Difference Between Exine and Intine

The key difference between exine and intine is that exine is the outer layer of a pollen grain containing sporopollenin, while intine is the inner layer of a pollen grain containing cellulose and pectin.

Pollen is the actual male gametophyte of seed plants. It is a reduced form of the gametophyte. Also, pollen is a single cell. Further, it contains male reproductive cells of these plants. Moreover, anthers bear pollens in sacs and via pollination pollens deposit on the stigma of flowers. Besides, there are two layers that surround the interior of the pollen. They are exine and intine. The exine is harder, thicker and more resistant than the inner layer: intine.

CONTENTS

1. Overview and Key Difference
2. What is Exine
3. What is Intine
4. Similarities Between Exine and Intine
5. Side by Side Comparison – Exine vs Intine in Tabular Form
6. Summary

What is Exine?

The exine is the outer layer of a pollen grain. Sporopollenin is the main component of the exine. The organic material is one of the most resistant and hardest substances. Hence, exine is also more resistant and harder than the inner layer of the pollen, which is the intine. Furthermore, exine is a thick layer compared to intine. Therefore, exine can tolerate harsh environmental conditions, including high temperature, strong acid, strong alkali and other factors.

Besides, exine has folds, creases and spikes rising from its surface. These structures help pollen grains to stick to the legs of insects and catch the wind.

What is Intine?

Intine is the inner layer of a pollen grain containing cellulose and pectin. In comparison to exine, intine is thin and a less hard layer.

Moreover, it is less resistant to harsh environmental conditions. Intine is situated interior to exine.

What are the Similarities Between Exine and Intine?

• Exine and intine are two layers of a pollen grain.
• Both are hardcovers that protect the pollen grain.
• They are composed of polymers.

What is the Difference Between Exine and Intine?

The exine is the outer layer composed of sporopollenin. In contrast, intine is the inner layer composed of cellulose and pectin. So, this is the key difference between exine and intine. Moreover, a further difference between exine and intine is that the exine is more resistant and thicker, while the intine is less resistant and thinner. Furthermore, exine has folds and spikes while they are absent in intine.

Below infographic summarizes the difference between exine and intine.

Summary – Exine vs Intine

In summarizing the difference between exine and intine, the exine and intine are the two layers that cover the pollen grain. Here, exine is the outer layer composed of sporopollenin while intine is the inner layer composed of cellulose and pectin. Furthermore, the exine is a thick layer. Besides, it is more resistant to harsh environmental conditions. Also, it has folds, creases and spikes that help the pollen grain to stick to the legs of insects and catch the wind. But, in contrast, intine is a thin layer and is less resistant and harder.

Reference:

1. “Pollen.” Wikipedia, Wikimedia Foundation, 28 July 2019, Available here.
2. ” Pollen Grain: Definition, Structure & Function.” Study.com, Available here.

Image Courtesy:

1. “Figure 32 01 06f” By CNX OpenStax – (CC BY 4.0) via Commons Wikimedia
2. “Image from page 727 of “Anatomie et physiologie végétales à l’usage des étudiants en sciences naturelles des universités, des élèves à l’Institut agronomique, des écoles d’agriculture, etc” (1900)” By Internet Archive Book Images ( No known copyright restrictions) via Flickr