Calicotome Villosa Research Articles

Bacterial Products and Their Effect on the Shrubby Legume Calicotome villosa (Poir.) Link

Calicotome villosa is a eurioic legume with broad distribution in the south of Europe. It can grow in almost any type of soil as well as in humid and dry and nutrient-deficient ecosystems. The broad distribution and eurioic nature of C. villosa may be attributed to its ability to establish endophytic associations with plant-growth-promoting (PGP) bacteria housed in the nodules and rootlets. This study examined the legume–microbe interaction of C. villosa growing in two contrasting locations: a hilltop with high sun irradiance and drought, and a valley bottom with a low level of radiation and sufficient soil humidity for plant growth. Calicotome villosa adult plants established endophytic interactions with bacteria in six genera: Pseudomonas, Stenotrophomonas, Bacillus, Paenibacillus, Brevicacterium, and Rhizobium. Plants growing on the hilltop had associated lower bacterial richness than those grown on the valley bottom. All strains were drought-tolerant and produced siderophores, IAA, HCN, and NH3 that stimulated plant performance in C. villosa plants and the other four legumes commonly present in the understory of the shrub communities. The legumes’ capacity to selectively host symbiotic bacteria that enhance plant survival in harsh conditions partly accounts for the diverse partnerships between C. villosa plants and their symbionts, ultimately explaining the wide distribution of this plant species.

Seasonal Differences in Ecophysiological Performance between Resprouters and Non-Resprouters across an Aridity Gradient in Northwest Tunisia

Understanding the functioning of shrub species during dry periods is necessary to forecast ecosystem responses to future climates, particularly in Mediterranean environments. We evaluated the seasonal changes in leaf gas exchange, hydraulic traits, carbon and nitrogen isotopes, and non-structural carbohydrates of seeders and resprouting shrub species typical of Aleppo pine forests across an aridity gradient in Tunisia: Djebel Zaghouan (subhumid climate), Djebel Mansour (semiarid transitional climate), and Djebel El Sarj (semi-arid climate). We monitored seven woody species: Pistacia lentiscus, Erica multiflora, Phillyrea latifolia (resprouters), Cistus monspeliensis, Rosmarinus officinalis (seeders), Globularia alypum, and Calicotome villosa (resprouters-seeders). The seasonal variation in leaf water content was usually higher in seeders than in resprouters and was associated with higher resistance to embolism. In contrast, the seasonal variation in non-structural carbohydrates was higher in resprouters, especially at the driest site. Both δ13C and δ15N displayed seasonal enrichment-depletion patterns, with seeders showing an overall higher δ13C in summer than in spring, consistent with a water-saving strategy of increasing water use efficiency. Discriminant analysis suggested that resprouters can sustain a positive carbon balance during drought periods. The differential impact of summer droughts on water status and the ecophysiology of these plant strategies may lead to different ecosystem dynamics depending on whether climate change tips the balance towards a preponderance of stressors (drought) or disturbances (fire) in dry Mediterranean areas.

Hypoglycemic and Hypotensive Effects of Calycotome villosa Subsp. intermedia Seeds in Meriones shawi Rats: In Vivo, Ex Vivo, and In Vitro Investigations.

