Salicylic Acid-Induced Changes in Photosystem II Reactions in Barley Plants

ABSTRACT

In vivo effect of salicylic acid (SA) on photosynthetic oxygen evolution and thermoluminescence emission curves were investigated in barley (Hordeum vulgare L.).

Increasing concentrations of SA (0.1mM, 0.5mM and 1mM), imposed through the root medium for a period of 7 days have a marked effect on the energetics of the charge recombination of barley leaves and isolated chloroplast. Data showed a reduction of Hill reaction activity and oxygen flash yields in accordance with the changes in membrane permeability and malondialdehyde content. When 7-day old barley seedlings were supplied with SA through the transpiration stream for 24 h no marked changes in photosynthetic reactions were observed.

Possible reasons for the responses of photosynthetic light reactions to SA are discussed.

Keywords:

• barley
• photosynthetic activity
• Salicylic acid
• thermoluminescence