Chapter 10Plant Anatomy & Physiology

Michael G. Simpson

Plant Anatomy

Study of tissue and cell structure of plants.

(In zoology, anatomy is study of internal organs; histology is study of tissues/cells.)

Plant Physiology

Study of metabolic processes in plants.

Cell Theory

All of life is composed of 1 or more cells.

Cells arise only from pre-existing cells, via cell division or cell fusion.

Cells are units of metabolic processes.

Each cell contains set of hereditary information (DNA), transferred from cell to cell, coding for structural & functional features.

contains DNAstorage: pigments, acids, ergastic substances

respiration

protein synthesis & transport of materials

transport &

modification

photosynthesis

cell recognition, transport

structural support

ribosomes: site of protein synthesis

storage high energy carbs.

Ergastic Substances:not actively metabolized (storage/waste)

chromoplasts

amyloplasts (starch grains):

alpha-1,4-glucopyranoside

crystals (Ca-oxalate; silica)

druses raphides styloids prismatics

aleurone grains: protein oil bodies

cell wall

mainly cellulose: beta-1,4-glucopyranoside

lignin - secondary cell wall

primary cell wall(cellulosic)middle lamellaplasmamembraneCell #1 Cell #2

secondary cell wall(lignified)plasmodesmataprimary pit field(collection of severalplasmodesmata)pit(pits of two adjacentcells = pit-pair)

Cell #2Cell #1

function?

lateral branch

rootshoot

axillarybudshootapex

lateralbranchnodeinternode

root tip

root apicalmeristemroot caproot hairs

shoot tipshoot apicalmeristembudprimordium

lateral roots

meristem - region of actively dividing cells 1) apical (shoot & root); 2) lateral (vascular & cork cambia)

Cell differentiation:1) Cell expansion (elongation)2) Cell maturation / specialization

Plant Tissues & Cell Types

Tissue:

= group of cells with common function or structure.

Three broad tissue types:

1) Dermal - outside layer(s)

2) Vascular - conduction

3) Ground - between dermal and vascular

Simple vs. Complex Tissue:

1 versus 2 or more cell types

Ground Tissue

Parenchyma: Gen. metabol.

1) Isodiametric to elongate

2) Primary cell wall

3) Living

Collenchyma: support

1) Elongate

2) Primary cell wall thick, uneven, rich in pectins

3) Living

Ground Tissue

Sclerenchyma

1) Secondary cell wall (+ primary)

2) Dead at maturity (usually)

Fibers

Elongate, sharply tapering

Ground Tissue

Sclerenchyma

1) Secondary cell wall (+ primary)

2) Dead at maturity (usually)

Sclereids

Isodiametric to irregular

Vascular Tissue

Xylem

Water & mineral conduction

Tracheary elements + parenchyma + sclerenchyma

Phloem

Sugar conduction

Sieve members + parenchyma + sclerenchyma

- Both complex tissues

Tracheary Elements

Tracheids - Imperforate Vessels - Perforate

Angiosperms (most)

Gnetales

A few Monilophytes

Sieve Elements

Sieve cells - No sieve plates Sieve tube members - Sieve plates

Apomorphy of Angiosperms

Dermal & Secretory tissues & cells

Epidermis Glands

Laticifers Nectaries

Stomates

Dermal tissues: Trichome anatomy

Epidermis

lateral branch

rootshoot

axillarybudshootapex

lateralbranchnodeinternode

root tip

root apicalmeristemroot caproot hairs

shoot tipshoot apicalmeristembudprimordium

lateral roots

root caproot apical meristem

ROOT (l.s.)1) Protective root cap

2) Absorptive root hairs

ROOT (c.s.)3) Give rise to new roots endogenously

(from within)

Casparian StripFunction: forces fluids from outside

through plasma membrane = selective absorption

lateral branch

rootshoot

axillarybudshootapex

lateralbranchnodeinternode

root tip

root apicalmeristemroot caproot hairs

shoot tipshoot apicalmeristembudprimordium

lateral roots

SPOROPHYTICSHOOT

Stems:• Give rise to leaves exogenously• Do not have a protective “cap” of cells• Do not have root hairs (but may have trichomes)

Stelar types

eustele atactostele

Protoxylem maturation

Vascular cambium - a lateral meristem

Conifers: non-porous

Ring porous Diffuse porous

Wood Ray Anatomy

Leaf anatomy

Stomata

C3 Photosynthesis

Kranz anatomy

C4 Photosynthesis

CAM photosynthesis