THE EFFECT OF RADIONUCLIDES AND HEAVY METALS ON THE ULTRASTRUCTURAL FEATURES OF LEAVES IN HELIANTHUS ANNUUS

The ultrastructural features of the leaf in mature plants of Helianthus annuus (during flowering), cultivated in three different areas: in normal culture (Floresti village, Cluj district) and in cultures on sites polluted with heavy metals and radionuclides: (a) near the power station Turceni and (b) on sterile waste dump in the Pedological Research Station of Rovinari (Gorj district), were analyzed. The soil analysis in the three sites showed a higher content in radionuclides and heavy metals, especially on the soil from Turceni, as compared to Control. The ultrastructural analysis pointed out the effect of the presence of high amounts of radionuclides and heavy metals, as well as the plant reaction: the parietal disposition of the heterochromatin in the nucleus in the shape of bodyguard, synthesis and accumulation of some substances (probably with antioxidant or chelating role) in vacuoles, which interacted with exogenous particles, a/

Comparison of some morpho-anatomical features at fossil vegetal species and their actual correspondent species

The values of some morpho-anatomical features (the size and shape of the epidermic cells of the leaves, as well as the size and features of the stomata) recorded in some fossil vegetal species and their actual correspondent species were analysed. These differences offer information about the evolution process. In the case of the analysed species (Ginkgo sp., Taxus sp., Magnolia sp. and Buxus sempervirens), two hypotheses concerning the genetic mechanisms involved in evolution and in the speciation processes or in the adaptation to the environmental conditions can be considered. These genetic mechanisms are: the multiplication of genomes and the process of gene amplification. They both result in an increase in epidermic cells and stomata size, as well as in the enzymatic activity, which determines a better adaptation to the environmental conditions, as well as to the settlement of the speciation process

Comparison of some morpho-anatomical features at fossil vegetal species and their actual correspondent species

The values of some morpho-anatomical features (the size and shape of the epidermic cells of the leaves, as well as the size and features of the stomata) recorded in some fossil vegetal species and their actual correspondent species were analysed. These differences offer information about the evolution process. In the case of the analysed species (Ginkgo sp., Taxus sp., Magnolia sp. and Buxus sempervirens), two hypotheses concerning the genetic mechanisms involved in evolution and in the speciation processes or in the adaptation to the environmental conditions can be considered. These genetic mechanisms are: the multiplication of genomes and the process of gene amplification. They both result in an increase in epidermic cells and stomata size, as well as in the enzymatic activity, which determines a better adaptation to the environmental conditions, as well as to the settlement of the speciation process