Horticulture I 3.00 Plant Anatomy Mrs. Schratwieser

Unit B Plant Physiology 3.01 Discuss biological terms used to describe plants.

A. Life Cycle of Plants 1.Annual –completes its life cycle in 1 year 2.Biennial – completes its life cycle in 2 years Usually grows the 1 st and flowers the 2 nd 3.Perennial – lives more than 2 years Some grow and bloom the first year

B. Leaf Retention of a Plant 1.Deciduous – lose their leaves during dormant season 2.Evergreen – plants retain their leaves and remain green year round

C. Moisture in Plants 1.Turgid – swollen with moisture 2.Wilted – plant is limp because it does not have enough moisture

D. Plant Growth 1.Dormant – resting or growing very little Generally a response to adverse conditions (extreme heat or cold) 2.Botany – plant part of biology

E. Season Crop Type 1.Cool season plants – relish cool temperatures Grow best in spring or fall Pansy 2.Warm season plants – relish warm temperatures Grow best in summer and early fall Zinnia, Marigold, Vinca

Plant Physiology 3.02 Discuss the anatomy and functions of plants

A. Leaves

External Parts of Leaf Petiole Midrib Blade Veins Margin Apex

Petiole (leaf stalk-connects leaf to stem)

Midrib- large center vein

Blade-large, flat part of leaf

Veins-structural framework of leaf

Margin – edge of leaf

Apex- leaf tip

Internal Parts of leaf Epidermis Stomates Guard cells Chloroplasts

Epidermis – “skin” part of leaf prevents water loss

Stomates – small openings under the leaf that allow the plant to breath or transpire

Guard Cells – regulate the opening and closing of stomates

Chloroplasts – small green particles (chlorophyll) needed for photosynthesis

Functions of Leaf Photosynthesis Respiration Transpiration

Photosynthesis- process of capturing sunlight to convert carbon dioxide and water into food 6 CO H 2 O → 6(CH 2 O) + 6 O 2

Respiration- converts sugars and starches into energy

Transpiration – release of water vapor from leaves (cools the plants)

Leaves additional Sessile Bracts Needles & Scales Glaborous Pubescent

Sessile-leaves without a petiole (Zinnia)

Bracts – modified leaves (poinsettia)

Needles & Scales – modified leaves (pine tree, cedar)

Glaborous – leaves/stems with a smooth, non hairy feel (magnolia)

Pubescent – leaves/stems with hairy feel (fuzz) (African Violet)

B. Stems

External Parts Lenticels Bud scale scars Leaf scars Terminal bud Axillary bud Lateral bud

Lenticels Breathing pores On stems and branches

Bud Scale Scars Indicates where a terminal bud has been located

Leaf Scar Indicates where a leaf was attached

Terminal Bud Bud on end of stem

Axillary bud Bud located at the axil of the leaf

Lateral Bud Buds on side of stem

Internal parts of stem Xylem Phloem Cambium Bark Heartwood Sapwood

Internal Stems 1.Xylem - Tissue transporting water and nutrients up from the roots to the stems and leaves 2.Phloem – Tissue transporting food down from leaves to the roots 3.Cambium – Thin, green, actively growing tissue between the bark and wood Produces all new stem cells 4.Bark – Old, inactive phloem 5.Heartwood – Old, inactive xylem 6.Sapwood – New, active xylem

Cotyledons 1.Monocots – plant stems with vascular bundles Each bundle contain both xylem and phloem Produce one seed leaf Many grasses and corn 2.Dicots – plant stems have a phloem and xylem layer separated by cambium Produce 2 seed leaves Trees and many vegetables

Functions of the stem 1.Translocation – movement of water and minerals through plant Phloem moves food down to roots Xylem moves water & nutrients up to leaves from roots

C. Roots

External parts (much different than stems) 1.Root cap – located at tip of root Where new cells are produced 2.Root hairs – absorb moisture (water) and minerals

Internal Parts (much like stems) Contain phloem, cambium, xylem layers 1.Phloem – outer layer of root, carries food down the root 2.Xylem- inner layer of root, carries water and minerals up to stem

Types of roots 1.Fibrous – many branched shallow roots Easy to transplant 2.Tap – long roots with few branched roots More difficult to transplant

Functions of Roots 1.Anchorage 2.Absorption 3.Asexual reproduction 4.storage

D. Flowers

External Sepals – green parts that cover and protect flower bud before it opens Petals – really modified leaves that attract insects for polination

Internal Develop into seeds & fruits Stamens – Male flower part 1.Anther: sac-like structure, contains pollen (male sex cells) 2.Filament: short stalk, holds up anther Pistil – Female flower part 1.Stigma: sticky part on top of style, where pollen is deposited 2.Style: holds up stigma, connects it to the ovary 3.Ovary: becomes fruit if fertilized 4.Ovules: eggs (female sex cells) becomes seeds if fertilized

Functions Attracts insects for pollination Produces seeds for sexual reproduction Produces fruit to nourish and protect seed

Additional Information Complete flower – contains male and female parts Incomplete flower – have only male or only female parts Fertilization – pollen travels down the style, joining sperm and ovule Pollination – transfer of pollen from anther to stigma Cross-pollination – transfer of pollen from stamen to stigma of one flower to a flower on another plant Self-pollination – transfer of pollen from stamen to stigma of a flower on the same plant

Additional Information Corolla – auxiliary parts of the flower, not including reproductive organs (collective term for all the petals of flower) Calyx – external, usually green, leafy part of the flower (collective term for all sepals of a flower) Receptacle – enlarged tip of a stem on which a flower is born Fruit – protects seed & helps with seed dispersal Juvenile stage – plant first begins to grow from a seed

Read and summarize “Why leaves Change Color”