Plant Tissues

3.1.3

Meristematic Tissues

Apical

Lateral

Intercalary

Dermal Tissue

Skin

Ground Tissue

Bark

Vascular Tissue

Water + Food

Connective

Major Groups of organs

Roots

Leaves

Stems

Reproductive (flower)

Mersitems

Permanent regions of growth and active cell division

Apical Meristems

Tip of stem, branch, roots

Roots and shoots increase in length as the apical meristems produce new cells (PRIMARY growth)

Lateral Meristems

Produce secondary tissues that increase the girth and strength of roots and stems

Vascular cambium produces

Wood

Cork cambium produces

Inner bark

Intercalary Meristems

Grasses

Vicinity of notes (leaf attachment area)

Add to stem length

Dermal Tissue

Epidermis

Protective layer that is ONE cell layer thick covering all plant organs

Epidermis is comprised of ?

Parenchyma cells, guard cells of stomata, secretory glands, and hairs

Cutin

Fatty substance on the surface outer walls of epidermis that forms cuticle

Waxy layer

Prevents water loss by evaporation

Resistant to bacteria and other disease organisms

Leaves have stomata bordered by?

Pairs of guard cells

Trichomes

Epidermal outgrowths

What produces root hairs?

Root epidermal cells

Increase ______ of the root surface

absorptive area

Periderm

Secondary Tissue

Replaces epidermis when cork cambium produces new tissue

Constitutes outer bark

Cork cells

Suberin

Cytoplasm secretes

Makes cork cells waterproof and protects phloem

Dead at maturity

Lenticels

Loosely arranged pockets of parenchyma cells formed by cork cambium that protrude through the surface of periderm.

Allows for gaseous exchange

Ground Tissues?

Parenchyma

Collenchyma

Sclerenchyma

Parenchyma tissue

Composed of living parenchyma cells

Thin, pliable walls

Usually 14-sided at maturity

Large vacuoles and various secretions

Intercellular space

Aerenchyma

Parenchyma tissue with extensive connected air spaces, usually in aquatic plants

Chlorenchyma

Parenchyma cells containing chloroplasts that function in photosynthesis

Transfer cells

Develop irregular extensions of inner wall that greatly increase surface area of plasma membrane

Nectaries of flowers

Pine needles

Collenchyma Tissue

Composed of collenchyma cells

Living cytoplasm

Cell walls thick, uneven

Pliable and strong, flexible support

Sclerenchyma tissue

Sclerenchyma cells

Thick, tough, secondary walls, normally impregnated with LIGNIN

Dead at maturity and contain LUMEN (tiny cavity)

Function in support

Two Types of Sclerenchyma Tissue

Sclereids/Stone cells

Fibers

Sclereids or Stone cells

Scattered in tissue

Cells as long as wide

Fibers

Much longer than wide

Xylem Tissue

Usually dead

Chief conducting tissue for water and minerals that are absorbed by the roots

Composed of vessels, tracheids, fibers, parenchyma cells, and ray cells

vessels

Long tubes made of vessel elements

Thick secondary walls with pits

Open at both ends

Secondary walls develop irregularly

Perforation plate between end walls

Tracheids

Tapered at the ends with pairs of pits

Thick secondary cell walls

May have spiral thickenings on cells walls

Ray parenchyma

Function in lateral conduction and food storage (living type)

Long-lived parenchyma cells

Most abundant tissue?

Parenchyma

Which dead tissue is also a ground tissue?

Sclerenchyma

Lenticels replace the?

Stomata

Periderm is a _______ tissue?

Secondary

Phloem tissue

Conducts dissolved food materials produced by photosynthesis throughout plant

Composed of sieve tube elements, companion cells, fibers, parenchyma cells, and ray cells

Sieve tube elements:

Lack of secondary wall or nuclei

Lay end to end to form sieve tubes

Walls have sieve plates with small pores

Callose forms callus plug- Prevents leaking of tube contents when cell is injured

Secretory Cells and tissue

Secretory cells may function individually or as part of a tissue

Flower nectar

Citrus oils

Glandular hair mucilage

Latex

Resins