Download presentation
Presentation is loading. Please wait.
1
Plant Structure, Growth, and Development
Chapter 35 Plant Structure, Growth, and Development
2
The Three Basic Plant Organs: Roots, Stems, and Leaves
Three basic organs evolved: roots, stems, and leaves They are organized into a root system and a shoot system © 2011 Pearson Education, Inc.
3
Reproductive shoot (flower)
Figure 35.2 Reproductive shoot (flower) Apical bud Node Internode Apical bud Shoot system Vegetative shoot Axillary bud Blade Leaf Petiole Stem Figure 35.2 An overview of a flowering plant. Taproot Root system Lateral (branch) roots
4
Roots A root is an organ with important functions:
Anchoring the plant Absorbing minerals and water Storing carbohydrates Roots rely on sugar produced by photosynthesis in the shoot system, and shoots rely on water and minerals absorbed by the root system © 2011 Pearson Education, Inc.
5
Most eudicots and gymnosperms have a taproot system:
A taproot, the main vertical root Lateral roots, or branch roots, that arise from the taproot Most monocots have a fibrous root system, which consists of: Adventitious roots that arise from stems or leaves Lateral roots that arise from the adventitious roots © 2011 Pearson Education, Inc.
7
Absorption of water and minerals occurs near the root hairs, where vast numbers of tiny root hairs increase the surface area © 2011 Pearson Education, Inc.
8
Many plants have root adaptations with specialized functions
Figure 35.4 Many plants have root adaptations with specialized functions “Strangling” aerial roots Storage roots Prop roots Buttress roots Figure 35.4 Evolutionary adaptations of roots. Pneumatophores
9
Stems A stem is an organ consisting of
An alternating system of nodes, the points at which leaves are attached Internodes, the stem segments between nodes © 2011 Pearson Education, Inc.
10
Apical dominance helps to maintain dormancy in most axillary buds
An axillary bud is a structure that has the potential to form a lateral shoot, or branch An apical bud, or terminal bud, is located near the shoot tip and causes elongation of a young shoot Apical dominance helps to maintain dormancy in most axillary buds © 2011 Pearson Education, Inc.
11
Figure 35.5 Rhizomes Rhizome Many plants have modified stems (e.g., rhizomes, bulbs, stolons, tubers) Root Bulbs Storage leaves Stem Stolons Stolon Figure 35.5 Evolutionary adaptations of stems. Tubers
12
Leaves The leaf is the main photosynthetic organ of most vascular plants Leaves generally consist of a flattened blade and a stalk called the petiole, which joins the leaf to a node of the stem Blade Petiole © 2011 Pearson Education, Inc.
13
Figure 35.7 Tendrils Some plant species have evolved modified leaves that serve various functions Spines Storage leaves Reproductive leaves Figure 35.7 Evolutionary adaptations of leaves. Bracts
14
Dermal, Vascular, and Ground Tissues
Each plant organ has dermal, vascular, and ground tissues Dermal tissue Ground tissue Vascular tissue © 2011 Pearson Education, Inc.
15
In nonwoody plants, the dermal tissue system consists of the epidermis and cuticle.
The vascular tissue system carries out long-distance transport of materials between roots and shoots Xylem conveys water and dissolved minerals upward from roots into the shoots Phloem transports organic nutrients from where they are made to where they are needed © 2011 Pearson Education, Inc.
16
Tissues that are neither dermal nor vascular are the ground tissue system
Ground tissue internal to the vascular tissue is pith; ground tissue external to the vascular tissue is cortex Ground tissue includes cells specialized for storage, photosynthesis, and support © 2011 Pearson Education, Inc.
17
The major types of plant cells are:
Parenchyma Collenchyma Sclerenchyma Water-conducting cells of the xylem Sugar-conducting cells of the phloem © 2011 Pearson Education, Inc.
18
Parenchyma Cells Mature parenchyma cells
Have thin and flexible primary walls Lack secondary walls Are the least specialized Perform the most metabolic functions Retain the ability to divide and differentiate (indeterminate) Parenchyma cells in Elodea leaf, with chloroplasts (LM) © 2011 Pearson Education, Inc.
19
Collenchyma Cells Collenchyma cells help support young parts of the plant shoot These cells provide flexible support without restraining growth Collenchyma cells (in Helianthus stem) (LM) © 2011 Pearson Education, Inc.
20
Sclerenchyma Cells Sclerenchyma cells are rigid because of thick secondary walls strengthened with lignin They are dead at functional maturity Sclereid cells in pear (LM) Cell wall © 2011 Pearson Education, Inc.
21
Water-Conducting Cells of the Xylem
Vessel Tracheids 100 m The two types of water-conducting cells, tracheids and vessel elements, are dead at maturity Tracheids are found in the xylem of all vascular plants (Tracheophytes) Tracheids and vessels (colorized SEM) © 2011 Pearson Education, Inc.
22
Sugar-Conducting Cells of the Phloem
Sieve-tube elements are alive at functional maturity, though they lack organelles Sieve plates are the porous end walls that allow fluid to flow between cells along the sieve tube Each sieve-tube element has a companion cell whose nucleus and ribosomes serve both cells © 2011 Pearson Education, Inc.
