Plant Parts and their Functions

Leaves-Internal Upper Epidermis: single layer of cells used to protect the leaf from loss of too much moisture. Guard Cells: open and close the stoma to allow the leaf to breathe and transpire (will open when the plant becomes turgid) Stoma: space or pore on the underside of the leaf that is used to exchange gases as oxygen and carbon dioxide (transpiration) Chloroplasts: green particles that contain chlorophyll and are contained in food making cells Chlorophyll: the green substance that gives many plants their green color and is necessary for photosynthesis Photosynthesis: process by which carbon dioxide and water in the presence of light are converted to sugar and oxygen. (begins the food chain process for all living things) 6CO2 + 6H20 + 672kcal(kilocalorie) = 6C6H12O6 + 6O2 or carbon dioxide + water + light energy = glucose (sugar) + oxygen Food is moved through the leaves down to the roots to be stored in the form of sugar, starch or protein. Molecular Expressions

Leaves-Internal Upper and lower epidermis-skin of the leaf that prevents the loss of too much moisture Cuticle: waxy protective coating on outer surface Stomas-small openings under the leaf for breathing or transpiration Guard Cells-open and close stomas

Leaves-Internal Air Space: CO2 & O2 Vein: Movement of Fluid Xylem: transport water up Phloem: transport glucose 4

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

Leaves-Internal

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 Leaves Transpiration – loss of water through the leaves or stems of plants Transpiration exchange gases as oxygen and carbon dioxide

Stems Movement of Materials Support of the leaves and reproductive structures Food storages Reproduction with stem cuttings or grafting

Stems-Internal (dicot)

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

Stems-Internal (Translocation) 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 Phloem Phloem Xylem

Stems-Internal Monocot : examples: corn, grasses Dicot: example: trees

Functions of Stems Translocation – move water and minerals from roots up to leaves & move food from leaves down to the roots Xylem and phloem cells help with this process.

Functions of Stems & Leaves Transpiration – plant lose water from leaves and stems through evaporation Occurs in stomas and lenticels 15

Root Functions Anchor the plant and hold it upright Absorb water and minerals from the soil and conduct them to the stem Store large quantities of plant food Propagate or reproduce some plants

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

Layers 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 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

Dioecious Male and female, imperfect flowers on same plant Examples: Squash & Pumpkin

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

Functions of Whole Plant Respiration – the process through which plant leaves, stems and roots consume oxygen and give of carbon dioxide. Plants produce much more oxygen through photosynthesis than they use through respiration.