[SCREENING OF WILD SPREAD AND CULTIVATED OF BUXUS SPECIES GROWING IN GEORGIA ON THE CONTENT OF ALKALOIDS AND BIOLOGICAL ACTIVITY].

Georgian flora is represented by about 4150 plant species. Many important alkaloid-containing plant species and among of them are species Buxus L. of genus in Adjara. The aims of the research were: sequential screening of the plants for the consistence of alkaloids; Study of anatomical characteristics of Buxus colchica Pojark. and revealing of specific pharmacological activity of steroidal alkaloids. The objects of research were B. colchica, B. balearika and B. sempervirens, growing in Adjara (Georgia), collected in active phase of flowering of the plants. There were revealed 370 species of alkaloid containing plants. Sum of alkaloids and crude aqueous extract have spasmolitic and antihistaminic activity. Experimental anatomical research of diagnostic characteristics of the bines showed the existence of monocyclic transient system with fiber like tracheids, dorsoventral mesophyll of the leaves; the structure for the upper part of epidermis is linear and the lower part is curved, type of stomata is paracitic.

Patterns of spatio-temporal distribution of winter chronic photoinhibition in leaves of three evergreen Mediterranean species with contrasting acclimation responses.

High irradiance and relatively low temperature, which characterize Mediterranean winters, cause chilling stress in plants. Downregulation of photosynthetic efficiency is a mechanism that allows plants to survive these conditions. This study aims to address whether this process shows a regular spatial pattern across leaf surface or not. Three species (Buxus sempervirens, Cistus albidus and Arctostaphylos uva-ursi) with contrasting responses to winter stress were studied. During 7 days, macro and micro Fv/Fm spatial patterns were monitored by the use of chlorophyll fluorescence imaging techniques. In the field, the strongest photoinhibition was found in B. sempervirens, while there was almost no chronic photoinhibition in C. albidus. In leaves of the first species, Fv/Fm decreased from base to tip while in C. albidus it was uniform over the leaf lamina. An intermediate behavior is shown by A. uva-ursi leaves. Spatial heterogeneity distribution of Fv/Fm was found inside the leaves, resulting in greater Fv/Fm values in the inner layers than in the outer ones. Neither xanthophyll-linked downregulation of Fv/Fm nor protein remobilization were the reasons for such spatial patterns since pigment composition and nitrogen content did not reveal tip-base differences. During recovery from winter, photoinhibition changes occurred in Fv/Fm, pigments and chloroplast ultrastructure. This work shows for the first time that irrespective of physiological mechanisms responsible for development of winter photoinhibition, there is an acclimation response with strong spatio-temporal variability at leaf level in some species. This observation should be taken into account when modeling or scaling up photosynthetic responses.

Variation in sexual expression in the monoecious shrub Buxus balearica at different scales.

Monoecy allows high plasticity in gender expression because the production of separate female and male flowers increases the ability to respond to specific environmental circumstances. We studied variation in sexual expression and its correlates in the monoecious shrub Buxus balearica, for two years, in six populations in the Balearic Islands and four in the Iberian Peninsula. Phenotypic gender varied among populations; while island populations showed slight variations around an average gender, mainland populations showed a broad range of variation in gender among individuals, always biased towards increasing maleness compared with the other populations. Within populations, gender was not related to plant size. Between-year changes were slight and mainly consisted of an increase in relative maleness in the mast year. Reproduction did not affect gender in the next year, as assessed by either observational or experimental methods. Most variation in gender expression occurred among individuals within populations (83.6 %), followed by variation among populations (13.6 %) and years (2.8 %). Our results suggest that male-biased gender at population and plant levels was related to stressful conditions and resource limitation, because: (1) maleness was higher in mainland populations, where summer drought was stronger; (2) maleness increased with elevation; (3) fruit set was positively correlated with femaleness; (4) the percentage of male inflorescences increased over the flowering period; and (5) male inflorescences were preferentially in lower parts of the branch nodes. Higher maleness in mast years, however, could be related to increased male success under synchronic flowering.