2/25/2013. o Plants take up water and minerals from below ground o Plants take up CO2 and light from above ground THREE BASIC PLANT ORGANS ROOTS

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1 o Plants take up water and minerals from below ground o Plants take up CO2 and light from above ground THREE BASIC PLANT ORGANS o Roots o Stems o Leaves ROOTS o Anchor plant o Absorb water and minerals o Store carbohydrates LARGE AMOUNT OF ABSORPTION OCCURS THROUGH ROOT HAIRS MODIFIED ROOTS 1

2 STEMS o Raise and separate leaves o Support plant o Conduct materials from roots to leaves APICAL DOMINANCE o Inhibition of lateral buds by an apical bud MODIFIED STEMS LEAVES o Main photosynthetic organ Consist of blade and petiole Can be simple or compound MODIFIED LEAVES PLANT TISSUES o Dermal o Vascular o Ground 2

DERMAL TISSUE SYSTEM o Epidermis with waxy cuticle o

Epidermal cells that can provide protection from

minerals upward o Phloem conducts sugars from where they

are bundled in the stele XYLEM o Dead at maturity PHLOEM

cellular support GROUND TISSUE o All tissue that is

tissue is pith o External to vascular tissue is cortex o

3 DERMAL TISSUE SYSTEM o Epidermis with waxy cuticle o Periderm replaces epidermis in woody plants TRICHOMES o Epidermal cells that can provide protection from herbivores VASCULAR TISSUE o Xylem conducts water and minerals upward o Phloem conducts sugars from where they are produced to where they are needed o Xylem and phloem are bundled in the stele XYLEM o Dead at maturity PHLOEM o Partially alive at maturity o Companion cells provide cellular support GROUND TISSUE o All tissue that is neither epidermal nor vascular o Internal vascular tissue is pith o External to vascular tissue is cortex o Ground tissue includes cells specialized for storage, photosynthesis, and support 3

PARENCHYMA o Thin-walled with large vacuole o

ground tissue COLLENCHYMA o Flexible support with unevenly

secondary walls with lignin PLANTS HAVE INDETERMINATE

juvenile periods o Animals show determinate growth, as do

Cell division and growth occurs in meristems Apical

4 PARENCHYMA o Thin-walled with large vacuole o Intercellular spaces may be present o Most common type of ground tissue COLLENCHYMA o Flexible support with unevenly thickened cell walls SCLERENCHYMA o Rigid support o Thick secondary walls with lignin PLANTS HAVE INDETERMINATE GROWTH o Growth in plants is not limited to embryonic or juvenile periods o Animals show determinate growth, as do some plant organs such as flowers, thorns and leaves o Cell division and growth occurs in meristems Apical meristems initiate primary growth Lateral meristems initiate secondary growth (wood) 4

5 TYPES OF LIFE CYCLES o Annuals complete life cycle in one year o Biennials complete life cycle in two years o Perennials live many years PRIMARY ROOT GROWTH ROOT STRUCTURE LATERAL ROOT GROWTH PRIMARY GROWTH OF SHOOTS STEM STRUCTURE 5

0.5 mm 2/25/2013 LEAF STRUCTURE SECONDARY GROWTH o Lateral meristems add thickness to woody plants, a process called

adds layers of vascular tissue called secondary xylem (wood) and secondary phloem The cork cambium replaces the

WOODY PLANTS o Secondary growth occurs in stems and roots of woody plants but rarely in leaves o The secondary plant

of gymnosperms and many eudicots, but not monocots Secondary xylem Secondary phloem Vascular cambium Late wood Early

6 0.5 mm 2/25/2013 LEAF STRUCTURE SECONDARY GROWTH o Lateral meristems add thickness to woody plants, a process called secondary growth o There are two lateral meristems: the vascular cambium and the cork cambium The vascular cambium adds layers of vascular tissue called secondary xylem (wood) and secondary phloem The cork cambium replaces the epidermis with periderm, which is thicker and tougher SECONDARY GROWTH INCREASES THE DIAMETER OF STEMS AND ROOTS IN WOODY PLANTS o Secondary growth occurs in stems and roots of woody plants but rarely in leaves o The secondary plant body consists of the tissues produced by the vascular cambium and cork cambium o Secondary growth is characteristic of gymnosperms and many eudicots, but not monocots Secondary xylem Secondary phloem Vascular cambium Late wood Early wood Bark Cork cambium Periderm Cork 0.5 mm Vascular ray Growth ring (b) Cross section of a three-yearold Tilia (linden) stem (LM) 6

USING TREE RINGS TO STUDY HISTORY AN EXAMPLE OF A LIVING PLANT CELL THAT LACKS A NUCLEUS WOULD BE a) a guard cell. b) a companion cell. c) fiber. d) a mesophyll cell. e) a sieve tube element.

d) sclerenchyma tissue. e) hypocotyl tissue. YOU CARVE YOUR INITIALS 1.5 M ABOVE THE GROUND IN A 10-M-TALL TREE SAPLING.

7 USING TREE RINGS TO STUDY HISTORY AN EXAMPLE OF A LIVING PLANT CELL THAT LACKS A NUCLEUS WOULD BE a) a guard cell. b) a companion cell. c) fiber. d) a mesophyll cell. e) a sieve tube element. a guard cell. a companion cell. fiber. a mesophyll cell. a sieve tube element. NEW SHOOTS ON AN ACTIVELY GROWING STEM COME FROM a) stipules. b) axillary buds. c) epidermal cells. d) sclerenchyma tissue. e) hypocotyl tissue. YOU CARVE YOUR INITIALS 1.5 M ABOVE THE GROUND IN A 10-M-TALL TREE SAPLING. IF YOU RETURN 20 YEARS LATER AND THE TREE IS 25 M TALL, YOUR INITIALS WILL BE ABOVE THE GROUND. A. 1.0 m B. 1.5 m C. 2.5 m D m E m stipules. axillary buds. epidermal cells. sclerenchyma tissue. hypocotyl tissue. 1.0 m 1.5 m 2.5 m 11.5 m 18.5 m THE INCREASE IN GIRTH OF WOODY PLANTS IS PRIMARILY DUE TO THE INCREASE IN THE PRODUCTION OF a) phloem. b) xylem. c) pith. d) cortical tissue. e) bark. THINK ABOUT THE STRUCTURE OF A ROOT TIP. IN WHICH REGION WOULD YOU EXPECT THE MAJORITY OF WATER AND NUTRIENT UPTAKE TO OCCUR? A. Root cap B. Apical lens (meristem) C. Zone of cell division D. Zone of cell elongation E. Zone of cell maturation phloem. xylem. pith. cortical tissue. bark. Root cap Apical lens (meristem) Zone of cell division Zone of cell elongation Zone of cell maturation 7

8 A STEM CROSS SECTION WITH DISPERSED VASCULAR BUNDLES WOULD MOST LIKELY BE SEEN IN fern plants. moss plants. pine trees. maple trees. corn plants WHICH OF THE FOLLOWING TISSUE TYPES ARE UNIQUE TO LEAVES? A. Stomata B. Cortex C. Xylem D. Mesophyll E. Meristem fern plants. moss plants. pine trees. maple trees. corn plants Stomata Cortex Xylem Mesophyll Meristem 8

Chapter 35~ Plant Structure and Growth

Chapter 35~ Plant Structure and Growth Plant Organization Plant morphology is based on plant s evolutionary history Need to draw in nutrients from the ground and the air Plant Organs Root system = roots