Effects of Proline Treatments on Plant Growth, Lipid Peroxidation and Antioxidant Enzyme Activities of Tomato (Solanum Lycopersicum L.) Seedlings Under Chilling Stress

Abstract

Experiments were conducted in a climate room with split air conditioner to determine the effects of foliar proline treatments on chilling stress-tolerance of Bandita F1 tomato (Solanum lycopersicum L.) seedlings through some morphological and physiological parameters. Chilling treatments were initiated when the seedlings had 3-4 true leaves. Seedlings to be chilled were sprayed with distilled water containing 0, 5, 10 and 15 mM proline. Seedlings were exposed to chilling stress in an incubator for 7 days and untreated (control) seedlings were kept in a climate chamber under normal conditions (25/20 degrees C day/night). Total weight of green parts, MDA (malondialdehyde) content and antioxidative enzyme activities (catalase (CAT), ascorbate peroxidase (APX), superoxide dismutase (SOD)) were determined on sample leaves. Stress-induced damages were assessed using a 1-5 scale. It was determined that foliar applications of proline to plants subjected to chilling stress had a positive effect on the development and damage of the plant. It was determined that there was a positive relationship between the scale values and the MDA amounts, and the MDA levels of the application with a high scale value were also high. Likewise, under the application of 10 mM proline, which had a low scale value, the plants were less affected by chilling stress and the amount of MDA was observed to be low. Since the antioxidative enzyme activities were at the highest level in the 10 mM proline application, the plants were found to be affected by the cold stress at the lowest level. It was observed that 10 mM foliar proline application had the most positive effect on all parameters measured in tomato plants and relatively protected the plants against chilling stress.