1. Plant Growth Way too much information for a single presentation…

2. Plant Growth Outline • Indeterminate growth • Determinate growth • Plant Hormones • Shoot apical meristem (and shoot tip), hormones • Root apical meristem (and root tip), hormones • Lateral Buds / Nodes • Cambium ring/Secondary growth

3. Two types of growth Indeterminate and Determinate

4. Indeterminate Growth • Animals = maximum size & shape • Plants = no maximum size or shape • Able to keep growing all their lives • Limited by resources

5. Indeterminate Growth • If injured, plants can grow more: • Branches • Leaves • Roots • Being bigger means being more susceptible to: • Disease • Pests • Weather & Gravity

6. Determinate Growth • Maximum size and shape • Certain parts of the plant have determinate growth: • Leaves • Flowers • Fruit • Cannot heal/fix these when injured

7. Indeterminate vs. Determinate Growth

8. Hormones All growth is influenced by hormones

9. Hormones Influence Growth • Auxin • Associated with (root) growth • Cell elongation • Keeps leaves from dropping • Apical meristem (not lateral buds)

11. Hormones Influence Growth • Cytokinin • Associated with (stem) growth • Cell division • Lateral bud growth

12. Hormones Influence Growth • Ethylene • Gas that encourages fruiting/ripening

13. Hormones Influence Growth • Abscisic Acid • Shoot dormancy

14. Hormones Influence Growth • Gibberellic Acid • Stem elongation and division

15. Meristems The tips of the root and the shoot

16. Shoot Apical Meristem • At the tip of the shoot • Growing tip can turn into any type of tissue • Hormone-controlled • Makes hormones that keep lateral buds from growing

18. Shoot Tip Anatomy • Cell Division • Elongation • Differentiation • Dermal tissue • Ground tissue • Vascular tissue

19. Getting plants to fill out…

20. Root Apical Meristem • At the tip of the root • Growing tip can turn into any type of tissue • Hormone-controlled

21. Root Tip Anatomy • Root Cap (protection) • Cell Division • Elongation • Differentiation • Dermal tissue • Ground tissue • Vascular tissue

22. Growth is Hormone Controlled

23. Growth is Hormone Controlled Auxin • What’s in the rooting powder we use in the greenhouse? • Auxin • Cytokinin Cytokinin

24. Growth isHormone-Controlled

25. Lateral Bud/Nodes • Next to leaf • Could become meristem • Hormone-Controlled

26. Lateral Bud/Node

27. Secondary Growth Plants getting wider

28. Secondary Growth • Stems getting fatter • Woody tissue • Only some plants can do this!

29. Scattered in the stem In a ring in the stem Vascular Bundles

30. If the stem gets fatter… • It needs more xylem and phloem to support the new tissue • Vascular Bundles in a RING only!

31. Vascular CambiumAlso called the Lateral Meristem • Between the Xylem and Phloem • Xylem is ALWAYS on the inside • Phloem is ALWAYS on the outside

32. Secondary Growth • Cambium produces more xylem on the inside (DEAD thick walled-cells) • More phloem on the outside (slightly alive) • Tree bark is actually old, dead PHLOEM • Neato!

34. Tree rings • In the spring/summer cambium makes big cells since it is growing fast • In the fall cambium makes smaller cells since it is growing slowly • Change in cell size throughout time is seen as a ring…

35. Tree rings

36. Size of Rings • You can tell the climate of an area using tree rings… • “Good” years are really wide because the tree grew fast in the spring and summer. • When plants grow at a steady rate all year there are NO TREE RINGS!

37. Plant Growth Outline • Indeterminate growth • Determinate growth • Plant Hormones • Shoot apical meristem (and shoot tip), hormones • Root apical meristem (and root tip), hormones • Lateral Buds / Nodes • Cambium ring/Secondary growth

38. The End