The protective effects of cobalt on potato seedling leaves during osmotic stress

The protective effects of cobalt on potato seedling leaves during osmotic stress were reported and discussed in this paper. The results showed that the membrane damage was significantly alleviated after 24 h of osmotic stress when cobalt of appropriate concentrations was added in PEG solutions. During -1.0 MPa PEG osmotic stress cobalt of 25 μmol L inhibited ethylene production rate significantly. Cobalt of 25 μmol L had no significant influence on the content of thiobarbituric acid reacting substances or chlorophyll in the first 16 h. When the stress lasted 20 h and 24 h, treatment with cobalt effectively restrained the increment in the levels of reactive oxygen species, hampered the decline in the content of putrescine, spermidine and spermine. The decline in the activities of antioxidative enzymes, thus inhibited the accumulation of thiobarbituric acid reacting substances and alleviated the reduction of chlorophyll content. It can be concluded that when the potato leaves were deeply stressed and damaged, through the inhibition of ethylene production, cobalt alleviated the decline in polyamine content and the activities of anti-oxidative enzymes, and hence alleviated the increment in reactive oxygen species levels and membrane damage and showed protective effects on the leaves.