Plant Characteristics and Special Functions Plants Plant Characteristics and Special Functions

Overview of Plants all shapes and sizes all types of environments

Common Characteristics of Plants About 260,000 species of plants live on Earth today. All plants: Are multicellular Have a nucleus surrounded by a cell wall. Are producers – capture light from the Sun. Have life cycles divided into two stages (generations).

Special Functions Below ground: roots Absorb water and nutrients from soil. Transport materials to leaves through the stem. Above ground: stems and leaves = shoot system Leaves use materials + CO2 to make sugars and carbohydrates through photosynthesis.

Transporting Materials Materials move through a vascular system. Stems transport the materials from one part of the plant to another. The vascular tissues are bundled together from the root to the leaves; look like tubes.

Transporting Materials - Tissue Xylem: carries water and dissolved nutrients up from roots. Phloem: transports energy-rich materials, such as sugar, down from leaves. Both are long, hollow tubes that contain fibers to support the body of the plant. Xylem is a little larger.

Transporting Materials - Tissue

Making Sugars - Photosynthesis Plants make sure through photosynthesis. What is the formula? Co2 + H2O + sunlight  oxygen + glucose (C6H12O6) Where does it take place? In the chloroplasts, which contain chlorophyll

Inside of the Leaf Upper layer is filled with chloroplasts. Vascular tissue is located toward the center. Stomata, or tiny openings, are located on the bottom of the leaf – gas exchange occurs here (CO2 comes in, O2 goes out).

Controlling Gas Exchange Stomata can open and close to let CO2 and oxygen in and out. Water is able to evaporate from open stomata  transpiration. Sunlight and wind cause transpiration.

Water Loss Plants have a waxy cuticle, or protective layer, to prevent too much water from evaporating. Stomata can open and close to prevent this, also.

Adapting to Environment - Cactus Special adaptation – no leaves – uses spines instead. Photosynthesis occurs in the stem, where the cactus is able to hold more nutrients without the threat of transpiration.

Plant Growth Plants grow as long as they live. They get bigger when cells at the tips of their roots and stems divide and multiply more quickly than other cells. Only stems grow leaves – leaves grow from buds.

The Stem – Three Functions Holds the vascular system Provide support and plant structure Store sugars produced by photosynthesis

Soft Stems Wildflowers, garden flowers, and vegetables Survive by using the carbs stored in its roots to grow new, soft, green stems and leaves in warmer weather.

Woody Stems Trees and shrubs Tough, thick stems that do not die each year. Keep growing longer/thicker Tough xylem layer  wood