BIOA02H3 Lecture 8: From Tree to Seed
BIOA02 Module 1 Lecture 8: From Tree to Seed
What are flowers?
• Highly modified leaves
Sepals
• Protect inner flower organs before bud opens
• Frequently green
• Can be fused to form tube = calyx
Petals
• Typically colorful to attract pollinators
• Can be fused to form tube = corolla
Stamen
• Filament + anther
• Pollen producing
• Anther: 4 pollen sacs
• When the pollen is not ripe they are connected to internal epidermis
• When they are mature they will break open and one opening releases the pollen grains
to be taken by pollinators for pollen dispersal
Carpel: Stigma
• Velvety surface and pollen surface fit together nicely almost like key and lock bound
Carpel: Style
• Connects stigma with ovary
• Pollen tubes are hollow and lots of pollen tubes for competition
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BIOA02H3 Full Course Notes
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Document Summary
Bioa02 module 1 lecture 8: from tree to seed. Sepals: protect inner flower organs before bud opens, frequently green, can be fused to form tube = calyx. Petals: typically colorful to attract pollinators, can be fused to form tube = corolla. Carpel: stigma: velvety surface and pollen surface fit together nicely almost like key and lock bound. Carpel: style: connects stigma with ovary, pollen tubes are hollow and lots of pollen tubes for competition. Ovary, ovule, egg cell: carpel can have 1 to many ovaries, ovary can have 1 to many ovules, ovule only has one egg cell. One ovary with one ovule: cherry, peach, apricot, almond, olive. Many ovaries with one ovule each: raspberries, blackberries, aggregate fruits. One ovary with many ovules: cucumber, tomato, zucchini, melon, pepper, blueberry. Four whorls: sepals (0,3,4,5,many, petals (0,3,4,5,many, stamen (0,many, carpel (0 to many)
