Read the following statements regarding the mineral nutrition in plants
(1) For the elements that are actively mobilized within the plants, the deficiency symptoms tend to appear first in the young tissues.
(2) Manganese competes with iron and magnesium for uptake and with magnesium for binding with enzymes.
(3) Manganese inhibits calcium traslocation in shoot apex.
(4) Rhodospirillum is aerobic free-living nitrogen fixing microbe.
Which of these are correct

Options

A. (i), (iii) & (iv)
B. (ii) & (iv)
C. (ii) & (iii)
D. (ii), (iii) & (iv)

Answer

To solve the question regarding the mineral nutrition in plants, we will analyze each statement one by one to determine which ones are correct.

### Step 1: Analyze Statement 1
**Statement 1:** For the elements that are actively mobilized within the plants, the deficiency symptoms tend to appear first in the young tissues.

- **Analysis:** This statement is incorrect. For elements that are highly mobile (like nitrogen, potassium, and magnesium), deficiency symptoms appear first in the older tissues because these elements are mobilized from older parts of the plant to support the younger tissues. Therefore, the correct observation is that deficiency symptoms appear in older tissues first.

### Step 2: Analyze Statement 2
**Statement 2:** Manganese competes with iron and magnesium for uptake and with magnesium for binding with enzymes.

- **Analysis:** This statement is correct. Manganese can indeed compete with iron and magnesium for uptake in plants. When manganese is present in excess, it can lead to deficiencies of these other elements due to competition.

### Step 3: Analyze Statement 3
**Statement 3:** Manganese inhibits calcium translocation in the shoot apex.

- **Analysis:** This statement is also correct. Excess manganese can interfere with the translocation of calcium, leading to calcium deficiency in the shoot apex. This is due to the competitive interactions and the physiological roles of these minerals in plant nutrition.

### Step 4: Analyze Statement 4
**Statement 4:** Rhodospirillum is an aerobic free-living nitrogen-fixing microbe.

- **Analysis:** This statement is incorrect. Rhodospirillum is actually an anaerobic free-living nitrogen-fixing bacterium. It does not require oxygen for its metabolic processes, which contradicts the statement.

### Conclusion
Based on the analysis of each statement:
- Statement 1 is incorrect.
- Statement 2 is correct.
- Statement 3 is correct.
- Statement 4 is incorrect.

Thus, the correct statements are 2 and 3.

### Final Answer
The correct statements are **2 and 3**.

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