Plant Form and Function

• Module 1A.1 covers plant form and function.

Plant Anatomy

• Plant anatomy involves an in-depth examination to identify the position, relations, structure, and function of body parts.

Plant Morphology

• Plant morphology studies the external structure of plants.
• It is the general term for the study of a plant's physical form and external structure.

The Plant Body

• The plant body consists of two main systems: the root system and the shoot system.
• The root system is typically unseen, located below ground and primarily composed of roots.
• The shoot system is visible above ground and includes stems, leaves, flowers, and fruits.

Anatomy of Root System

• The root system includes primary root, lateral roots, root hairs, root tip, and root cap.

Key Features of Root System

• An outer layer (epidermis) may have root hairs, these protrusions increase available surface area for material exchange.
• The central region, known as the stele, is surrounded by an endodermis containing a Casparian strip which controls water transport.
• The pericycle/cambium provides strength to the root and is involved in the development of lateral roots.
• The vascular bundle is located centrally to withstand stretching forces.

Anatomy of Shoot System

• The shoot system includes the shoot tip (apical bud), epidermis, lateral bud, flower, node, internode, leaf, vascular tissues, seeds, and fruits.

Key Features of Shoot System

• The epidermis covers the outer surface of the stem, offering waterproofing, protection, and control of gas exchange.
• Ground tissue, made up of cortex and pith, is found internally, assisting in the transportation and storage of materials within the stem.
• The cambium is a centrally located circular layer of undifferentiated cells responsible for the lateral growth of the stem.
• Vascular bundles are arranged in bundles near the outer edge of the stem to resist compression and bending.
• Xylem is situated on the interior side of the bundle.

Leaf Anatomy

• Leaves are usually green, flattened, lateral structures attached to a stem that function as the main organ of photosynthesis.
• Leaves anatomy includes the apex, margin, vein, blade, midrib, base, petiole and stipules.
• Leaves are where gas exchange (CO2-O2) occurs

Key Features of Leaves

• Palisade mesophyll is the site of photosynthesis, positioned on the upper surface of the leaf to face sunlight.
• Spongy mesophyll is the primary location for gas exchange, found on the lower surface of the leaf, near stomata.
• Stomata are located on the underside of the leaf to prevent obstruction, maintaining an open channel for gas exchange.
• A thick, waxy cuticle covers the top surface to prevent water absorption which would affect transpiration
• Vascular bundles, including xylem and phloem, are located centrally to allow for optimal access by all leaf cells.

Flower Anatomy

• Flowers are present in angiosperms only.
• Flowers possesses whorls of colorful petals or sepals
• Flowers bear the reproductive parts.
• Flowers anatomy includes the stamen(male parts), anther, filament, petal, sepal, stigma, style, ovary, ovule, and pedicel.

Seed Anatomy

• Seeds are mature ovules of flowering plants; they serve as the embryo, from which young plants are produced.
• Seed anatomy includes the hilum, micropyle, cotyledon, endosperm, radicle, hypocotyl, epicotyl(plumule), and seed coat.

Fruit Anatomy

• Fruits are the seed-bearing structure which are formed from the ovary.
• Fruit antomy includes the pericarp, exocarp, mesocarp, endocarp, and seed.