Roots, Stems, and Leaves The three main plant organs are roots, stems, and leaves. These organs are made up of three main kinds of tissues: dermal tissue vascular tissue ground tissue.

Plant Tissues Dermal tissue – the “skin” of a plant. protects the plant and prevents water loss.

Plant Tissues cont. Vascular tissue moves water and nutrients throughout the plant. Xylem tissue moves water. made up of tracheids and vessel elements. Phloem tissue moves sugars. consists of sieve tube elements and companion cells.

Plant Tissues cont. Ground tissue- all the cells that lie between dermal and vascular tissues. made up mostly of parenchyma cells. Parenchyma cells have thin cell walls and function in photosynthesis and storage. Collenchyma and sclerenchyma These cells have thick cell walls that help support the plant.

Plant Tissues cont. Meristematic tissue- responsible for plant growth. Produces new cells by mitosis. Develop specialized structures and functions when mature in a process called differentiation found at the tips of stems and roots.

Roots 2 types of roots- Functions: Taproot : One big primary root + small secondary roots Fibrous root: Primary and secondary roots = same size Functions: anchor a plant in the ground. absorb water and dissolve nutrients from the soil. Root pressure forces water upward through the xylem toward the stem.

Stems Functions: Arrangement of tissues Growth: They produce leaves, branches, and flowers. They hold leaves up to the sunlight. They also carry water and nutrients between roots and leaves. Arrangement of tissues Monocots: vascular bundles are scattered Dicots : vascular bundles are arranged in a ring. These vascular bundles contain xylem and phloem tissue. Growth: Primary : grows longer Secondary: grows wider

Leaves main organs of photosynthesis. veins : Xylem and phloem tissues make food (sugars) made up of a specialized ground tissue called mesophyll cells. Mesophyll : many chloroplasts responsible for photosynthesis veins : Xylem and phloem tissues Stomata: small openings prevent water loss.

Transport in Plants Capillary action: Transpiration pull Cohesion- forces between water and water molecules Adhesion – forces between water and other molecules Transpiration pull water moves from areas where there is plenty of water to areas where there is little water. Pressure-flow hypothesis explains how phloem transport happens sugars move from areas of high concentration to areas of low concentration.

Which part is responsible for photosynthesis? D C B A

If a plant becomes too dry, are the stomata in the leaves more likely to be open or closed?

Which tissue is found in the center of a plant stem? A. dermal tissue B. vascular tissue C. ground tissue

Which of the three kinds of ground tissue serve mainly for storage? A.parenchyma B. collenchyma C. sclerenchyma

Cells that can differentiate into many plant tissues are found in A. the vascular cylinder. B. dermal tissue. C.meristematic tissue.

Photosynthetic tissues in a leaf include the A.phloem. B.vein. C.palisade mesophyll. A process in which water is lost through the leaves of a plant is called A.transpiration. B.photosynthesis. C.glycolysis.