Conifers
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Transcript of Conifers
Seed Plants
• Vascular Tissue
• Produce seeds– Dispersal of
offspring
• Produce pollen• Sperm transfer
without water
Seed Plants• Heterosporous
– Megaspore• Grows into
female gametophyte eggs
– Microspore• Grows into male
gametophyte sperm
– Photo Credit for Ovulate Cone: Dr. Stephen Bostic, ACC
– Circled area: Ovule
Pollen Production
• Pollen cones have microsporophylls
• Each microsporophyll has microsporangia
• Photo Credit for Immature Male Pine Cones: Menchi, Wikimedia Commons
Pollen Production• Meiosis occurs
within microsporangia microspores
• Photo Credit for Staminate Cone: Dr. Stephen Bostic, ACC
• Microsporangium circled in red• Microsporophyll at tip of yellow pointer• Microspores circled in pink
Pollination
• Pollen is released • Travels from male to
female• Pollination occurs
when pollen grain lands on female
• http://www.youtube.com/watch?v=Bwl4g48-uIE
Pollen Germination
• After landing pollen coat breaks open
• 1 cell produces pollen tube
• Photo Credit: Dr. David Byres, Florida Community College at Jacksonville
Pollen Germination
• A different cell produces 2 sperm cells by mitosis
• They will move down pollen tube as it grows
• Photo Credit: Dr. David Byres, Florida Community College at Jacksonville
Ovules
• Ovulate cones have megasporophylls
• Each megasporophyll has ovules containing megasporangia
• Photo Credit for Immature Female Ponderosa Pine Cones: Susan McDougall @ USDA-NRCS PLANTS Database
Ovules
• Meiosis occurs within megasporangium forms 1 megaspore and 3 haploid nuclei (degenerate)
• Photo Credit: Dr. Stephen Bostic, ACC• Megasporangium circled in red• Megasporophyll at tip of yellow pointer
Seeds
• Dispersed by:– Wind– Animals– Water– Mechanical
• Photo Credit for Pitch Pine Seeds: Steve Hurst @ USDA-NRCS PLANTS Database
Modern Gymnosperms• Conifers
– Oldest living plants
– Largest living plants
– Widespread– Reproductive
structure: Cones
Modern Gymnosperms
• Cycads– Wiry leaves– “Sago palms”
• Ginkgos• Deciduous
trees• One species• Herbal
supplement