Chapter 29: Plant Tissues

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1 Chapter 29: Plant Tissues

2 Shoots and Roots Shoots (Leaves and Stem) Produce food by photosynthesis Carry out reproductive functions Roots Anchor the plant Penetrate the soil and absorb water and dissolved minerals

3 Shoot Apical Meristem primary meristems active epidermis, ground tissues, primary vascular tissues forming epidermis, ground tissues, primary vascular tissues forming primary meristems active Root Apical Meristem Fig. 29-3a, p.494

4 The cellular descendants of apical meristems divide, grow, and differentiate. They form three primary meristems, the activity of which lengthens shoots and roots: Protoderm Ground meristem Procambium epidermis ground tissues primary vascular tissues Fig. 29-3a1, p.494

5 vascular cambium cork cambium thickening Lateral Meristems Fig. 29-3b, p.494

6 Angiosperm Body Plan EPIDERMIS Ground tissue system Vascular tissue system Dermal tissue system VASCULAR TISSUES GROUND TISSUES SHOOT SYSTEM ROOT SYSTEM Fig. 29-2, p.494

7 Monocots and Dicots: 1 cotyledon 2 cotyledons 3 floral parts 4 or 5 floral parts Parallel veins 1 pore Netlike veins 3 pores Vascular bundles in ring Vascular bundles dispersed

Inside seeds, two cotyledons seed leaves of embryo Inside seeds, one cotyledon seed leaf of embryo Usually four or five floral parts (or multiples of four or five) Usually three floral parts (or

8 Inside seeds, two cotyledons seed leaves of embryo Inside seeds, one cotyledon seed leaf of embryo Usually four or five floral parts (or multiples of four or five) Usually three floral parts (or multiples of threes) Leaf veins usually in a netlike array Three pores or furrows in the pollen grain surface Leaf veins usually running parallel with one another One pre or furrow in the pollen grain surface Vascular bundles organized as a ring in ground tissue Vascular bundles distributed throughout ground tissue Fig. 29-4, p.495

9 Parenchyma: A Simple Tissue Most of a plant s soft primary growth Pliable, thin walled, many sided cells Cells remain alive at maturity and retain capacity to divide Mesophyll is a type that contains chloroplasts

10 parenchyma vessel of xylem phloem fibers of sclerenchyma stem epidermis simple and complex tissues inside the stem Fig. 29-6, p.496

11 Collenchyma: A Simple Tissue Specialized for support for primary tissues Makes stems strong but pliable Cells are elongated Walls thickened with pectin Alive at maturity

12 Collenchyma: A Simple Tissue Supports mature plant parts Protects many seeds Thick, lignified walls Dead at maturity Two types: Fibers: Long, tapered cells Sclereids: Stubbier cells

13 collenchyma parenchyma lignified secondary wall Fig. 29-7, p.496

14 Complex Tissues Composed of a mix of cell types Xylem Phloem Epidermis

15 Xylem Conducts water and dissolved minerals up the shoot Conducting cells are dead and hollow at maturity tracheids vessel member

16 one cell s wall sieve plate of sieve tube cell a pit in wall b companion cell c Fig. 29-8, p.497

17 Phloem: A Complex Vascular Tissue Transports sugars down the shoot Main conducting cells are sieve-tube members Companion cells assist in the loading of sugars sieve-tube member companion cell sieve plate

18 Epidermis: A Complex Plant Tissue Covers and protects plant surfaces Secretes a waxy, waterproof cuticle In plants with secondary growth, periderm replaces epidermis

19 leaf surface cuticle epidermal cell photosynthetic cell Fig. 29-9, p.497

20 Meristems Regions where cell divisions produce plant growth Apical meristems Lengthen stems and roots Responsible for primary growth Lateral meristems Increase width of stems Responsible for secondary growth

into primary tissues Root apical meristem new cells

21 Apical Meristems Shoot apical meristem activity at meristems new cells elongate and start to differentiate into primary tissues Root apical meristem new cells elongate and start to differentiate into primary tissues activity at meristems

22 Fig a1, p.498

23 immature leaf shoot apical meristem lateral bud forming cortex vascular tissues pith Fig a2, p.498

24 immature leaf shoot apical meristem descendant meristems (orange) Fig b, p.498

25 Lateral Meristems Increase girth of older roots and stems Cylindrical arrays of cells cork cambium vascular cambium thickening Figure a Page 504

26 immature leaf shoot apical meristem descendant meristems (orange) cortex primary phloem primary xylem pith Stepped Art Fig b-d, p.498

27 Internal Structure of a Dicot Stem Outermost layer is epidermis Cortex lies beneath epidermis Ring of vascular bundles separates the cortex from the pith The pith lies in the center of the stem

28 Internal Structure of a Monocot Stem The vascular bundles are distributed throughout the ground tissue No division of ground tissue into cortex and pith Figure b Page 499

29 vessel in xylem meristem cell epidermis cortex vascular bundle pith sieve tube in phloem companion cell in phloem Fig a, p.499

