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Parts of a Leaf With Their Structure and Functions

The leaf is a flattened plant organ usually found above the ground and is borne at the node of the stem. They are also the principal lateral outgrowth of the stem. The leaves, together with the stem, make the shoot of the plant.

The presence of photosynthetic pigment ‘chlorophyll’ makes the leaf green in color. Collectively, green leaves are known as foliage.

What are the Different Parts of a Leaf

A typical labeled leaf diagram of a simple leaf shows three main parts: i) petiole, ii) leaf base, and iii) leaf blade or lamina, each performing specialized functions.

Parts of a Leaf Diagram

1. Petiole

The stalk that connects a leaf to the stem of the plant, it is made of vascular tissues. There are some exceptions where the leaves are attached directly to the stem without petioles. Those are called sessile leaves (e.g. saffron and Achyranthus).

Functions

  • Supporting the leaf in the plant
  • Transporting water and nutrients absorbed by the roots to the leaves
  • Transporting photosynthetic products from the leaves to the rest of the plant

2. Leaf Base

The lowermost part of a leaf, which is closest to the petiole.

Functions

  • Helping in the attachment of the leaf to the stem

3. Leaf-blade or Lamina

The broad, thin, flat part of the leaf that is typically green in color. It is generally further divided into multiple parts including the tip or leaf apex (outer end of the leaf) and leaf margin (edge of the leaf), veins and venules (small vein capillaries).

Functions

  • Helping plants to prepare their food using raw materials like water, carbon dioxide and minerals by a process known as photosynthesis
  • Performing evaporation from the aerial parts of a plant by a process known as transpiration
  • Transporting water and nutrients throughout the leaf with the help of veins and venules

FAQs

Q.1. What are the external parts of a plant leaf?

Ans. Petiole, leaf base, lamina, leaf apex, and leaf margin form the external parts of a leaf.

Q.2. What are the internal parts of a leaf?

Ans. Stomata, guard cells, epidermal cells, mesophyll cells, and vascular bundle (xylem, phloem, veins) form the internal parts of a leaf.

Q.3. What part of a leaf helps in gas exchange?

Ans. The absorption of carbon dioxide and release of oxygen occurs through tiny pores present in the leaves known as stomata.

Article was last reviewed on Saturday, January 4, 2020

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