Comparison of ex-situ germination response of Lavandula multifida L. in two populations of S-Italy and S-Spain

Lavandula multifida L. is a suffruticose chamaephyte with woody stems, but modest in size, belonging to Lamiaceae. In Italy is distributed only in two regions: Calabria and Sicily (1, 2). Here occupies the northernmost part of its distribution area. In fact, it can be found also in Egypt, Tunisia, Algeria, Morocco, Spain and Portugal (3). In Calabria is only present at Capo dell’Armi in the province of Reggio Calabria, and in Sicily is present at Capo S. Alessio, M. Pellegrino and Brucoli, whereas is disappeared from some historic Sicilian sites such as Capo Scaletta and Taormina (4). This species lives in the coastal garigues on marly substrates (5) and has a bloom from February to April, but often this period is more extended. L. multifida is considered as Critically endangered (specie CR) according to in IUCN criteria (6).In this study, we compared plants belonging from two stations geographically very distant: Capo dell’Armi (Italy) and Almeria (Spain). We sampled any plant as herbarium specimen, leaves, seeds (from both locations) and soil (only from Capo dell’Armi).The soil texture on which the plant spontaneously grows is sandy type (87 % of sand, 8 % of clay, 5 % of silt); it is characterized by an alkaline pH (= 8), and high electrical conductivity (85 milliSiemens/cm), and by the 27 % of total carbonates. The percentage of organic substance is 2,45.Among the macronutrients, exchangeable potassium, ammonia and magnesium were measured: the amounts were respectively 1 mg/L, 0.4 mg/L, and 10 mg/L, while total nitrogen amounted to 1.6 mg/gr of soil.Phenolic levels of this soil were 14 ppm. Fluorescein Diacetate hydrolisis test was performed in order to assess the general enzymatic activity of the soil: the levels of fluorescein diacetate (FDA) amounted to 1.5 μg/mL of soil sample. Among soil enzymes, dehydrogenase enzymatic activity was also measured: it was 9.7 μg/mL of soil sample.Germination tests on Lavandula multifida seeds were carried out: in order to make a comparison between two different populations of the same plant species, seeds were collected from two different locations where the plant spontaneously grows, that is from Almeria (Spain) and from Capo dell’Armi (Reggio Calabria, Italy). Seeds were selected and surface-sterilized with freshly prepared 30 % solution of commercial bleach for 15 minutes, followed by washing for several times with distilled-sterilized water; the seeds were placed on filter paper in Petri dishes and then transferred at dark at 4°C for 72 hours (stratification process). After that, Petri dishes were placed in climatic chamber at different temperatures, respectively 20°C, 25°C and 30°C, with a photoperiod of 12 hours light/12 hours dark, in order to assess possible differences in germination percentage at different temperatures. Experiment at dark at room temperature will be also carried out, so as to evaluate the effect of the dark on germination process.The preliminary results show that the optimum germination occurs at 25°C and that the seeds from Spain have a shorter germination time than Italian ones.