23
Sieve-tube elements: longitudinal view (LM) 3 m
Figure 35.10e Sieve-tube elements: longitudinal view (LM) 3 m Sieve plate Sieve-tube element (left) and companion cell: cross section (TEM) Companion cells Sieve-tube elements Plasmodesma Figure Exploring: Examples of Differentiated Plant Cells Sieve plate 30 m Nucleus of companion cell 15 m Sieve-tube elements: longitudinal view Sieve plate with pores (LM)
24
Core of parenchyma cells
Figure 35.14 Epidermis Cortex Endodermis Vascular cylinder Pericycle Core of parenchyma cells Xylem 100 m Phloem 100 m (a) Root with xylem and phloem in the center (typical of eudicots) (b) Root with parenchyma in the center (typical of monocots) 50 m Key to labels Figure Organization of primary tissues in young roots. Endodermis Pericycle Dermal Xylem Ground Phloem Vascular
25
Root with xylem and phloem in the center (typical of eudicots)
Figure 35.14aa Epidermis Key to labels Cortex Endodermis Dermal Vascular cylinder Ground Vascular Pericycle Xylem Phloem Figure Organization of primary tissues in young roots. 100 m (a) Root with xylem and phloem in the center (typical of eudicots)
26
50 m Endodermis Pericycle Xylem Phloem Key to labels Dermal Ground
Figure 35.14ab 50 m Endodermis Pericycle Xylem Phloem Key to labels Figure Organization of primary tissues in young roots. Dermal Ground Vascular
27
Core of parenchyma cells
Figure 35.14b Epidermis Key to labels Cortex Dermal Endodermis Ground Vascular Vascular cylinder Pericycle Core of parenchyma cells Figure Organization of primary tissues in young roots. Xylem Phloem 100 m (b) Root with parenchyma in the center (typical of monocots)
28
Concept 35.2: Meristems generate cells for primary and secondary growth
A plant can grow throughout its life; this is called indeterminate growth Some plant organs cease to grow at a certain size; this is called determinate growth Which of these types do animals typically exhibit? © 2011 Pearson Education, Inc.
29
Meristems are perpetually embryonic tissue and allow for indeterminate growth
Apical meristems are located at the tips of roots and shoots and at the axillary buds of shoots Lateral meristems add thickness to woody plants, a process called secondary growth 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 © 2011 Pearson Education, Inc.
30
Primary growth in stems
Figure 35.11 Primary growth in stems Epidermis Cortex Primary phloem Shoot tip (shoot apical meristem and young leaves) Primary xylem Pith Vascular cambium Secondary growth in stems Cork cambium Lateral meristems Cork cambium Axillary bud meristem Cortex Periderm Primary phloem Figure An overview of primary and secondary growth. Pith Secondary phloem Root apical meristems Primary xylem Vascular cambium Secondary xylem
31
This year’s growth (one year old) Leaf scar
Figure 35.12 Apical bud Bud scale Axillary buds This year’s growth (one year old) Leaf scar Node Bud scar One-year-old side branch formed from axillary bud near shoot tip Internode Last year’s growth (two year old) Leaf scar Stem Figure Three years’ growth in a winter twig. Bud scar Growth of two years ago (three years old) Leaf scar
32
Concept 35.3: Primary growth lengthens roots and shoots
Primary growth produces the parts of the root and shoot systems produced by apical meristems © 2011 Pearson Education, Inc.
33
Primary Growth of Roots
Figure 35.13 Cortex Vascular cylinder Key to labels Epidermis Dermal Zone of differentiation Ground Root hair Vascular Primary Growth of Roots Zone of elongation Figure Primary growth of a root. Zone of cell division (including apical meristem) Mitotic cells 100 m Root cap
34
Figure Lateral roots arise from within the pericycle, the outermost cell layer in the vascular cylinder 100 m Epidermis Emerging lateral root Lateral root Cortex Vascular cylinder Pericycle Figure The formation of a lateral root. 1 2 3
35
Primary Growth of Shoots
A shoot apical meristem is a dome-shaped mass of dividing cells at the shoot tip Leaves develop from leaf primordia along the sides of the apical meristem Axillary buds develop from meristematic cells left at the bases of leaf primordia © 2011 Pearson Education, Inc.
