Plant Organ Systems Lecture Notes

Vocabulary flashcards covering key terms and definitions from the lecture on plant organ systems, roots, stems, and leaves.

Shoot System

Above-ground portion of a plant that includes leaves, buds, stems, flowers, and fruits; functions in photosynthesis, reproduction, storage, transport, and hormone production.

Root System

Below-ground portion of a plant consisting of roots (and some modified stems such as tubers and rhizomes); functions in anchorage, absorption, storage, transport, and hormone production.

Root

Plant organ that typically grows below the soil surface but can be aerial or aerating; responsible for water and mineral uptake and anchorage.

Root Tip

The growing end of a root containing the meristem and protected by the root cap.

Meristem (Root)

Region of rapid mitosis at the root tip that produces new cells for root growth.

Root Cap

Sheath of cells that protects the apical meristem from abrasion as the root pushes through soil.

Region of Elongation

Zone just behind the root tip where newly formed cells lengthen, showing sensitivity to gravity (gravitropism).

Region of Differentiation

Root zone where cells mature into specialized tissues such as epidermis, cortex, and vascular tissues.

Epidermis (Root)

Single outer layer of flattened cells that protects the root and bears root hairs.

Cortex (Root)

Parenchyma tissue lying beneath the epidermis; stores food and conducts water and minerals inward.

Stele

Central cylinder of vascular tissue in a root, containing pericycle, xylem, and phloem.

Pericycle

Outer boundary of the stele that can give rise to lateral roots.

Xylem

Vascular tissue arranged in a spoke-like pattern in roots; transports water and dissolved nutrients upward in the plant.

Phloem

Vascular tissue alternating with xylem in roots; distributes products of photosynthesis from leaves to other parts.

Cambium

Lateral meristem located between xylem and phloem in older roots; produces secondary xylem inward and secondary phloem outward.

Root Hair

Extension of an epidermal cell that increases surface area for water uptake and adheres to soil particles.

Water Uptake

Process by which water enters roots through root hairs along with a film of soil moisture.

Mineral Uptake

Active transport of mineral ions into roots, sometimes against a concentration gradient, independent of water absorption.

Gravitropism

Growth response of plant organs (especially roots) toward or away from gravity; roots exhibit positive gravitropism.

Stem

One of the two main structural axes of a vascular plant, bearing nodes and internodes.

Node

Point on a stem where buds, leaves, or branches originate.

Internode

Segment of a stem between two successive nodes.

Leaf Scar

Mark left on a stem after a leaf falls off.

Terminal Bud

Apical bud at the tip of a stem responsible for primary growth in length.

Lenticel

Small spongy opening in bark that allows gas exchange between internal tissues and the atmosphere.

Flower Bud

Immature floral structure that has not yet opened into a bloom.

Growth Rings

Annual rings visible in a cross section of woody stems, indicating yearly growth.

Leaf

Vascular plant organ specialized for photosynthesis and gas exchange.

Chloroplast

Organelle in plant cells where photosynthesis occurs.

Flower

Reproductive structure of flowering plants that produces seeds; also called a bloom or blossom.

Tubers

Thickened, underground stem structures involved in food storage and vegetative reproduction (e.g., potato).

Rhizomes

Horizontal underground stems that often store nutrients and produce new shoots and roots.

Bud

Embryonic shoot with meristematic tissue that may develop into a leaf, flower, or branch.

Anchorage

Function of roots in securing the plant firmly in the soil.

Hormone Production (Plant)

Synthesis of growth regulators such as auxins and cytokinins in both shoot and root systems.