WebA prothallus, or prothallium, (from Latin pro = forwards and Greek θαλλος ( thallos) = twig) is usually the gametophyte stage in the life of a fern or other pteridophyte. Occasionally the term is also used to describe the young gametophyte of a liverwort or peat moss as well. In lichens it refers to the region of the thallus that is free of algae . WebMay 20, 2015 · The prothallium has one recombinant copy of one of the sporophyte's chromosomes: by the time the prothallium has formed, meiosis and thus crossing over have already occurred. Even if the resulting gametes from the same prothallium fertilized each other [cont] May 20, 2015 at 15:06
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WebDepartment of Veterans Affairs VA Directive 0321 Washington, DC 20420 Transmittal Sheet June 6, 2012 WebApr 7, 2024 · The prothallium or prothallus is known to produce both male and female gametophytes of the plant. To understand the role of the prothallus it is important to understand what prothallus is, the structure of the prothallus. In this article, the discussion will be focused on the basic understanding to define prothallus, the reproductive phase … reach separations strasbourg
6.2.2: Ferns - Biology LibreTexts
WebThe distinctive fronds make great accents among groundcovers, or in drifts with perennials, shrubs, and trees. Noteworthy Characteristics Leathery 1.5- to 2-foot-long, upright, evergreen, pale green fronds with distinctive, broadly scythe-shaped leaflets. Care Grow in moderately fertile, humus-rich, moist but well-drained, neutral to acidic soil. WebDescription Rhizome: erect, massive, bearing a few fronds, scales lanceolate, rather suddenly narrowing to rhizome apex, larger ones commonly 1 cm long, soft-papery, dark brown, polished. Frond: 70 cm high by 30 cm wide, evergreen, monomorphic, blade/stipe ratio: 1:1 to 2:1. Stipe: straw-colored, with dark base, scaly but more sparse upwards, … WebMar 4, 2012 · In this study, we at first hypothesized that genetic segregation through homoeologous chromosome pairing has occurred in significant frequencies in … reach security