What is the Difference Between Cotyledons and True Leaves

The main difference between cotyledons and true leaves is that the cotyledons do not resemble the regular foliage of the plant whereas the true leaves are exactly similar in appearance to the regular foliage of the plant. Furthermore, cotyledons are the first leaves emerging from the embryo during seed germination whereas true leaves emerge after cotyledons.

Cotyledons and true leaves are the two types of leaves that occur in a young plant following the germination of the seed. Both types of leaves produce food through photosynthesis.

Key Areas Covered

1. What are Cotyledons
     – Definition, Appearance, Role
2. What are True Leaves
     – Definition, Appearance, Role
3. What are the Similarities Between Cotyledons and True Leaves
     – Outline of Common Features
4. What is the Difference Between Cotyledons and True Leaves
     – Comparison of Key Differences

Key Terms

Cotyledons, Dicots, Monocots, Photosynthesis, Seed Germination, True Leaves

What are Cotyledons

Cotyledons are the firstly-emerging leaves from a germinating seed. Another name for them is seed leaves. Generally, they consist of a smooth surface and are plain looking. Their shape is very basic and mostly oval. Moreover, the number of cotyledons produced by a seed plant is a distinguishing feature between monocots and dicots as monocots produce a single cotyledon while dicots produce two cotyledons. The two cotyledons of dicots are opposite to each other in the stem. However, some plants like conifers may contain more than two cotyledons.

Figure 1: Monocot and Dicot Cotyledons

Furthermore, the position of the cotyledons depends on the type of seed germination. That means; in the hypogeal germination, cotyledons occur inside the soil. On the other hand, cotyledons come out of the soil only in the epigeal germination. In fact, cotyledons are the first type of leaves that start photosynthesis to produce food for the growing plant.

What are True Leaves

True leaves are the leaves that emerge after cotyledons. They have a similar appearance to the foliage of the plant. But, they may be small in size. Also, they develop different structures of leaves like hairs and trichomes. The two main types of leaves are the simple leaves and compound leaves. The basic types of leaves are:

• Fronds in ferns
• Needle- or scale-like leaves in conifer
• Leaves of the flowering plants
• Mesophyll leaves in lycophytes
• Sheath leaves in monocots
  

  Figure 2: Cotyledons and True Leaves

The main function of the true leaves is to undergo photosynthesis in order to produce food for the growth of the plant.

Similarities Between Cotyledons and True Leaves

• Cotyledons and true leaves are two types of leaves that occur in seed plants.
• Both emerge in a consequent manner after the germination of the seed.
• Also, both undergo photosynthesis to produce food.

Difference Between Cotyledons and True Leaves

Definition

Cotyledons refer to the embryonic leaves in seed-bearing plants and, one or more of which are the first leaves to appear from a germinating seed. True true leaves refer to the foliage leaves of a plant, as opposed to a seed leaf or cotyledon. Thus, this explains the main difference between cotyledons and true leaves.

Also Known as

Cotyledons are also known as seed leaves or embryonic leaves while true leaves are known as the foliage of the plant.

Consequence

Also, another difference between cotyledons and true leaves is that the cotyledons emerge first from the germinating seed while the true leaves follow the cotyledons.

Appearance

Further, one more difference between cotyledons and true leaves is that the cotyledons have a different appearance from the regular foliage of the plant while the true leaves resemble the regular foliage of the plant.

Texture

Moreover, based on texture, a difference between cotyledons and true leaves is that the cotyledons are thick and hard while the true leaves are thin and soft.

Occurrence in the Stem

Cotyledons occur at the lower level in the stem while true leaves occur above the cotyledons.

Nourishment

Besides, the cotyledons obtain nutrients from the embryo while the true leaves take nutrients from the young plant. Hence, this is another difference between cotyledons and true leaves.

Conclusion

Cotyledons are the embryonic leaves that first emerge from the seed during germination. It is thick, hard and is capable of undergoing photosynthesis. True leaves emerge after the emergence of cotyledons. They resemble the regular foliage of the plant in size and shape. Therefore, the main difference between cotyledons and true leaves is their appearance and occurrence.

References:

1. Arrington, Derrick. “Cotyledon: Definition & Function.” Study.com, Study.com, Available Here

Image Courtesy:

1. “Monocot vs dicot crop Pengo” By w:User:Pengo – This is a retouched picture, which means that it has been digitally altered from its original version. Modifications: crop and paste. The original can be viewed here: Monocot vs dicot Pengo.jpg. Modifications made by Pengo. (CC BY-SA 3.0) via Commons Wikimedia  
2. “1094913” (CC0) via pxhere