Biol 200 Unit 1

3 basic plant organs

Roots, stems, and leaves

Roots

collect/ store nutrients (water & minerals), and provide structural support

Stems

transport water and nutrients up, sugars and nutrients down, structural support

Leaves

synthesizing sugars, cellular respiration

Modded Roots

Prop

Storage

Pneumatophores

Prop Roots

Stabilize, better anchoring, aerial roots

Storage Roots

Stored energy that would be used for flowering, but we eat before it can

Pneumatophores

Enable roots to obtain oxygen, “air roots”

Reproductive shoot

Flowers

Apical bud

where vertical growth of the stem occurs

Node

intersection of anything growing out

Internode

sections in between extensions coming off of the stem

vegetative shoot

outgrowth of plant that supports many leaves

axillary bud

growth to fill in extra capacity (leaves prevent plant from becoming top heavy)

petiole

supports a single leaf

blade

the leaf

stem

provides structure, contains minerals and water for transportation between roots and shoots

Apical bud functions

growth of shoot allows for vertical growth, on top of stem

Axillary bud functions

can grow into branches or flowers, at the base of leaves

Modified Stems

Rhizomes

Tuber

Stolons

Rhizomes

Horizontal shoot below surface

Tuber

Enlarged ends of rhizomes, specialized food storage

Stolons

Horizontal shoot on surface. maximize photosynthesis opportunity

3 different leaf shapes

Simple

Pinnate compound

Palmate compound

Simple

single blade (can be lobed)

Pinnate compound

blade consists of multiple leaflets

Palmate compound

leaflets arise from common point

Modified leaf

Tendrils

Spines

Storage leaves

Tendrils

Clings for support, vertical growth for sunlight

Spines

Protection

Storage leaves

Storage of food Short underground stem and modified leaves store food underground

Phyllotaxy

The arrangement of leaves on a stem

Alternate

Opposite

Whorled

Alternate

staggered, maximizes exposure to sunlight

Opposite

opposite of each other

Whorled

take advantage of heavy resources, sunlight may be limited

3 tissue systems

Dermal

Vascular

Ground

Dermal

outer protective covering.

First line of defense against physical damage/pathogens.

Barrier between inside and outside of the plant.

Vascular

xylem and phloem (nutrient and water transport)

Ground

everything else (photosynthesis

5 structures of the dermal system

Epidermis

Cuticle

Root hairs

Trichomes

Periderm

Epidermis

outer layer of tightly packed cells

Cuticle

waxy layer reducing water loss

Root hairs

extensions of epidermal cells

Trichomes

hair-like extensions of shoot epidermis (can deter insects (defense) and prevent/reduce water loss)

Periderm

replaces epidermis in woody plants

General function of the vascular system

Transporting materials between roots and shoots (water/ sugar/ nutrients)

2 basic components of the vascular system

Xylem

Phloem

Xylem

moves water and minerals from roots to shoot

Phloem

moves sugars from site of synthesis/storage to where sugars are needed (fruits or roots) (both directions)

What is the ground system?

Everything else; storage, photosynthesis, support

difference between the primary and secondary cell wall

Primary cell wall: relatively thin and flexible, all cells have this

Secondary cell wall: strong, between cells plasma membrane and primary cell wall, only some cells have this

Cell types

Parenchyma

Collenchyma

Sclerenchyma

Parenchyma

Primary Wall - Yes

Secondary Wall - No

Structure - Thin, flexible

Function - Metabolic functions like storage and photosynthesis (synthesize/store products)

Collenchyma

Primary Wall - Yes

Secondary Wall -No

Structure - Thicker primary cell wall than parenchyma, grouped in strands

Function - Provides flexible support

Sclerenchyma

Primary Wall - Yes

Secondary Wall - Yes

Structure - Thick 2˚ wall. Dead at maturity

Function - Rigid support

Indeterminate growth

throughout life, doesn’t stop, plants have indeterminate growth

Determinate growth

organisms stop growing when they reach a critical size (humans, associated with sexual maturity)

3 different plant life cycles

Annuals

Biennials

Perennials

Annuals

complete life-cycle in under a year

Biennials

complete life cycle in 2 growing seasons

Perennials

live many years

Meristems

Perpetually dividing, unspecialized tissues, found in areas of growth (root/shoot tips)

