PLANT CYTOLOGY

Author: CASTRO LAPORTTE MERCEDES EUNICE.
Year: 2006.
University: VALENCIA [More theses of this university] [www.uv.es].
Place of defense: JARDÍN BOTÁNICO - UNIVERSITAT DE VALÈNCIA.
Place of preparation: JARDÍN BOTÁNICA - UNIVERSITAT DE VALÈNCIA.

Summary: The Balearic archipelago, located in the Western Mediterranean, is composed of continental islands and contains one of the most diverse flora of this region, with about 121 endemic species, of which 21 are apomictic. It has been pointed out repeatedly that knowledge cariológico a given plant may help to identify patterns and processes of interspecific hybridization, as well as patterns of speciation changes associated with chromosome euploides and aneuploids. In the particular case of taxa endemic to the Mediterranean, data cariológicos have been used for a long time to establish classifications according to their age and phylogenetic relationships. Knowledge cariológico of endemic baleáricos has some shortcomings as most of the counts chromosome has been made from low populations and in some cases have been reported contradictory results which do not have an adequate database for analysis . Based on these premises was raised explore cariología of endemic flora of the Balearic Islands in order to determine the chromosome number of taxa not studied; studying those taxa with chromosome numbers contradictory; assess patterns of chromosomal variation within and between islands; discuss the role of poliploidia at the root of the endemic flora Balearic and compare the patterns of evolution cariológica of endemic flora of the continental and oceanic islands. The plant material used in this study was collected almost entirely in natural populations and for some taxa was used material from genebanks and living collections of some botanical gardens. The plants were grown in greenhouse or seeds that were germinated on agar plates with solid at 20 ° C. All observations were made in somatic tissues and for the preparation of chromosomes followed the routine for cariología classical techniques and the study of chromosomes was performed by analyzing digital images and the computer image processing and cariológicos. For descriptions of the karyotypes continued classification Levan et al. (1964) and in cases where it was possible were conducted idiogramas and calculated rates of asymmetry Romero-Zarco (1986). Altogether studied 81 taxa not apomictic, with new counts to 16 of them and 8 indications of new citotipos. For groups apomictic in Hieracium and Limonium studied populations Balearic in a broader context (P. Iberian). The variation chromosome intraespecifíca in endemic apomictic is not less than 10% and only checked for Ranunculus paludosus subsp. Barceloi (Grau) L. Saez et al. With citotipos diploid (2n = 16) in Pitiusas and citotipos tetraploid (2n = 32) in Gimnesias. Approximately 42% of the flora is endemic polyploid and it is suggested that a 26.2% of them originated by processes poliploidia native, representing a value much greater than those specified in the floras of oceanic islands. In Hieracium was detected ascendancy of citótipos triploid (76.2%) and on the basis of the available evidence supports the view that the Iberian Peninsula acted as a safe haven for groups diploids. Gender Limonium also showed a predominance of citótipos triploid (84.6%). This raises the hypothesis that chromosome polymorphisms found in various species of Limonium polyploids can be because these are not yet genetically stable. Based on the analysis of the karyotypes of the groups studied, it is suggested that those species that have two sets of chromosomes and a matched set of paired chromosomes not possibly originated by alopoliploidia from ancestors with basic numbers x = 8 and x = 9, while the species with several sets of chromosomes matched (3 or 4) may occur through autopoliploidia. As a result of the morphological studies cariológicos and changed the taxonomic range of Carduus bourgeanus subsp. Ibizensis Devesa & Talavera to specific and described a new species (Bellium artrutxiensis Fraga & Rossello). For 33 species not endemic 8 of 3f5 Balearic established their chromosome number and observed new citotipos in three of them. The tallies in Urginea gr. Maritima from Cabrera revealed the citótipo diploid, a fact that confirms its attribution to U. Pancration, species endemic to the Western Mediterranean Balearic poorly known.