1. Plant Transport

2. Transport Overview Water and minerals Sugars

3. Vascular Tissue • Xylem • Water • Dissolved minerals • Phloem • Water • Sugars • Amino acids • Hormones

4. Uptake of Minerals and Water • Lateral movement – soil to xylem • Diffusion and active transport of minerals • Increased surface area • Root hairs • Mycorrhizae • Symplastic and apoplastic movement • All minerals must pass through a selective membrane • Casparian strip prevents direct apoplastic movement into the xylem

5. Lateral Transport of Minerals and Water from Roots

6. Bulk Flow Transport Through Xylem • Root pressure – pushing water • Active transport of minerals into root creates lower water potential • Water enters cells and is pushed up xylem • Transpiration – pulling water • Water evaporates from leaves • Water pulled up xylem because of cohesion of water molecules • Transpiration controlled by openings in leaf called stoma

7. Transpiration

8. Control of Transpiration • Stoma open • K+ enter guard cell • Cell becomes turgid from influx of water • Stoma closed • K+ pumped out of guard cell • Cell becomes flaccid from efflux of water

9. Photorespiration • Response to high heat and low water • Stoma close to prevent water loss causing low CO2 and high O2 levels in leaf • Carbon fixation low • Carbon is removed from RuBP to produce CO2 • Rubisco runs in reverse

10. Loading of Sucrose into Phloem • Transport is in either direction at different times • Transport from sugar source to sugar sink • Sugar is pumped from source to sieve tube member

12. Mass Flow in a Sieve Tube