Chapter 35 Plant Structure Growth and Development Power

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Chapter 35 Plant Structure, Growth, and Development Power. Point Text. Edit Art Slides for

Chapter 35 Plant Structure, Growth, and Development Power. Point Text. Edit Art Slides for Biology, Seventh Edition Neil Campbell and Jane Reece Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings

Figure 35. 1 Fanwort (Cabomba caroliniana) Copyright © 2005 Pearson Education, Inc. publishing as

Figure 35. 1 Fanwort (Cabomba caroliniana) Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings

Figure 35. 2 An overview of a flowering plant Reproductive shoot (flower) Terminal bud

Figure 35. 2 An overview of a flowering plant Reproductive shoot (flower) Terminal bud Node Internode Terminal bud Shoot system Vegetative shoot Leaf Blade Petiole Axillary bud Stem Taproot Lateral roots Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Root system

Figure 35. 3 Root hairs and root tip Copyright © 2005 Pearson Education, Inc.

Figure 35. 3 Root hairs and root tip Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings

Figure 35. 4 Modified roots (a) Prop roots (b) Storage roots (d) Buttress roots

Figure 35. 4 Modified roots (a) Prop roots (b) Storage roots (d) Buttress roots Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings (c) “Strangling” aerial roots (e) Pneumatophores

Figure 35. 5 Modified stems (a) Stolons. Shown here on a strawberry plant, stolons

Figure 35. 5 Modified stems (a) Stolons. Shown here on a strawberry plant, stolons are horizontal stems that grow along the surface. These “runners” enable a plant to reproduce asexually, as plantlets form at nodes along each runner. Storage leaves (d) Rhizomes. The edible base of this ginger plant is an example of a rhizome, a horizontal stem that grows just below the surface or emerges and grows along the surface. Stem Node Root (b) Bulbs are vertical, underground shoots consisting mostly of the enlarged bases of leaves that store food. You can see the many layers of modified leaves attached to the short stem by slicing an onion bulb lengthwise. (c) Tubers, such as these red potatoes, are enlarged ends of rhizomes specialized for storing food. The “eyes” arranged in a spiral pattern around a potato are clusters of axillary buds that mark the nodes. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Rhizome Root

Figure 35. 6 Simple versus compound leaves (a) Simple leaf. A simple leaf is

Figure 35. 6 Simple versus compound leaves (a) Simple leaf. A simple leaf is a single, undivided blade. Some simple leaves are deeply lobed, as in an oak leaf. Petiole (b) Compound leaf. In a compound leaf, the blade consists of multiple leaflets. Notice that a leaflet has no axillary bud at its base. Axillary bud Leaflet Petiole Axillary bud (c) Doubly compound leaf. In a doubly compound leaf, each leaflet is divided into smaller leaflets. Leaflet Petiole Axillary bud Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings

Figure 35. 7 Modified leaves (a) Tendrils. The tendrils by which this pea plant

Figure 35. 7 Modified leaves (a) Tendrils. The tendrils by which this pea plant clings to a support are modified leaves. After it has “lassoed” a support, a tendril forms a coil that brings the plant closer to the support. Tendrils are typically modified leaves, but some tendrils are modified stems, as in grapevines. (b) Spines. The spines of cacti, such as this prickly pear, are actually leaves, and photosynthesis is carried out mainly by the fleshy green stems. (c) Storage leaves. Most succulents, such as this ice plant, have leaves modified for storing water. (d) Bracts. Red parts of the poinsettia are often mistaken for petals but are actually modified leaves called bracts that surround a group of flowers. Such brightly colored leaves attract pollinators. (e) Reproductive leaves. The leaves of some succulents, such as Kalanchoe daigremontiana, produce adventitious plantlets, which fall off the leaf and take root in the soil. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings

Figure 35. 8 The three tissue systems Dermal tissue Ground tissue Copyright © 2005

Figure 35. 8 The three tissue systems Dermal tissue Ground tissue Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Vascular tissue

Figure 35. 9 Examples of Differentiated Plant Cells PARENCHYMA CELLS WATER-CONDUCTING CELLS OF THE

