Transport in Living Things

1. Transport in Living Things Chapter 25 Chapter 25.5 Transport System in Flowering Plants

2. What did we learn? Gaseous exchange in the lungs Movement of substances Transport of water into roots Passive process Diffusion Active process Osmosis Movement of molecules from a region of lower concentration to a region of higher concentration with the use of energy Net movement of molecules from a region of higher concentration to a region of lower concentration Net movement of water molecules from a region of higher water potential to a region of lower water potential through a partially permeable membrane Active Transport Carbon dioxide and oxygen inside leaves Transport of mineral salts into the roots

4. Lesson Objectives At the end of the lesson, You should be able to: • State what the vascular bundle consists of • Describe the structure and function of xylem and phloem • Identify the position of xylem vessels and phloem in sections of the stem • relate the structure and functions of root hairs to their surface area, and to water and ion uptake

5. Looking at the rose… • How do you turn a white flower into a blue one? • How does the coloured water travel up the stem to the flower?

6. Vascular tissues Xylem Phloem

7. Xylem tissue Structure • composed of hollow, nonliving cells (continuous lumen) • Lignified walls Function • transports water and mineral salts from roots → stem → leaves • provides mechanical support to plant

8. Structure of Xylem

9. QUESTION • How is the straw similar to the xylem?

10. Phloem tissue Structure • Living cells Function • Transports manufactured food (sucrose and amino acids), usually from leaves → other parts of the plant

11. Identifying a vascular bundle

12. Identifying a vascular bundle in a dicotyledonous stem

13. A vascular bundle cambium

14. Transverse section of a stem

15. Why do you think the xylem is positioned on the inside?

16. How to distinguish xylem vessels from phloem in microscopic slides? Xylem vessels have • Thicker walls • - due to lignified walls (either annular, spiral or pitted) to provide mechanical support to the plant • Larger lumen compared to phloem • Xylem vessels have a darker stain.

17. Locate the xylem and phloem phloem xylem

18. Leaf structure xylem phloem

19. Transport of water

20. Structure of root • Presence of Root hairs • Increased surface area Function of root • Absorb water and mineral salts from the surroundings • Water absorbed from the root enters the xylem

21. Entry of water into the plant Thin film around particle = dilute solution of mineral salts

22. Soil solution Sap in root hair Strong solution of sugars and salts Dilute solution of mineral salts H2O Higher water potential Low water potential Entry of water from soil Plasma membrane of root hair cell Osmosis

23. Transport of water from root hair → xylem

24. High water potential Low water potential

25. Transport of mineral salts

26. Transport of mineral salts Soil solution Sap in root hair Mineral salts Mineral concentration low Mineral concentration high Plasma membrane of root hair cell Diffusion

27. Qn: Can the root hair absorb ions if the concentration is higher in the root hair sap compared to the soil solution? Transport of mineral salts Soil solution Sap in root hair Plasma membrane of root hair cell Mineral salts? Mineral concentration high Mineral concentration low Yes!!! Active transport

28. Mineral salts move into the root hair cell via Diffusion OR ACTIVE TRANSPORT Summary Plant Transport system Consists of Xylem Phloem transports Water containing dissolved mineral salts from the roots to the leaves Manufactured food substances (eg. sugars) from the leaves to the other parts of the plant where Water moves into the root hair cell via OSMOSIS

29. In the next lesson… We will be learning about • what is transpiration • what is translocation • MINI QUIZ!