Biology lecture 3/23/15Intro to vascular plants1. Vascular plants: origins and general features2. Heterosporous vs. homosporous plants3. Seedless vascular plants- Phyla lycophyta and monilophyta (pterophyta)First vascular plants- Appeared about 420 million years ago- Known only from xylem cells- Complete fossil vascular plants: 400 million years ago- CooksoniaFeatures distinguishing vascular plants from bryophytes1. Vascular tissues- Xylem- Phloem2. Below-ground roots3. Water-proof cuticle4. Stomata5. Sporophyte is dominantPlant vascular tissues2 related systems of plant vascular tissues: xylem and phloem Xylem: - Water/mineral nutrient transport- Walls reinforces with ligninProvides rout for water and nutrient transport uptake and transportMovement of water through xylem relies on evaporation from leavesTranspiration: evaporation from leavesCuticle: prevents excessive water loss from plant tissues by interrupts CO2 uptake.Stomata: openings through cuticle/epidermis. Allows gas diffusion in and out of leavesTurgidity: Plants regulated stomatal aperture via this guard cellTurgid: stomata openFlazzid: stomata closingPhloem:- Sugar (sucrose) transport- Cells living, metabolically active- Transports sugars from photosynthesis to or from rootsSeedless vascular plants may be homosporous or heterosporousMicrosporangia and megasporangia: 2 types of sporangia possessed by heterosporousLycophyta and minilosphyta (pterophyta): 2 extant phyla of seedless vascular plantsQuizlet link:
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