third chapter plant organs section one roots organ ones that are formed by many kinds of tissues,...
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Third Chapter Plant OrgansSection One Roots
Organ Ones that are formed by many kinds of tis
sues , having certain external shape and inside structure and plant body component of carrying out certain physiological function .(review tissue)
vegetative organ (root ,stem ,leaf) Organ reproductive organ(flower ,fruit ,seed)
Tissue The source similar to the function is the same , sh
ape structure and the cell group contacting each other closely is called the tissue.
Vegetative organ : Absorb playing , make and supply the body nutriment function of the plant , making the plant body grow , development with. Including the root , stem , leaf.
Reproductive organ :Play a role in breed the later generation and extend ethnicallying. Including the flower , fruit , seed.
absorb function transportation supportion Physiological function breeding preservation assimilation function
Medicinal value
Radix
Ginseng
Radix
Notoginseng
Radix
Astragali
Radix
Ophiopogonis
Part One Forms and Types of Roots
★Forms of Roots★ Root Types1 Main root and lateral root 2 Normal root and adventitious root
Types of Root system
tap root system and fibrous root system
4 Abnormal root storage root fleshy tap root
root tuber prop root aerial root climbing root water root parasitic root
Part Two Inner Structure of Roots Basic Structure of the Root Tip Root cap Region of Division Region of Elongation Region of Maturation
Primary Structure Epidermis
exodermis
Cortex cortex parenchyma endodermis casparian dots
passage cell
Primary Structure of Dicotyledon Radicle
1.Epidermis
2.Cortex
3.Endodermis
4.Pericycle
5.Protoxylem
6.Metaxylem
7.Primary phloem
8.Immature metaxylem
Ⅰ.solid view of endodermis cells ( show casparian strip )
Ⅱ.transverse section view of endodermis cells ( show casparian dots )1.Cortex cell 2.endodermis 3.casparian strip 4.pericycle
Vascular cylinder pericycle
primary xylem (diarch , triarch ,
tetrarch,hexarch,polyarch,etc)
primary phloem ☆Definition : Exarch: The order of differentiation and maturation of
primary xylem of root is from the outside to inside, and is known as exarch.
Secondary Structure of Roots
①Origin and Activities of the Vascular Cambium
Cambium secondary phloem
secondary xylem
Ⅰ.radicle ( dot and line show beginning place of cambium )
Ⅱ.cambium becomes consecutive tissue
Ⅲ.whole cambium make secondary structure
Ⅳ.cambium becomes a ring
1.Primary xylem 2.primary phloem 3.cambium
4. secondary xylem5.secondary phloem
The transverse section of MaDouLing
Ⅰ.( 1.phellem 2.phellogen 3.cortex 4starch grain 5.secretory cell)
Ⅱ.( 1.phloem 2.sieve tube gang 3.cambium 4.ray 5.xylem)
Ⅲ.( 1.xylem 2.ray)
②Origin and Activities of the Cork Cambium Phellogen phellem phelloderm
Periderm and lenticel1.Origination of phellogen 2.epidermis3.phellogen 4.phellem 5.phelloderm 6.c
ortex parenchyma7.supplementary cell
Anomalous Structurethe model sketch of root anomalous structure
Ⅰ.shanglu root
Ⅱ.niuxi root
Ⅲ.chuanniuxi root
Ⅳ.heshouwu root
1.Phellem
2.Cortex
3.Phloem
4.Cambium
5.xylem
Review Questions 一 .Definition Organ , primary structure , exarch , secondary stru
cture , anomalous structure 二 .simple answer 1.which is vegetative and reproductive organs re
spectively? 2.what is the function of the root? 3.How about the structure of the root tip? 4.How much parts in primary structure of the root?