Plant Anatomy and Plant Anatomy and PhysiologyPhysiology

1. Plant Parts a.k.a. Plant Organs1. Plant Parts a.k.a. Plant Organs2. Plant Tissues2. Plant Tissues3. Water Transport3. Water Transport4. Food Transport4. Food Transport

Plant Parts/Organs Plant Parts/Organs

RootRoot StemStem LeafLeaf ReproductiveReproductive

Root FunctionRoot Function

1. support and anchor plant 1. support and anchor plant 2. absorb water and minerals2. absorb water and minerals 3. transports water and minerals to stem3. transports water and minerals to stem

some also serve as food-storage some also serve as food-storage

Root TypesRoot Types Taproots Taproots

a long, thick main root with a long, thick main root with branching secondary rootsbranching secondary roots

in dicots in dicots e.g. dandelions, carrotse.g. dandelions, carrots

Fibrous RootFibrous Root many main roots about the many main roots about the

same size same size not as deep in the ground not as deep in the ground

but extends laterallybut extends laterally in monocots in monocots e.g. grasse.g. grass

Root StructureRoot Structure

In the center of the root is the In the center of the root is the vascular cylinder vascular cylinder (vein) (vein) – xylem and phloem. – xylem and phloem.

Roots grow from the tips where the Roots grow from the tips where the apical apical meristemmeristem is found and protected by the root is found and protected by the root cap.cap.

In the In the zone of maturationzone of maturation root hairs are found. root hairs are found. Root hairsRoot hairs increase the root’s surface area and increase the root’s surface area and is where water and minerals are absorbed.is where water and minerals are absorbed.

Cross Section of Growing RootCross Section of Growing Root

Root ModificationsRoot Modifications

Adventitious roots – prop roots of corn

Pneumatophores – mangrove swamps

Aerial roots – develop along stem as in ivy

Modified storage of beets

Epiphytes – strangler fig

Stem FunctionStem Function

1. support the leaves1. support the leaves 2. transport water and minerals from root to 2. transport water and minerals from root to

leaves leaves 3. transport sugars from leaves3. transport sugars from leaves

some may store foodsome may store food

Stem TypesStem Types Herbaceous StemsHerbaceous Stems

stems that are green, stems that are green, soft and regrown each soft and regrown each yearyear

Woody StemsWoody Stems stems contain thick, stems contain thick,

tough tissue – woodtough tissue – wood allows plants to live for allows plants to live for

more than 2 years and more than 2 years and grow taller than 1 metergrow taller than 1 meter

hard tissue called wood hard tissue called wood is dead xylemis dead xylem

Stem StructureStem Structure must have must have vascular bundles (vein) vascular bundles (vein) containing xylem containing xylem

and phloemand phloem Xylem Xylem is always closer to the centre of the stem.is always closer to the centre of the stem. PhloemPhloem is always closer to the outside of the stem. is always closer to the outside of the stem. In monocots vascular bundles are scattered throughout In monocots vascular bundles are scattered throughout

the stem.the stem. In dicots vascular bundles are arranged in rings.In dicots vascular bundles are arranged in rings.

In woody stemsIn woody stems sapwoodsapwood is younger xylem – conducts water, on outside is younger xylem – conducts water, on outside each year a new ‘ring’ of sapwood is laid down –annual each year a new ‘ring’ of sapwood is laid down –annual

ringsrings heartwoodheartwood is older/dead xylem – filled with resins giving is older/dead xylem – filled with resins giving

it a darker color; can’t conduct fluidsit a darker color; can’t conduct fluids bark is the protective layer on the outside – consists of bark is the protective layer on the outside – consists of

cork and phloemcork and phloem

Stem ModificationsStem Modifications

Leaf FunctionLeaf Function

to act as solar panels trapping sunlight to to act as solar panels trapping sunlight to convert carbon dioxide and water into convert carbon dioxide and water into glucose by the process called glucose by the process called photosynthesis – create food for the plantphotosynthesis – create food for the plant

plants now are ‘food’ for organismsplants now are ‘food’ for organisms photosynthesis also produces oxygenphotosynthesis also produces oxygen

Leaf TypesLeaf Types broad verse narrowbroad verse narrow

simple verse compoundsimple verse compound

needles of needles of gymnospermsgymnosperms

Leaf StructureLeaf Structure contain contain chlorophyll chlorophyll to photosynthesize – thus are to photosynthesize – thus are

green green designed to maximize exposure to sunlight – thus designed to maximize exposure to sunlight – thus

tend to be widetend to be wide contain special cells to protect against excessive contain special cells to protect against excessive

water loss and damage – water loss and damage – cuticle and epidermiscuticle and epidermis have special cells to allow gases (COhave special cells to allow gases (CO2, 2, OO2,2, H H22OO ) to ) to

be exchanged – be exchanged – guard cells form stomataguard cells form stomata contain contain veinsveins to transport needed water and to transport needed water and

produced glucoseproduced glucose

Cross Section of a Cross Section of a LeafLeaf

Leaf ModificationsLeaf Modifications

Tendrils – of grapevine

Spines – of cacti

Petal – of flowers

Succulents – jade plantStorage leaf – onion

Venus fly trap

Reproductive OrgansReproductive Organs

Gymnosperms – conesGymnosperms – cones

Ferns - sporesFerns - spores

Angiosperms – flowersAngiosperms – flowers