conifers
DESCRIPTION
Conifers. BIOL 1407. Seed Plants. Vascular Tissue Produce seeds Dispersal of offspring Produce pollen Sperm transfer without water. Seed Plants. Sporophyte dominant Gametophytes Greatly reduced in size Dependent on sporophyte. Seed Plants. Heterosporous Megaspore - PowerPoint PPT PresentationTRANSCRIPT
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