Download presentation
Presentation is loading. Please wait.
1
Figure 35.10 Review of General Plant Cell Structure
2
Shoot and Root Systems Shoot system produces sugars by photosynthesis
carries out reproduction Shoot System Root system anchors the plant penetrates the soil and absorbs water and minerals stores food Root System
3
Shoot and root systems are interdependent
water & minerals sugar SHOOT SYSTEM ROOT SYSTEM
4
Plant Tissue Systems Ground tissue system Vascular tissue system
EPIDERMIS Ground tissue system Vascular tissue system Dermal tissue system VASCULAR TISSUES GROUND TISSUES SHOOT SYSTEM ROOT SYSTEM
5
Meristems – Where Tissues Originate
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
6
Apical Meristems Lengthen shoots and roots
activity at meristems Cells that form at apical meristems: new cells elongate and start to differentiate into primary tissues protoderm epidermis ground meristem ground tissues procambium primary vascular tissues
7
Lateral Meristems Increases girth of older roots and stems
Cylindrical arrays of cells vascular cambium secondary vascular tissues periderm cork cambium thickening
8
Made up of only one type of cell
Simple Tissues Made up of only one type of cell Parenchyma Collenchyma Sclerenchyma
9
Morphology of three simple tissue types
parenchyma collenchyma sclerenchyma
10
Figure 35.11 The three major categories of plant cells
11
Parenchyma: A Simple Tissue
Comprises most of a plant’s soft primary growth Cells are pliable, thin walled, many sided Cells remain alive at maturity and retain capacity to divide Mesophyll is a type of parenchyma that contains chloroplasts
12
Collenchyma: A Simple Tissue
Specialized for support for primary tissues Cells are elongated, with walls (especially corners) thickened with pectin Makes stems strong but pliable Cells are alive at maturity
13
Sclerenchyma: A Simple Tissue
Supports mature plant parts Protects many seeds Cells have thick, lignified walls and are dead at maturity Two types: Fibers: Long, tapered cells Sclereids: Stubbier cells
14
Composed of a mix of cell types
Complex Tissues Composed of a mix of cell types Xylem Phloem Epidermis
15
Xylem Conducts water and dissolved minerals
Conducting cells are dead and hollow at maturity vessel member tracheids
16
Figure 35.8 Water-conducting cells of xylem
17
Phloem: A Complex Vascular Tissue
sieve plate Transports sugars Main conducting cells are sieve-tube members Companion cells assist in the loading of sugars sieve-tube member companion cell
18
Figure 35.9 Food-conducting cells of the phloem
19
Epidermis: A Complex Plant Tissue
- Covers and protects plant surfaces - Secretes a waxy, waterproof cuticle - In plants with secondary growth, periderm replaces epidermis
20
Monocots and Dicots – same tissues, different features
1 cotyledon 2 cotyledons 4 or 5 floral parts 3 floral parts Netlike veins Parallel veins 3 pores 1 pore Vascular bundles dispersed Vascular bundles in ring
21
Shoot Development shoot apical meristem protoderm procambrium
ground meristem cortex procambrium pith primary xylem primary phloem
22
Bud = undeveloped shoot of meristematic tissue
Leaves Internode Axillary bud at node Longitudinal section of terminal bud
23
Roots also have meristems
24
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
25
Figure 35.18 Organization of primary tissues in young stems
26
Internal Structure of a Monocot Stem
The vascular bundles are distributed throughout the ground tissue No division of ground tissue into cortex and pith
27
Dicots Monocots Ground tissue system Dermal tissue system
Vascular tissue system Dicots and Monocots have different stem and root anatomies
28
Leaf Gross Structure DICOT MONOCOT petiole axillary bud blade node
sheath blade node
29
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 Arrange so they don’t shade one another
30
Leaf Structure UPPER EPIDERMIS cuticle PALISADE MESOPHYLL xylem SPONGY
phloem LOWER EPIDERMIS CO2 one stoma O2
31
Figure Leaf anatomy
32
Mesophyll: Photosynthetic Tissue
A type of parenchyma tissue Cells have chloroplasts Two layers in dicots Palisade mesophyll Spongy mesophyll
33
Collenchyma Parenchyma
34
Leaf Veins: Vascular Bundles
Xylem and phloem – often strengthened with fibers In dicots, veins are netlike In monocots, they are parallel
35
Root Systems
36
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 root apical meristem root cap
37
Figure 35.14 Primary growth of a root
38
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
39
Figure 35.15 Organization of primary tissues in young roots
40
epidermis endodermis cortex pericycle root hair phloem xylem
41
Root Hairs and Lateral Roots
Both increase the surface area of a root system Root hairs are tiny extensions of epidermal cells Lateral roots arise from the pericycle and must push through the cortex and epidermis to reach the soil new lateral root
42
Figure 35.16 The formation of lateral roots
43
Figure 35.17 The terminal bud and primary growth of a shoot
44
Secondary Growth Occurs in perennials
A ring of vascular cambium produces secondary xylem and phloem Wood is the accumulation of these secondary tissues, especially xylem
45
Secondary Growth
46
Woody Stem periderm (consists of cork, cork cambium,
and secondary cortex) secondary phloem HEARTWOOD SAPWOOD BARK vascular cambium
47
Figure 35.23 Anatomy of a tree trunk
48
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
49
Types of Wood Hardwood (oak, hickory) Softwood (pine, redwood)
Dicot wood Xylem composed of vessels, tracheids, and fibers Softwood (pine, redwood) Gymnosperm wood Xylem composed mostly of tracheids Grows more quickly
Similar presentations
