Uniconazole-induced changes of stress responses of Vicia faba: polyphenole oxidase activation pattern serves as an indicator for membrane stability

Influence of uniconazole and different salt concentrations on growth and development of broad bean (Vicia faba L.) were investigated. Addition of salt to the irrigation water caused significant reduction of plant growth but uniconazole treated plants revealed better biomass. The number of phenolic compounds in V. faba leaf extracts changed with the age of the leaves, and the antioxidative potentials of uniconazole treated plants were slightly lower. The activity of polyphenoloxidase and its activation after plastid membrane desintegration by SDS were lower in uniconazole treated plants. Further studies with varying SDS-concentrations revealed a remarkable difference in membrane disintegration by SDS in uniconazole pretreated plants. This finding supports the hypothesis that uniconazole enhanced stress tolerance after uniconazole treatment is based on physiological change in thylakoid membrane stability.

Physiological response of mung bean "Vigna radiata" plants to some bioregulators

Pot experiments were conducted in the screen of the National Research Centre during two summer seasons 2006 and 2007 to study the physiological response of mung bean plants to some bioregulators (salicylic acid, glutathione or paclobutrazole). Vigna rediata plants were treated with different concentrations of salicylic acid (5, 10 and 15 mg/l ), glutathione or paclobutrazole (PBZ) each at 50, 100 and 150 mg/I. The obtained results indicate that foliar application of glutathione or paclobutrazole each at a rate of 150 mg/l or salicylic acid at a rate of 15 mg/l significantly increased plant height, number of branches/plant, fresh and dry weights 01' leaves, fresh and dry weights of branches and yield (g/plant). On the other hand, an application of paclobutrazole at all the used treatments led to significant decrease in the plant height. Total carbohydrates and total proteins and mineral ions content of the produced seed were significantly increased as a result of foliar application of salicylic acid, glutathione or paclobutrazole at all the used levels. All the used treatments of bioregulators caused positive changes in the gels of protein electrophoresis and photosynthetic pigments of mung bean plants