Calycotome villosa subsp. intermedia is used in traditional medicine for the prevention and self-treatment of a variety of illnesses, including diabetes mellitus, obesity, and hypertension. The present study aims to investigate the in vivo, ex vivo, and in vitro hypoglycemic and hypotensive effects of the lyophilized aqueous extract of Calycotome villosa subsp. intermedia seeds (CV) on Meriones shawi submitted to hypercaloric diet and physical inactivity (HCD/PI) for 12 weeks. This diet induces a type 2 diabetes/metabolic syndrome phenotype with hypertension. Furthermore, HCD/PI decreased aorta contraction due to noradrenaline, enhanced L-arginine, and depressed insulin-evoked relaxation, while the relaxing effects of the NO donor SNAP and of diazoxide were unchanged. In vivo experiments showed that the oral administration of the CV extract (50 mg/kg b.wt) for 3 consecutive weeks significantly attenuated the development of type 2 diabetes, obesity, dyslipidemia, and hypertension. These effects may involve the improvement of lipid metabolism, insulin sensitivity, systolic arterial pressure, and urine output. Additionally, ex vivo and in vitro investigations revealed that CV treatment improved vascular contraction to noradrenaline, induced a slight aorta relaxation in response to carbachol, increased the vasorelaxation effect evoked by insulin, and depressed the L-arginine evoked relaxation. However, CV did not change the endothelium-independent vasorelaxation response evoked by SNAP or diazoxide. Hence, the present study provides useful information and supports the traditional use of CV in the prevention and self-treatment of numerous ailments. Overall, it can be concluded that Calycotome villosa subsp. intermedia seed extracts might be useful in the management of type 2 diabetes and hypertension.

Novelty predictors for shrub (and climbers) ecological niche modeling, based on their successional stage

The identification of species' environmental predictors constitute a key challenge for decision making, especially when using ecological niche modeling based on these drivers and when presence points are limited. More specifically, shrub species are affected by ecosystem dynamics, and appear in degraded formations, in dense mid-stage vegetation formations, or under late climax-forest canopy. In this study, we tested novelty predictors to understand the drivers that affect the selected species distribution in the Mediterranean biome, targeting different vegetation successional stages, and further improve ecological models' performance, when presence points are limited. Land surface temperature (LST) in association with temperature related predictors, allowed differentiating between species thriving in the understory of the forest canopy, from those that are co-dominant with dense vegetation cover and a third group/species, thriving in degraded vegetation. In addition, the Normalized Difference Vegetation Level Index (NDVI) played a key role in the models for species growing in highly degraded ecological niches such as Spartium junceum, Calicotome villosa, but also forest-fringe vegetation like the climber Hedera helix. Our study highlights the importance of integrating remote sensed predictors, combined with appropriate climate drivers, when using ecological niche modeling.

In Vitro Antioxidant, Antibacterial and Mechanisms of Action of Ethanolic Extracts of Five Tunisian Plants against Bacteria

Pistacia lentiscus, Rosmarinus officinalis, Erica multiflora, Calicotome villosa, and Phillyrea latifolia were considered important medicinal herbs and were used to treat various ailments. The present study was designed to evaluate the antioxidant and antimicrobial activities of ethanolic extracts (EEs). P. lentiscus and R. officinalis were the richest species in phenolic compounds. Similarly, both species showed the highest values of flavonoids. While the EEs of P. lentiscus, E. multiflora, and C. villosa had higher amounts of tannins. These phenolic compounds were evaluated by two different tests, namely diphenyl picrylhydrazyl (DPPH) and ferric iron-reducing power (FRAP). The IC50 values were found to be significant (p < 0.05) for P. lentiscus and E. multiflora. Similarly, both plants showed the highest ferric-reducing antioxidant power (FRAP). This study has been conducted to evaluate the antibacterial potential of EEs against selected bacteria—Gram-positive bacteria (Staphylococcus aureus ATCC 29213, Listeria monocytogenes ATCC 7644) and Gram-negative bacteria (Escherichia coli ATCC 8739, Salmonella typhimurium NCTC 6017)—and determine their modes of action. The ethanolic extracts inhibited bacterial growth by producing concentration-dependent zones of inhibition. Treatment with these extracts at their minimum inhibitory concentrations (MICs) showed a significant reduction (p < 0.05) in the viability of bacteria. The extracts did not induce total lysis. Bacteria organisms treated with EEs at MICs showed a significant (p < 0.05) loss of tolerance to NaCl (5%). Our results highlighted the use of plant extracts as natural antibacterials that can be safely used in health care and led to the understanding of the antibacterial mechanism of plant extracts.

