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Roots, Stems, and Leaves. Roots, Stems, and Leaves. Three of the principal organs of seed plants are roots, stems, and leaves. Together these plant organs function in: Transport Protection Coordination of plant activities. Plant Tissue Systems.
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Roots, Stems, and Leaves Three of the principal organs of seed plants are roots, stems, and leaves. Together these plant organs function in: • Transport • Protection • Coordination of plant activities
Plant Tissue Systems Each part of a plantconsists of 3 types of tissue: • Dermal tissue • Vascular tissue • Ground tissue
Dermal Tissue • The “skin” of a plant • Contains a “waxy” layer called a cuticle • Functions to prevent water loss
Vascular Tissue • Plants “bloodstream” • Transports water and nutrients throughout the plant. • Made of Xylem and Phloem
XYLEM = 5 letters WATER = 5 letters Xylem • Water moving tissue • The xylem is part of the vascular system of a plant. Similar to veins and arteries in animals. • It also provides stability to the plant through turgor pressure. • Damage to the xylem would effect how well the plant could move water throughout its tissue and the plant may not be able to support the weight of the leaves and branches (with decreased pressure).
Phloem PH- loem : F- ood • Food transport tissue. • Transports solutions of nutrients and carbohydrates • Damage to the phloem can decrease or stop the flow of nutrients throughout the plant and cause all or part of the plant to die.
Nutrient Transport through Phloem • Using the Phloem, many plants pump sugars out of the leaves and roots and into their fruit.
Ground Tissue • Cells that lie between dermal and vascular tissue • Made of cells whose cell walls have different thicknesses
Meristematic Tissue • The only plant tissue that produces new cells by mitosis • Located at the tips of stems and roots • Apical Meristem - increase plant length • Cells start out alike but then differentiate Just like our cells do!
Monocots vs Dicots branched 3 fibrous tap
Roots Two main types: • Taproots–The taproot and its lateral roots penetrate deeper into the soil than fibrous roots. Found mainly in dicots. • Fibrous rootsusually do not penetrate the soil very deeply. Because their roots attach themselves firmly to soil particles, plants with fibrous root systems are especially useful in preventing soil erosion. Found mainly in monocots.
Root Structure and Growth • The root’s surface is covered with cellular projections called root hairs. Root hairs provide a large surface area through which water and nutrients can enter the plant. Root hairs
Root Function • 1. Anchor a plant • 2. Absorb water • 3. Absorb dissolved nutrients
Root Functions • Minerals enter the roots through active transport. • Water enters by osmosis Root hairs Active transport of minerals Movement of water by osmosis
Stems- Functions • Produce leaves, branches and flowers • Hold leaves up in the sunlight • Transportvarious substancesbetween roots and leaves
Leaves • The structure of a leaf is optimized for absorbing light and carrying out photosynthesis.
Why don’t Plants dry out in the sun? • Stomata are pore-like openings in the underside of the leaf that allow carbon dioxide and oxygento diffuse into and out of the leaf. • Plants keep their stomata open just enough to allow photosynthesis to take place but not so much that they lose an excessive amount of water. • The stomata open and close in response to changes in water pressure within the guard cells. When it is dry, the stomata are closed. When there is enough water the stomata are open
Transport in Plants • Root pressure – the starting point for the movement of water through the vascular system of the plant. • Capillary Action – The tendency of water to rise in a thin tube. • Transpiration – loss of water through a plant’s leaves. • All work together to move water through xylem tissue of even the tallest plant.
Transport in Plants The ability of a liquid to flow in narrow spaces without the assistance of, and in opposition to external forces like gravity. Paper towels absorb liquid through capillary action, allowing a fluid to be transferred from a surface to the towel. The small pores of a sponge act as small capillaries, causing it to absorb a comparatively large amount of fluid. Some modern sport and exercise fabrics use capillary action to "wick" sweat away from the skin. Video?
