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Parts of the plant and their functions. Importance of plants. Without plants life on earth would not exist. Plants:. Primary source of food for people and animals Produce oxygen help to keep us cool renew the air. Plants:. slow wind speed provide a home for wildlife
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Importance of plants • Without plants life on earth would not exist
Plants: • Primary source of food for people and animals • Produce oxygen • help to keep us cool • renew the air
Plants: • slow wind speed • provide a home for wildlife • beautify surroundings • perfume the air • furnish building materials and fuel
Parts of a plant • *Four basic parts • *leaves • *stems • *roots • *flowers
Leaves • the food factory of the plant • *produce the food used by the plant or stored for later use
Shape and size of leaves • vary among plants • used for identification of plants
Leaf arrangement • *alternate • *opposite • *whorled • arranged in a circle around the stem
External leaf structure • *petiole - leaf stalk • *leaf blade (leaf) • has veins • forms structural framework of the leaf
Midrib • *large center vein from which all other leaf veins extend
Margins • *edges of leaves • assists in plant identification
Internal leaf structure • *epidermis • skin of the leaf • single layer of cells • protects leaf from loss of too much moisture
Guard Cells • open and close the small pore on the underside of the leaf
Stomates • *allow the plant to breathe and transpire • *give off moisture
Chloroplasts • *contain chlorophyll • *located inside the cells
Photosynthesis • process by which CO2 and H2O in the presence of light are converted to sugar and oxygen
Chemical formula • 6CO2 + 6H2O • -----> in reaction with sunlight and chlorophyll ------> • C6H12O6 (glucose) + 6O2
food • *manufactured in the leaves moves downward through the stem to the roots • used by the plant • stored in stem or root and leaf in the form of sugar, starch or protein.
Respiration • *plants respire 24 hours a day • consume O2 and give off CO2 • plants produce more O2 through ps. Than they consume during respiration and growth.
Stems • *have two main functions • *movement of water and minerals from the roots upward and movement of manufactured food down
Stem functions • *support of leaves and reproductive structures
Stems also • *used for food storage and reproduction of plants involving cuttings • *Green stems manufacture food just as leaves do
Internal Stem Structure • *phloem- bark, carries manufactured foods down. • *Xylem- wood, carries water and minerals up. • *Cambium- separates the 2 and produces all new cells. • *Characteristic of dicots
Internal Stem Structure • *dicot- dicotyledon, a plant with 2 seed leaves
Monocot • *Monocotyledon - a plant with one seed leaf. • *Have vascular bundles, contain both xylem and phloem in each small bundle
Monocot • stems have no cambium • cells enlarge to create size of mature stem
Economic Importance • food • building materials
Roots • *Usually underground • *functions: • *anchor plant and hold upright • *absorb water and minerals form soil and conduct to stem • *store food, & propagation
Root Structure • internal • similar to stems • older roots have xylem, phloem and cambian
external • root cap • produces continuous supply of new cells • protects roots as they push through soil
Structure • *root hairs • *absorb moisture and minerals • *small roots
Functions other than water and mineral absorption • *cash crops for food • carrots • beets • radishes • sweet potatoes • propagation
Type of root systems • *fibrous- grasses • *easier transplanting • *shorter, smaller, more compact • tap root- carrot • *longer and fewer roots
Flowers, Fruits, and Seeds • pollination- color of flower attracts insects to fertilize flower • beginning of fruit and seed formation • fruits and seed are attractive to birds who eat and spread seeds. • Reproduces plant • some seeds carried on animals coats
Parts of the Flower • differ in size, shape, and color, some basic parts • sepal • green leaf-like part, covers and protects bud before opening
Petals • are actually leaves • usually bright colors to attract pollinating insects.
Parts of the Flower • stamens • male part of flower • has two parts • filament-stalk
Anther • anther- sac-like structure on top of filament, contains pollen
Parts of the Flower • Pistil - female part • in the center of flower • has three parts
Pistil • three parts • stigma - top - sticky • style - tube leading from stigma to ovary
Ovary • egg cells develop here • grows to become fruit or seedcoat
Types of Flowers • complete • contains 4 main parts
Incomplete • does not have all 4 main parts
Perfect • has stamens and pistils
Imperfect • lacks stamens or pistils
Types of Flowers • monoecious • stamens and pistils are found in separate flowers on the same plant • ex: Corn
dioecious • male or staminate flowers found on one plant, female or pistilate flowers on another plant • ex: holly