Plant Organ Systems and Functions Quiz

Plant Organ Systems and their Functions

• Roots hold the plant in the ground and take in water and nutrients for the plant's growth.
• There are two types of root systems: Tap (develops a main tap root with lateral rooting) and Fibrous (develops small roots that spread out in a mat-like growth).

Stem

• Holds up the plant parts above the ground.
• Has tiny tubes to transport water and nutrients to the plant's parts.
• Canes are stems that live only a year or two and contain a large amount of pith (soft tissue) in the center.

Vascular Tissues

• Xylem transports water, nutrients, and minerals from roots to upper portions of the plant and forms the "wood" of woody plants.
• Phloem conducts sugars from leaves to growing points, fruits, and storage areas and comprises much of the bark of woody plants.

Leaves

• Are attached to the stem by petioles.
• Consist of: Blade, Midrib, and Smaller Veins.
• Function to manufacture sugars in a process called photosynthesis.
• Petiole expands the leaf area and orients the leaf.
• Blade provides a large area for the efficient absorption of light.
• Midrib and Veins conduct water, sugar, and other compounds throughout the leaf.

Outer Structure of Leaves

• Epidermis is the outer protective layer.
• Cuticle is a waxy layer (cutin) in some plants that protects plants from dehydration and penetration by some diseases.
• Guard Cells are special epidermal cells that are capable of enlarging and contracting.
• Stomates are openings that develop between enlarged guard cells, usually on the underneath side of the leaf, and regulate the passage of water, oxygen, and carbon dioxide in and out of the leaf.

Inner Structure of Leaves

• Mesophyll is where photosynthesis occurs and is comprised of two layers: Palisade cells and Parenchyma layer.
• Palisade cells are dense upper layers of the leaf.
• Parenchyma layer is the lower spongy area with considerable air space.
• Chloroplasts are the actual site of photosynthesis and are found in the palisade cells and the parenchyma layer.

Special Leaves

• Tendrils are specialized leaves that aid in climbing.
• Bract is a leaf-like structure that serves a different purpose.
• Cotyledons are seed leaves that provide nutrients to the growing plant.

Types of Leaf Veins

• Pinnate: veins that are arranged in a feather-like pattern.
• Parallel: veins that are arranged in a parallel manner.
• Palmate: veins that are arranged in a palm-like pattern.

Leaf Arrangements

• Alternate: leaves that are arranged in an alternating pattern.
• Rosulate: leaves that are arranged in a rose-like pattern.
• Whorled: leaves that are arranged in a circular pattern.
• Opposite: leaves that are arranged in an opposite pattern.

Flowers

• Are made of petals.
• Vascular plants include all the seed-containing plants, angiosperms (flowering plants), gymnosperms, and the pteridophytes (lycophytes, horsetails, and ferns).

Non-Vascular Plants

• Characteristics: small, lack vascular tissues, lack true leaves, seeds, and flowers, and have hair-like rhizoids.
• Occupy niches in moist habitats and depend on moisture to reproduce.
• Reproduce by spores.

Diversity of Non-Vascular Plants

• Liverworts: tiny nonvascular plants with leaf-like, lobed, or ribbon-like photosynthetic tissues.
• Hornworts: minute nonvascular plants with very fine rhizoids and lack stems.
• Mosses: larger nonvascular plants with coarser, multicellular rhizoids and tiny, photosynthetic structures similar to leaves.

Vascular Plants

• Plants with seeds: Seedless plants, Angiosperms (flowering plants), Gymnosperms (non-flowering plants), Ferns, Horsetails, Club Mosses.
• Gross Anatomy of a Plant (Angiosperm = Flowering Plant): Root System, Shoot System (leaves, flowers, fruits).

Angiosperm Reproduction

• From Seed to Fruit: After fertilization, the embryo begins growing, and the result is a seed.
• The ovary will develop into a fruit, which serves to disperse the seeds the plant produces.
• Gymnosperm (non-flowering plant): Produces "naked" seeds (they are not inside a fruit) and usually has needle-like or scale-like leaves and a deep growing root system.