PL SC221 Lecture Notes - Lecture 1: Smallpox, Allium, Glyphosate
14 Oct 2016
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Plant growth = limited by water (ex. drought stress) Are the dispersal units of seed plants. Seed is a mature, fertilized ovule containing 3 basic parts: Seed coat (testa) protects embryo food source nourishes embryo. Seeds often become widely scattered by wind or animals. Advantage over free-sporing plants, whose embryos are at the mercy of the environment. All plants characterized by an alternation of generations life cycle. Def: alternation between a haploid (n) gametophyte phase and a diploid (2n) sporophyte phase in the life cycle of a sexually reproducing plant. Gametophyte = haploid gamete-producing phase in the life cycle. Gametes are formed in sexual organs: antheridia ( sperm) and archegonia ( egg). The sporophyte is the diploid spore-producing phase in the life cycle. Bryophytes (some of the first land plants) need h2o for sperm to swim to eggs > 2 homologous pairs of chromosomes (diploid = only 1 1n)
