1 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. *See PowerPoint Lecture Outline for a complete, ready-made presentation integrating art and lecture notes. Introductory Plant Biology Ninth Edition Kingsley Stern Chapter 4 Image Slides*

Botany Chapter 4 Tissues

3 Overview §4 organs of plants 1. Roots 2. Stems 3. Leaves 4. Flowers All formed from tissues

4 Meristematic Tissue §Meristematic tissue/meristems- permanent regions of growth in plants; 3 Types of Meristems 1. Apical meristem- found at or near the tips of roots and shoots - increases the length of plant; this is primary growth

5 Meristems cont. 2. Lateral meristems- produce tissues that increase the girth of roots and stems; secondary growth 2 types of lateral meristems 1. Vascular cambium/ cambium- produces secondary tissues; xylem and phloem

6 Meristems cont. -a thin cylinder of brick-shaped cells that extends through root and stems 2. Cork cambium-produces bark - lies just inside the outer bark - thin cylinder of cells that runs length of roots and stems

7 Meristems cont. 3. Intercalary meristems- found at nodes in grasses and related plants instead of vascular and cork cambium - node- point of leaf attachment - develop at intervals along stems - also add to stem length

8 Fig. 4.1

9 Tissues produced by meristems §3 Types of Simple Tissues 1. Parenchyma tissue- made of parenchyma cells; most abundant - Cells generally have 14 sides and large vacuoles

10 Parenchyma cont. - may contain numerous chloroplasts (referred to as chlorenchyma) - w/out chloroplast, function in food and water storage - can multiply and repair wounds and form roots on a cutting

11 Simple tissues cont. 2. Collenchyma tissue- made of collenchyma cells - found beneath epidermis - provide flexible support - “strings” of celery

12 3 Simple tissues cont. 3. Sclerenchyma tissue - made of sclerenchyma cells - thick, tough, secondary walls with lignin (a polymer) - most are dead at maturity and function in support

13 2 Types of sclerenchyma tissue 1. Sclereids or stone cells- produce gritty texture of pears and hardness of shells and peach pits 2. Fibers- used to manufacture textile goods, ropes, string, canvas

14 Complex tissues-2 or more types of cells 1. Xylem- plumbing and storage systems - chief conducting tissue throughout all organs for water and minerals absorbed by roots

15 Xylem cont. - consists of parenchyma cells, fibers, vessels, tracheids and ray cells - vessels- made of dead cells called vessel elements; straw-like with bars of wall material across open areas

16 Xylem cont. - tracheids- dead cells with thick cell walls - no vessel-like openings, but have pits which allow water to pass from cell to cell -rays-long-lived parenchyma cells produced in horizontal rows; conduct water laterally

17 Fig. 4.6

18 Complex tissues cont. 2. Phloem- conducts food produced by photosynthesis throughout the plant - made of 2 types of cells 1. Sieve tube members- cells layed end to end forming sieve tubes

19 Complex tissue cont. 1. Sieve tube members cont. - Walls are full of small pores through which cytoplasm extends cell to cells - sieve plates porous regions of sieve tube members

20 Complex tissues cont. 2. Companion cells - help control transport of sugar through sieve tube member

21 Complex tissues cont. 3. Epidermis- outermost layer of cells of all young plants - one cell thick - cuticle- protective layer on the surface of the outer wall - made of fatty cutin

22 Complex tissues cont. Epidermis cont. -stomata- (sing. Stoma)- pores in leaves -guard cells- cells that border stoma

23 Complex tissues cont. 4. Periderm- consists of outer bark (woody plants) -made of cork cells- dead at maturity - Suberin- fatty substance secreted by cork cells that waterproofs and protects the plant

24 Complex tissues cont. Periderm cont. -lenticels- pockets of parenchyma cells with no suberin (pg. 63) - function in gas exchange between air and interior of the stem

25 Secretory Cells and Tissues Examples of secretions: §nectar in flowers §oils in citrus fruits and mint §resins in pine trees §opium

26 Fig. 4.7

27 Fig. 4.8

28 Fig. 4.10

29

30 Fig. 4.11

31 Fig. 4.14