Abstract:As a result of our field floristic studies in the recent years (2012 and 2013), we recorded some new data on the occurrence and chorology of three vascular plant species in Romania. Two of these are alien plants, invasive in many geographic regions of the world, namely: Acroptilon repens (an Asian species, reported as a newcomer in the flora of Romania, in this paper), and Picris echioides (a Mediterranean species, which is reported now in new localities). The third species, Pedicularis sylvatica, is a quite rare indigenous plant, critically threatened in Romania, reported here for the first time in the flora of Moldavia (eastern Romania).

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Of the Euphorbia dentata aggregate, both E. dentata and E. davidii have been reported from Europe. A revision of herbarium and published materials, however, indicates that only E. davidii can be confirmed in Europe. Although known in Europe since 1968, most records are from the 1990s. There are 46 known populations scattered throughout the continent, in Russia, Ukraine, Moldova, Romania, Bulgaria, Hungary, Italy, Belgium, Switzerland and France. Most populations are small and restricted to railway areas; however, the species can also invade agricultural fields. Due to its wide distribution, the growing number of recently established populations, and its invasive ability, special attention should be paid to changes in distribution and population sizes in Europe.

Biological invasions are one of the main drivers of modern human-induced species losses. Research on the distribution of alien species and their pathways of introduction is essential for understanding and tackling the invasion process. A comprehensive overview on invasive alien plant (IAP) species in Romania is lacking. With this paper, we aim to contribute to filling this gap and to provide a visualization of national patterns regarding plant species invasions, geographical origins and pathways of introductions. Based on plant species occurrence records in the published literature and herbaria we compiled a national database of 102 invasive and potentially invasive alien plant species. We georeferenced 42776 IAP species occurrences and performed an analysis of their spatial patterns. The spatial analyses revealed a biased sampling, with clear hotspots of increased sampling efforts around urban areas. We used chord diagrams to visualize the pathway of introduction and geographical origins of the IAP species, which revealed that species in Romania originate mainly in North and Central America, while the dominant pathway of plant introduction was horticulture. Our results provide an important baseline in drafting management and action plans, as invasive alien plant species represent a priority for the European Union through the Biodiversity Strategy for 2030, and a good starting point for various analyses as the database is further developed and regularly updated.

Abstract:The presence in the spontaneous flora of Romania of the species Fritillaria meleagroides is reported in this paper. It was identified in the North of the village Cotu Morii (Popricani Commune, Iaşi County), on (meso-) hygrophilous, slightly halophilous meadows, placed on the both sides of an old meander of the Jijia river. This place is at the western limit of natural area of F. meleagroides, which stretches from the Central Asia to the Eastern Europe (European Russia, Ukraine and Bulgaria). Since F. meleagroides is an endangered species in large part of its natural range, we consider that urgent actions to protect its populations from Romania are necessary.

The grassland area of Romania covers over 4.8 million hectares, of which more than a half are located in upland areas. In the present research it has been studied the influence of organic fertilization on the productivity, vegetal canopy and fodder quality of the intramontane Depression of Vatra Dornei, from the North-Eastern Romanian Carpathians, at rates of 20-50 Mg ha-1, applied either on a yearly basis, or every two years. The purpose of this study is to underline the dynamics of productivity and phytocenosis biodiversity, due to the application of some practical, technical measures meant to improve the production and fodder quality of Nardus stricta L. permanent grasslands, with minimal effects on the environment. The organic fertilizer rates triggered changes in the canopy structure by reducing the percentage of Nardus stricta L species, from 70% to 14-31%, and increasing the percentage of legumes, as well as the productivity and fodder quality 5-30%, respectively.

In this work, potential contamination by invasive plant propagules as a result of trade exchange between Slovakia and Romania, was assessed. National lists, describing biology and ecology of 30 worst invasive plant taxa, were formulated, and trading in period 2006-2010 between countries analysed. Using norms for commodity impurity level, information on species habitat occupancy and literature data dealing with seed/fruit attachment on roads we calculated then potential invasive plant propagule export (PE) for each taxon. We found three fold higher total good export from Slovakia than in opposite direction, increasing export of commodities potentially containing invasive plant propagules exported from Romania to Slovakia and rise of road compared to railway transport. PEs for Slovak invasive plant taxa were one-two orders higher than those for Romanian ones. Potentially most exported taxa for Slovakia were: Amaranthus sp., Ambrosia artemisiifolia, Galinsoga sp., Kochia scoparia and Sorghum halepense (tens to hundreds tonnes each). And these could mostly be exported from Romania: Amaranthus sp., Ambrosia artemisiifolia, Artemisia annua, Conyza canadensis, Cuscuta campestris, Datura stramonium, Erigeron annus, Galinsoga sp., Iva xanthiifolia, Kochia scoparia, Lycium barbarum, Sorghum halepense, Veronica persica and Xanthium orientale subsp. italicum (units to tens tonnes each). High PE was significantly associated with cereals export. Our formula for PE is applicable for any inter- and intra-continental trade exchange.

The symbiotic nitrogen fixing legumes play an essential role in sustainable agriculture. White clover (Trifolium repens L.) is one of the most valuable perennial legumes in pastures and meadows of temperate regions. Despite its great agriculture and economic importance, there is no detailed available information on phylogenetic assignation and characterization of rhizobia associated with native white clover plants in South-Eastern Europe. In the present work, the diversity of indigenous white clover rhizobia originating in 11 different natural ecosystems in North-Eastern Romania were assessed by a polyphasic approach. Initial grouping showed that, 73 rhizobial isolates, representing seven distinct phenons were distributed into 12 genotypes, indicating a wide phenotypic and genotypic diversity among the isolates. To clarify their phylogeny, 44 representative strains were used in sequence analysis of 16S rRNA gene and IGS fragments, three housekeeping genes (atpD, glnII and recA) and two symbiosis-related genes (nodA and nifH). Multilocus sequence analysis (MLSA) phylogeny based on concatenated housekeeping genes delineated the clover isolates into five putative genospecies. Despite their diverse chromosomal backgrounds, test strains shared highly similar symbiotic genes closely related to Rhizobium leguminosarum biovar trifolii. Phylogenies inferred from housekeeping genes were incongruent with those of symbiotic genes, probably due to occurrence of lateral transfer events among native strains. This is the first polyphasic taxonomic study to report on the MLSA-based phylogenetic diversity of indigenous rhizobia nodulating white clover plants grown in various soil types in South-Eastern Europe. Our results provide valuable taxonomic data on native clover rhizobia and may increase the pool of genetic material to be used as biofertilizers.