Figure 35. 9 Examples of Differentiated Plant Cells PARENCHYMA CELLS WATER-CONDUCTING CELLS OF THE XYLEM Tracheids Vessel Parenchyma cells 100 m Pits 60 m COLLENCHYMA CELLS Cortical parenchyma cells 80 m Tracheids and vessels Vessel elements with partially perforated end walls Tracheids SUGAR-CONDUCTING CELLS OF THE PHLOEM Sieve-tube members: longitudinal view Collenchyma cells SCLERENCHYMA CELLS 5 m Companion cell Sclereid cells in pear Sieve-tube member 25 m Sieve plate Nucleus Cell wall 30 m 15 m Cytoplasm Fiber cells Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Companion cell

Figure 35. 10 An overview of primary and secondary growth Primary growth in stems

Figure 35. 10 An overview of primary and secondary growth Primary growth in stems Shoot apical meristems (in buds) Epidermis Cortex In woody plants, there are lateral meristems that add secondary growth, increasing the girth of roots and stems. Primary phloem Vascular cambium Cork cambium Primary xylem Lateral meristems Pith Secondary growth in stems Apical meristems add primary growth, or growth in length. Pith Primary xylem Root apical meristems Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Secondary xylem Periderm Cork cambium The Cork cambium adds secondary dermal tissue. Cortex Primary phloem The vascular cambium adds Secondary secondary phloem xylem and Vascular cambium phloem.

Figure 35. 11 Three years’ past growth evident in a winter twig Terminal bud

Figure 35. 11 Three years’ past growth evident in a winter twig Terminal bud Bud scale Axillary buds Leaf scar This year’s growth (one year old) Node Stem Internode One-year-old side branch formed from axillary bud near shoot apex Leaf scar Last year’s growth (two years old) Scars left by terminal bud scales of previous winters Leaf scar Growth of two years ago (three years old) Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings

Figure 35. 12 Primary growth of a root Cortex Vascular cylinder Epidermis Key Root

Figure 35. 12 Primary growth of a root Cortex Vascular cylinder Epidermis Key Root hair Dermal Zone of maturation Ground Vascular Zone of elongation Apical meristem Root cap 100 m Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Zone of cell division

13. 12 Time Lapse Root Copyright © 2005 Pearson Education, Inc. publishing as Benjamin

13. 12 Time Lapse Root Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings

Figure 35. 13 Organization of primary tissues in young roots Epidermis Cortex Vascular cylinder

Figure 35. 13 Organization of primary tissues in young roots Epidermis Cortex Vascular cylinder Endodermis Pericycle Core of Parenchyma cells Xylem 100 m Phloem 100 m (a) Transverse section of a typical root. In the roots of typical gymnosperms and eudicots, as well as some monocots, the stele is a vascular cylinder consisting of a lobed core of xylem with phloem between the lobes. Endodermis Pericycle (b) Transverse section of a root with parenchyma in the center. The stele of many monocot roots is a vascular cylinder with a core of parenchyma surrounded by a ring of alternating xylem and phloem. Key Dermal Ground Vascular Xylem Phloem 50 m Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings

Figure 35. 14 The formation of a lateral root 100 m Emerging lateral root

Figure 35. 14 The formation of a lateral root 100 m Emerging lateral root Cortex 1 Vascular cylinder 2 Epidermis Lateral root 3 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings 4

Figure 35. 15 The terminal bud and primary growth of a shoot Apical meristem

Figure 35. 15 The terminal bud and primary growth of a shoot Apical meristem Leaf primordia Developing vascular strand Axillary bud meristems 0. 25 mm Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings

Figure 35. 16 Organization of primary tissues in young stems Phloem Xylem Sclerenchyma (fiber

Figure 35. 16 Organization of primary tissues in young stems Phloem Xylem Sclerenchyma (fiber cells) Ground tissue connecting pith to cortex Pith Epidermis Key Epidermis Cortex Vascular bundle 1 mm Dermal Ground Vascular (a) A eudicot stem (sunflower), with vascular bundles forming a ring. Ground tissue toward the inside is called pith, and ground tissue toward the outside is called cortex. (LM of transverse section) Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Vascular bundles 1 mm (b) A monocot stem (maize) with vascular bundles scattered throughout the ground tissue. In such an arrangement, ground tissue is not partitioned into pith and cortex. (LM of transverse section)

