Download WHAT IS LIFE?

PLANT FORM AND
FUNCTION
Chapter 27
A. Plant Tissues
Gymnosperms (겉씨식물) &
Angiosperms(속씨식물) consist of 4
basic tissue types.
1. Meristems
Regions of active cell division; contain
undifferentiated cells.
• Apical meristems
• located near tips of shoots & roots
in all plants
•
allow shoots & roots to lengthen
•
give rise to:
(primary growth)
protoderm (원표피) dermal tissue
procambium(전형성층)  vascular tissue
ground meristem (기본분열조직) 
ground tissue
• Lateral meristems (측생분열조직:
cambia)
• located in older roots & shoots of
woody dicots (수목 쌍자엽) &
gymnosperms (겉씨식물)
• allow shoots & roots to increase in
diameter (secondary growth)
• Intercalary meristems(절간분열조직)
• located in bases of grass leaves
• allow rapid regrowth
2. Ground(기본) Tissue(조직)
•
Makes up(구성) the bulk of plant’s
interior; consists of 3 cell types.
Parenchyma (유조직) cells
•
•
•
relatively unspecialized
thin primary cell walls
function in cellular
respiration,
photosynthesis &
storage of metabolic
products
•
Collenchyma cells(후각조직)
• unevenly thickened
primary cell walls (can
stretch)
•
function to support
growing regions of shoots
• Sclerenchyma cells (후벽 조직)
• thick secondary cell walls
• usually dead at maturity
• function to support
non-growing regions
of plant
Sclereids
(보강세포)
Fibers
(밧줄로 사용되는 마닐라삼)
3. Dermal Tissue
Single layer of tightly packed cells
(epidermis) covering plant.
Dermal Specializations:
• Cuticle - waxy coating
produced by epidermis
of stems & leaves
Functions to protect plant
& conserve water.
•
Stomata - pores
extending through
epidermis
Regulate gas & water
exchange with environment.
•
Trichomes - epidermal outgrowths
Root hairs increase surface area for
absorption.
Leaf hairs slow air movement over
leaf, reducing water loss.
Some trichomes deter predators.
(공변세포)
4. Vascular Tissue
Specialized conducting tissue in plants;
xylem & phloem.
• Xylem
• transports water & dissolved minerals from
roots to shoots
•
•
•
consists of tracheids
(헛물관:물의이동느림) & vessel
elements (물의 이동 빠름 why:
직경크고, 직접적인 물의 흐름)
dead at maturity but do its
function
thick secondary cell walls
Tracheids - long, narrow cells. Water moves from
one cell to the next through thin areas (pits).
Vessel elements - short, barrel-shaped cells; more specialized than tracheids. Water moves
directly from one cell to the next because the end walls usually disintegrate. Water moves
faster through vessel elements because of their larger diameter & direct water movement.
• Phloem
• transports organic compounds
throughout plant
•
•
•
•
consists of sieve
cells (체세포) or
sieve tube
members
(체관요소) &
companion cells
(동반세포)
alive at maturity
(체판)
B. Plant Anatomy
Basic parts of a flowering plant include
stems, leaves, roots, flowers & fruits.
1. Stems - central axes of shoots
Function to:
• support plant
• transport nutrients/water
• produce/store nutrients
Consist of nodes, internodes &
axillary buds.
Vascular bundle: scattered throughout ground tissue
each vascular bundle somewhat resembles a “monkey” face”
Modified Stems:
stolons
fleshy stems
thorns
tubers
tendrils
rhizomes
2. Leaves - primary photosynthetic
organs of most plants.
Most consist of:
• flattened blade
• stalk-like petiole
• central midrib
• numerous veins
Leaves are shed from an
abscission zone (탈리층)
at base of petiole.
Leaves are classified based on form &
type of venation.
Leaf Forms
 simpleleaflets all attach to one point
at the top of the petiole
 palmate
compound
Leaf Venation
 netted(호박)
parallel
 pinnate
compound
leaflets are paired
along a central line
surrounds outer portion of leaf. It typically
secretes a cuticle & contains numerous stomata
epidermal layers
Vein
xylem
phloem
epidermal layers
Modified Leaves:
•
Cotyledons
•
Tendrils
Spines (Cacti)
Bracts (Poinsettia “flower”)
Storage leaves(Onion bulbs)
•
Insect-trapping leaves
•
•
•
3. Roots
underground part of a plant
Function to:
• anchor plant
• absorb, transport, & store water
and minerals
• absorb oxygen
Two main types:
• taproots
•
fibrous roots
Cortex (피층)
Pericycle(내초)
(원 표피)
(뿌리골무)
Monocot root
Dicot root
(stele)
Enlargement of
dicot stele(관다발)
Modified Roots:
•
•
•
•
Storage roots
Pneumatophores
(통기근)
Aerial roots(기근)
•
•
Buttress roots
Prop roots
(부정근)
C. Secondary Plant Growth (growth
in diameter)
Lateral meristems (vascular & cork
cambia) increase diameter of stems
& roots in woody dicots &
gymnosperms.
1. Vascular Cambium
Ring of meristematic tissue that
produces secondary xylem & phloem.
Woody stem
secondary growth
2. Cork Cambium
Ring of meristematic tissue that
produces phelloderm & cork.
• phelloderm - parenchyma cells; alive
at maturity
• cork - waxy, densely packed cells;
insulates, waterproofs, & protects
underlying tissues; dead at maturity
Periderm(주피) = cork + cork cambium +
phelloderm(코르크피층)
Woody stem
secondary growth
periderm
Bark = periderm + phloem
Woody stem
secondary growth