Growth, anatomy and enzyme activity changes in maize roots induced by treatment of seeds with low-temperature plasma

The seeds of Zea mays L. cv. KWS were exposed to low-temperature plasma (LTP) by using Diffuse Coplanar Surface Barrier Discharge (DCSBD) for 60 and 120 seconds respectively. Growth parameters, anatomy of roots and activity of some enzymes (CAT, G-POX, SOD and DHO) isolated from roots grown from the seeds treated by LTP were evaluated. Our results indicate that LTP treatment of maize seeds affects post-germination growth of seedlings and this effect depends on the duration of LTP treatment. LTP treatment in duration of 60 seconds significantly increased the length, fresh and dry weight of the roots. However, the increase in time of LTP treatment to 120 seconds had inhibitive effect on the studied growth parameters. The activities of all studied antioxidant enzymes significantly increased with the age of maize seedlings in control conditions. On the other hand the application of LTP resulted in small, mostly non significant changes in the activity of antioxidant enzymes. Significant decrease in CAT activity was observed both in 3 and 6-day old maize roots and G-POX activity in 3-day old maize roots grown from seeds exposed to LTP for 60 seconds. A small, significant increase was detected only in SOD activity in 3-day old maize roots grown from seeds treated with LTP for 120 seconds and in 6-day old maize roots treated with LTP for 60 seconds. Significantly higher DHO activity was determined in embryos isolated from seeds treated with LTP for 60 seconds. On the contrary, in roots the DHO activity decreased with the time of LTP treatment. LTP treatment of seeds did not affect the anatomy of maize roots and caused only minor changes in the isoenzyme composition of G-POX and SOD.