Iron chlorosis

Definition

Iron chlorosis is a condition in plants characterized by yellowing of leaves due to insufficient iron, which is essential for chlorophyll production. This deficiency often arises in high pH soils where iron becomes less available, linking it closely to soil pH levels, cation exchange capacity, and the buffering systems that affect nutrient availability.

5 Must Know Facts For Your Next Test

1. Iron chlorosis typically appears first on younger leaves as a yellowing between the veins while the veins themselves remain green.
2. Soils with a high pH (above 7) can cause iron to become insoluble, making it unavailable for plant uptake and leading to chlorosis.
3. Iron can be supplied through soil amendments or foliar applications if deficiencies are detected early enough.
4. Certain plant species are more susceptible to iron chlorosis than others, especially those that prefer acidic soils.
5. Improving cation exchange capacity and adjusting soil pH through organic matter addition can help mitigate iron chlorosis.

Review Questions

• How does high soil pH contribute to iron chlorosis in plants?
  • High soil pH reduces the solubility of iron, making it less available for plant uptake. When the pH exceeds 7, iron compounds can precipitate out of solution, leading to deficiencies even when total iron levels in the soil may seem adequate. This lack of available iron is critical for chlorophyll production, resulting in the characteristic yellowing of leaves seen in iron chlorosis.
• Discuss the role of cation exchange capacity in preventing iron chlorosis in plants.
  • Cation exchange capacity (CEC) is essential for determining how well soil retains essential nutrients like iron. Soils with high CEC can hold onto more cations and make them available to plant roots. If CEC is low, nutrients may leach away or become unavailable, increasing the risk of deficiencies such as iron chlorosis. Enhancing CEC through organic amendments can improve nutrient availability and help prevent this condition.
• Evaluate strategies that can be employed to correct iron chlorosis and their effectiveness based on environmental factors.
  • To correct iron chlorosis, strategies like adjusting soil pH through acidifying agents or adding chelated iron supplements are commonly employed. The effectiveness of these methods depends on various environmental factors such as existing soil conditions, plant species, and moisture levels. For instance, foliar applications may work well under certain conditions but could be less effective if the underlying soil pH remains high or if the plant's root system is compromised. Thus, a comprehensive approach considering both immediate corrections and long-term soil health is vital for managing iron chlorosis effectively.

Related terms

Chlorophyll: A green pigment found in plants that is crucial for photosynthesis, allowing plants to convert sunlight into energy.

Cation Exchange Capacity (CEC): A measure of how well soil can retain and supply cations to plant roots, which affects the availability of essential nutrients like iron.

pH Buffering: The ability of soil to resist changes in pH, which helps maintain nutrient availability, including iron, in the root zone of plants.