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EX SITU CONSERVATION OF SEVERAL SPECIES OF SUCCULENT PLANTS IN THE CLUJ-NAPOCA AGROBOTANICAL GARDEN Stoie A. University of Agricultural Sciences and Veterinary Medicine, Faculty of Agriculture, 3-5 Mănăştur Street, 3400 Cluj-Napoca, Romania, [email protected] Abstract. The species of succulent plants belong to several families of angiosperms and are spread throughout several regions of the globe. In nature, many species of succulent plants are endangered, especially as a result of human intervention in their natural habitats. In the climatic conditions of Transylvania, Romania, a large number of succulent plants can be successfully cultivated outdoors during their entire growth period by means of a special conditioning of the soil with plastic foil and pebbles. Most of the species under scrutiny in the Agrobotanical Garden of the University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca have shown a good or satisfactory development. Two species only have shown an unsatisfactory development. In case of the plants that have been kept unprotected during the entire year, 7 taxons out of 9 have shown a good development, one taxon a satisfactory response and one taxon an unsatisfactory response. In case of the plants that require protection during their dormant period, out of 114 examined taxons, belonging to 100 species, 102 taxons have shown a good response, 12 taxons a satisfactory response and only one taxon an unsatisfactory response. All the species under scrutiny have shown a harmonious development showing a nature-like habit, thanks to the favourable weather conditions during their growing period (summer). Plants originating directly from natural areas, as well as those belonging to endangered species have shown a harmonious development and good vitality. Key words: ex situ conservation, botanical garden, succulent plants, Cactaceae, Sempervivum INTRODUCTION

Succulents are an ecological range of plants especially adapted to store water. The water is generally stored in the stems and/or in the leaves of the plant, that acquire a succulent consistency. The water reserve is consumed during their dormant period of the life cycle. In general, succulent plants enter a state of relative physiological inactivity (their dormant period) during those adverse periods. From a systematic point of view, some families are comprised exclusively of succulent plants. In some families, only several species have developed the capability to store water. Succulent species are spread worldwide, but their diversity reaches its summit in tropical regions. In temperate climates, with continental influences, a large number of succulent plants can be cultivated outdoors during their entire growth period. However, during their dormant period, many species require protection in terms of temperature and humidity. This group of plants constitutes a main attraction in botanical gardens, due to their diversity and their less than ordinary appearance. In nature, many species of succulent plants are endangered especially as a result of human intervention in their natural habitat. That's why 39

a large number of succulent species are on the red lists of the countries where they occur naturally. Conservation, both in situ and ex situ, plays an important role in preserving the diversity of this group. For example, Eddie Esteves Pereira (2006) points out Discocactus subterraneo-proliferans as an extinct species in its natural habitat that survives solely due to ex situ cultivation outside its country of origin, Brazil. MATERIALS AND METHODS

In 2001, the Agrobotanical Garden of University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca, Romania, set out to create a collection of succulent plants, using my own private collection (initiated in 1987) as a starting point. As a result of seed exchanges with other botanical gardens and sampling activities in natural habitats, the succulent plants collection of the Cluj-Napoca Agrobotanical Garden in 2007 contains 2530 plants belonging to 334 taxons, 291 species and 8 botanical families. Each item of the collection is fitted with an aluminium table that displays the individual ID number of the plant, its species, origin and date of procurement. These tags allow an easy reference to a data bank that contains all available information on the relevant plant. The object of the study carried out within the Agrobotanical Garden was the possibility to accommodate several species of succulents in the temperate climates with continental influences of Transylvania. Most of these plants were obtained from seeds, and only a very small number through vegetative propagation. They underwent an accommodation period of 2-4 years. The plants are arranged on a slightly sloping area (5º) facing North-West. The soil has been covered with a strong plastic foil and a 5-10 cm thick layer of pebbles (with a diameter of 3-5 cm) over which a number of larger boulders were scattered. Parts of the succulent species have been planted directly in holes cut out in the plastic foil. In this case, sand and leaf compost