Folia Geobotanica

Chytrý, Milan; Pešout, Pavel; Anenchonov, Oleg A.

doi: 10.1007/bf02853303pmid: N/A

Natural and semi-natural plant communities of Svjatoj Nos Peninsula on the East coast of Lake Baikal, Eastern Siberia, Russia, are classified and described using the methods of Braun-Blanquet phytosociology. A total of 48 associations and communities were recognized, comprising alpine tundra, subalpine forb vegetation, aquatic macrophyte vegetation, tall-herb and poor fens, mires, bogs, meadows, sand-dune and steppe vegetation. Twenty six syntaxa of ranks ranging from subassociation to class are described or validated for the first time. All communities are documented by phytosociological relevés.

Krahulcová, Anna; Jarolímová, Vlasta

doi: 10.1007/bf02853305pmid: N/A

Chromosome numbers were counted inButomus umbellatus from 99 localities in both Czech and Slovak Republics and the karyotype morphology was studied. Basic chromosome sets are asymmetrical and uniform among diploids (2n=26) and triploids (2n=39). Diploids occur less frequently than triploids in this region. Their clonal populations are usually fertile owing to self-compatibility. The clonal populations of triploids are selfincompatible and usually sterile. Thus, the different self-compatibility is the main biological character distinguishing diploids from triploids. Pollen of triploids is viable in spite of meiotic irregularities in pollen mother cells (PMCs). Hybridization both between cytotypes and between the different triploid genets may take place, if they occur sympatrically. Offspring having diverse chromosome numbers between diploid and triploid level can originate as the consequence of such hybridization.

Hroudová, Zdenka; Zákravský, Petr

doi: 10.1007/bf02853307pmid: N/A

Generative and vegetative reproduction of diploid and triploidButomus umbellatus L., and growth and biomass production of both cytotypes under two different nutrient levels were compared.Seedling survival was studied under controlled conditions in a growth chamber; the response of plants to different nutrient conditions was studied in experimental garden.Both cytotypes do not differ in seed germination and seedling survival. Triploids produce more aboveground and underground biomass, more numerous lateral rhizome buds, and have significantly higher flowering stalks. Low generative reproduction (limited seed production) in triploids is compensated for by more intensive vegetative reproduction. High nutrient level appeared to be stressful for plants of both cytotypes: it limits plant growth and causes plant mortality. Triploids are more viable than diploids in this case, which may be important for their survival under conditions of high trophic level.

Hroudová, Zdenka; Zákravský, Petr

doi: 10.1007/bf02853308pmid: N/A

The distribution, total frequency of occurrence, regional differences and habitat conditions of diploid and triploidButomus umbellatus L. were studied in the Czech and Slovak Republics. Triploids are more frequent than diploids, with numerous localities in warm lowland regions in river floodplains. Diploids were found primarily in the South Bohemian Třeboň basin, outside the warm regions. The two cytotypes do not differ in dependence on water depth. Triploids occur more in habitats with more alkaline and base-rich soils. Considering the total distribution of both cytotypes in the area studied, triploidB. umbellatus appears to be more successful than its diploid progenitor, owing to its wider habitat range and superiority in vegetative reproduction.

Měsíček, Josef; Soják, Jiří

doi: 10.1007/bf02853310pmid: N/A

Chromosome numbers are reported for 19 collections representing 16 AsiaticPotentilla taxa. The first chromosome records are reported forP. desertorumBunge var.arnavatensisWolf (2n=28),P. festivaSoják (2n=28),P. griffithiiHook f. subsp.beauvaisii(Cardot) Soják (2n=42),P. micropetalaD. Don subsp.byssitecta(Soják) Měsíček etSoják (2n=14),P. mollissimaLehm. (2n=28),P. moorcroftiiWall. exLehm. (2n=42),P. multicaulisBunge (2n=14),P. [x]omissaSoják (2n=35, 56, 70) andP. stanjukovicziiOvcz. exKoczk. (2n=14). Counts differing from those previously recorded are given forP. algidaSoják (2n=56) andP. flagellarisWilld. exSchlecht. (2n=42). Chromosome numbers of the following species were confirmed:P. [x]agrimonioidesBieb. (2n=42),P. chinensisSer. in DC. (2n=14),P. fragarioides L. (2n=14),P. lineataTrev. (2n=14) andP. sericea L. (2n=28). Taxonomy is briefly discussed. A new combinationP. micropetalaD. Don subsp.byssitecta(Soják) Měsíček etSoják stat. nov. is proposed.