Objective 3.02 Discuss the anatomy and functions of plants.

Leaves-External Petiole-Leaf stalk or part that connects the leaf to the stem Blade-The large, flat part of the leaf Midrib-The large center vein Veins-The structural framework of the leaf Margin-The edge of the leaf Apex – Leaf Tip

Leaves-External

Leaves-Internal Upper and lower epidermis-skin of the leaf that prevents the loss of too much moisture Stomates-small openings under the leaf for breathing or transpiration Guard Cells-open and close stomates

Leaves-Internal Chloroplasts-small green particles that contain chlorophyll –gives leaves their green color –necessary for photosynthesis

Leaves-Internal

Leaves-Functions Photosynthesis –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 –release of water vapor from the leaves of plants –It also cools the plant

Photosynthesis vs. Respiration

Sessile describes leaves without a petiole –Example zinnia Bracts are modified leaves –Example poinsettia Needles and scales are modified leaves –Example pine tree Leaves-Additional Terms

Leaves-Additions Glabrous leaves or stems have a smooth non- hairy feel –Example southern magnolia Pubescent leaves or stems have a hairy feel –Example African violet

Stems-External Lenticels-breathing pores found on stems and branches Bud scale scars-show where terminal buds have been located Leaf Scars-show where leaves were attached Terminal bud-bud on the end of a stem Axillary bud- bud located at the leaf axil Lateral bud- bud on side of stem

Stems-External

Stems-Internal Xylem-tissue that transports water and nutrients up from the roots to stems and leaves Phloem-tissue that transports food down from leaves to roots

Stems-Internal

Phloem Xylem

Stems-Internal Cambium-thin, green, actively growing tissue located between bark and wood and produces all new stem cells Bark-old inactive phloem Heartwood-old inactive xylem Sapwood-new active xylem

Stems-Internal

Cambium Heartwood Sapwood Bark

Stems-Internal Monocots-plant stems have vascular bundles that contain both xylem and phloem in each bundle. Produce one seed leaf. –examples: corn, grasses Dicots-plant stems have the phloem layer and xylem layer separated by cambium. Produce two seed leaves –example: trees, many vegetable plants

Stems-Internal MonocotDicot

Stems-Internal

Stems-Functions Translocation- the movement of water and minerals through the plant Phloem moves food down from leaves to roots Xylem moves water and nutrients up from roots to leaves Stems provide support for the branches of the plant

Roots-External Root cap- located at the tip of the root and is where new cells are produced Root hairs-absorb moisture (water) and minerals Root images from a rice plant

Roots-Internal Much like stems in that they have a phloem, cambium, and xylem layer Phloem-the outer layer that carries food down the root Xylem-the inner layer that carries water and minerals up to the stem

Types of Roots Fibrous-many branched shallow roots –are easier to transplant Tap-long root with few branched ones –more difficult to transplant

Functions of Roots Anchorage Absorption Asexual reproduction (propagation) Storage

Flowers 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 Stamen-male part of the flower Pistil-female part of the flower

Flowers

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

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

Parts of the Pistil Stigma Style Ovary

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

Additional Flower and Fruit Terms Complete flower- has both male and female parts Incomplete flower- has only male or female parts

Additional Flower and Fruit Terms Fertilization – when pollen travels down the style, joining the sperm and the ovule Pollination – 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

Additional Flower and Fruit Terms Corolla – all auxiliary parts of the flower not including reproductive organs –Collective term for all petals of a flower Calyx – external, usually green or leafy part of a flower –Collective term for all sepals of a flower Receptacle – enlarged tip of stem on which a flower is borne Fruit serves as protection for seeds Function of fruit is to help with seed dispersal

REVIEW OF FUNCTIONS!

What are the functions of these plant parts?

Functions of Leaves Photosynthesis-manufactures food in green plants which is the beginning of the food chain for all living things Photosynthesis is the process by which carbon dioxide and water in the presence of light are converted to sugar and oxygen

Functions of Stems Translocation-moves water and minerals from roots up to the leaves and move food from the leaves down to the roots Supports branches, leaves, flowers, fruits and seeds

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

Functions of Flowers Produce seeds used for sexual reproduction Attract insects for pollination (Pollination is the transfer of pollen from anther to stigma.) Produce fruit to protect, nourish and carry seeds