Somatic embryogenesis of Vitis vinifera L. (cv. Sugraone) from stigma and style culture

Somatic embryo and plant regeneration were induced from stigma and style culture of grapevine (Vitis vinifera L. cv. Sugraone). To obtain somatic embryogenesis, explants were cultured on Nitsch and Nitsch basal medium (NN) supplemented with 88 mM sucrose and various combinations of the auxin β-naphthoxyacetic acid (NOA, 0-10 μM) and the cytokinin 6-benzylaminopurine (BA, 0-9 μM). Growth regulators (BA and NOA) in the culture medium were essential for induction of somatic embryogenesis since explants incubated on hormone-free medium never regenerated somatic embryos. Usually, the regenerated somatic embryos become visible as small white globular structures on the surface of the callus 3-4 months after culture initiation. The best embryogenic response (27 %) was obtained when stigma and style explants were cultured on NN medium supplemented with 5 μM NOA and 9 μM BA. Somatic embryos developed into plantlets when transferred to a hormone-free semisolid NN medium. 35 % of primary somatic embryos showed secondary embryogenesis

Influence of Culture Conditions on In Vitro Asymbiotic Germination of Anacamptis longicornu and Ophrys panormitana (Orchidaceae)

This study is the first approach to in vitro asymbiotic germination of two species of Sicilian threatened terrestrial orchids, Anacamptis longicornu and Ophrys panormitana. Seeds were collected in the wild and cultured in two different media—Orchimax medium (OM) and Murashige and Skoog (MS)—and exposed to different photoperiods and temperatures to evaluate the best conditions for the specific stages of development. The germination of A. longicornu was very high on OM (95.5%) and lower on MS medium (21.4%), whereas O. panormitana germinated only on OM medium, with significantly lower percentages (12.0%), compared with A. longicornu. This difference is caused by variation in quality and quantity of nutrients used, primarily by nitrogen source. The results show that temperature and photoperiod widely affect seed germination and development. Although further investigations on asymbiotic and symbiotic germination are needed for the improvement of conservation of Mediterranean terrestrial orchids, our results contribute to the conservation of this group of plants

Leaf water relation traits in typical Sicilian varieties of Vitis vinifera L.

In Italy, grapevines are extensively cultivated, with Sicily representing one of the most significant wine regions. The high number of autochthonous grapevine varieties represents an important source of genetic diversity, and the many Sicilian varieties have anatomical and physiological traits that allow them to resist to different levels of drought stress. We investigated the water relation parameters of four cultivars of Vitis vinifera L. (Catarratto, Corinto, Nero d'Avola and Zibibbo) and characterized their leaf hydraulics. Measurements were conducted during summer on plants growing in the experimental field of the IBBR-CNR near Palermo. Daily patterns of leaf water potential (Yleaf) and stomatal conductance (gs) were measured in the field. Pressure-volume curves were constructed by the bench dehydration method to obtain leaf water potential at turgor loss point (Ytlp), osmotic potential at full rehydration (p0) and bulk modulus of elasticity (εmax). Leaf samples were collected to determine vein density using ImageJ. Major vein density was measured on digitally scanned leaves, while minor vein density was measured on photomicrographs of cleared and stained leaf portions

Potassium deficiency and drought stress in grapevine cultivars

Potassium availability affects drought responses in plants through several metabolic roles, among which stomatal regulation, cell growth and xylem hydraulics. Vitis vinifera L. is a highly valuable crop and several genotypes have been selected during its millennial cultivation. Varieties show differences in their adaptability to stress conditions, making them more or less suitable to certain climatic and edaphic conditions. The varieties cultivated in Sicily are characterized by high variability. We investigated the response of two Sicilian cultivars (Nero d'Avola and Catarratto) to potassium deficiency and drought stress. Two-year-old grafted plants were grown in agriperlite, with or without potassium in the fertigation solution, and subjected to moderate drought stress by suspending irrigation for 6-8 days. Potassium content of xylem sap, leaf and root tissues were measured with an ion-selective electrode. Changes in stomatal conductance, plant transpiration and hydraulic conductance were compared between genotypes and treatments, in order to gain information for the development of optimal fertigation practices and the selection of the most drought tolerant varieties

