Plant StructuresPlant Science

Major Plant Parts

• roots

• stems

• leaves

• buds

• flowers

2www.OneLessThing.net

Functions of Roots

• anchor the plant

• absorb water and minerals

• store manufactured food

3www.OneLessThing.net

Parts of the Root

• primary root: the single main root

• secondary roots: small branches that form off the main root

• root hairs: tiny roots that increase the absorption surface area

• root cap: protects the growing tip of roots

4www.OneLessThing.net

Root System Types1. adventitous roots: grow from the

stem or leaf of a plant (ex. corn stalks have prop roots)

2. tap root system: root system with one thick main root (examples: pine trees, carrots, dandilions)

3. fibrous root system: root system with many small main roots (examples: grasses, soybeans, impatiens)

5www.OneLessThing.net

Functions of Stems

• support the leaves, flowers, and fruit

• conduct water, minerals, and food

• store food and water

• produce new stem tissues

6www.OneLessThing.net

Parts of the Stem

• 2 types of conductive tissues

– xylem: transports water and minerals from the roots

– phloem: transports food from the leaves

• cambium: the layer of dividing cells that creates the xylem and phloem

– becomes growth rings in trees

7www.OneLessThing.net

Vascular Bundles

• made up of the xylem and pholem • in monocots, they are

scattered• in dicots, they are in a circle

(or a ring)

8www.OneLessThing.net

Buds

• contain undeveloped plant structures

• bud scales: protect and cover the bud

• terminal bud: a large bud at the tip of a stem

• lateral buds: grow along the side of stems

• apical meristem: primary growing point of the stem

9www.OneLessThing.net

Leaves• produce food for the plant through photosyntheis

• epidermis: a protective layer of cells on the leaf

• cuticle: a waxy coating that prevents water loss

• stomata: pore-like openings on the underside of the leaf that allow gas exchange

• guard cells: control the opening and closing of the stomata

• veins: carry nutrients and products of photosynthesis (contain the xylem and phloem)

10www.OneLessThing.net

Mesophyll

• layer of the leaf where photosynthesis takes place

• made up of two layers:

– palisade layer

– spongy layer

11www.OneLessThing.net

Function of Flowers

• reproduction (to produce seeds)

• sepals: protect the unopened flower

• calyx: the collection of sepals

• petals: attract pollinators (insects and birds)

12www.OneLessThing.net

Male Part of the Flower

• as a whole, known as the stamen

• made up of two structures:

1. filament: supports the anther

2. anther: produces pollen

• pollen: contains the male sex cells

• pollination has to occur for seeds to develop

13www.OneLessThing.net

Female Part of the Flower• as a whole, known as the pistil

• made up of three parts:

1. stigma: sticky surface for pollen to land on

2. style: supports the stigma

3. ovary: contains the female sex cells

• fruit: contains the seeds; develops from the ovary

14www.OneLessThing.net

Types of Flowers

• complete flowers: have sepals, petals, stamen, and pistil

• incomplete flowers: are lacking one of the four main parts

15www.OneLessThing.net

Monoecious vs. Dioecious

• monoecious plants: have male and female flowers on the same plant

• dioecious plants: have male and female flowers on separate plants

• imperfect flowers: do not have male and female parts on the same flower

16www.OneLessThing.net

www.OneLessThing.netwww.OneLessThing.net

Thank you for learning with us!