30 Common Leaf Forms DICOT petiole axillary bud MONOCOT blade blade node sheath node Figure a,b Page 500

31 Adapted for Photosynthesis Leaves are usually thin High surface area-to-volume ratio Promotes diffusion of carbon dioxide in, oxygen out Leaves are arranged to capture sunlight Are held perpendicular to rays of sun Arranged so they don t shade one another

32 POPLAR (Populus) OAK (Quercus) MAPLE (Acer) leaflet RED BUCKEYE (Aesculus) BLACK LOCUST (Robina) HONEY LOCUST (Gleditsia) Fig c,d, p.500

33 Leaf Structure cuticle UPPER EPIDERMIS xylem phloem PALISADE MESOPHYLL SPONGY MESOPHYLL LOWER EPIDERMIS O 2 CO 2 one stoma Figure b Page 501

leaf blade leaf vein Leaf Vein (one vascular bundle) cuticle Upper Epidermis Palisade Mesophyll stem xylem Water, dissolved mineral ions from roots and stems move into leaf vein (blue arrow) Spongy

34 leaf blade leaf vein Leaf Vein (one vascular bundle) cuticle Upper Epidermis Palisade Mesophyll stem xylem Water, dissolved mineral ions from roots and stems move into leaf vein (blue arrow) Spongy Mesophyll Lower Epidermis phloem 50 m Photosynthetic products (pink arrow) enter vein, will be transported throughout plant body Oxygen and water vapor diffuse out of leaf at stomata. Carbon dioxide in outside air enters leaf at stomata. cuticle-coated cell of lower epidermis one stoma (opening across epidermia) Fig , p.501

35 Leaf Veins: Vascular Bundles Xylem and phloem; often strengthened with fibers In dicots, veins are netlike In monocots, they are parallel

36 Leaf Veins Fig a, p.501

37 Leaf Veins Fig b, p.501

38 Root Systems Taproot system of a California poppy Fibrous root system of a grass plant Figure Page 503

39 Internal Structure of a Root Outermost layer is epidermis Root cortex is beneath the epidermis Endodermis, then pericycle surround the vascular cylinder In some plants, there is a central pith

40 Root Structure Root cap covers tip Apical meristem produces the cap Cell divisions at the apical meristem cause the root to lengthen Farther up, cells differentiate and mature Figure a Page 502

41 pith cortex epidermis VASCULAR CYLINDER primary xylem primary phloem Fig , p.503

42 Fig , p.503

43 Function of Endodermis Ring of cells surrounds vascular cylinder Cell walls are waterproof Water can only enter vascular cylinder by moving through endodermal cells Allows plant to control inward flow

44 Root Hairs and Lateral Roots Both increase the surface area of a root system Root hairs are tiny extensions of epidermal cells new lateral root Lateral roots arise from the pericycle and must push through the cortex and epidermis to reach the soil

45 Fig a, p.503

46 Fig b, p.503

47 Secondary Growth Occurs in all gymnosperms, some monocots, and many dicots A ring of vascular cambium produces secondary xylem and phloem Wood is the accumulation of these secondary tissues, especially xylem

48 Fig , p.504

49 VASCULAR CAMBIUM stem surface primary xylem primary phloem VASCULAR CAMBIUM secondary xylem secondary phloem Fig b, p.504

50 Secondary Growth Ongoing cell divisions enlarge the inner core of secondary xylem and displace vascular cambium toward the stem Figure c Page 504

51 Woody Roots primary xylem epidermis cortex procambium endodermis primary phloem pericycle Fig a, p.505

vascular ray primary xylem primary phloem procambium secondary xylem secondary

52 epidermis cortex endodermis pericycle vascular cambium produced by pericycle vascular cambium produced by procambium vascular cambium pericycle derivatives vascular ray primary xylem primary phloem procambium secondary xylem secondary phloem cortex, epidermis slough off crushed primary phloem Stepped Art Fig , p.505

53 A Coast Redwood Fig , p.506

54 periderm (includes cork cambium, cork, new parenchyma) secondary phloem HEARTWOOD SAPWOOD BARK vascular cambium Fig a, p.507

55 Annual Rings Concentric rings of secondary xylem Alternating bands of early and late wood Early wood Xylem cells with large diameter, thin walls Late wood Xylem cells with smaller diameter, thicker walls

56 Fig a, p.507

57 Annual Rings Narrow annual rings mark severe drought years Fig c, p.509

Plants. Plant Form and Function. Tissue Systems 6/4/2012. Chapter 17. Herbaceous (nonwoody) Woody. Flowering plants can be divided into two groups:

Plants. Plant Form and Function. Tissue Systems 6/4/2012. Chapter 17. Herbaceous (nonwoody) Woody. Flowering plants can be divided into two groups: Monocots Dicots 6/4/2012 Plants Plant Form and Function Chapter 17 Herbaceous (nonwoody) In temperate climates, aerial parts die back Woody In temperate climates, aerial parts persist The Plant Body Functions