BIS 2C Lecture Notes - Lecture 17: Pollen Tube, Ginkgoales, Gymnosperm
30 Aug 2016
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Gymnosperms naked seed = include cycads, ginkgo, gnetophytes, and. There are approximately 1000 species and are sister to the angiosperms. Gymnosperm seeds are not enclosed in a carpel. Woody cones have megasporangia, leafy cones have microsporangia. Unlike non-seed plants, spores develop into gametophytes in place and never leave the parent plant. Female cone = compound strobilus (stem with leaves, fertile branches) Male cone = simple strobilus (stem with sporophylls) In gymnosperms, pollen (microgametophyte) transfers sperm to the egg using a pollen tube. How they connect: pollen makes pollen tube to the egg (n) which is in the archegonium end up with an embyro (n), which is the next sporophyte generation. Clicker question: the nutritive tissue inside the seeds of gymnosperms is different than that in angiosperms because it is haploid. Clicker question: secondary growth increases width and is produced by bvc. Clicker question: the structure from a pine tree is best referred to as strobilus.
