1. 9-1 Honors Biology Chapter 9 Plant Anatomy John Regan Wendy Vermillion Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

2. 9-2 9.1 Plant organs Plant organs –Roots –Stems –Leaves –Flowers Roots 1.Anchor plant to soil and give support 2.Absorb water and minerals 3.Increased surface area for absorption from root hairs Epidermal extensions 4.Produce growth hormones 5.Food storage in perrenials-live year after year

3. 9-3 Organization of plant body Fig 9.1

4. 9-4 Vegetative organs of a tomato plant Fig 9.2

5. 9-5 Plant organs cont’d. Stems 1.Provide structural support for leaves 2.Transport substances through plant body Water and minerals from roots to leaves Products of photosynthesis from leaves to other organs for storage 3.Photosynthetic in some varieties 4.Store water in succulents –Node- point of attachment of leaf to stem –Internode- regions between nodes –Apical meristem- region of growth in length

6. 9-6 Plant organs cont’d. Leaves –Major synthetic organs in most varieties –Blade- wide portion of leaf –Petiole- stalk that attaches leaf to stem –Deciduous leaves- lost in cold weather Separates from stem at abscission layer

7. 9-7 Plant organs cont’d. Monocots versus eudicot plants –Eudicots are the larger group which includes many of the most familiar flowering plants –Monocots include grasses, palms, and many important food plants such as rice, wheat, and corn

8. 9-8 Flowering plants are either monocots or dicots Fig 9.3

9. 9-9 Plant tissues cont’d. Vascular tissue –Specialized for transport of substances through plant body –Two types of vascular tissue- xylem and phloem –Xylem- transports water and minerals –Phloem-transports food

10. 9-10 9.3 Organization of leaves Leaf Structure –Cuticle – outer waxy covering, prevents water loss –Upper epidermis- protection –Mesophyll- cells have many chloroplasts Palisade mesophyll- elongated cells Spongy mesophyll- irregular cells with many air spaces which increase surface area for gas exchange - Lower epidermis- protection, contains stomata(holes) surrounded by guard cells-regulate opening and closing of stomata

11. 9-11 Leaf structure Fig 9.8

12. 9-12 Classification of leaves Fig 9.9

13. 9-13 Shot tip and primary meristems Fig 9.11

14. 9-14 Organization of stems cont’d. Herbaceous stems-mature nonwoody stems –Exhibit only primary growth –Epidermis covered by waxy cuticle –Distinctive vascular bundles-xylem oriented to inside, phloem to outside –Eudicots-vascular bundles in ring, central pith stores water and carbohydrates, cortex wide and photosynthetic –Monocot-vascular bundles scattered, narrow cortex, large amount of pith

15. 9-15 Herbaceous eudicot stem Fig 9.12

16. 9-16 Monocot stem Fig 9.13

17. 9-17 Organization of stems cont’d. Woody stems- have both primary and secondary tissues –Primary- formed from primary meristems behind shoot apical meristem –Secondary-develop from lateral meristems: vascular cambium and cork cambium –Primary growth is growth in length –Secondary growth increases girth and occurs only in conifers and woody dicots

18. 9-18 Diagrams of secondary growth of stems Fig 9.14

19. 9-19 Tree trunk Fig 9.15

20. 9-20 Organization of stems cont’d. Stem diversity –Stolons- above ground horizontal stems, also called runners; vegetative reproduction –Rhizomes- underground horizontal stems; vegetative reproduction –Corms-bulbous underground stems

21. 9-21 Stem diversity Fig 9.16

22. 9-22 9.5 Organization of roots Root tip –Apical meristem protected by root cap –Root is divided into zones –Zone of primary cell division-primary meristems –Zone of elongation-cells lengthen as they differentiate –Zone of maturation- fully differentiated cells; root hairs present

23. 9-23 Eudicot root tip Fig 9.17

24. 9-24 Organization of roots cont’d. Tissues of an eudicot root –Epidermis-single layer of cells; root hairs present –Cortex-parenchymal cells containing starch granules –Endodermis-controls entrance of water and nutrients; boundary between cortex and inner vascular cylinder –Vascular tissue-pericycle is the first layer of vascular cylinder;can divide and give rise to lateral roots

25. 9-25 Organization of roots cont’d. Organization of monocot roots –Same growth zones as eudicot roots –Do not undergo secondary growth like many eudicot roots –Pith is surrounded by a vascular ring of alternating xylem and phloem bundles

26. 9-26 Monocot root Fig 9.19

27. 9-27 Root diversity Fig 9.20

28. 9-28 Uptake and transport of nutrients cont’d. Stomata and water transport –Stomata must be open for water and mineral transport to occur –Each stoma is surrounded by a pair of guard cells –Guard cells regulate the opening and closing of the stomata –Blue light activates a flavin protein, which initiates activity of a H + pump –K + is actively transported into the guard cells

29. 9-29 Opening and closing of stomata Fig 9.23