To analyze the statements regarding essential macronutrients and micronutrients in plants, let's evaluate each statement step by step:
### Step-by-Step Solution:
1. **Statement I: Essential macronutrients are nine in number, micronutrients are eight in number.**
- **Analysis:** This statement is correct. The essential macronutrients include carbon, hydrogen, oxygen, nitrogen, phosphorus, potassium, sulfur, magnesium, and calcium, totaling nine. The micronutrients include iron, zinc, nickel, molybdenum, copper, chlorine, manganese, and boron, totaling eight.
2. **Statement II: Every mineral element that is present in a cell is needed by the cell.**
- **Analysis:** This statement is incorrect. Not every mineral element present in a plant cell is essential for its growth and development. Some elements may be present due to environmental factors but are not necessary for the plant's metabolic processes.
3. **Statement III: Nitrogen as a nutrient element is highly immobile in the plants.**
- **Analysis:** This statement is also incorrect. Nitrogen is considered a highly mobile nutrient within plants. It can move from older tissues to younger tissues as needed, especially during periods of growth.
4. **Statement IV: Deficiencies of essential elements disrupt plant growth and development.**
- **Analysis:** This statement is correct. A deficiency in essential nutrients, whether macronutrients or micronutrients, can lead to stunted growth, poor development, and various physiological disorders in plants.
5. **Statement V: Although the functions of essential elements are diverse, they can be grouped into four general categories.**
- **Analysis:** This statement is correct. The functions of essential elements can indeed be categorized into four groups:
- Structural components (e.g., building blocks of proteins and nucleic acids)
- Enzyme activators or inhibitors
- Nutrients that play roles in energy transfer (e.g., ATP)
- Elements that alter osmotic potential and regulate water balance.
### Conclusion:
- **Correct Statements:** I, IV, and V are correct.
- **Incorrect Statements:** II and III are incorrect.
### Final Answer:
The correct statements are I, IV, and V.
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