Figure 35. 17 Leaf anatomy Key to labels Guard cells Dermal Ground Vascular Cuticle

Figure 35. 17 Leaf anatomy Key to labels Guard cells Dermal Ground Vascular Cuticle Stomatal pore Epidermal cell Sclerenchyma fibers 50 µm (b) Surface view of a spiderwort (Tradescantia) leaf (LM) Stoma Upper epidermis Palisade mesophyll Bundlesheath cell Spongy mesophyll Lower epidermis Guard cells Cuticle Xylem Phloem Vein Guard (a) Cutaway drawing of leaf tissues cells Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Vein Air spaces Guard cells (c) Transverse section of a lilac 100 µm (Syringa) leaf (LM)

Figure 35. 18 Primary and secondary growth of a stem (layer 1) (a) Primary

Figure 35. 18 Primary and secondary growth of a stem (layer 1) (a) Primary and secondary growth in a two-year-old stem 1 Pith Primary xylem Vascular cambium Primary phloem Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Epidermis Cortex

Figure 35. 18 Primary and secondary growth of a stem (layer 2) (a) Primary

Figure 35. 18 Primary and secondary growth of a stem (layer 2) (a) Primary and secondary growth in a two-year-old stem 1 Pith Primary xylem Vascular cambium Primary phloem 3 Xylem 2 Growth ray Primary xylem Secondary xylem Vascular cambium Epidermis Cortex Phloem ray Cork 4 First cork cambium Primary phloem Secondary phloem Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings

Figure 35. 18 Primary and secondary growth of a stem (layer 3) (a) Primary

Figure 35. 18 Primary and secondary growth of a stem (layer 3) (a) Primary and secondary growth in a two-year-old stem Epidermis Cortex Primary phloem Vascular cambium Primary xylem Pith 1 Pith Primary xylem Vascular cambium Primary xylem 3 Xylem 2 Growth ray Primary xylem Secondary xylem Vascular cambium Epidermis Cortex Phloem ray Cork 4 First cork cambium Primary phloem Secondary phloem Periderm (mainly cork cambia and cork) th Grow 6 9 Bark Primary phloem 8 Layers of periderm Secondary phloem Vascular cambium Secondary xylem Primary xylem Pith Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Secondary 7 Cork xylem (two years of 5 Most recent production) Secondary phloem cork cambium Vascular cambium

Secondary phloem Vascular cambium Cork Secondary Late wood Early wood xylem Periderm (b) Transverse

Secondary phloem Vascular cambium Cork Secondary Late wood Early wood xylem Periderm (b) Transverse section of a three-yearold stem (LM) Xylem ray Bark 0. 5 mm Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings 0. 5 mm

Figure 35. 19 Cell division in the vascular cambium Vascular cambium C X C

Figure 35. 19 Cell division in the vascular cambium Vascular cambium C X C C C P (a) Types of cell division. An initial can divide transversely to form two cambial initials (C) or radially to form an initial and either a xylem (X) or phloem (P) cell. X X C X C P P C C (b) Accumulation of secondary growth. Although shown here as alternately adding xylem and phloem, a cambial initial usually produces much more xylem. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings P P

Figure 35. 20 Anatomy of a tree trunk Growth ring Vascular ray Heartwood Secondary

Figure 35. 20 Anatomy of a tree trunk Growth ring Vascular ray Heartwood Secondary xylem Sapwood Vascular cambium Secondary phloem Bark Layers of periderm Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings

Figure 35. 21 Arabidopsis thaliana Unknown (36. 6%) Cell organization and biogenesis (1. 7%)

Figure 35. 21 Arabidopsis thaliana Unknown (36. 6%) Cell organization and biogenesis (1. 7%) DNA metabolism (1. 8%) Carbohydrate metabolism (2. 4%) Signal transduction (2. 6%) Protein biosynthesis (2. 7%) Electron transport (3%) Protein modification (3. 7%) Protein metabolism (5. 7%) Transcription (6. 1%) Other metabolism (6. 6%) Other biological processes (18. 6%) Transport (8. 5%) Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings

Figure 35. 22 The plane and symmetry of cell division influence development of form

