What is the Difference Between Leucoplast and Chromoplast

The main difference between leucoplast and chromoplast is that leucoplast is a colorless plastid, occurring in the unexposed areas of plants whereas chromoplast contains orange-red pigments and is found in fruit and flowers. Furthermore, leucoplast stores starch, fat, and proteins while chromoplast contains carotenoids and lipids.

Leucoplast and chromoplast are two types of plastids that occur in different parts of the plant. They perform important functions in the plant.

Key Areas Covered

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

Key Terms

Carotenoids, Chloroplast, Chromoplast, Leucoplast, Plastids, Storage

What is Leucoplast

Leucoplast is a type of plastid that mainly occurs in the unexposed parts of a plant. In contrast to chloroplasts and chromoplasts, leucoplasts are non-pigmented plastids. Due to the lack of photosynthetic pigments, leucoplasts generally occurs in non-photosynthetic parts of a plant including roots, bulbs, and seeds. Therefore, the main function of leucoplasts is to store nutrients. Here, amyloplasts are the type of leucoplasts that store starch. Moreover, elaioplasts store fat while proteinoplasts or aleuroplasts store proteins.

Figure 1: Plastids

However, leucoplasts in some plants are responsible for performing biochemical functions including the synthesis of fatty acids, many amino acids, and tetrapyrrole compounds like heme. Significantly, etioplasts are a type of immature chloroplasts which do not have active pigments. They are also known as leucoplasts.

What is Chromoplast

Chromoplast is a type of plastid which contains stored pigments. They are responsible for the biosynthesis and storage of pigments in plants. Thus, they are responsible for the distinctive colors in fruits, flowers, as well as aging or stressed leaves. Especially in aging leaves, a massive increase in the accumulation of carotenoids can be observed, which in turn converts chloroplasts into chromoplasts, giving a red, orange or yellow color to the leaf.

Figure 2: Colors of an Ophrys apifera Flower

Furthermore, chromoplasts can be classified based on the presence of proteic stroma with granules, protein crystals and amorphous pigment granules, protein and pigment crystals, and crystals. Furthermore, due to the various color patterns produced by chromoplasts in the plant, it becomes a key factor to attract animals such as birds, insects, etc. Thereby, chromoplasts facilitate different stages of the sexual reproduction of plants including pollination, fertilization, and dispersal of fruit.

Similarities Between Leucoplast and Chromoplast

• Leucoplast and chromoplast are two types of plastids that occur in different parts of plants.
• They are heterogeneous organelles with a storage function.
• Besides, it is thought that these plastids are descended from symbiotic prokaryotes.

Difference Between Leucoplast and Chromoplast

Definition

Leucoplast refers to a colorless organelle found in plant cells, used for the storage of starch or oil, while chromoplast refers to a colored plastid other than a chloroplast, typically containing a yellow or orange pigment. Thus, this is the main difference between leucoplast and chromoplast.

Color

Moreover, leucoplasts are colorless plastids while chromoplast may have different colors except for green, ranging from yellow, orange to red.

Pigments

Another difference between leucoplast and chromoplast is that leucoplasts are non-pigmented while chromoplasts contain pigments.

Occurrence

Leucoplasts occur in the non-photosynthetic parts of the plant including roots, bulbs, and seeds while chromoplasts occur in the exposed parts of the plant including fruits, flowers, and stressed parts of the leaves. Hence, this is also a difference between leucoplast and chromoplast.

Internal Lamellae

Furthermore, one other difference between leucoplast and chromoplast is that leucoplasts contain internal lamellae while the internal lamellae of chromoplasts are degraded.

Shape

Their shape is another difference between leucoplast and chromoplast. Leucoplasts have a more regular rounded shape while chromoplasts have an irregular shape due to the crystallization of pigments.

Function

Leucoplasts store nutrients including starch, fat, and proteins while chromoplasts are responsible for the synthesis and storage of pigments.

Transformation

Besides, leucoplasts can transform into other types of plastids while chromoplast cannot transform into other types of plastids.    

Attracting Animals

While leucoplasts are not responsible for attracting animals, chromoplasts are responsible for attracting animals, facilitating pollination and fertilization.

Conclusion

Leucoplasts is a type of colorless plastids found in plants. Their main function is to store nutrients. Amyloplasts are a type of leucoplasts that store starch; elaioplasts store fat; aleuroplasts stores proteins. Also, leucoplasts can transform into other types of plastids. In comparison, chromoplast is the plastid which stores carotenoids, giving colors to flowers, fruit, and aging leaves. The main function of chromoplasts is to facilitate pollination, fertilization, and dispersal of fruit. Therefore, the main difference between leucoplast and chromoplast is their color and function.

References:

1. Kochunni, Deena T, and Jazir Haneef. “Plastids – Leucoplasts, Chromoplasts and Chloroplasts.” Biology Exams 4 U, Available Here.

Image Courtesy:

1. “Plastids types en” By Mariana Ruiz Villarreal LadyofHats – Own work. Image renamed from File:Plastids types.svg (Public Domain) via Commons Wikimedia
2. “Ophrys apifera flower1” (CC BY-SA 3.0) via Commons Wikimedia