Plant Anatomy & Physiology By: Johnny M. Jessup Agricultural Instructor/FFA Advisor
The Four Basic Parts of Plants n Leaves n Stems n Roots n Flowers
Leaves n Functions n n Make food through photosynthesis Site of gas exchange Respiration n Photosynthesis n n Store food
Tissues of the Leaf (Epidermis) n Cuticle n n Waxy substance that covers the leaves & stems Waterproof layer that keeps water in plants
Tissues of the Leaf (Epidermis) n Stomata n n Openings in the epidermis mainly located on the underside of leaves Exchange of gases
Tissues of the Leaf (Epidermis) n Guard Cells n n Two cells located on each side of stomata Open and closes stomata
Tissues of the Leaf (Mesophyll Layer) n Palisade mesophyll n n Primary site of photosynthesis Spongy mesophyll n n Contains air & chloroplasts Site of photosynthesis and gas exchange
Tissues of the Leaf n Vascular Bundles n n Called veins In spongy mesophyll Phloem moves food from leaf to the rest of the plant Xylem moves water & minerals up to leaves from roots
Tissues of the Leaf
External Parts of the Leaf n Petiole n n Blade n n Leaf stalk or part that connects the leaf to the stem. The large, flat part of a leaf. Midrib n The large center vein.
External Parts of the Leaf
Leaf Arrangements (Simple)
Leaf Arrangements (Compound)
Stems n Functions n Movement of materials Water & minerals from roots to leaves n Manufactured food from leaves to roots n n n Support leaves & reproductive structures Food storage
External Stem Structure n Lenticels n n Bud Scale Scars n n Breathing pores. Show where terminal buds have been located. Leaf Scars n Show where leaves were attached.
External Stem Structure n Terminal Bud n n Bud on the end of the stem. Axillary Lateral Bud n Bud on the side of the stem.
External Stem Structure
Internal Stem Structure n Xylem n n Phloem n n The tissue that transports water & nutrients up from roots to stems & leaves. Tissue that transports food down from leaves to roots. Cambium n Thin, green, actively growing tissue located between bark & wood and produces all new stem cells.
Internal Stem Structure n Bark n n Heartwood n n Old, inactive phloem. Old, inactive xylem. Sapwood n New, active xylem.
Internal Stem Structure (Monocots) n n Vascular bundles contain both xylem & phloem. Examples: n n Grasses Corn
Monocot Stems (Vascular Bundle)
Internal Stem Structure (Dicots) n n Plant stems have xylem & phloem separated by the cambium. Example: n Trees
Internal Stem Structure (Dicots)
Specialized Types of Stems n Corm n n n Underground Solid, fleshy, scale covered Examples n n Gladiolus Crocus
Specialized Types of Stems n Bulb n n n Layers of fleshy scales that overlap each other Underground stem Examples n n n Tulips Lilies Onions
Specialized Types of Stems n Tubers n n n Food Storage Area Short, thick underground stem Examples n n Potato Caladium
Specialized Types of Stems n Crown n Closely grouped stems or plantlets Just above or below ground Examples n n African violet Ferns
Specialized Types of Stems n Spurs n n Short stems found on woody limbs adapted for increased fruit production Examples n n Apple Pear
Specialized Types of Stems n Rhizomes n n Underground stems that produce roots on the lower surface and extend leaves and flower shoots above ground Examples n n Iris Lily of the Valley
Specialized Types of Stems n Stolons n n Stem that grows horizontally above the soil surface Examples n n Strawberries Airplane Plant
Roots n Functions n n Anchor the plant Absorb water & minerals Store food Propagate or reproduce some plants
Different Types of Roots n Tap Root n n n One main root, no nodes Continuation of the primary root Ideal for anchorage Penetration is greater for water Storage area for food
Different Types of Roots n Fibrous Root n n Many finely branched secondary roots Shallow roots cover a large area n n More efficient absorption of water & minerals Roots hold the soil to prevent erosion
Different Types of Roots n Aerial Roots n Clinging air roots n n n Short roots that grow horizontally from the stems Roots that fasten the plant to a support Absorptive air roots n Absorb moisture from the air
Different Types of Roots n Adventitious Roots n n Develop in places other than nodes Form on cuttings & rhizomes
External Parts of Roots n Root Cap n Indicates growth of new cells.
External Parts of Roots n Root Hairs n n n Tiny one celled hairlike extensions of the epidermal cells located near the tips of roots. Increase surface area. Absorb water & minerals.
Internal Parts of Roots Much like those of stems with phloem, cambium and xylem layers. n Phloem n n The outer layer. Carries food down the plant. Xylem n n The inner layer. Carries water & minerals up to the stem.
Flowers n Function n Contain the sexual organs for the plant. Produces fruit, which protects, nourishes and carries seeds. Attracts insects for pollination.
Parts of the Flower n Sepals n n n Outer covering of the flower bud. Protects the stamens and pistils when flower is in bud stage. Collectively known as the calyx.
Parts of the Flower n Petals n n Brightly colored Protects stamen & pistils. Attracts pollinating insects. Collectively called the corolla.
Parts of the Flower (Stamen) n Male reproductive part n Anther n n Produces pollen Filament n Supports the anther
Parts of the Flower (Pistil) n Female reproductive part n Ovary n n n Enlarged portion at base of pistil Produces ovules which develop into seeds Stigma n Holds the pollen grains
Parts of the Flower (Pistil) n Style n n Connects the stigma with the ovary Supports the stigma so that it can be pollinated
Parts of the Flower
Imperfect Flower n n Male or female reproductive organs, but not both. Example: n n A male flower has sepals, petals, and stamen, but no pistils. A female flower has sepals, petals, and pistils, but no stamen.
Perfect Flowers n Contains both male and female reproductive structures.
Incomplete Flowers n Missing one of the four major parts of the flower. n n Stamen Pistil Sepal Petal
Complete Flowers n Contains male and female reproductive organs along with petals and sepals.
Flowers Imperfect flowers are always incomplete but……. . n Perfect flowers are not always complete and……. . n Complete flowers are always perfect. n
Importance of Flowers Important in florist & nursery businesses. n Many plants are grown solely for their flowers. n Plants have flowers to attract insects for pollination, but people grow them for beauty & economic value. n
Important Flower Crops
Designed By: n Johnny M. Jessup, FFA Advisor n Hobbton High School