Plant Structure and Function

Front

Dermal Tissue Noun

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[dur-muhl tish-oo]

Back

Dermal Tissue

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The outermost protective tissue layer of a plant's organs, shielding the plant from damage and preventing water loss.

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Example: This image shows a magnified view of a plant's dermal tissue, or 'skin', revealing pores called stomata that open and close to control gas exchange.

Front

Vascular Tissue Noun

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[vas-kyuh-ler tish-oo]

Back

Vascular Tissue

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The transport system tissue in plants, composed of xylem and phloem, that moves water, minerals, and nutrients.

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Example: This diagram shows a cross-section of a plant stem, highlighting the vascular bundles which contain xylem and phloem, the two types of vascular tissue.

Front

Ground Tissue Noun

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[ground tish-oo]

Back

Ground Tissue

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The tissue between dermal and vascular systems that produces and stores carbohydrates and provides structural support for the plant.

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Example: This diagram shows a plant stem cross-section. Ground tissue is the tissue that fills the space between the outer dermal and central vascular tissues.

Front

Xylem Noun

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[zy-luhm]

Back

Xylem

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The vascular tissue responsible for transporting water and dissolved minerals upward from the roots to the rest of the plant.

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Example: This diagram shows that xylem (blue arrows) acts like a set of straws, pulling water and minerals up from the plant's roots to the leaves.

Front

Phloem Noun

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[floh-em]

Back

Phloem

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The living vascular tissue that transports sugars, produced during photosynthesis, from the leaves to other parts of the plant.

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Example: This diagram shows phloem (orange arrows) transporting food made during photosynthesis from the leaves to all other parts of the plant, like flowers and roots.

Front

Tracheids Noun

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[tray-kee-ids]

Back

Tracheids

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Elongated, tapering cells in the xylem that are dead at maturity and function in water conduction and structural support.

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Example: This diagram shows a tracheid, a long, tapered plant cell that helps transport water. It is shown next to other xylem cells for comparison.

Front

Sieve Tube Elements Noun

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[siv toob el-uh-ments]

Back

Sieve Tube Elements

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Specialized cells arranged end-to-end in the phloem, forming a continuous tube for transporting sugars throughout the plant.

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Example: This diagram shows sieve tube elements are long, stacked cells connected by sieve plates, forming a tube to transport sugars within the plant's phloem.

Front

Companion Cells Noun

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[kuhm-pan-yuhn sels]

Back

Companion Cells

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Specialized phloem cells that are closely associated with sieve tube elements and regulate their function in sugar transport.

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Example: This diagram shows a companion cell located next to a sieve tube element, illustrating its key structural relationship within the plant's phloem tissue.

Front

Stomata Noun

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[stoh-muh-tuh]

Back

Stomata

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Microscopic pores, typically on the underside of leaves, that facilitate gas exchange between the plant and the atmosphere.

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Example: This diagram shows a stoma, a small pore on the leaf's surface, which is located next to air spaces inside the leaf to allow for gas exchange.

Front

Guard Cells Noun

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[gard sels]

Back

Guard Cells

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A pair of specialized cells surrounding a stoma that control its opening and closing to regulate gas exchange.

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Example: This diagram shows how two guard cells swell with water, causing them to curve and open a pore called a stoma, which allows for gas exchange.