Mineral ion concentration in tissues that reduces the dry weight of tissues by about 10% is considered as

Options

A. critical concentration
B. toxic concentration
C. optimum concentration
D. beneficial concentration

Explanation

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks about the mineral ion concentration in plant tissues that leads to a reduction in the dry weight of those tissues by approximately 10%.

2. **Identifying the Role of Mineral Ions**: Mineral ions are essential for plant growth and development. They must be present in specific amounts for optimal functioning. Both deficiency and excess of these ions can harm the plant.

3. **Effects of Excess Mineral Ions**: When mineral ions are present in excessive amounts, they can lead to toxicity. This toxicity can interfere with the plant's metabolism and nutrient absorption, ultimately affecting the plant's health.

4. **Defining Toxic Concentration**: The term that describes the concentration of mineral ions that causes a reduction in dry weight by about 10% is known as "toxic concentration." This concentration varies among different plants and different minerals.

5. **Examples of Toxic Concentration**: For instance, the toxic concentration of magnesium ions can differ from one plant species to another. In soybeans, it might be around 600 micrograms per gram, while in sunflowers, it could be around 5300 micrograms per gram.

6. **Conclusion**: Based on the understanding that excessive mineral ion concentration can lead to a decrease in dry weight, the correct answer to the question is "toxic concentration."

**Final Answer**: Toxic concentration.

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