Anti-oxidant and Immunomodulatory Effects of newlectins extracted from Algerian plants: Ephedra alata, Zizyphus jujuba and Calycotome villosa

Anti-oxidant and Immunomodulatory Effects of newlectins extracted from Algerian plants: Ephedra alata, Zizyphus jujuba and Calycotome villosa

Tenuipalpidae and Tetranychidae (Trombidiformes, Tetranychoidea) from Syria with a description of a new species of Bryobia

Surveys of Tenuipalpidae and Tetranychidae were conducted at three locations in Latakia governorate, Syria, in 2021. Eight species were collected; four flat mite species of which Aegyptobia beglarovi, Cenopalpus lineola, and Pentamerismus juniperi were new records for Syria; and four spider mite species among which Petrobia (Mesotetranychus) tunisiae represented a new record. A new tetranychid species, Bryobia (Lyobia) hadizeni sp. nov., collected from Calicotome villosa, is described and illustrated. The number of Tenuipalpidae species known from Syria increases to 16 and there are now 25 species of Tetranychidae.

Forage Availability and Quality, and Feeding Behaviour of Indigenous Goats Grazing in a Mediterranean Silvopastoral System

The aim of this study was to evaluate the feeding behaviour of indigenous goats and the selection drivers of different plant species in a Mediterranean forest rangeland. To achieve this goal, the seasonal variations in terms of forage availability and quality of ingested plant species were studied during three grazing seasons. In the same period, eight indigenous goats of Beni Arouss breed were selected to explore the seasonal changes in their browsing behaviour. Forage quality was determined by the hand-plucking technique. The results showed a wide seasonal variation in forage availability and quality, and feeding behaviour. Woody species were more selected independently of the season (p < 0.001). The crude protein content varied from 53.3 g/kg of dry mater (DM) for Erica arborea in summer to 197 g/kg DM for Calicotome villosa in autumn (p < 0.001). Despite the high condensed tannins content in selected shrubs, they were highly consumed. In vitro organic matter digestibility (IVOMD) and metabolizable energy (ME) had recorded the highest contents in herbaceous during spring. Shrubs and trees contain the lowest levels of IVOMD (<500 g/kg) and ME (<7.2 MJ/kg) during autumn and summer. It is concluded that seasonal changes in forage availability and quality did not necessarily affect the indigenous goats’ preference. These findings could help goat herders to develop feeding and grazing systems while increasing the performance of goats in the Mediterranean silvopastoral system.

Soil nitrogen regulates symbiotic nitrogen fixation in a legume shrub but does not accumulate under it

AbstractLegumes in dryland ecosystems face the challenge of maintaining energetically costly symbiosis with N2‐fixing rhizobia, in a water‐ and nutrient‐limited environment. Controlled experiments showed a strong reduction in symbiotic N2fixation in response to elevated levels of nitrogen availability, but this regulation of N2fixation was not found in dryland field settings. Here, we ask whether regulation of N2fixation occurs in the field and what are the possible consequences for dryland soil nitrogen. We measured plant investment in root nodules and rates of bacterial activity, in seedlings and adults of a common N2‐fixing shrub,Calicotome villosa,in five field sites naturally varying in soil nitrogen and phosphorus availabilities. Additionally, we measured nitrogen concentrations and availabilities in the soil underC.villosaand a reference non‐fixing shrub. Biomass investment in root nodules was significantly reduced in response to elevated levels of soil nitrate in adult shrubs, but no such effect was found for seedlings. Soil nitrogen concentration underC.villosashrubs was low compared to the soil under a non‐fixing reference shrub. We provide evidence that symbiotic N2‐fixing plants in drylands tightly regulate their investment in symbiotic N2fixation, therefore controlling nitrogen inputs into the soil. These findings challenge the long‐held notion that the growth of N2‐fixing plants necessarily leads to the accumulation of soil nitrogen in their surroundings over time.

