01:119:115 Lecture Notes - Lecture 7: Meristem, Lycopodiopsida, Fern
13 Jul 2016
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Document Summary
Closest relative of land plants: characteristics of charophytes that enables move to land: a. i. 1. Edges of ponds and lakes subject to occasional drying. Natural selection favors survival for periods without being submerged. Similar adaptation found in plant spores wall: land plants shared traits with only charophytes a. i. 1. a. i. 2. a. i. 3. Group of microtubules forms between daughter nuclei during cell division. Cell plate forms in middle of phragmoplast gives rise to new cross walls that separate daughter cells: derived traits of plants. 5 key traits appear in nearly all land plants but are absent in the charophytes: alternation of generations, multicellular, dependent embryos, walled spores produced in sporangia, multicellular gametangia, apical meristems. Alternate between 2 multicellular stages: haploid gametophyte. Produces haploid gametes by mitosis: diploid sporophyte. Produces haploid spores by meiosis (figure 29. 3) a. i. 2. The diploid embryo is retained within the tissue of the female gametophyte. Nutrients are transferred from parent to embryo through placental transfer cells.
