Plants as Living Organisms Plant and Soil Science

The Plant Kingdom Plants are found in biomes from the tundra to the desert. Four Major Groups of plants: mosses, ferns, gymnosperm, and angiosperm. Gymnosperm: produce plants that produce seeds on the scales of cones. Ex. Pine, spruce, fir

The Plant Kingdom Angiosperm: Flowering plants Ex. Corn, wheat, apples, petunias, oak Two Classes Monocots: send up a single cotyledon Long narrow blades, with parallel veins, flowers in multiples of three, vascular bundles are scattered Dicots: send up two cotyledons Broad leaves, netted veins, vascular bundles in a circle, flowers in fours or fives

The Plant Kingdom- Life Cycles Life Cycle: the time from when a plant begins growing until it dies Annual: germinates, grows, and reproduces in one year. Biennial: two growing seasons, first year they grow, second year they reproduce.

The Plant Kingdom- Life Cycle Perennial: life cycle of two or more years Herbaceous: soft shoots that are killed by frost. Send up new shoots in the spring Woody: trees, shrubs, and vines above ground that survive winter Hardy: how tolerant to cold a plant is

Structures- Roots Function: Absorb water and minerals from soil Anchor plant Store food

Structures- Roots Most roots found in top 2 feet of soil Primary root (radical) is the first root put out by the plant Root hairs are near the growing tip of the root and increase surface area for absorption.

Structures- Roots Root Systems Tap Root Fibrous Root Thick main root that grows straight down Can work for storage Ex. Carrots, beets, and radishes Fibrous Root Branching slender roots Less tolerant of dry conditions Hold soil in place, and prevents erosion

Structures- Roots

Structures- Roots Secondary roots: branch off the primary root Root cap: tip of root, protects root from soil as the root grows

Structures- Stems Function: Hold leaves upright Conduct water and minerals Conduct food Store food

Structures- Stems Conducting food and water Two types of conductive tissue- Xylem and Phloem Xylem Transports water from the roots up to the leaves Phloem Transports food to the roots and other parts of the plant

Structures- Stems/ Buds Buds- contain undeveloped leaves, stems, or flowers. Bud scales protect the bud. Terminal bud: large tip of the twig, the growing tip, contains the apical meristem Apical meristem is the primary growing point Lateral buds are located along the sides of the branch

Structures- Modified Stems Some stems have been modified for food storage and underground growth Bulbs, corms, rhizomes, and tubers are all examples of modified stems

Structures- Modified Stems Bulbs- tulips and onions, have scales

Structures- Modified Stems Corms- Gladiolus and crocus, fleshy and scale covered

Structures- Modified Stems Rhizomes- underground stem that produces branches, irises and lily of the valley

Structures- Modified Stems Tubers- storage organs, potatoes and caladium

Structures-Leaves Responsible for food production Photosynthesis Transpiration

Structure-Leaves Comprised of specialized cells Epidermis-protective layers Cuticle-waxy coating Stomata-pores allowing O2, CO2, and H2O exchange Guard cells-controls stomata (xylem and phloem)

Structure-Leaves Photosynthetic tissues Mesophyll- “Middle of the leave” Bulk of Photosynthesis Palisade layer Spongy layer

Structure-Leaves Simple leaves Compound Single leaf blade and petiole Broadleaf Plants- wide flat leaves Simple leaves Single leaf blade and petiole Compound Petiole, 2 or more leaves called leaflets

Structure-Leaves Deciduous Evergreen Looses leave in Fall Narrow leaf plants- needle or scale shape leaves Deciduous Looses leave in Fall Evergreen Keep leaves year round

Structures- Flowers

Structures- Flower Female- Pistil Stigma- Top sticky portion to catch the pollen Style-Tube that carries the pollen to the ovary Ovaries-Where the seed will develop

Structures- Flower Male- Stamen Anther- Holds pollen Filament- Holds the anther Pollen- Male gamete