Effects of Salicylic Acid on Germination and Vegetative Growth Properties of Radish (Raphanus sativus L.) Cultivars Grown under Drought Stress Conditions

Abstract

In this study, firstly different PEG 6000 concentrations (%5, %10, %15, %20) were applied to four different radish cultivars (black, white, big red, little radish) to determine germination and vegetative growth parameters under drought conditions. As germination parameter; germination percentage (%), germination time and vigor index were determined. After germination, number of leaves, shoot length (cm), root length (cm), leaf width (cm) leaf length (cm), stem diameter (mm), plant fresh and dry weights (g) were measured in germinated plants. Vegetative growth parameters decreased in %15 PEG6000 for white, black and red little radish cultivars and in %20 for big red radish cultivar, and these doses were determined as the threshold value for salicylic acid applications. In second step, in order to increase the drought tolerance of the cultivars, different doses of salicylic acid (0.25, 0.50, 0.75, 1.00 mM) were applied in addition to PEG6000 application. The effect of different doses of salicylic acid on germination and vegetative growth parameters of radish seeds under drought conditions varied depending on the cultivar, and it was determined that it caused a stimulatory effect on germination of the cultivars. Except for the large red radish cv, it has a positive effect on plant growth in general. It was found that SA doses applied in this cultivar had an inhibitory effect. 0.50 mM salicylic acid in black radish; 0.25 mM salicylic acid applications in white and little red radish provided positive results in terms of improving vegetative parameters at %15 PEG6000 concentration.