The key difference between chlorosis and necrosis is that chlorosis is yellowing of plant tissues as a result of decreased amounts of chlorophyll, while necrosis is the death of plant cells or tissues.
Plants show different symptoms as a result of diseases, injuries or nutrient deficiencies. Some of the common symptoms include chlorosis, necrosis, wilting, mosaic and mottle, and water soaking. Chlorosis is the appearance of yellow spots on leaves. It occurs due to the lack of chlorophylls. In contrast, necrosis is the appearance of brown spots on leaves due to death of plant cells or tissues.
CONTENTS
1. Overview and Key Difference
2. What is Chlorosis
3. What is Necrosis
4. Similarities Between Chlorosis and Necrosis
5. Side by Side Comparison – Chlorosis vs Necrosis in Tabular Form
6. Summary
What is Chlorosis?
Chlorosis refers to the yellowing of plant parts, mainly leaves and veins. Yellow spots appear on the leaves, giving a mosaic pattern. Yellowing occurs due to insufficient amounts of chlorophylls. Chlorophyll production can be decreased due to many reasons. One of the major reasons is nutrient deficiency. Iron is one of the key elements in chlorophyll. Thus, iron deficiency is a major cause of chlorosis. Furthermore, chlorosis can also occur as a result of disease, herbicide injury, poor water drainage, damaged roots, high alkalinity, compacted soil, etc. However, the reasons for chlorosis may vary from plant species to species. For example, some plants grow well in alkaline soils, but they also may show chlorosis due to some other reason.
Figure 01: Chlorosis
Chlorosis can be overcome by supplementing the plants with adequate amounts of nutrients via fertilization. Moreover, diagnosing the specific reason for chlorosis and treating it in accordance is the best solution for chlorosis.
What is Necrosis?
In plants, necrosis refers to the death of plant cells or tissues. Necrosis occurs due to injuries or diseases. Furthermore, necrosis takes place as a result of nutrient deficiency. Necrotic areas appear as brown spots. Necrosis can occur on leaves, stems, roots, leaf margins, veins, etc. Unlike chlorosis, necrosis is irreversible.
Figure 02: Necrosis
Viral infections often lead to necrosis in plants since viruses use plant cells to replicate, and they often come out by lysing the host cell. Tobacco necrosis virus affects tobacco plants causing necrosis. Similarly, Soybean vein necrosis virus affects the vascular system, while cymbidium mosaic virus affects orchid flowers. Bacteria and fungi also cause necrosis in plants. Some bacteria degrade cell walls of plant cells, leading to cell death and necrosis. Some fungi attack the vascular system of plants and cause different diseases like anthracnose that lead to necrosis in plants.
What are the Similarities Between Chlorosis and Necrosis?
- Chlorosis and necrosis are two types of symptoms shown by the plants.
- One of the major reasons for chlorosis and necrosis is a nutrient deficiency.
- Also, both can occur as a result of viral infections.
What is the Difference Between Chlorosis and Necrosis?
Chlorosis refers to yellowing of green colour plant parts, while necrosis refers to the death of plant cells and tissues. So, this is the key difference between chlorosis and necrosis. Chlorosis appears as yellow spots, while necrosis appears as a brown or black spots or areas. Therefore, another difference between chlorosis and necrosis is their reversal; severe chlorosis cannot be reversed. But, if identified early, it is reversible. However, necrosis is not reversible.
Summary – Chlorosis vs Necrosis
Chlorosis and necrosis are two visible symptoms in plants. Chlorosis is the yellowing of leaf tissue due to a lack of chlorophyll, while necrosis is the death of plant cells or tissues. So, this is the key difference between chlorosis and necrosis. Chlorosis appears as yellow spots, while necrosis appears a brown or black spots on leaves.
Reference:
1. Norris, Lori. “Necrosis Plant Diseases.” Home Guides | SF Gate, 21 Nov. 2017, Available here.
2. “Chlorosis.” Chlorosis | Focus on Plant Problems | U of I Extension, Available here.
Image Courtesy:
1. “Raspberry vein chlorosis virus NT5 (1)” By Jerzy Opioła – Own work (CC BY-SA 4.0) via Commons Wikimedia
2. “‘Awa: Whitefly; ‘Awa Whitefly — spiral leaf necrosis” By Scot Nelson (Public Domain) via Flickr