What is the Difference Between Coleoptile and Coleorhiza

The main difference between coleoptile and coleorhiza is that coleoptile is a pointed protective sheath which covers the emerging shoot in monocots, whereas coleorhiza is the sheath-like structure which connects the coleoptile to the primary root, protecting the radicle in monocots. Furthermore, coleoptile comes out of the soil and turn into green while coleorhiza remains inside the soil. 

Coleoptile and coleorhiza are two types of sheaths that arise from the monocot seed. Moreover, they occur inside the seed prior to the seed germination.

Key Areas Covered 

1. What is Coleoptile
     – Definition, Structure, Function
2. What is Coleorhiza
     – Definition, Structure, Function
3. What are the Similarities Between Coleoptile and Coleorhiza
     – Outline of Common Features
4. What is the Difference Between Coleoptile and Coleorhiza
     – Comparison of Key Differences

Key Terms 

Coleoptile, Coleorhiza, Monocot Seed, Plumule, Protective Sheaths, Radicle

What is Coleoptile 

Coleoptile is the protective sheath of a monocot seed, surrounding the plumule or the shoot tip. Moreover, it grows with the plumule up to a certain point. The flag leaves inside it penetrate the top of the coleoptile and continue their growth.

Figure 1: Leaves Emerge from Coleoptiles

Furthermore, coleoptile has two vascular bundles on either side. It is pale in color since it does not develop much chlorophyll. Additionally, some coleoptiles contain anthocyanin pigments, which are purple in color. 

What is Coleorhiza 

Coleorhiza is a sheath-like structure in the monocot seed. Generally, it surrounds the radicle. Moreover, it connects the coleoptile to the primary root.

Figure 2: Coleoptile and Coleorhiza

However, like the coleoptile, coleorhiza does not grow to a considerable length. Therefore, it stops its growth after it just emerges from the seed. Moreover, it does not come out but remains inside the soil. 

Similarities Between Coleoptile and Coleorhiza 

• Typically, coleoptile and coleorhiza are two sheaths covering the shoot and the root in the germinating monocot seed. 
• Moreover, both occur inside the seed as well.  

Difference Between Coleoptile and Coleorhiza 

Definition 

Coleoptile refers to a sheath protecting a young shoot tip in grass or cereal while coleorhiza refers to a sheath protecting the root of a germinating grass or cereal grain. This explains the main difference between coleoptile and coleorhiza.

Type of Sheath 

Also, while coleoptile is a protective sheath, coleorhiza is an undifferentiated sheath. 

Covering 

Furthermore, coleoptile covers the plumule while coleorhiza covers the radicle and root cap. 

Type of Growth 

Coleoptile breaks the seed coat and elongates while coleorhiza breaks the seed coat but, stops further growth. Hence, this is another important difference between coleoptile and coleorhiza.

Significance  

Moreover, coleoptile comes out from the soil and turns green while coleorhiza remains inside the soil. 

Conclusion 

Basically, coleoptile is the protective sheath arise from the monocot seed, surrounding the plumule. Moreover, it continuously grows with the shoot to a certain point and turns into green. On the other hand, coleorhiza is the undifferentiated sheath-like structure that arises from the monocot seed, covering the radicle and the root cap. However, it does not continuously grow with the root. Therefore, the main difference between coleoptile and coleorhiza is their occurrence and type of growth. 

References:

1. “Coleoptile.” Wikipedia, Wikimedia Foundation, 4 Apr. 2019, Available Here.
2. “Coleorhiza.” Wiktionary, MediaWiki, Available Here.

Image Courtesy:

1. “Kecambah jagung Pj IMG 20150525 172519” By Kembangraps – Own work (CC BY-SA 3.0) via Commons Wikimedia   
2. “Monocot seedling” By The original uploader was Marshman~enwikibooks at English Wikibooks. – Also transferred from en.wikibooks to Commons. (GFDL) via Commons Wikimedia