Evidence of interpopulation variation in the germination of Eryngium maritimum L. (Apiaceae)

Germination is considered as one of the most crucial steps in a plant’s lifetime. The germination of Eryngium maritimum, a dune species located across all European coasts, has been extensively analysed in Northern populations, where it is considered a locally endangered species. However, less attention has been given to southern populations, where the knowledge about the germination of the species is very limited. The main objective of the present study was to analyse the effect of cold stratification in one Mediterranean and one Atlantic population of the species, as well as to compare the potential variation of seed dormancy among a latitudinal gradient in European populations based on current literature. Seeds collected from Mallorca (Mediterranean, Spain) and Asturias (Atlantic, Spain) were germinated at different temperatures and cold stratification periods ranging from 4 to 20 weeks. These results were merged with the results of previous studies to test the potential effect of latitude and climatic variables in germination. Although the optimal incubation temperature was 10 ºC, the highest final germination percentages (up to 96%) was obtained in both populations combining specific cold stratification periods (5 ºC) and constant incubation temperatures (15–20 ºC). Atlantic seeds needed longer cold stratification times to reach high germination percentages compared with Mediterranean seeds. Apart from the stratification response, significant differences in viability and in germination were observed between the Atlantic and the Mediterranean populations. Considering data from previous studies in the analysis, the results suggest that there is a potential effect of latitude in the ecological germination requirements, by which the higher the latitude, the longer the cold stratification period required to germinate, with a correlation with the mean annual temperature. These results suggests that two factors, modulation of dormancy relating to adaptative or maternal effects and viability, govern the germination of the species.

Chemical Composition of Essential Oils from Rare and Endangered Species—Eryngium maritimum L. and E. alpinum L.

In the present study, the essential oils obtained by hydrodistillation of the organs of Eryngium maritimum and E. alpinum were analyzed by GC-FID-MS. The dominant constituents assessed in the essential oil of E. maritimum were germacrene D (45.2%) in the fruits; hexadecanoic acid (18.5%), menthol (16.8%), and menthone (10.9%) in the roots; 2,3,4-trimethylbenzaldehyde (11.3%) and germacrene D (10.5%) in the leaves; 2,3,4-trimethylbenzaldehyde (11.3%) in the shoot culture. In the case of E. alpinum, the main components of the leaf oil were: β-elemenone (10.3%), germacrone (5.8%), two selinadienes (7.1% and 6.7%), and 1,8-cineole (5.3%), which were not found in the oil from shoot culture, whereas the shoot culture oil was dominated by hexadecanoic acid (15.5%), spathulenol (7.5%), (E)-β-farnesene (4.9%), germacra-4(15),5,10(14)-trien-1α-ol (4.7%), and falcarinol (4.3%). The essential oils obtained from E. maritimum fruits and leaves of the intact plants, measured by the broth microdilution method, were the most active against T. mentagophytes and S. aureus. Moreover, the essential oil of leaves had the moderate activity against C. albicans and E. coli. The results showed that the chemical compositions of the essential oils differed decidedly between the two studied species and between the organs. Furthermore, the essential oil of E. maritimum may play an important role as antimicrobial agent.

Genetic Diversity and Structure of Northern Populations of the Declining Coastal Plant Eryngium maritimum

Genetic diversity among 13 northern populations of the declining coastal plant Eryngium maritimum L. at the northernmost extent of the species distribution range was studied using retro-transposon-based SSAP molecular markers. Diversity indices varied extensively among populations; some showing extremely low diversity whereas other populations exhibited moderate amounts of genetic variation. Differentiation among populations was highly variable as well. Interestingly, differentiation among northern populations was not influenced strongly by geographic distance. Closely situated populations were often more divergent than more distant populations suggesting other factors may be responsible for genetic structuring of E. maritimum populations. We propose that the following genetic and environmental factors combine together in a complex relationship to mould the present genetic structure of E. maritimum populations in this region: (1) historic biogeographical processes; (2) local environmental conditions at each site; (3) success of sexual reproduction and proportion of clonal propagation; (4) size of the population and influence of genetic drift; (5) level of fragmentation and isolation. Lastly, we suggest that the sustainable existence of Latvian populations is seriously threatened, unless recommended conservation measures are implemented.

