Lecture 1 - Introduction to Plant Anatomy

Lecture # 1

INTRODUCTION TO PLANT

ANATOMY

Introduction

Definition

Plant anatomy the study of the internal structure of various parts of the plant

Applications of plant anatomy

Taxonomic application e.g. problem plants

Proper authentication of crude drug material For safety and quality to be maintained

Morphology and anatomy of drug source is published in British and English pharmacopoeias

Introduction

Applications of plant anatomy

Avoids food adulterants and contaminants

Sambong (Blumea balsamifera L)

Mango (Mangifera indica L)

FORENSIC APPLICATIONS Forensic botany refers to the use of plant materials to help solve

crimes or resolve other legal problems.

The first botanical testimony to be heard in a

North American court concerned the

analysis of the wood grain of the ladder used

in the kidnapping of Charles Lindbergh Jr.,

and led to the conviction of Bruno

Hauptmann for the crime in 1935.

Xylotomist Arthur Koehler of the United States

Forest Service undertook a meticulous examination

of the ladder and when the case finally came to trial

four years later, offered the first botanical testimony

ever to be heard and accepted in American courts.

LIVING ORGANISMS

Prokaryotes

Kingdom

Monera

Eukaryotes

Unicell/simple

multicellular

organisms

Kingdom

Protista

Multicellular

organisms

Autotroph

Kingdom

Plantae

Heterotroph

Saprophytes

Kingdom

Fungi

Ingestion of

other

organisms

Kingdom

Animalia

The five-kingdom

system prevailed in

biology for over 20

years.

LIVING ORGANISMS

During the last three decades, systematists

applying cladistic

analysis, including the

construction of

cladograms based on

molecular data, have

been identifying

problems with the five-

kingdom system.

WHAT IS A PLANT?

A multicellular, eukaryotic, photosynthetic autrotroph.

With cell walls made mostly of cellulose

Stored food in the form of starch

Chlorophyll a directly involved in the conversion of light energy to chemical energy

Chloroplasts contain chl b as accessory pigment

Embryophytes

Kingdom Plantae

Vascular Non-Vascular

Bryophyta- Mosses

Hepatophyta-Liverworts

Anthocerophyta-Hornworts

With seeds

(Phanerogams)

Without seeds

(Cryptogams)

Psilophyta

Lycophyta

Sphenophyta

Pterophyta

Naked seeds

Coniferophyta

Cycadophyta

Ginkgophyta

Gnetophyta

Covered seeds

Anthophyta

Monocots Eudicots

Kingdom Plantae

Bryophytes (Mosses and allies)

Small plants that lack true roots, stems and leaves

They lack vascular tissue

Water is necessary for the transfer of sperm prior to fertilization

Gametophyte is dominant and nutritionally independent

Kingdom Plantae


Sporophyte is permanently attached to

the gametophyte and dependent upon it

for water and minerals

Sex organs and sporangia are multicellular and have an outer layer of

sterile cells

Chlorophyll a and b and carotenoids are present in the plastids

The first true land plants, a cuticle is present

Influential in soil development by their participation in plant succession, assists

in preventing soil erosion

Kingdom Plantae


Kingdom Plantae


Bryophyta- Mosses



With seeds

(Phanerogams)

Without seeds

(Cryptogams)

Psilophyta

Lycophyta

Sphenophyta

Pterophyta

Naked seeds

Coniferophyta

Cycadophyta

Ginkgophyta

Gnetophyta

Covered seeds

Anthophyta

Monocots Eudicots

Division Psilophyta (whisk fern)


Sporophyte have scalelike leaves (enations)

No roots

Dichotomously branched

Terminal sporangia (synangium, plural synangia)


Homosporous with only one type of meiospore

Water is necessary for transfer of sperm previous to fertilization

Both sporophyte and gametophyte are nutritionally independent



sterile cells

Genera: Psilotum, Tmesipteris

Division Lycophyta (club

mosses)

Division Lycophyta (club mosses)

Sporophytes may be homosporous or

heterosporous (two kinds of meiospores)

Have roots, stems and small leaves

Single sporangia are borne on the upper surface of leaves (sporophylls) which are

arranged in the form of a cone or

strobilus

Water is necessary for fertilization to occur

The sporophyte is dominant over gametophyte

Both sporophyte and gametophyte are nutritionally independent


Sex organs and sporangia are multicellular and have an outer layer of sterile cells

