Romanian Journal of Biology - Plant Biology
Volume 54, No. 1, 2009
1. NICOLAE BOªCAIU, Member of the Romanian Academy (1925-2008) - In Memoriam
V. CRISTEA, C. TOMA
2. Comparative studies regarding ultrastructure of Marsilea quadrifolia l. (Pteridophyta) leaf mesophyll cells in vivo and in vitro culture
AURELIA BREZEANU, C. BANCIU
A comparative analysis of the ultrastructural peculiarities of Marsilea quadrifolia L. mesophyll cells of the leaves belonging to the plants grown in in vitro system and in natural habitat are presented in the paper. Cytological observations enabled. to remark that the experimental protocol used by us for in vitro plant regeneration and clonal multiplication did not affect the normal pattern of plant development. At the ultrastructural level severe alterations of the cells' organe1les structure were not observed. Polymorphic aspect of the chloroplast was revealed in in vitro culture and this could represent adaptive modifications to culture conditions. In respect of this we consider that this protocol could be used as a successful experimental system for ex situ conservation of this threatened species.
3. The effect of mannitol on antioxidative enzymes in vitro long term cultures of Dianthus tenuifolius and Dianthus spiculifolius
ELENA MONICA MITOI, IRINA HOLOBIUC, RODICA BLÎNDU
The decline of the number of plants species worldwide strongly imposed, besides the habitats protection and management, the use of ex situ conservation methods based on biotechnologies. The in vitro gene banking as a main direction of ex situ conservation relies on tissues cultures. At present, there are many papers concerning the use of in vitro cell and tissues cultures for propagation, preservation and introduction of the rare plants species in the recovery programs. In vitro active gene bank is based on living plant tissues culture maintained during medium-term period. In our laboratory, studies concerning the in vitro preservation of several Dianthus rare species involved different methods that reduced the growth of in vitro cultures. In this respect, the addition· of mannitol was proved the most efficient for regeneration and conservation of genetic resources. We obtained in vitro minimized cultures by subcultivation once at 3-4 months. The mannitol induced a stimulatory effect on the regeneration capacity. The present study reports on expression of some antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT) and peroxidase (POX) in long term cultures on media supplemented with different concentrations of mannitol in two rare species Dianthus spiculifolius and Dianthus tenuifolius. The results showed changing of the activity expression of SOD and CAT and significant differences in response between these Dianthus species to mannitol treatments. The loss of some isoforms with SOD and CAT activity of the variants maintained on medium supplemented with mannitol (0.16 M and, respectively, 0.30 M) in the cultures of Dianthus spiculifolius was observed. There was no difference in the enzymes expression in the case of in vitro cultures of Dianthus tenuifolius. The mannitol can act as a scavenger of hydroxyl radicals and osmoregulator which can preserve the growth and the development of in vitro cultures.
4. Rhythmobiochemistry: algal photosynthetic pigments
Utilizing biorhythmological methodology there were recorded the diurnal biorhythms of the photosynthetic pigments from the green alga Scenedesmus quadricauda (Turp.) Breb. These biochemical compounds varied significantly quantitatively and qualitatively, proving the importance of certain moments which may be considered as "biochemical key times". Considering new scientific knowledge of Physics, the Rhythmobiophysics is also founded. Practically, the investigations of these biophenomena may be useful for varied domains of Biorhythmotechnology.
5. Peroxidase activity in Eustoma grandiflorum plants transformed by Agrobacterium rhizogenes
GABRIELA POPA, AURELIA BREZEANU, C. PETRUÞA CORNEA, J.P. BOE
The effects of inoculation with wild type of Agrobacterium rhizogenes strains: A4, 8196 and LBA 9402, on the protein content and on peroxidase activity and isoenzymes in the normal and transformed plants of Eustoma grandiflorum Griseb. (roots, hairy root and leaves) were evaluated. Three cultivars of in vitro micropropaagated plants of E. grandiflorum cultivars: 'Heidi Pink', 'Heidi Blue' and 'Echo White' were used for the experiments. Among the cultivars the highest level of the peroxidase production was archived in the Heidi Blue hairy roots induced following infection with both A. rhizogenes strains 8196 and LBA9402. By contrast, peroxidase activity was increased in Echo White hairy roots induced by A. rhizogenes strain A4. The highest protein content was found in Echo White hairy root induced by A. rhizogenes strain 8196. These results demonstrate that the total protein content and peroxidase activity were significantly affected by genotype and by A. rhizogenes strain used in the infection process.
