Plant Functions BIOL 1407. Essential Nutrients Chemicals that organism cannot produce Must be...
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Transcript of Plant Functions BIOL 1407. Essential Nutrients Chemicals that organism cannot produce Must be...
Plant Functions
BIOL 1407
Essential Nutrients
• Chemicals that organism cannot produce
• Must be acquired from environment
• Required to complete life cycle
• Photo Credit: BIOL 1407 Student, Austin Nature Center, Fall 2006
Macronutrients
• Large quantities– Carbon– Hydrogen– Oxygen– Nitrogen– Sulfur– Phosphorus– Potassium– Calcium– Magnesium
Zea mays Vascular Bundle (Orange = Sclerenchyma)
Photo Credit: Barnading, 2002, Wikimedia Commons
Micronutrients
• Tiny quantities• Cofactors or
components of enzyme systems
Source of Plant Nutrients
• Inorganic Compounds
– Soil
– Air
Transport Systems
• Why are they necessary?
Types of Transport
• Cell Transport– Across membrane
• Short-distance– Diffusion from cell to
cell
• Long-distance– Bulk Flow– Down pressure
gradients
Absorption of Water & Minerals
• From soil (most)• Absorption
– Diffusion– Osmosis– Facilitated
Diffusion– Active Transport
Mineral Uptake: Cation Exchange
• Cations firmly bound to soil particles
• Roots secrete H+ – Directly by H+
pump– Indirectly by
cellular respiration
Short-Distance Transport
• Lateral Transport – Symplast
Pathway– Apoplast
Pathway– Transmembrane
Pathway
Short-Distance Transport in Roots
Long-Distance Transport
• Xylem– Water – Minerals
• Phloem– Organic
compounds
Xylem
Xylem Transport
• Root Pressure• Cohesion and
Adhesion of Water in Xylem tubes
• Transpiration
Root Pressure
• Loading of water and minerals into xylem vessels hydrostatic pressure in stele
Cohesion &
Adhesion
Transpiration
• Evaporation of water from plant surfaces
• Mainly through leaf stomata
Transpiration Pull
Shoot Gas Exchange
• Leaves– Cuticle– Stomata – Opening– Guard Cells –
Regulate Gas Exchange
• Stem– Lenticels
• Photo Credit of Lenticels: Sten Porse, 2007, Wikimedia Commons
Root Gas Exchange
• No cuticle • No stomata
Phloem Transport
• Sugar Sources• Sugar Sinks
Phloem Cells
Lateral Transport of Sugars
Apoplast
Sieve tube element or companion cell
Phloem Transport
Plant Video
• http://www.youtube.com/watch?v=J1PqUB7Tu3Y
The End
Unless otherwise specified, all images in this presentation came from:
Campbell, et al. 2008. Biology, 8th ed. Pearson Benjamin Cummings.