Plant Parts and Functions Biology I Curriculum Update

4 types of Plant tissue Meristematic Ground Dermal Vascular

Meristematic tissue Function-division of new cells for new growth or repair Location-Tips of shoots Tips of roots In buds In a ring around the stem in woody plants

Meristematic Tissue Plants undergo two types of growth, primary and/or secondary growth. In primary growth, plant stems and roots elongate by cell enlargement as opposed to new cell production. Primary growth occurs in areas called apical meristems. This type of growth allows plants to increase in length and to extend roots deeper into the soil. All plants undergo primary growth.

Primary growth

Secondary Growth Plants that undergo secondary growth, such as trees, have lateral meristems that produce new cells. These new cells increase the thickness of stems and roots. Lateral meristems consist of the vascular cambium and the cork cambium. It is the vascular cambium that is responsible for producing xylem and phloem cells. The cork cambium is formed in mature plants and yields bark.

Secondary growth

Meristematic Tissue

Ground tissue Makes up bulk of the plant mass, it’s made up of cells that fill the space between the epidermis & vascular bundles Function-structural support of the plant & the site of metabolic-life functions like photosynthesis & cellular respiration Location- roots, stems, & leaves

Ground tissue

Dermal Tissue Skin of the plant, protects the plant & prevents water loss-epidermis Located-roots, stem & leaves Site of transpiration Stomata (pl.), Stoma (sing.): Small openings scattered throughout the epidermis. Stomata are important for gas exchange and transpiration. Each stoma is surrounded by two guard cells which contain chloroplasts. The guard cells control the size of the stomatal opening, and thus control the amount of gas exchange and transpiration. Stomata & guard cells are located within the dermal tissue.

Dermal tissue (Guard cells)

Stoma

Transpiration

Bark (Dermal tissue) The periderm, also called bark, replaces the epidermis in plants that undergo secondary growth. The periderm is multilayered as opposed to the single layered epidermis. It consists of (cork cambium) & cork cells. Cork cells are nonliving cells that cover the outside of stems and roots to protect and provide insulation for the plant. The periderm protects the plant from pathogens, injury, prevents excessive water loss, and insulates the plant.

Vascular Tissue The vascular tissue system is important in transport. The vascular tissue system is composed of the xylem (transport of water and dissolved minerals) and phloem (transport of food - usually sucrose and other sugars-, nitrogen containing compounds, and hormones). The xylem and phloem in the primary plant body are usually closely associated in the form of vascular bundles. In woody plants the xylem forms the wood of trunks and branches as well as the central core of the roots. The bark of a tree is a mixture of old, nonfunctional phloem and the young functional phloem (periderm).

Vascular tissue

Parts of The Plant Roots Leaves Stem Flower Fruit

Roots 2 Types of Root Systems –Taproot –Fibrous System

Roots Taproot System Primary roots grow down from the stem with some secondary roots forming

Roots Fibrous Root System Small lateral roots that spread out just below the soil surface

Can you identify these root types?

Root Functions Absorption of water and nutrients –performed by root hairs Transportation of water and nutrients to stem Anchor plant to maintain stability Store food and water Roots have 4 primary functions

Parts of the Root Epidermis –Outermost layer of cells, like the skin of the root (dermal tissue) Cortex –Tissue inside epidermis that stores starch and other substances for the growth of the root (ground tissue)

Parts of the Root Root Cap –Provides protection for the root tip Root Hairs –Site of absorption (increases surface area) Vascular Tissue –Within cortex, contains cells that transport water, nutrients, and minerals to all parts of the plant

Important Functions of Leaves Photosynthesis –Process that plants use to produce their food –6CO 2 + 6H 2 O  C 6 H 12 O 6 + 6O 2 Transpiration –Loss of water and exchange of carbon dioxide

Leaf Parts Blade –Main body of leaf Petiole –Attaches blade to stem Midrib –Large central vein

Stems

Functions of the Stem Transport water and nutrients from roots to leaves Supports leaves, fruit, and flowers Food storage

Flower Function Flowers are pollinated by: –Wind –Insects –Birds Sexual Reproduction!!!!

Flower Parts Pistil –Female part of plant –Containing: Stigma Style Ovary

Flower Parts Stamen –Male reproductive part –Contains Anther Filament

Flower Parts Petals –Highly colored part of the flower, may contain perfume and/or nectar glands Sepals –Small green structures on the base of a flower that protect the flower bud

A fruit is the mature ovary of a seed plant, usually developed from a flower. Fruits have seeds so they further the reproductive cycle.

Fruit Formation

Examples of Common Seeds

Parts of the Seed Embryo –Growing part of seed containing: Plumule – “Shoot” Hypocotyl – Stem Radical – “Root” Endosperm –Tissue that provides nutrition for the developing seed Cotyledon –Food Storage Seed Coat –Protective outer covering of the seed

Parts of the Seed

Fruit

Cones Trees that grow cones are in a group called conifers. The cones of the conifers are very important because they are the place where the tree makes and shelters its seeds. Cones are made up of many scales. Scales are a kind of shelter for the seed. When it's time, the scales of the cone open and the seeds fall to the ground. Because the seeds sit on the scales and are not totally protected, conifer trees can also be grouped as gymnosperms. The word gymnosperm means naked seed.

Pine Cone Seeds 400 × educazionete cnica.dantect.it

200 × sites.google.com

Cones