Breeding system and conservation strategy of the extremely endangered Cistus carthaginensis Pau (Cistaceae) of Spain
2001
BOSCAIU, MONICA | GÜEMES, JAIME
Cistus carthaginensis is one of the most endangered plants in Europe: at present there exist only a few individuals in Murcia and one in Valencia (SE and E Spain). To design an adequate conservation strategy able to avoid the extinction of this species, various aspects of its reproductive biology were studied. The extreme rarity of C. carthaginensis is not related to problems of development and/or fertility of pollen or ovules produced by the few existing specimens. Meiosis in the pollen mother cells is always regular and chromosome segregation is completely equilibrated in the male gametes. Pollen and ovule production is high and similar to that reported for other related species of Cistus. Pollen grains have high viability and germination rates, and the ovules are well-developed and functional. However, hand pollination treatments and microscopic observation of pollen tube growth along the style revealed that the species, like many others of this genus, shows gametophytic self-incompatibility. The isolated Valencian plant cannot, therefore, reproduce and regenerate a population. The conservation strategy of C. carthaginensis in the territory of Valencia should be based on the recovery of the reproductive capacity of the Valencian plant through pollen transfer from the unique population found in Murcia, once the viability of the crosses and the seed productivity have been assessed.
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