3.02 Discuss the anatomy and functions of plants B. Plant Physiology 3.02 Discuss the anatomy and functions of plants

Six Major Plant Parts Roots Stems Leaves Flowers Fruit Seeds

Leaves – External Parts Petiole leaf stalk or part that connects leaf to stem. Midrib Large central vein of the leaf

Leaves – External Parts Blade the large, flat part of a leaf.

Leaves – External Parts Veins the structural framework of a leaf.

Leaves – External Parts Margin the edge of the leaf. There are several different styles (draw these) Entire Serrated Lobed Crenate margin

Leaves – External Parts Apex leaf tip apex

Leaves – Internal Parts Upper and lower epidermis skin of the leaf that prevents the loss of too much moisture.

Leaves - Internal Parts Stomates small openings under the leaf for breathing or transpiration.

Leaves – Internal Parts Guard cells opens and closes the stomata.

Leaves – Internal Parts Chloroplasts small green particles that contain chlorophyll, gives leaves their green color and are necessary for photosynthesis.

Functions of the Leaf Photosynthesis is a process by which plants capture sunlight and use it to convert carbon dioxide and water into food Respiration converts sugars and starches into energy Transpiration is the release of water vapor from the leaves of plants It also cools the plant

Leaves – Additional Notes Sessile leaves with no petiole. Sessile

Leaves – Additional Notes Bracts modified leaves usually found on a poinsettia.

Leaves – Additional Notes Needles and scales Modified leaves found on a pine tree

Leaves – Additional Notes Glabrous Leaves or stems have a smooth, non-hairy feel Southern Magnolia

Leaves – Additional Notes Pubescent Leaves or stems have a hairy feel African Violets

Stem – External Parts Lenticels breathing pores.

Stem – External Parts Bud scale scar shows where the terminal buds were located the previous year. Bud scale scar

Stem – External Parts Leaf scar shows where leaves were attached.

Stem – External Parts Terminal bud bud at the end or tip of the stem. terminal buds

Stem – External Parts Axillary bud Bud located at the axil of the leaf

Stem – External Parts Lateral bud bud on the side of the stem.

Stem – Internal Parts Xylem Phloem Cambium tissue that transports water and nutrients up from roots to stems and leaves. Phloem tissue that transports food down from the leaves to the roots. Cambium thin, green actively growing tissue located between the bark and wood and produces all new stem cells.

Monocot Stem: Vascular Bundles Stem – Internal Parts Xylem Heartwood Monocot Stem: Vascular Bundles Cambium Bark Phloem Dicot Stem: Layers

Stem – Internal Parts Bark Old inactive phloem Protection for the stem

Stem – Internal Parts Heartwood Old inactive xylem.

Stem – Internal Parts Sapwood New active xylem.

Stem Structure - Cotyledons Monocot ~ one seed leaf Plant stems that have vascular bundles that contain both xylem and phloem in each bundle. Examples: grasses, corn Dicot ~ two seed leaves plant stems have phloem layer and a xylem layer separated by cambium. Examples: trees

Vascular Bundles - Monocots Phloem Xylem Top View

Functions of the Stem Translocation is the movement of water and minerals through the plant The phloem moves food down from the leaves to the roots The xylem moves water and nutrients up from the roots to the leaves Supports the branches of the plant

Root – External Parts Root cap Root hairs Located at the tip of the root and is where new cells are produced Root hairs absorb moisture (water) and minerals.

Root – External Parts Phloem Xylem the outer layer and carries food down the root. Xylem the inner layer and carries water and minerals up to the stem.

Types of Roots Fibrous many branched shallow roots. They are easier to transplant.

Types of Roots Tap long root with few branched ones, are more difficult to transplant.

Functions of the Roots Anchor the plant and hold it upright. Absorption – take water and nutrients from the soil and conduct them to the stem. Asexual reproduction. Store food for plant use.

Flowers Flowers develop into seeds and fruits. External Parts of the Flower Sepals green parts that cover and protect flower bud before it opens. Petals are really leaves that are modified to attract insects for flower pollination, the pretty part that we call flowers.

Flowers – External Parts petal sepal

Stamen - Male Parts of the Flower Anther a sac like structure that contains pollen, the male sex cells. Filament short stalk that holds up the anther anther filament

Pistil – Female Parts of the Flower Stigma sticky part on top of style where insects leave pollen. Style holds up the stigma and connects it to the ovary. Ovary if fertilized becomes a fruit or seed coat. Ovules the eggs or female sex cells that become seeds if fertilized.

Functions of the Flower 1. Attracts insects for pollination. 2. Produces seeds for sexual propagation. 3. Produce fruit to protect, nourish and carry seeds.

Flower Complete flower Incomplete flower Fertilization Pollination has both male and female parts. Incomplete flower has only male or female parts. Fertilization When pollen travels down the style, joining the sperm and the ovule Pollination The transfer of pollen from the anther to the stigma Cross pollination transfer of pollen from the stamen to the stigma of one flower to a flower on another plant. Self pollination transfer of the pollen to the stigma of a flower on the same plant.

Flower Additional Notes Corolla all auxiliary part of the flower not including reproductive organs. The collective term for all petals of a flower. Calyx the external usually green or leafy part of a flower. The collective term for all sepals of a flower. Receptacle the enlarged tip of a stem on which a flower is born.

Flower – Additional Parts receptacle calyx

Additional Information The fruit serves as protection for the seeds The function of the fruit is to help with seed dispersal