Phytochemical analysis, antioxidant and in vitro \u03b2-galactosidase inhibition activities of Juniperus phoenicea and Calicotome villosa methanolic extracts

BackgroundJuniperus Phoenicea (JP) and Calicotome Villosa (CV) are used by Jordanian populations as herbal remedies in traditional medicine. Herein, the phytochemical contents of their methanolic extracts were analyzed and their antioxidant as well as in vitro anti- β-Galactosidase activities were evaluated; their effect on β-Galactosidase enzyme kinetics was evaluated and the thermodynamic of the enzyme was determined.MethodsThe antioxidant activity of JP and CV crude methanolic extracts was evaluated using 1,1-diphenyl,2-picrylhydrazyl (DPPH) free radical scavenging and ferric reducing antioxidant power (FRAP) assays; however, the effect of the plants’ crude extracts on β-Galactosidase activity and kinetics was evaluated in vitro. Moreover, total phenolic, flavonoids, and flavonols content in plants’ extracts were determined and expressed in Gallic acid equivalent (mg GAE/g dry extract) or rutin equivalent (mg RE/g dry extract).ResultsPhytochemical screening of the crude extracts of JP and CV leaves revealed the presence of phenols, alkaloids, flavonoids, terpenoids, anthraquinones, and glycosides. Flavonoids and flavonols contents were significantly higher in JP than in CV (p < 0.05). Furthermore, an analogous phenolic content was detected in both JP and CV methanolic extracts (103.6 vs 99.1 mg GAE/g extract). The ability of JP extract to scavenge DPPH radicals was significantly higher than that of CV extract with IC50 = 11.1 μg/ml and 15.6 μg/ml, respectively. However, their extracts revealed relatively similar antioxidant capacities in FRAP assay; their activity was concentration dependent. The JP extract inhibited β—galactosidase enzyme activity with a significant IC50 value compared to CV extract; they exhibited their inhibitory activities at IC50 values 65 µg/ml and 700 µg/ml, respectively. Rutin revealed anti-β-galactosidase activity at IC50 = 75 µg/ml. The mode of inhibition of β-galactosidase by JP, CV, and rutin was non-competitive, mixed, and competitive inhibition, respectively. Thermodynamic and enzyme inactivation kinetics revealed that β-galactosidase has a half-life time of 108 min at 55 °C, activation energy of 208.88 kJ mol−1 and the inactivation kinetics follows a first-order reaction with k-values 0.0023–0.0862 min−1 and positive entropy of inactivation (∆S°) values at various temperatures, indicating non-significant processes of aggregation.ConclusionsThe methanolic extracts of JP and CV possess anti-hyperglycemic and antioxidant activities with potential pharmaceutical applications.

English

As typical arid vegetation, Calycotome villosa is an annual herb playing an important role in folk medicine. In this research, the influences of temperature and salinity on germination of C. villosa seeds gotten from southern Tunisia were investigated. The germination responses of the seeds in total darkness were determined over an extensive array of temperatures (5, 10, 15, 20, 25, 30, 35 and 40&deg;C) as well as salinities (0, 50, 100, 150, 200, 250 and 300 mM NaCl). Seeds of C. villosa were able to germinate at temperatures between 5 and 40&deg;C. Temperatures between 20 and 25&deg;C seemed favorable to germinate these species. The minimum temperature beyond which no germination is expected was 0&deg;C. Utmost germination percent were gotten in non-saline situations as well as arise in NaCl absorptions&nbsp; increasing&nbsp; repressed germination of seed. The rate of growth reduced with arises in salinity on all temperatures. Salt stress decreased both the percentage and the rate of germination. Percent of germination reduced with growing salinity and sternly restricted at 250 and 300 mM. Findings from this research might function as valuable information for C. villosa habitat establishment and renovation plans. Key words: Calycotome villosa, germination, salinity, temperature, Tunisia.

The ACC-Deaminase Producing Bacterium Variovorax sp. CT7.15 as a Tool for Improving Calicotome villosa Nodulation and Growth in Arid Regions of Tunisia.

