Multilocus genetic structure at contrasted spatial scales of the endangered water fern Marsilea strigosa Willd. (Marsileaceae, Pteridophyta)
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چکیده
منابع مشابه
The fine structure of fertilization in the fern Marsilea vestita.
The ultrastructural details of fertilization in the fern Marsilea vestita, including gamete approach and fusion, the fate of the spermatozoid organelles and the development of a possible block to polyspermy are described. The spermatozoid approaches the egg through layers of mucilage that surround the megaspores. It moves down the neck of the archegonium into the cavity above the egg. In order ...
متن کاملEffects of nickel on the fern Regnellidium diphyllum Lindm. (Marsileaceae).
The heterosporous fern Regnellidium diphyllum occurs in southern Brazil and some adjoining localities in Uruguay and Argentina. Currently it is on the list of threatened species in the state of Rio Grande do Sul. Anthropic alterations such as the conversion of wetlands into agricultural areas or water and soil contamination by pollutants may compromise the establishment and survival of this spe...
متن کاملStructure and Function of Spores in the Aquatic Heterosporous Fern Family Marsileaceae
Spores of the aquatic heterosporous fern family Marsileaceae differ markedly from spores of Salviniaceae, the only other family of heterosporous ferns and sister group to Marsileaceae, and from spores of all homosporous ferns. The marsileaceous outer spore wall (perine) is modified above the aperture into a structure, the acrolamella, and the perine and acrolamella are further modified into a r...
متن کاملSpermiogenesis in the fern Marsilea microtubules, nuclear shaping, and cytomorphogenesis.
Spermiogenesis in Marsilea is a complex series of events, including the formation of a helically wound organelle coil. The coil begins to appear in early development when a multilayered structure (MLS) is formed de novo in association with a mitochondrion. The outermost layer of the MLS is a ribbon of microtubules. As the microtubules grow out from the MLS, they grow along the nuclear envelope....
متن کاملGenetic Diversity and Spatial Structure of Spartina alterniflora at Four Spatial Scales
Spartina alterniflora, salt marsh cordgrass, is the dominant plant in coastal wetlands along the North American Atlantic coast. Ecological disturbances in salt marshes, such as coverage by wrack, disease, and eat-outs, affects Spartina marshes from the Gulf of Mexico to New England and may reduce the diversity of S. alterniflora clones within a population or alter other genetic characteristics ...
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ژورنال
عنوان ژورنال: American Journal of Botany
سال: 2002
ISSN: 0002-9122,1537-2197
DOI: 10.3732/ajb.89.7.1142