36
Developing vascular strand
Figure 35.16 Shoot apical meristem Leaf primordia Young leaf Developing vascular strand Figure The shoot tip. Axillary bud meristems 0.25 mm
37
Tissue Organization of Stems
Figure 35.17 Tissue Organization of Stems Phloem Xylem Sclerenchyma (fiber cells) Ground tissue Ground tissue connecting pith to cortex Pith Epidermis Key to labels Epidermis Cortex Vascular bundles Figure Organization of primary tissues in young stems. Vascular bundle Dermal 1 mm 1 mm Ground (a) Cross section of stem with vascular bundles forming a ring (typical of eudicots) (b) Vascular Cross section of stem with scattered vascular bundles (typical of monocots)
38
Sclerenchyma (fiber cells) Phloem Xylem
Figure 35.17a Sclerenchyma (fiber cells) Phloem Xylem Ground tissue connecting pith to cortex Pith Key to labels Figure Organization of primary tissues in young stems. Epidermis Cortex Dermal Vascular bundle Ground 1 mm Vascular (a) Cross section of stem with vascular bundles forming a ring (typical of eudicots)
39
Figure 35.17b Ground tissue In most monocot stems, the vascular bundles are scattered throughout the ground tissue, rather than forming a ring Key to labels Dermal Ground Vascular Epidermis Figure Organization of primary tissues in young stems. Vascular bundles 1 mm (b) Cross section of stem with scattered vascular bundles typical of monocots)
40
Tissue Organization of Leaves
Figure 35.18 Tissue Organization of Leaves Guard cells Key to labels Stomatal pore Dermal Ground Epidermal cell 50 m Vascular Sclerenchyma fibers (b) Surface view of a spiderwort (Tradescantia) leaf (LM) Cuticle Stoma Upper epidermis Palisade mesophyll Spongy mesophyll Bundle- sheath cell Figure Leaf anatomy. Lower epidermis 100 m Xylem Vein Cuticle Phloem Guard cells Guard cells Vein Air spaces (a) Cutaway drawing of leaf tissues (c) Cross section of a lilac (Syringa) leaf (LM)
41
(a) Cutaway drawing of leaf tissues
Figure 35.18a Key to labels Sclerenchyma fibers Dermal Cuticle Stoma Ground Vascular Upper epidermis Palisade mesophyll Spongy mesophyll Bundle- sheath cell Figure Leaf anatomy. Lower epidermis Xylem Vein Cuticle Phloem Guard cells (a) Cutaway drawing of leaf tissues
42
Figure 35.19 Concept 35.4: Secondary growth increases the diameter of stems and roots in woody plants (a) Primary and secondary growth in a two-year-old woody stem Epidermis Pith Cortex Primary xylem Primary phloem Vascular cambium Epidermis Primary phloem Cortex Vascular cambium Primary xylem Growth Vascular ray Pith Primary xylem Secondary xylem Vascular cambium Secondary phloem Primary phloem First cork cambium Cork Periderm (mainly cork cambia and cork) Growth Figure Primary and secondary growth of a woody stem. Secondary phloem Bark Vascular cambium Primary phloem Secondary xylem Late wood Cork cambium Early wood Periderm Secondary phloem Cork Secondary xylem (two years of production) Vascular cambium 0.5 mm Secondary xylem Vascular cambium Bark Secondary phloem Primary xylem Most recent cork cambium Layers of periderm Vascular ray Growth ring Cork (b) Cross section of a three-year- old Tilia (linden) stem (LM) Pith 0.5 mm
43
Cross section of a three-year- old Tilia (linden) stem (LM)
Figure 35.19b Secondary phloem Bark Vascular cambium Cork cambium Late wood Secondary xylem Periderm Early wood Cork 0.5 mm Figure Primary and secondary growth of a woody stem. Vascular ray Growth ring (b) Cross section of a three-year- old Tilia (linden) stem (LM) 0.5 mm
44
After one year of growth After two years of growth
Figure 35.20 Vascular cambium Growth Vascular cambium Secondary phloem Secondary xylem Figure Secondary growth produced by the vascular cambium. After one year of growth After two years of growth
45
Tree rings are visible where late and early wood meet, and can be used to estimate a tree’s age
Dendrochronology is the analysis of tree ring growth patterns and can be used to study past climate change © 2011 Pearson Education, Inc.
46
RESULTS 2 1.5 Ring-width indexes 1 0.5 1600 1700 1800 1900 2000 Year
Figure 35.21 RESULTS 2 1.5 Ring-width indexes 1 0.5 1600 1700 1800 1900 2000 Figure Research Method: Using Dendrochronology to Study Climate Year
47
Figure 35.22 As a tree or woody shrub ages, the older layers of secondary xylem, the heartwood, no longer transport water and minerals Growth ring Vascular ray Heartwood Secondary xylem Sapwood Figure Anatomy of a tree trunk. Vascular cambium Secondary phloem Bark Layers of periderm
48
Figure 35.23 Figure Is this tree living or dead?
49
Genetic Control of Flowering
Figure 35.34 Sepals Genetic Control of Flowering Petals Stamens (a) A A schematic diagram of the ABC hypothesis B Carpels C C gene activity B C gene activity Carpel A B gene activity Petal A gene activity Stamen Sepal Active genes: B B B B B B B B A A A A A A C C C C A A C C C C C C C C A A C C C C A A A B B A A B B A Whorls: Figure The ABC hypothesis for the functioning of organ identity genes in flower development. Carpel Stamen Petal Sepal Wild type Mutant lacking A Mutant lacking B Mutant lacking C (b) Side view of flowers with organ identity mutations
50
(a) Normal Arabidopsis flower Pe
Figure 35.33 Pe Ca St Se Pe Se (a) Normal Arabidopsis flower Pe Pe Figure Organ identity genes and pattern formation in flower development. Se Abnormal Arabidopsis flower (b)
Similar presentations
