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Parts of a Leaf With Their Structure and Functions

A leaf is a plant organ that is flat, thin and usually green in color. It is mostly found above the ground and remains attached to the stem.

The presence of pigment ‘chlorophyll’ makes the leaf green in color that helps to prepare food in plants through photosynthesis. Collectively, green leaves are called foliage.

What are the Different Parts of a Leaf

A typical leaf shows three main parts: 1) petiole, 2) leaf base, and 3) leaf blade or lamina, each performing specific functions.

Parts of a Leaf Diagram

1. Petiole

It is the stalk that connects a leaf to the stem of the plant, it is made of complex conducting tissues called vascular tissues.

Functions

  • Providing support to the leaf and keeps it erect
  • 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

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

Functions

  • Helping in the attachment of the leaf to the stem
  • It protects the young axillary bud

3. Leaf-blade or Lamina

It is the thin, flat part of the leaf that is typically green in color. It is further divided into three parts:  i) leaf apex – the tip of the leaf blade, ii) leaf margin – the edge of the leaf and, iii) leaf veins – the small channels or capillaries, which are further subdivided into venules.

Functions

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

FAQs

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

Ans. Petiole, leaf base, lamina, leaf apex, and leaf margin are 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 bundles (xylem, phloem, veins) are the internal parts of a leaf.

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

Ans. The gas exchange which involves the absorption of carbon dioxide and release of oxygen occurs through tiny pores present in the leaves called stomata.

Q4. What is a sessile leaf? 

Ans. Leaves that are attached directly to the stem without the petioles are called sessile leaves. Saffron and Achyranthus plants have sessile leaves.

Article was last reviewed on Friday, July 3, 2020

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