BIOLOGY 1002 NOTES - • {*the 2 sperm cells are not...

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BIOLOGY 1002 10-7-2011 Angiosperms {flowering plants} wind-pollinated flowers: inconspicuous and unscented produce lots of pollen {hit or miss strategy} animal-pollinated flowers 1. attract pollinators using colors and scents {*what bees see and humans see is sometimes very different bees’ light vision is shifted to the left, so they can see near UV light; humans can only see up to violet light.} 2. stop unwanted visitors using physical modification {i.e., tubes that only specific pollinators can access} 3. ensure pollination is the goal {*some flowers have structures that work mechanically once a pollinator lands on the flower} Angiosperm Gametophyte Development {*gametophyte: multi-cellular haploid plant; sporophyte: diploid} develop inside sporophyte {i.e., parent} flowers very small and parasitic, {so they can’t live on their own} pollen grains are the male gametophyte pollen develops within the pollen sacs pollen grain consists of 2 sperm cells
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Unformatted text preview: • {*the 2 sperm cells are not flagellated because they rely on the wind for movement} • embryo sac: female gametophyte • produces 7 egg cells: • 1 haploid egg cell • 1 primary endosperm cell with 2 nuclei {dikaryotic} • 5 cells that degenerate {and we don’t really care about} • {*3 rounds of mitosis take place to produce 8 nuclei • 1 round = 2 nuclei • 2 rounds = 4 nuclei • 3 rounds = 8 nuclei} • pollination & fertilization • 1. pollen lands on carpel • 2. tube grows from pollen down through carpel • 3. 2 sperm go down tube to egg for double fertilization • 1 sperm fertilizes egg to form diploid zygote • 1 sperm fertilizes primary endosperm cell to form triploid tissue • becomes part of the food for the developing plant • genetic self-incompatibility: gauged by S-genes • if 2 plants have same S-genes, fertilization can not take place • if 2 plants have different S-genes, fertilization can take place...
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This note was uploaded on 01/16/2012 for the course BIO 1002 taught by Professor Hrinchevich during the Fall '10 term at LSU.

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BIOLOGY 1002 NOTES - • {*the 2 sperm cells are not...

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