01:119:116 Lecture Notes - Lecture 8: Sphagnum, Non-Vascular Plant, Antheridium
19 Feb 2018
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Document Summary
Characteristics of charophytes that enabled move to land: Sporopollenin- complex polymer that protects from desiccation: rings of cellulose- synthesizing proteins- make microfibrils of cell walls, flagellated sperm- similar in both, phragmoplast- scaffold for cell plate assembly. Seven derived traits of land plants: alternation of generations. Gametophyte (n) > gametes (n) by mitosis. Sporophyte (2n) > spores (n) by meiosis: multicellular dependent embryos, walled spores produced in sporangia. Sporocytes (2n) > meiosis to produce spores (n: multicellular gametangia produce gametes. Growth occurs at specific locations: cuticle. 470 mya fossils of spores from land plants. Rhizoids instead of true roots transport is through osmosis tied to water (like amphibians of the plant kingdom) Vascular plants (tubes for transport of fluid) Osmosis only three phyla of small non-vascular herbaceous plants: liverworts (phylum hepatophyta, mosses (phylum bryophyta, hornworts (phylum anthocerophyta) Colonize soil > retain nitrogen in soil > some harbor n-fixing cyanobacteria > more n availability in environment.
