About accumulation of thionins in barley seedling (Hordeum vulgare)

Abstract

The localization and dynamics of an antimicrobial protein thionin in green and etiolated barley seedlings cv Honar was studied. It was shown that the content of thionin in etiolated barley seedlings is much higher than that registered in green plants. In the bottom of the green leaf the content of thionin greatly exceeds that of the upper part of the sheet. It was found that only in the bottom part of the leaf thionin content increases with age of the seedlings. When placed in a dark, green seedlings show increasing thionin content but it does not reach the amount registered in the etiolated leaves of the same age. It was assumed that the high level of thionin in the lower part of seedlings and increase of it in darkness is consistent with the general strategy of plant defence against pathogens and caused by the fact that the nature of the lower part of the plant is contacted with the soil (located closer to the ground), where due to the presence of pathogenic micro-organisms and their spores as well as high humidity, especially at night, chances of infection are high.