The aim of the article is the syntaxonomic interpretation of hyperhalophilous woody or semi-woody vegetation with Halocnemum M. Bieb. along the coasts of the Mediterranean Basin. For this area, the two species of Halocnemum, H. strobilaceum (Pall.) M. Bieb. and H. cruciatum (Forssk.) Tod. are identified; their morphological characteristics, synonymy and distribution are here described. The study carried out of particular aspects of the plant morphology and the micromorphological characteristics of the seeds collected from different places in the Mediterranean allows to better differentiate the two species. Vegetation studies already done in many communities of the Mediterranean by several authors threw into great confusion because only H. strobilacem has been recognized as a dominant species. As regards the syntaxonomic analyses of the vegetation, the authors refer to the proposals already made by various scientists for the vegetation of inland salt basins of Eurasia and the Irano-Anatolian area, who suggested the classes Kalidietea foliate and Halocnemetea strobilaceiirano-anatolica, respectively. Conversely, in the Mediterranean Basin, the vegetation study is present only in coastal areas where it is considerably impoverished in the number of species. Therefore, the authors propose to include hyperhalophilous, woody and fruticose vegetation in the class Sarcocornietea fruticosae. However, the phytosociological and ecological diversity is highlighted proposing the order Halocnemetalia cruciati in which both the alliance Halocnemion strobilacei, for middle Eastern Europe, and the alliance Halocnemion cruciati, for North Africa with penetrations in the Western and Eastern Europe up to the Middle East coast, are included. This new interpretation has required the correction of the names of two associations (Frankenio corymbosae–Halocnemetum cruciati and Zygophylloalbi–Halocnemetumcruciati) and the proposal of two new associations Arthrocnemo machrostachyi–Halocnemetum cruciati and Halocnemo cruciati–Sarcocornietum fruticosae. A further proposal concerns the addition of the alliance Limoniastrion monopetali, previously included in the order Limonietalia, in the order Halocnemetalia cruciati.

Ornamental plant species introduced into new environments can exhibit an invasive potential and adaptability to abiotic stress factors. In this study, the drought stress responses of four potentially invasive ornamental grass species (Cymbopogon citratus, Cortaderia selloana, Pennisetum alopecuroides and P. setaceum) were analysed. Several seed germination parameters were determined under increasing polyethylene glycol (PEG 6000) concentrations. Additionally, plants in the vegetative stage were subjected to intermediate and severe water stress treatments for four weeks. All species registered high germination rates in control conditions (no stress treatment), even at high PEG concentrations, except C. citratus, which did not germinate at −1 MPa osmotic potential. Upon applying the water stress treatments, P. alopecuroides plants showed the highest tolerance, and C. citratus appeared the most susceptible to drought. Stress-induced changes in several biochemical markers (photosynthetic pigments, osmolytes, antioxidant compounds, root and shoot Na⁺ and K⁺ contents), highlighted different responses depending on the species and the stress treatments. Basically, drought tolerance seems to depend to a large extent on the active transport of Na⁺ and K⁺ cations to the aerial part of the plants, contributing to osmotic adjustment in all four species and, in the case of the most tolerant P. alopecuroides, on the increasing root K⁺ concentration under water deficit conditions. The study shows the invasive potential of all species, except C. citratus, in dry areas such as the Mediterranean region, especially in the current climate change scenario. Particular attention should be given to P. alopecuroides, which is widely commercialised in Europe as ornamental.

Agriculture is highly exposed to climate warming, and promoting traditional cultivars constitutes an adaptive farming mechanism from climate change impacts. This study compared seed traits and adaptability in the germinative process, through temperature and drought response, between a commercial cultivar and Mediterranean Phaseolus lunatus L. landraces. Genetic and phylogenetic analyses were conducted to characterize local cultivars. Optimal germination temperature, and water stress tolerance, with increasing polyethylene glycol (PEG) concentrations, were initially evaluated. Base temperature, thermal time, base potential and hydrotime were calculated to compare the thermal and hydric responses and competitiveness among cultivars. Eight molecular markers were analyzed to calculate polymorphism and divergence parameters, of which three, together with South American species accessions, were used to construct a Bayesian phylogeny. No major differences were found in seed traits, rather different bicolored patterns. A preference for high temperatures and fast germination were observed. The ‘Pintat’ landrace showed marked competitiveness compared to the commercial cultivar when faced with temperature and drought tolerance. No genetic differences were found among the Valencian landraces and the phylogeny confirmed their Andean origin. Promoting landraces for their greater resilience is a tool to help overcome the worldwide challenge deriving from climate change and loss of agrobiodiversity.

Chasmophytic vegetation growing on the cracks of cliffs in the Mediterranean and in the Euro-Siberian phytogeographic regions shows a great regional diversity, with a large number of endemic plant species, many of them endangered and at risk of extinction. Moehringia papulosa is an example of a threatened plant living in this kind of habitat. It is an endemism of the Marche region in central Italy, whose natural populations are considered as critically endangered (CR) under the IUCN criteria and the habitat is protected by the E.U. (Directive 92/43/EEC) with the habitat 8210 “calcareous rocky slopes with chasmophytic vegetation”. The phenology of natural populations was analyzed, seed morphology is described and type and level of seed dormancy were determined. The effects of different collecting dates, localities and the influence of elaiosome on germination responses were also considered in order to establish germination requirements to provide optimal protocols for conservation and restoration programmes. Interpopulation differences on seed morphological features were not found and our results also confirm the fact that removal of the elaiosome stimulates germination. The seeds of this species show a non-deep physiological dormancy. The pretreatments proposed as optimal for germination are as follows: a combination of scarification and gibberellins, and 12 weeks of cold stratification.

Gypsophila tomentosa and G. struthium are closely related species, characteristic of two European priority habitats, salt and gypsum inland steppes, respectively. Germination strategies of the two taxa were investigated in plants from two nearby populations, growing under the same climatic conditions but on different types of soil, and belonging to different plant communities. Their germination patterns were studied at five constant temperatures in darkness: 5oC, 10oC, 15oC, 20oC and 25oC, and the base temperature and the thermal time requirement were calculated. As the distribution area of both species is subjected to a Mediterranean continental climate with significant differences between day and night, the possible preferences for an alternating temperature regime (25/10oC) were contrasted, as well as the influence of cold stratification and freezing. The effects on seed germination of light at constant 20oC and a 12/12 h photoperiod were also compared in the two species. The main conclusions of the work are the similarity of behaviour of both species, with an absence of seed dormancy, their opportunistic germination strategy, and water availability as the principal limitation to seed germination and plant establishment. The base temperature and thermal time indicate higher competitiveness of G. struthium at low temperatures, but seed germination of G. tomentosa is the most efficient at temperatures higher than 13.3oC. Optimal temperature and illumination conditions for nursery propagation depend on the species. The high viability of seeds observed after freezing prove the orthodox character of these seeds, providing additional information for long term seed conservation procedures.