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Bryophytes, an informal group that taxonomists now treat as three separate land-plant divisions, namely: Bryophyta (mosses), Marchantiophyta (liverworts), and Anthocerotophyta (hornworts). In all bryophytes, the primary plants are the haploid gametophytes , with the only diploid portion being the attached sporophyte, consisting of a stalk and ...
Like all land plants (embryophytes), bryophytes have life cycles with alternation of generations. [11] In each cycle, a haploid gametophyte, each of whose cells contains a fixed number of unpaired chromosomes, alternates with a diploid sporophyte, whose cells contain two sets of paired chromosomes. Gametophytes produce haploid sperm and eggs ...
Rhizoids are protuberances that extend from the lower epidermal cells of bryophytes and algae. They are similar in structure and function to the root hairs of vascular land plants. Similar structures are formed by some fungi. Rhizoids may be unicellular or multicellular. [1]
An organelle present in plant cells which contains chlorophyll. chlorosis An abnormal lack or paleness of color in a normally green organ. cilia. sing. cilium; adj. ciliate. Very small hairs or hair-like protrusions more or less confined to the margin s of an organ, as with eyelashes; in motile cells, minute, hair-like protrusions which aid ...
By contrast, mosses and other bryophytes have only a single set of chromosomes and so are haploid (i.e. each chromosome exists in a unique copy within the cell). There is a period in the moss life cycle when they do have a double set of paired chromosomes, but this happens only during the sporophyte stage.
Land plants all have heteromorphic (anisomorphic) alternation of generations, in which the sporophyte and gametophyte are distinctly different. All bryophytes, i.e. liverworts, mosses and hornworts, have the gametophyte generation as the most conspicuous. As an illustration, consider a monoicous moss.
In all land plants a disc-like structure called a phragmoplast forms where the cell will divide, a trait only found in the land plants in the streptophyte lineage, some species within their relatives Coleochaetales, Charales and Zygnematales, as well as within subaerial species of the algae order Trentepohliales, and appears to be essential in ...
Desiccation can lead to oxidation and the destruction of nutrients, amino acids, and cell membranes in the microorganisms that make up biological soil crust. [16] However, the biological soil crust has adapted to survive in very harsh environments with the aid of cyanobacteria. Cyanobacteria have evolved the ability to navigate the extreme ...