Abstract

Juglone (5-Hydroxy-1, 4-naphthoquinone) is an allelochemical responsible for walnut allelopathy. The effects of gibberellic acid (GA) and kinetin (KIN) in overcoming juglone stress on seed germination and seedling growth were investigated in cress (Lepidium sativum cv. Bandırma). Pretreated seeds with plant growth regulators were used in the study to test their alleviation effect after juglone stress. It was found that seed germination of cress was inhibited by juglone in range of 0.2 - 1 mM concentrations but GA and KIN alleviated this inhibition significantly. Both elongation and fresh and dry weights of the seedlings were also reduced by juglone, and the plant growth regulators alleviated them. GA was found more effective than KIN in alleviation of juglone stress.

Key words: Alleviation, cress, gibberellic acid, juglone stress, kinetin, seed germination, seedling growth.