Plant Structures and Their Functions

Plants

• multicellular

• eukaryotic organisms

Plants belong to the kingdom?

Plantae

Plants are characterized by?

their ability to perform photosynthesis

Photosynthesis

a process by which they convert light energy into chemical energy stored in the form of carbohydrates

What are plant’s role in the earth’s ecosystems?

• providing oxygen

• source of food

• serves as a habitat for many organisms

What’s the function of the roots?

• anchors plants in the soil

• absorbs water and minerals

Structure of the roots?

• underground

• root hairs increases in the surface area for absorption

What’s the function of the stems?

• supports the overall structure of the plant

• transports water, minerals and, sugars between roots and leaves

Structure of the Stems

• herbaceous or woody

• contains vascular bundles for transport

Function of the leaves?

• site of photosynthesis

• gas exchange (through stomata)

• transpiration

transpiration

when plants take up liquid water from the soil and release water vapor into the air from their leaves

Structure of a leaf?

• Epidermis

• mesophyll cells

• veins containing xylem and phloem

Epidermis of leaf

• outermost layer of the leaf

• consist of the upper and lower epidermis

• regulation of gas exchange

adaxis (adaxial surface)

upper side of epidermis

abaxial (abaxial surface)

lower side of epidermis

Mesophyll cells in leaf

internal ground tissue located between the two epidermal cell layers of the leaf
found between the upper and lower epidermis; it aids in gas exchange and photosynthesis via chloroplasts

A single vascular bundle, no matter how large or small, always contains both?

xylem and phloem tissues

Xylem Function

consists of tracheids and vessels, which transport water and minerals to the leaves.

Xylem Structure

has lignified cells for strength (woody)

Function of a Phloem

• transports sugars throughout the plant

• transports the photosynthetic products to the other parts of the plant

Phloem Structure

consists of sieve tubes (component of the phloem in plants. They function as the vessel that transports organic food and other material across the plant.)

Parts of the leaf

Tip (Leaf apex)
Midrib
Lamina
Margin
Veins
Petiole

Tip (Leaf apex)

• the tip or protruding part of the leaf.

• can vary in shapes and sizes in different plants.

Midrib

commonly found at the back part of the leaf, which becomes the storage of the stomata

Lamina

entire flat and extended section of the leaf (blade of the leaf)

Margin of the leaf

even and smooth around the entire leaf edge

Veins

small channels or capillaries that transport water and minerals to and from the leaf of a plant

Petiole

the stalk that joins the blade (the flat part of the leaf, also called a lamina) to the node (the attachment point on a stem).

Flower’s function?

reproduction; production of seeds and fruits

Structure of a flower

• Sepals

• Petals

• Stamens (male) - anther, filament

• Carpels (female) - stigma, style, pollen tube, ovary, ovule

Parts of a Flower under Stamens?

anther
filament

Parts of a Flower under Carpel?

stigma

style

pollen tube

ovary

ovule

Stigma

part of the female reproductive system of a flower. It is found in the center of a flower and helps to collect pollen

Style

the stalk that supports the stigma and connects it to the ovary.

One major function of Style

to assist with fertilization by being the location where pollen tubes travel to deliver sperm cells to the egg

Pollen Tube

to deliver sperm cells to the female gametophyte for double fertilization

Ovary

• enlarged basal portion of the pistil, the female organ of a flower.

• The ovary contains ovules, which develop into seeds upon fertilization.

• The ovary itself will mature into a fruit, either dry or fleshy, enclosing the seeds.

The ovary contains __________, which develop into seeds upon fertilization.

ovules

Ovule

the organ that forms the seeds of flowering plants

Anther

part of the stamen where pollen is produced

Filament

a stalk-like structure that attaches to the base of the flower and supports the anther, which is the structure that produces pollen

Sepals

outer parts of the flower (often green and leaf-like) that enclose a developing bud

Petal

parts of a flower that are often conspicuously colored

Receptacle

the part of a flower stalk where the parts of the flower are attached

Stamens

male reproductive structures that produce pollen

Carpels

female reproductive structures that produce egg cells and protect a developing baby plant, or embryo

Function of the Stomata

• regulation of gas exchange (carbon dioxide in, oxygen out)

• reduces water loss in plants

Structure of a Stomata

small openings on the leaf surface; underside

Meristems Function

• type of tissue found in plants. It consists of undifferentiated cells (meristematic cells) capable of cell division

• responsible for growth and development

Meristems Structure

• Apical meristems (tips of roots and shoots)

• Lateral meristems (secondary growth)

Chloroplasts’ function?

contains chlorophyll for photosynthesis

Structure of Chlorophyll

Double membrane with thylakoid stacks and stroma

Outer membrane

contains porins and is therefore freely permeable to small molecules.

Inner membrane

is impermeable to ions and metabolites, which are therefore able to enter chloroplasts only via specific membrane transporters

Thylakoids

• an internal system of interconnected membranes, that carry out the light reactions of photosynthesis

  • They are arranged into stacked and unstacked regions called grana and stroma thylakoids, respectively, that are differentially enriched in photosystem I and II complexes.

Stroma

• the liquid material found throughout the cavity of the chloroplast

• it is where the light-independent reaction process of photosynthesis, also called the carbon cycle, takes place.

Function of Stroma

to provide volume around the different structures inside the chloroplast for protection