Romanian Journal of Biology - Plant Biology
CURRENT ISSUE: Volume 53, No. 2, 2008
1. Ultrastructural characterization of the in vitro gametophyte of Bucegia romanica Radian – a rare liverwort
Aurelia Brezeanu, Gina Cogălniceanu, Raluca Stoiculescu
Ultrastructural characterization of the in vitro propagated gametophyte of Bucegia romanica Radian is presented in this paper. We have previously established an experimental protocol for ex situ conservation of this rare liverwort. Knop mineral nutritive medium without any source of carbon, temperature between 22 °C-25 °C and 16 hs light/8 hs dark photoperiod represent the experimental growth conditions. No anomaly of the thallus structure and ultrastructure has been observed. Much more, strong similarities at this level between Bucegia and other Hepatics were noticed, which allow us to consider the in vitro system established by us suitable for conservative purpose. The evolutive significance of the cell peculiarities, especially plasmodesmata biogenesis and features, was also underlined.
2. Ultrastructural peculiarities of the Usnea barbata (L.) Mott. mycobiont and phycobiont cells in "in vivo" and "in vitro" culture
Aurelia Brezeanu, DIANA VOICU
An electronomicroscopical study of native Usnea barbata (L.) Mott. species thallus in comparation with symbiotrophic appearance that developed in "in vitro" culture was achieved, in order to help elaborating an experimental system appropriate for artificial biosynthesis of lichen thalli. The inner structure of phycobiont in "in vitro" culture is from many points of view similar to the cells belonging to native thallus. Some changes such as the reduction of the cell dimensions, or of the number of chloroplasts, thyllacoids and pyrenoid globules (pyrenoglobules) randomly spread are recorded. As a characteristic is the presence of the "storage droplets", a possible reserve of lipids, proteins and other metabolic substrates which can be used by cells for future differentiation processes. These structures may also be involved in enabling the phycobiont to endure adverse environmental conditions and may represent adaptative modification induced by "in vitro" culture conditions.
3. In vitro conservation strategy in Veronica multifida ssp. capsellicarpa (Dubovik) a. Jelen
IRINA HOLOBIUC, RODICA BLÎNDU, MONICA CARASAN, FLORENȚA HELEPCIUC, CARMEN VOICHIȚĂ, G. NEGREAN
In the last decades, the biodiversity had a rapid decline, being necessary to approach the conservation using both in situ and ex situ strategies. The aim of our study was to establish a reproducible in vitro conservation methodology in the rare taxon Veronica multifida ssp. capsellicarpa. An efficient medium-term conservation strategy was developed in Veronica multifida ssp. capsellicarpa involving an efficient regeneration protocol, a medium-term maintaining method and plant evaluation procedures. The preservation on the media variant with mannitol 3% and 6 % ensured the stop of the growth, the limitation of lateral shoots formation and an acceptable rooting, the plant material having a good vigour. The biochemical analyses proved that there are not differences between clones on the same medium variant, the prolonged maintenance on mannitol added media ensuring the limitation of the growth and reduced supplementary handling of the in vitro preserved material during 3 months without transfers. This medium-term preservation conditions do not affect the viability and the variability of the plants. From these medium-term cultures healthy plants can be regenerated whenever it isnecessary to reintroduce the laxon in the origin habitats or in other collections or to provide material for international changes of germplasm.
4. In vitro reactivity of Usnea barbata (l.) Mott.
DIANA VOICU, AURELIA BREZEANU
The investigations presented in this paper focused on Usnea barbata (L.) Mott. in vitro reactivity. Different variants of basal media BBM (1965) and Honegger (1993), have been used. The effects of nutrient media composition on this lichen species in vitro culture have been studied. A lower growth rate was registered in both cases on the basal medium with no additives. The presence of kinetin in a concentration of 0,1 mg/l stimulated the induction of proliferation. For the initiation of the in vitro culture two kinds of explants were used. The best results were obtained in the case of the grinding paste inoculi. The results we have obtained determine us to say that Usnea barbata (L.) Mott. proved to be highly responsive to the in vitro culture and it could be used as an experimental system for secondary metabolites biosynthesis.
5. The chorology of Stipa dasyphylla in Romania
Based on the existing data, in this paper was designed the chorological map of Stipa dasyphylla (Czern. ex Lindem.) Trautv. for Romania. The paper reports the presence of S. dasyphylla in three new sites in Romania. The species is newly reported for Moldavia Province (Romania).
6. Alluvial Salix purpurea and Hippophaë rhamnoides collinar shrublands in Prahova and Doftana zone
Mihaela Paucă-Comănescu, Dorina Purice, Marilena Onete, G. Dihoru, O. MOUNTFORD, Viorica Honciuc, Liliana Vasiliu-Oromulu, Minodora Stănescu, cristina Fiera, M. Falcă, Sanda Maican, Mihaela Ion, cristina Munteanu
The biological diversity of shrublands dominated by Hippophaë rhamnoides and Salix purpurea along the collinar floodplain of rivers Prahova and Doftana is presented in this paper. Hippophaë rhamnoides shrubland is included in the 3240th European Habitats. The diversity of plant species is high at the level of shrubs (15-17 species) and of herbs as well (55-80 species). There are differences between sites concerning both shrub biomass (67 t/ha, respective 35 t/ha) and herbaceous biomass (360 kg/ha, respectively 1 123 kg/ha). The identified invertebrates' communities are represented by detritophagous, predator and phytophagous populations in endogeous-epigeous gradient. The highest degree of specific diversity is noticed mainly in Cornu shrubland as well as the highest numerical densities. The degree of similarity between the three communities of invertebrates is generally low, varying between 0.28 and 0.66 in the soil communities and between 0.16 and 0.5 in epigeous communities. The common characteristic of the three invertebrate communities is the model of season dynamics: the humidity, organic matter and predators' presence influencing the endogenous groups and the vegetation characteristics influencing directly the epigeous phytophagous and indirectly the predators.
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