Urgent need for preservation of grapevine (Vitis vinifera L. subsp. vinifera) germplasm from small circum-Sicilian islands as revealed by SSR markers and traditional use investigations

Since the last decades grapevine germplasm is undergoing a process of rapid genetic erosion. This process is of particular concern in minor circum-Sicilian islands, because of the sharp reduction of the cultivated surfaces and the shift of their economy from agriculture to tourism. Aiming at valorising and preserving the surviving varieties we collected 185 accessions during several surveys since 2007. Six nuclear microsatellite markers were used for germplasm characterization, yielding 75 different genetic profiles. We found out that most genetic profiles (39) were not listed in national and international grapevine databases, confirming that the Sicilian minor islands represent underexplored hotspots of genetic diversity for grapevine. We also identified several synonymies, often due to geographic isolation, having 20 varieties at least two names. Conversely, 18 homonyms collectively indicated 34 genetically different accessions. Interviews with farmers provided information on current and past usage, and the origin and type of cultivation practices as well. The study also shows the urgent need for preservation of local grapevine germplasm, due to the disappearance of the elder caretakers of these traditional varieties. For rare germplasm preservation most part of the collected grapevine cultivars were introduced in an ex situ collection field

Regeneration of Algerian

Stigma/style somatic embryogenesis is one of the efficient methods in plant regeneration of most Citrus ssp., without inducing somaclonal variations. Furthermore, somatic embryogenesis from style/stigma proved to be effective in the elimination of the main citrus virus and virus-like diseases. This technique was applied on Algerian citrus collection. Different Citrus species [Citrus sinensis (L.) Osbeck, C. limon (L.) Burm, C. reticulata Blanco, C. paradisi Macfad, C. reshni Hort. ex Tan., C. jambhiri Lush and C. maxima (Burm.) Merrill] were chosen and tested for the presence of the main virus and virus-like agents. Most of the genotypes showed to be infected, mainly by viroid agents. Closed flowers were collected and in vitro cultured on a Murashige and Skoog (MS) medium supplemented with 6- benzylaminopurine. All explants produced callus about 4 to 9 days after culture initiation, whereas embryogenesis occurred after 38 to 150 days in most of the cultured genotypes. Formed embryos were cultured in a single tube before in vivo acclimatization. After sanitary assays, regenerated plants were shown to be free from the agents detected in the mother trees.Key words: Algeria, citrus germplasm, plant regeneration, sanitation, somatic embryogenesis

Morpho-agronomic and genetic diversity among twelve Sicilian agro-ecotypes of lentil (Lens culinaris)

Although Sicily is relatively small (about 25000 km2), it accounts for several agro-ecotypes of lentil (Lens culinaris Medik.), for many of which no data on morphological, agronomic, and organoleptic characteristics are available to date. Thus, experiments were performed to characterize 12 lentil agro-ecotypes from different areas of Sicily, including some small islands surrounding the main island, and to assess the extent of genetic diversity (by means of six inter-simple sequence repeat [ISSR] primers). A famous agro-ecotype from central Italy (CastellucciodiNorcia) and two commercial varieties from Canada (Eston and Laird) were also included in the study. The results showed a large degree of genetic diversity (based on ISSR markers) and variability in pheno-morphological and agronomic traits. In contrast, the intra-accession variability was on average rather low. The agronomic (productivity, nitrogen fixation capacity) and qualitative (lipid content, hydration coefficient) attributes of several Sicilian agro-ecotypes were more pronounced than those of the controls. This fact certainly represents a prerequisite for their future economic valorization. Moreover, the observed variability may be of interest from the point of view of breeding