6. Phytocenoses specific to the vegetation of Dobrogea
T. CHIFU, ELIZA ÞUPU
The authors present two associations on Tulcea Hills, Teucrio capitatae-Convolvuletum lineatae association, which has already been described in specialized literature, and the second, built by Tanacetum millefolium, is referred to as Agropyro pectinatae-Tanacetum millefoliae.
7. Chorology of Amorpha fruticosa in the Danube Delta
In this paper a comprehensive review of the relevant field data is provided, with the purpose to determine the state of knowledge regarding the distribution of Amorpha fruticosa in the Danube Delta.
8. Investigations over the phytocoenotic role of Aster sedifolius L. in the eastern part of Romania (Moldavia)
C. SÎRBU, A. OPREA
Aster sedifolius L. is a vascular plant, sporadically met in Romania, from forest-steppe to hills region, settled in meadows, bushes, in everglades of the forests, on slopes, on eumesobasic soils, moist (often wet in springs), poor in humus, moderately salinized. We analyzed here the role of this species in edification of some meso-halophilous communities, unknown till now in the eastern part of Romania (Moldavia). On the basis of the field relevees, arranged in an analytic table, we made coenotaxonomic, phytogeographic, as well as ecologic analyses of those plant communities, framed by us in the next coenotaxa: Cl. Puccinellio-Salicornietea Topa 1939, Ord. Puccinellieetalia Soó1947 em. Vicherek 1973, Al. Festucion pseudovinae Soó1933, Ass. Achilleo-Festucetum pseudovinae (Magyar 1928) Soó (1933) 1945, subass. asteretosum sedifolii sub ass. nova.
9. Analysis of Cerasus fruticosa shrubland from comana (Giurgiu county) - habitat protected with priority within the european ecological network NATURA 2000
pp. 81 - 91
The paper presents the structure of a Cerasus fruticosa shrub land in southern Gavanu Burdea plain, close to Comana locality and forest. The area covered by the shrub land is very small (300 rn2). The species richness is significant (46 species), most of them being southern, Balkan, Pontic and Pannonic geoelements. The shrub land is included in an artificial “peri-Pannonic” European habitat, given that the area of the species stretches from Central Europe to Central Asia, and Romania, in the Romanian Plain, Dobrudga and Moldova, shelters many populations. The phytocoenosis is dominated by hemicryptophytes and phanerophytes. Only one rare species, Knautia macedonica, is present. Biometrically, the population of Cerasus fruticosa from Comana is 0.79 m ± 0.12 tall and 0.68 cm ± 0.21 (thickness); the largest specimen was 1.35 m (height) and the largest diameter was 1.30 cm. The density of the Cerasus fruticosa population was 21 specimens/m2 with 40% coverage, while the entire phytocoenosis, including the herbs layer, covered practically the entire area. The phenology of the population, under the conditions of 2007, fit within the annual active cycle between March 15 and October 15. The population was in a state of balance, had both young and mature specimens producing fruits and seeds, but it did not have the capacity for spatial expansion when competing with other shrub land species. The population from Comana is included on a map of the current dispersion of Cerasus fruticosa in Romania.
10. Paeonio peregrinae - Carpinetum orientalis association on Tulcea hills Dihoru et Donita, 1970
ELIZA ÞUPU, T. CHIFU
This paper deals with the Paeonio peregrinae - Carpinetum orientalis association, identified on Tulcea hills, association described in Dobrogea, but which has not been mentioned in this area before.
11. Rediscovery of Pietrosia levitomentosa E. I. Nyárády ex Sennik., an endemic and endangered plant species from Pietrosul Bistritei Mountain, Romania
B.M. NEGREA, E. PRICOP
This paper presents a study upon the scientific knowledge of the conservation status and perspectives of an endemic Carpathian plant. The paper aims at improving our understanding of the extinction risk of the endemic species Pietrosia levitomentosa E. 1. Nyárády ex Sennik. Further, the present study case is being used to highlight the main features of biodiversity conservation in Romania, a country with a high number of endemic species.
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