Riella Mont., with ca. 27 species is the most diversified of the Riellaceae (Sphaerocarpales). Species of Riella grow commonly submerged in clean, shallow, fresh or brackish waters of seasonal ponds, more rarely in permanent waters of arid and semiarid regions and have disjunct distributions and scattered populations. The species of Riella are rare and/or underrecorded due to their specific habitat types, ecology and biology. They are aquatic ephemerals that survive drought periods in the spore bank. For species of conservation importance such as Riella helicophylla, the presence of large spore banks serve as “insurance” against local extinction. Such strategy may take on special importance in Mediterranean temporary aquatic habitats where environmental conditions vary in unpredictable ways from year to year. In these variable habitats, there is no guarantee of yearly spore input into the spore bank. In this study, we test the effect of different culture media in the axenic establishment and propagation, of R. helicophylla (Mont.) Hook. Spanish genotype for the purpose of ex situ conservation and its biology research. We used ripe unopened sporophytes as starting material for in vitro cultures. The spores from the fresh capsules did not germinated immediately after collection but showed some kind of dormancy. The treatment with gibberellins shortly upon collection did not improved germinability. However, dry storage at 20ºC for about three months broke the dormancy of spores which germinated in high percentage (over 90%). Two phase system (solid and liquid) culture media were developed for the purpose of achieving fully developed gametophytes. Spores were able to germinate on solid medium rather than in pure liquid, and they developed some kind of callous tissue that developed into green plants – gametophores, after being transferred to the two phase culture. Testing on many media which were tried as solid and liquid phases showed that the germination were best in solid BCD medium free of liquid phase, which contained mineral salts. Therefore, we tested the plants establishment on solid BCD medium and cover it with two types of liquid phases: (1) distilled water and (2) water containing electrolytes simulating brackish water. The plant morphogenesis was better achieved on BCD medium covered with electrolyte-enriched liquid phase. The experiments on sporulation by growing female and male plants and acclimation to xenic condition are ongoing.
CONSERVATION BIOLOGY OF RARE AND ENDANGERED LIVERWORT FROM MEDITERRANEAN TEMPORARY PONDS: Riella helicophylla
COGONI, ANNALENA;
2015-01-01
Abstract
Riella Mont., with ca. 27 species is the most diversified of the Riellaceae (Sphaerocarpales). Species of Riella grow commonly submerged in clean, shallow, fresh or brackish waters of seasonal ponds, more rarely in permanent waters of arid and semiarid regions and have disjunct distributions and scattered populations. The species of Riella are rare and/or underrecorded due to their specific habitat types, ecology and biology. They are aquatic ephemerals that survive drought periods in the spore bank. For species of conservation importance such as Riella helicophylla, the presence of large spore banks serve as “insurance” against local extinction. Such strategy may take on special importance in Mediterranean temporary aquatic habitats where environmental conditions vary in unpredictable ways from year to year. In these variable habitats, there is no guarantee of yearly spore input into the spore bank. In this study, we test the effect of different culture media in the axenic establishment and propagation, of R. helicophylla (Mont.) Hook. Spanish genotype for the purpose of ex situ conservation and its biology research. We used ripe unopened sporophytes as starting material for in vitro cultures. The spores from the fresh capsules did not germinated immediately after collection but showed some kind of dormancy. The treatment with gibberellins shortly upon collection did not improved germinability. However, dry storage at 20ºC for about three months broke the dormancy of spores which germinated in high percentage (over 90%). Two phase system (solid and liquid) culture media were developed for the purpose of achieving fully developed gametophytes. Spores were able to germinate on solid medium rather than in pure liquid, and they developed some kind of callous tissue that developed into green plants – gametophores, after being transferred to the two phase culture. Testing on many media which were tried as solid and liquid phases showed that the germination were best in solid BCD medium free of liquid phase, which contained mineral salts. Therefore, we tested the plants establishment on solid BCD medium and cover it with two types of liquid phases: (1) distilled water and (2) water containing electrolytes simulating brackish water. The plant morphogenesis was better achieved on BCD medium covered with electrolyte-enriched liquid phase. The experiments on sporulation by growing female and male plants and acclimation to xenic condition are ongoing.
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