to four days of hypoxia and then re-aerated for four days. Plants were sampled daily during hypoxia and post aeration to measure root and shoot dry weight, RMP and TP of roots and leaves. RMP was assayed by level of electrolyte leakage from plasma membrane with electrical conductivity meter and TP was measured according to Bradford's method. Results: Hypoxia caused reduction of plant dry weight differently in different cultivars. Lacomca and Progress cultivars in comparison to Record and Hysun33 cultivars showed less reduction in root dry weight (almost 18% versus 49.4% and 36.1%, respectively). The highest and the lowest reduction in shoot dry weight was observed in Hysun33 (24.5%) and Lacomca (9.7%) cultivars; these reductions were correlated with the amounts of increase in leave RMP in the selfsame cultivars (14.5% and 5.0%, respectively). The highest increase in root and leave TP was obtained for Record cultivar (100.8% and 490.1%, respectively), nevertheless, the lowest increase was measured in root (26.6%) and leave (94.9%) of Lacomca cultivar. Re-aeration for 4 days after hypoxia showed continuous reduction in roots and shoots dry weight and also optimized the amount of RMP and TP of roots and leaves. Conclusion: Hypoxic condition caused plant dry weight reduction; however, root dry weight reduction was higher than shoot. Hypoxia also increased root and leave RMP and TP. The amount of leave RMP was higher than that of root. The addition of leave RMP was correlated with dry weight reduction; however, this trend was not the same in root.