Plant Anatomy and Transportchapters 35 and 36

--focus on sap flow--

Sap Flow in Plants

1. basic root structure2. water flow through the cortex cells3. the endodermis as a border crossing4. water flow in the xylem5. the fate of water in the leaf

—photosynthesis—transpiration

—stomate function6. sap flow and maple syrup

Figure 35.3 Radish root hairs

Figure 35.14 Primary growth of a root

epidermis

cortex

vascular cylinder

endodermis

Sap Flow in Plants

1. basic root structure2. water flow through the cortex cells3. the endodermis as a border crossing4. water flow in the xylem5. the fate of water in the leaf

—photosynthesis—transpiration

—stomate function6. sap flow and maple syrup

Figure 36.11 Ascent of water in a tree

Figure 36.6 Compartments of plant cells and tissues and routes for lateral transport

Sap Flow in Plants

1. basic root structure2. water flow through the cortex cells3. the endodermis as a border crossing4. water flow in the xylem5. the fate of water in the leaf

—photosynthesis—transpiration

—stomate function6. sap flow and maple syrup

Figure 36.7 Lateral transport of minerals and water in roots

Apoplast and Symplast

Crossing the endodermis boundary

Sap Flow in Plants

1. basic root structure2. water flow through the cortex cells3. the endodermis as a border crossing4. water flow in the xylem5. the fate of water in the leaf

—photosynthesis—transpiration

—stomate function6. sap flow and maple syrup

A cross section of a dicot root(the purple is starch, the red is lignin)

cortex epidermisvascular cylinder

Figure 35.10 Review of general plant cell structure

Figure 36.11 Ascent of water in a tree

Figure 35.8 Water-conducting cells of xylem

tracheids vessel elements

Tissue: XylemCell Type: Tracheary

Elements

Sap Flow in Plants

1. basic root structure2. water flow through the cortex cells3. the endodermis as a border crossing4. water flow in the xylem5. the fate of water in the leaf

—photosynthesis—transpiration

—stomate function6. sap flow and maple syrup

Figure 36.11 Ascent of water in a tree

Figure 10.2 Focusing in on the location of photosynthesis in a plant

Figure 10.9 Location and structure of chlorophyll molecules in plants

CO2 + H20 C6H1206 + O2

Light energy

Sap Flow in Plants

1. basic root structure2. water flow through the cortex cells3. the endodermis as a border crossing4. water flow in the xylem5. the fate of water in the leaf

—photosynthesis—transpiration

—stomate function6. sap flow and maple syrup

Figure 36.10 The generation of transpirational pull in a leaf

Figure 36.14 The generation of transpirational pull in a leaf

Figure 36.14 The generation of transpirational pull in a leaf

Figure 36.11 Ascent of water in a tree

Sap Flow in Plants

1. basic root structure2. water flow through the cortex cells3. the endodermis as a border crossing4. water flow in the xylem5. the fate of water in the leaf

—photosynthesis—transpiration

—stomate function6. sap flow and maple syrup

STEPS IN STOMATE OPENING 1. Sun comes up.2. Photosynthesis depletes CO2, stimulating proton pump enzymes.3. Proton pump enzyme turns on. H+ moved out of guard cells by

active transport (ATP is used).4. K+ diffuses into cells via K+ channel enzymes.5. Water diffuses in to balance its concentration relative to K+6. Guard cells swell and change shape.

Figure 36.2 A chemiosmotic model of solute transport in plant cells

Figure 36.13a The mechanism of stomatal opening and closing

Figure 36.13b The mechanism of stomatal opening and closing

STEPS IN STOMATE OPENING 1. Sun comes up.2. Photosynthesis depletes CO2, stimulating proton pump enzymes.3. Proton pump enzyme turns on. H+ moved out of guard cells by

active transport.4. K+ diffuses into cells via K+ channel enzymes.5. Water diffuses in to balance its concentration relative to K+6. Guard cells swell and change shape.

Sap Flow in Plants

1. basic root structure2. water flow through the cortex cells3. the endodermis as a border crossing4. water flow in the xylem5. the fate of water in the leaf

—photosynthesis—transpiration

—stomate function6. sap flow and maple syrup

Maple sap is collected from the xylem in wood before leaves appear.

Link to treemet

The osmotic theory of sap flow invokes the involvement of living cells and sucrose to generate an osmotic pressure difference between fibers and vessels, which are proposed to be separated by an osmotic barrier.

The secondary cell wall is an effective osmotic barrier for large molecules