IRAP-analysis for evaluating the genetic stability of endemic and endangered species of the Western Caucasus flora in the collection in vitro

The characterization of genetic diversity is one of the main components of the genetic resources collection and management. Molecular markers are the most effective tool for characterizing and assessing genetic diversity in plant collections. IRAP (inter-retrotransposons amplified polymorphism) markers have proven to be some of the most effective for characterizing and evaluating germplasm, confirming the genetic fidelity of in vitro preserved cultivars and species. In this regard, the aim of this work is to test several IRAP primers to identify genetic polymorphism and study the genetic fidelity of three rare and endemic flora species of the Western Caucasus during in vitro conservation. Approbation of 16 IRAP-primers on the investigated species was carried out for Eryngium maritimum L., Galanthus woronowii Losinsk. and Campanula sclerophylla Kolak. The results made it possible to select the most efficient of them for genetic fidelity analysis of micropropagated plants. Out of 16 IRAP primers 8 amplified PCR products in Eryngium maritimum. In Galanthus woronowii as well 8 of 16 IRAP primers resulted in the amplification with the number of DNA fragments ranging from 2 to 12. In Campanula sclerophylla 9 of 16 IRAP primers amplified 1 to 11 fragments, depending on the marker. The results of the genotyping of regenerants were compared with data on stock in situ plants, which were the source of explants for in vitro conservation. In total, 60 regenerants for each species of the natural flora of the Western Caucasus were involved in the study. The results obtained demonstrated no genetic changes of the regenerants in all the studied species. These results were confirmed using ISSR analysis of an extended sample set of microplants for each species. The results obtained can serve as evidence of a low probability of genetic disorders during in vitro propagation and conservation of the species Eryngium maritimum L., Galanthus woronowii Losinsk. and Campanula sclerophylla Kolak.

BIODIVERSITY OF PLANTS AND NATURAL HABITATS IN THE VICINITIES OF ARAPYA BAY, ROPOTAMO NATURAL RESERVE, ALEPU BEACH, SINEMORETS AND SILISTAR CAPE (BULGARIAN SOUTHERN BLACK SEA COAST)

The flora in the vicinities of Arapya Bay, Alepu beach, Sinemorets and Silistar cape of the Bulgarian Black Sea coast (which includes three beach zones and two protected natural areas) is rich in rare psammophytic and halophytic species: Hypecoum ponticum Velen., Pancratium maritimum L., Silene thymifolia Sm., Eryngium maritimum L., Limonium latifolium (Sm.) Kuntze, Tulipa thracica Davidov, Centaurea arenaria M. Bieb., Trachomitum venetum (L.) Woodson and Maresia nana (DC.) Batt. Within these areas some Mediterranean geo elements reach their northernmost point: Reichardia picroides (L.) Roth and Romulea linaresii Parl. All of the species mentioned above have been included in the Red List of Bulgarian vascular plants (1) The Tulipa thracica Davidov species fall under a Critically Endangered (CR) category. Nine species have an Endangered (EN) status: Hypecoum ponticum Velen., Pancratium maritimum L., Silene thymifolia Sm., Eryngium maritimum L., Trachomitum venetun (L.) Woodson, Reichardia picroides (L.) Roth, Cistus salviifolius L., Verbascum bugulifolium Lam. and Serapias vomeracea (Burm.) Briq. Six species fall under a Vulnerable (VU) category: Limonium latifolium (Sm.) Kuntze, Centaurea arenaria M. Bieb., Maresia nana (DC.) Batt. and Romulea linaresii Parl., Limodorum abortivum (L.) Schwarz and Orchis papilionacea L. Under a Least Concern (LC) are the following species: Fritillaria pontica Wahlenb. and Mespilus germanica L. Legally protected by (2) are: Pancratium maritimum L., Eryngium maritimum L., Limonium latifolium (Sm.) Kuntze, Tulipa thracica Davidov, Centaurea arenaria M. Bieb., Trachomitum venetum (L.) Woodson, Maresia nana (DC.) Batt, Reichardia picroides (L.) Roth, Romulea linaresii Parl., Verbascum bugulifolium Lam., Cistus salviifolius L., Serapias vomeracea (Burm.) Briq., Limodorum abortivum (L.) Schwarz, Orchis papilionacea L., Fritillaria pontica Wahlenb. In addition, there are five species from the Orchidaceae family with different conservation status: the Endangered Serapias vomeracea (Burm.) Briq., the Vulnerable Limodorum abortivum (L.) Schwarz and Orchis papilionacea L. and two species from the CITES convention - Orchis purpurea Huds.and Orchis morio L. Three habitats were with an Endangered Conservation status: 01B1 Pontic sand beach annual communities, 02B1 Pontic embryonic dunes and 04B1 Southwestern Pontic fixed dunes (3).