Euhalophyte eryngium maritimum L.: the microstructure and functional characteristics

The microstructure of the leaf surface, lipids composition, pigments spectrum, biological and photosynthetic activity, and hormones status of euhalophyte Eryngium maritimum L., one of the most salt-tolerant plants, were studied. It was shown that the existence in saline and dry soils is provided among others adaptive mechanisms by specific microstructure of leaf, adaxial and abaxial surfaces of which have well-developed cuticle and stomata slit placed below the surface of the epidermis. The presence of a large amount of saturated fatty acids provides decrease of membrane permeability and better resistance against soil salinity. The key role in photosynthetic activity is played by chlorophyll a. At the same time a high amount of carotenoids (as compared with amount of chlorophylls) points out that these pigments have a light-collecting function and could transfer an additional energy to chlorophylls. The data from thermoluminescence analyses showed a possible inhibition of recombination reactions in PS II by the assumed saline concentration in plant tissue. Besides, the fluorescence measurements indicate reduced efficiency of photosynthetic reactions. The high level of active ABA is correlated with salt tolerance and ability to survive and grow in stress conditions. The high level of conjugated form of IAA demonstrated that activity of this hormone is limited.