Figure 35. 22 The plane and symmetry of cell division influence development of form Division in same plane Single file of cells forms Plane of cell division Division in three planes Cube forms Nucleus (a) Cell divisions in the same plane produce a single file of cells, whereas cell divisions in three planes give rise to a cube. Asymmetrical Developing guard cells cell division Unspecialized epidermal cell Guard cell “mother cell” Unspecialized epidermal cell (b) An asymmetrical cell division precedes the development of epidermal guard cells, the cells that border stomata (see Figure 35. 17). Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings

Figure 35. 23 The preprophase band the plane of cell division Preprophase bands of

Figure 35. 23 The preprophase band the plane of cell division Preprophase bands of microtubules Nuclei Cell plates Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings 10 µm

Figure 35. 24 The orientation of plant cell expansion Cellulose microfibrils Vacuoles Nucleus 5

Figure 35. 24 The orientation of plant cell expansion Cellulose microfibrils Vacuoles Nucleus 5 µm Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings

Figure 35. 25 The fass mutant of Arabidopsis confirms the importance of cytoplasmic microtubules

Figure 35. 25 The fass mutant of Arabidopsis confirms the importance of cytoplasmic microtubules to plant growth (b) fass seedling (a) Wild-type seedling (c) Mature fass mutant Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings

Figure 35. 26 Establishment of axial polarity Copyright © 2005 Pearson Education, Inc. publishing

Figure 35. 26 Establishment of axial polarity Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings

Figure 35. 27 Overexpression of a homeotic gene in leaf formation Copyright © 2005

Figure 35. 27 Overexpression of a homeotic gene in leaf formation Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings

Figure 35. 28 Control of root hair differentiation by a homeotic gene When epidermal

Figure 35. 28 Control of root hair differentiation by a homeotic gene When epidermal cells border a single cortical cell, the homeotic gene GLABRA-2 is selectively expressed, and these cells will remain hairless. Here an epidermal cell borders two cortical cells. GLABRA-2 is not expressed, (The blue color in this light micrograph indiand the cell will develop a root hair. cates cells in which GLABRA-2 is expressed. ) Cortical cells 20 µm The ring of cells external to the epidermal layer is composed of root cap cells that will be sloughed off as the root hairs start to differentiate. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings

Figure 35. 29 Phase change in the shoot system of Acacia koa Leaves produced

Figure 35. 29 Phase change in the shoot system of Acacia koa Leaves produced by adult phase of apical meristem Leaves produced by juvenile phase of apical meristem Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings

Figure 35. 30 Organ identity genes and pattern formation in flower development Pe Ca

Figure 35. 30 Organ identity genes and pattern formation in flower development Pe Ca St Se Pe Se (a) Normal Arabidopsis flower. Arabidopsis normally has four whorls of flower parts: sepals (Se), petals (Pe), stamens (St), and carpels (Ca). (b) Abnormal Arabidopsis flower. Reseachers have identified several mutations of organ identity genes that cause abnormal flowers to develop. This flower has an extra set of petals in place of stamens and an internal flower where normal plants have carpels. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Pe Pe Se

Figure 35. 31 The ABC hypothesis for the functioning of organ identity genes in

Figure 35. 31 The ABC hypothesis for the functioning of organ identity genes in flower development Sepals Petals Stamens A B Carpels (a) A schematic diagram of the ABC hypothesis. Studies of plant mutations reveal that three classes of organ identity genes are responsible for the spatial pattern of floral parts. These genes are designated A, B, and C in this schematic diagram of a floral meristem in transverse view. These genes regulate expression of other genes responsible for development of sepals, petals, stamens, and carpels. Sepals develop from the meristematic region where only A genes are active. Petals develop where both A and B genes are expressed. Stamens arise where B and C genes are active. Carpels arise where only C genes are expressed. C C gene activity A+B B+C gene activity Active genes: Whorls: BB BB A ACCCCA A BB BB CCCC A ACCCCA A AA AA ABBA Mutant lacking B Mutant lacking C Carpel Stamen Petal Sepal Wild type (b) Side view of organ identity mutant flowers. Combining the model shown in part (a) with the rule that if A gene or C gene activity is Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings missing, the other activity spreads through all four whorls, we can explain the phenotypes of mutants lacking a functional A, B, or C organ identity gene.