Calicotome villosa is a spontaneous Mediterranean legume that can be a good candidate as pioneer plants to limit regression of vegetation cover and loss of biodiversity in Tunisian arid soils. In order to grow legumes in such soils, pairing rhizobia and nodule associated bacteria (NAB) might provide numerous advantages. In this work, cultivable biodiversity of rhizobial symbionts and NAB in nodules of C. villosa plants growing in five arid regions of south Tunisia was characterized. Phylogenetic analysis using 16S rDNA gene, dnak, recA and nodD sequences separated nodule-forming bacteria in six clades associated to genera Ensifer, Neorhizobium, Phyllobacterium and Rhizobium. Among NAB, the strain Variovorax sp. CT7.15 was selected due to its capacity to solubilise phosphate and, more interestingly, its high level of aminocyclopropane-1-carboxylate deaminase (ACC deaminase) activity. C. villosa plants were inoculated with representative rhizobia of each phylogenetic group and co-inoculated with the same rhizobia and strain CT7.15. Compared with single rhizobia inoculation, co-inoculation significantly improved plant growth and nodulation, ameliorated plant physiological state and increased nitrogen content in the plants, independently of the rhizobia used. These results support the benefits of pairing rhizobia and selected NAB to promote legume growth in arid or degraded soils.

Symbiotic dinitrogen fixation is seasonal and strongly regulated in water-limited environments.

Plants, especially perennials, growing in drylands and seasonally dry ecosystems are uniquely adapted to dry conditions. Legume shrubs and trees, capable of symbiotic dinitrogen (N2 ) fixation, often dominate in drylands. However, the strategies that allow symbiotic fixation in these ecosystems, and their influence on the nitrogen cycle, are largely unresolved. We evaluated the climatic, biogeochemical and ontogenetic factors influencing nitrogen fixation in an abundant Mediterranean legume shrub, Calicotome villosa. We measured nodulation, fixation rate, nitrogen allocation and soil biogeochemistry in three field sites over a full year. A controlled experiment evaluated differences in plant regulation of fixation as a function of soil nutrient availability and seedling and adult developmental stages. We found a strong seasonal pattern, shifting between high fixation rates during the rainy season at flowering and seed-set times to almost none in the rainless season. Under controlled conditions, plants downregulated fixation in response to soil nitrogen availability, but this response was stronger in seedlings than in adult shrubs. Finally, we did not find elevated soil nitrogen under N2 -fixing shrubs. We conclude that seasonal nitrogen fixation, regulation of fixation, and nitrogen conservation are key adaptations influencing the dominance of dryland legumes in the community, with broader consequences on the ecosystem nitrogen cycle.

Isolation of Bioactive Compounds from Calicotome villosa Stems.

A phenylethanoid, two steroids, a flavone glucoside and a chalcone have been isolated for the first time from the stems of Calicotome villosa together with a previously isolated flavone glucoside. Their structures were determined by spectroscopic analyses (NMR, HRMS) as basalethanoïd B (1), β-sitosterol and stigmasterol (2), chrysine-7-O-β-d-glucopyranoside (3), chrysine 7-((6′′-O-acetyl)-O-β-d-glucopyranoside) (4) and calythropsin (5). The crude extracts and the isolated compounds (except 4), were evaluated for their antioxidant, antimicrobial (against two Gram-positive bacterial strains: Staphylococcus aureus, Bacillus cereus, four Gram-negative bacterial strains: Staphylococcus epidermidis, Klebsiella pneumonia, Acinetobacter baumanii, and three yeasts: Candida albicans, Candida tropicalis, and Candida glabrata), hemolytic, antidiabetic, anti-inflammatory and cytotoxic activity. The crude extracts showed good ability to scavenge the free radical DPPH. Methanol stem extract followed by the dichloromethane stem extract showed moderate antimicrobial potency; furthermore, at 1 mg/mL the methanol extract showed an inhibition of C. albicans growth comparable to nystatin. Dichloromethane, methanol, and aqueous extracts inhibited 98%, 90%, and 80% of HeLa cell proliferation at 2 mg/mL respectively. Weak hypoglycemic and hemolytic effects were exhibited by the crude extracts. Among all the tested compounds, compound 3 showed remarkable hypoglycemic potential (93% at 0.1 mg/mL) followed by compound 5 (90% at 0.3 mg/mL). Compound 5 was the most effective in the DPPH. scavenging assay (100% at 0.1 mg/mL) and cytotoxic assay on HeLa cells (99% and 90% after 24 and 48 h of treatment at 0.1 mg/mL, respectively). No anti-inflammatory effects were displayed by any of the crude extracts or the isolated compounds at any of the tested concentrations.