Genera: Lycopodium, Selaginella


Division Sphenophyta

(Horsetails)


(Horsetails)

Sporophytes have roots, stems, and

small leaves

The leaves and branches are whorled

The stem is hollow, jointed and contains silica

Groups of sporangia are borne on stalked, umbrella-like structures, which

are grouped to form strobili

Sporophyte is the dominant phase

The gametophyte is small and both are nutritionally independent


(Horsetails)

Water is necessary for sperm transfer

Sex organs and sporangia are multicellular and have an outer

layer of sterile cells

Genus : Equisetum


(Horsetails)

Division Pterophyta (Ferns)

The dominant sporophyte usually have roots, stems and large leaves

Leaves are typically compound and uncoil as they develop (circinate

vernation)

Roots are typically adventitious from a horizontal rhizome

Most are homosporous


The gametophyte is nutritionally independent, like the larger sporophyte

Water is necessary for fertilization by swimming sperm


sterile cells


Sporangia are borne on the lower surface of leaves or sporophyll

Genera: Polypodium, Pteris, Adiantum


Kingdom Plantae


Bryophyta- Mosses



With seeds

(Phanerogams)

Without seeds

(Cryptogams)

Psilophyta

Lycophyta

Sphenophyta

Pterophyta

Naked seeds

Coniferophyta

Cycadophyta

Ginkgophyta

Gnetophyta

Covered seeds

Anthophyta

Monocots Eudicots

has fanlike leaves that turn gold before they fall off in the autumn.

Phylum Ginkgophyta

consists of only a single extant species, Ginkgo biloba.

Phylum Cycadophyta (Cycads)

superficially resemble palms. plants are heterosporous

Genus: Cycas, Zamia

Phylum Gnetophyta

Traits are intermediate between

gymnosperms and angiosperms

With vessels in xylem

The ovules are surrounded by 2 integuments

Pollen-producing structures superficially resemble stamens

Seeds naked; fruits absent

Consists of three very different genera.

Phylum Gnetophyta

Weltwitschia, from deserts in southwestern Africa, have straplike leaves.

Phylum Gnetophyta

Gnetum species are tropical trees or vines (mainly climbing lianas), the leaves very

much like dicots

Phylum Gnetophyta

Ephedra (Mormon tea), shrub of the American

deserts with whorls of small deciduous leaves)

.

Phylum Gnetophyta

Division Coniferophyta


Have roots, stems and large leaves

Leaves are usually evergreen needles or scales

Heterosporous (produce 2 kinds of meiospores)

Gametophytes are nutritionally dependent on the sporophyte

Wind pollinated; pollen tubes are formed

Genera: Pinus, Abies (Firs), Tsuga


Conifer sporophyte

All species of pines are trees

Conifer wood has no vessels

Typically with resin ducts

With sieve cells and albuminous cells in the phloem


Staminate cones

Borne in groups usually on the lower branches of trees

Two microsporangia develop on the under surface of each scale

Pollen grains are light weight and bear 2 wings that facilitate dispersal by wind


Ovulate (Seed) Cones

Develop at tips of young branches

Two ovules, each enclosing a single megasporangium, develops on the upper

surface of an ovuliferous scales

An ovule consists of : outer integument, nucellar tissue and the female gametophyte;

at one end are several archegonia



Fertilization is achieved by union of sperm with an egg; normally only one embryo

survive

The mature embryo consists of several cotyledons, radicle, epicotyl and hypocotyls

Division Anthophyta (Flowering

plants)

Dominant sporophytes have roots, stems

and leaves

Sporangia borne on stamens and carpels

Seeds develop from ovules which are enclosed by carpels

The gametophytes are very reduced and dependent upon the sporophyte

Female gametophyte retained within the sporangium

Wind or insect pollinated

Double fertilization occurs

Division Anthophyta

(Flowering plants)

Eudicots- With 2 cotyledons, flower parts in multiples of 4s or 5s, leaves

are net-veined, cambium is usually

present

Monocots- With one cotyledon, flower parts

in multiples of 3s; the leaves are parallel-

veined, a cambium is usually lacking

While most angiosperms belong to either

the monocots (65,000 species) or eudicots

(165,000 species) several other clades

branched off before these.

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Lecture 1 - Introduction to Plant Anatomy