Primary growth

growth in length. Roots through soil, shoots towards light. Apical meristems at shoot/root tips

Secondary growth

Not all plants, only woody plants. Growth in width and thickness

3 zones in a longitudinal section of a root tip

Zone of cell division

Zone of elongation

Zone of cell differentiation

Zone of cell division

cell division occurs here → apical meristem located here

Zone of elongation

cells are 10x original size

Zone of cell differentiation

cells become distinct types, contain root hairs

What is the function of the root cap

protects apical meristem, produces mucus making it easier for the root to slide into the soil

Monocots

1 cotyledon

leaf veins are parallel

fibrous root system

Dicots

2 cotyledons

leaf veins in net-like pattern

tap root system

Monocot root

Vascular tissue arrangement - Cylinder

Xylem/phloem arrangement - Xylem forms an O, phloem all around w/i stele

Core of parenchyma cells/Pith - Yes

Dicot root

Vascular tissue arrangement - Cylinder

Xylem/phloem arrangement - Xylem forms X, phloem around it in stele

Core of parenchyma cells/Pith - No

Monocot stem

Vascular tissue arrangement - Bundles

Xylem/phloem arrangement - Bundled together scattered throughout

Core of parenchyma cells/Pith - No

Dicot stem

Vascular tissue arrangement - Bundles

Xylem/phloem arrangement - Bundled together around outside border

Core of parenchyma cells/Pith - Yes

dicot

A-epidermis

B-cortex

C-endodermis

D-xylem

E-phloem

monocot

A-epidermis

B-cortex

C-endodermis

D-vascular cylinder

E-xylem

F-phloem

dicot

A-ground tissue

B-vascular bundle

C-xylem

D-phloem

E-pith

monocot

A-ground tissue

B-epidermis

C-vascular bundle

Apical dominance

inhibition of axillary buds by apical bud

Is an evolutionary adaptation that focuses plant’s energy on elongation to increase light exposure

Pruning

removal of apical buds, allows for growth out

If apical bud is removed, the axillary bud develops into a branch that takes over growing towards light

Label: palisade mesophyll, spongy mesophyll, guard cells, stoma, vein, cuticle, upper/lower epidermis, xylem, phloem, sclerenchyma fibers.

Top going around clockwise

Cuticle

Sclerenchyma fibers

Guard cell

Upper epidermis

Palisade mesophyll

Spongy mesophyll

Lower epidermis

Vein

Stoma

Xylem

Phloem

Bundle sheath

Mesophyll

specialized for photosynthesis

Cuticle

waxy outer layer reducing water loss

Stoma

openings/pores on the surface of leaves that allow for transfer of gasses (oxygen, carbon dioxide) and water

Spongy mesophyll

Allows gasses to circulate cells

Allows for gas exchange in diffusion (CO2 in, O2 out).

Contains chloroplasts for photosynthesis

Vascular cambium

adds secondary xylem and secondary phloem (located between xylem and phloem)

Cork cambium

creates thick, rough covering (develops from cortex), produces cork cells

What do cork cells do?

replaces the epidermis with the periderm

cork cells are filled with a hard wax that protects the tree

Periderm

mainly cork cambium and cork cells

Bark

everything outside vascular cambium (periderm + phloem)

Heartwood

The oldest part of the tree is the middle of the tree

made up of secondary xylem

Sapwood

secondary xylem that does still conduct water/minerals.

order from the most central to the outermost layer

Heartwood

Sapwood

Vascular cambium

Secondary phloem

Layers of periderm

Passive transport

diffusion across a membrane, no metabolic energy, moving down its concentration gradient

Active transport

pumping a solute across a membrane against its concentration gradient (ATP)

Transport proteins

embedded in membrane, help substances pass through membrane

Osmosis

diffusion of water across a membrane (moves lower to higher solute concentration - water chases solutes)

Aquaporins

Transport proteins that facilitate water transport across the plasma membrane of plant cells.

Channels open/close, affecting rate water moves osmotically across membranes.

3 cell-to-cell transport routes

Apoplastic route

Symplastic route

Transmembrane route