Kaj pravzaprav pomeni Split? Etimologija starogrške besede aspálathos

Članek podaja analizo uveljavljene etimologije imena mesta Split iz starogrškega poimenovanja rastline aspálathos »žuka ali brnistra, natančneje: lesni grm Alhagi maurorum s cvetovi barve v razponu od svetlo roza do kostanjevo rjave, trnov trolist Calycotome villosa s cvetovi svetlo rumene barve in rastlina Genista acanthoclada s cvetovi rumene barve«. Nadalje raziskuje etimologijo starogrškega poimenovanja rastline aspálathos in predlaga etimologijo *aspálax ali spálax (kot poimenovanje rastline) »lilija Colchicum parnassicum s cvetovi vijolične barve« + pripona -thos &gt; aspálathos, in sicer v prvem in najpogostejšem pomenu »lesni grm Alhagi maurorum s cvetovi barve v razponu od svetlo roza do kostanjevo rjave«.

Bulk soil bacterial community mediated by plant community in Mediterranean ecosystem, Israel

The Israeli Mediterranean ecosystem has a distinctive flora with high levels of plant diversity. Previous studies of soil microbial ecology from the region have paid little attention to the possibility of distinctive soil bacterial communities associated with particular habitats. This study looked at bacterial communities present in the bulk soil from the closed canopy of four indigenous plants – Quercus ithaburensis, Calicotome villosa, Sarcopoterium spinosum, and Rhamnus puncata. Soil DNA was amplified for the 16S rRNA gene and sequenced using MiSeq Illumina platform. Results indicated that the bacterial communities differed between open and closed canopy with no significant difference in community structure within closed canopy, with soil moisture and organic matter content significantly influenced the community. Only the relative abundance of Gemmatimonadetes varied significantly with the open canopy having the highest abundance, and the relative abundance of Spartobacteria and Saprospirae was unusually high compared to other Mediterranean soils. There was no difference in OTU richness between plant species. Additionally, this study revealed that open canopy community between plants was nested within closed canopy bacterial community implying that open canopy community potentially serves as a source for the closed canopy. It is then possible that the rhizospheric influence extends beyond the root-soil interface and to the surrounding bulk soil. Overall, this study indicates that in Israeli Mediterranean ecosystems native plants extend a selection beyond the rhizosphere, and like other studies from Mediterranean ecosystems pH does not seem to play an integral role in structuring bacterial communities.

Pastoral plants for rehabilitation of degraded soil in Tunisia: the case for use of Calicotome villosa and Genista spachiana (Fabaceae)

Calicotome villosa and Genista spachiana are classified as vulnerable in Tunisia and they are of great interest for the rehabilitation of degraded ecosystems, food for goats and camelids, and for the use of its essential oils in phytotherapy. The aim of this study was to examine the germination characteristics of both species through analysis of the effects of the salt stress and water stress on germination. We monitored and evaluated different germination characteristics (germination percentage, mean time to germination and germination speed) in the presence of the salt and water stress. Calicotome villosa and Genista spachiana can withstand salinity of up to 15 g/l of salt (31–37% germination at 15 g/l) and also tolerate large doses of PEG6000 (30–40% germination at –1.6 MPa: Polyethylene glycol (PEG) is a hydrophilic polymer). The tolerance of the two species to salinity and water stress allows them to be a source of food for goats and camelids during drought.

