BIOL 341 Lecture Notes - Lecture 20: Axillary Bud, Abaxial, Lanolin
17 Mar 2017
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Document Summary
Homeobox/ homeodomain genes (tfs) have important roles in patterning (e. g. knox, hd-zip proteins) Pavement cells: relatively unspecialized, default pathway. Guard cells: control stomatal aperature, photosynthetic parts of the shoot, tightly controlled cell differentiation and asymmetric cell divisions ensure proper spacing ( 1 cell apart to maximize gas exchange) Trichomes: protect against insects, pathogens, abiotic stresses, endoreduplication (genome replicates, no division) Initiated at base of leaf 3-4 cells apart, further separated by divisions of intervening cells: signals from trichome inhibit trichome formation in neighbouring cells. The stem was decapitated and the leaves and buds above the wound site were removed in order to lower the endogenous auxin. Immediate after the wounding, auxin in lanolin paste was applied to the stem above the wound. Canalization model- auxin flowing from source to sink forms files of polarized cells that can differentiate to form vascular tissue. In vascular development this joins together existing, discontinuous vascular tissue that arises from the procambium.