Spatial distribution of the burrows of Porcellio albinus in the coastal area of Zarat (Gabès, Tunisia)

Among the desert-dwelling Porcellio species, widespread in southern Tunisia, only Porcellio albinus exhibits a burrowing behaviour. In this study we investigated how P. albinus “choose” to dig their burrows, especially through the study of their burrow densities both in the nebkas and in flat, sandy-surface habitats; the direction of the openings of the burrows; and the influence of wind and vegetation type on the spatial distribution of P. albinus burrows in the nebkas. Several field samplings were carried out in the sandy coastal area of Zarat (Gabès, in the south-eastern part of Tunisia) between January and December 2013. The mean densities of burrows in the two habitats – nebkas and flat, sandy surfaces – were not significantly different. A low positive correlation was observed between burrow density and nebka area. In each nebka, the burrows of P. albinus were localised within a circular belt in a sector facing towards the south, thus avoiding the main wind direction (E–NE). P. albinus prefers to dig their burrows on nebkas covered with Astragalus armatus and Stipagrostis pungens, and avoids those covered with Calicotome villosa. The absence of burrows at the top of the nebkas might be caused by their exposure to sunlight and drying. The lack of burrows at the base of the nebkas is assumed to be the consequence of the presence of non-porous and non-permeable substratum in direct contact with this base. This substratum creates a barrier, which prevents P. albinus from digging sufficiently deep burrows.

Germination sensitivity to water stress in four shrubby species across the Mediterranean Basin.

Mediterranean shrublands are generally water-limited and fire-driven ecosystems. Seed-based post-fire regeneration may be affected by varying rainfall patterns, depending on species sensitivity to germinate under water stress. In our study, we considered the germination response to water stress in four species from several sites across the Mediterranean Basin. Seeds of species with a hard coat (Cistus monspeliensis, C.salviifolius, Cistaceae, Calicotome villosa, Fabaceae) or soft coat (Erica arborea, Ericaceae), which were exposed or not to a heat shock and smoke (fire cues), were made to germinate under water stress. Final germination percentage, germination speed and viability of seeds were recorded. Germination was modelled using hydrotime analysis and correlated to the water balance characteristics of seed provenance. Water stress was found to decrease final germination in the three hard-seeded species, as well as reduce germination speed. Moreover, an interaction between fire cues and water stress was found, whereby fire cues increased sensitivity to water stress. Seed viability after germination under water stress also declined in two hard-seeded species. Conversely, E.arborea showed little sensitivity to water stress, independent of fire cues. Germination responses varied among populations of all species, and hydrotime parameters were not correlated to site water balance, except in E.arborea when not exposed to fire cues. In conclusion, the species studied differed in germination sensitivity to water stress; furthermore, fire cues increased this sensitivity in the three hard-seeded species, but not in E.arborea. Moreover, populations within species consistently differed among themselves, but these differences could only be related to the provenance locality in E.arborea in seeds not exposed to fire cues.

Vegetation cover and species richness after recurrent forest fires in the Eastern Mediterranean ecosystem of Mount Carmel, Israel

Fire is a common disturbance in Mediterranean ecosystems, and can have a destructive, influential, and even essential, effect on vegetation and wildlife. In recent decades there has been a general increase in the number of fires in the Mediterranean Basin, including in Mount Carmel, Israel. The effects of recurrent forest fires on vegetation cover and species richness were determined in the spring of 2009 and 2010 by field surveys. The results of this study showed that the vegetation cover changes after recurrent forest fires, and can serve as a good indicator of the influence of fire and the resulting ecosystem rehabilitation. The dominant cover in most fire-damaged areas was composed of shrubs and dwarf-shrubs, especially Cistus salviifolius and Calicotome villosa. Tree cover was severely damaged after recurrent fires, and in those areas there was a drastic decrease of the total plant cover. Species richness increased mainly in the first decade after the recurrent fires, and decreased when the forest canopy began to close. Fire recurrence with short intervals (4–6years) between fires may lower the rehabilitated processes of the ecosystem and change its equilibrium.