Which of the following statements is incorrect?

Options

A. Shoot apices those modify themselves into flowering apices, cannot perceive photoperiods
B. Sugarbeet, cabbage and carrots are monocarpic plants.
C. To initiate flowering , LDP must be exposed to light for a period less than cirtical duration.
D. Ethephon causes thining of cotton, cherry & walnut

Answer

To solve the question of identifying the incorrect statement among the given options, we will analyze each statement step by step.

### Step 1: Analyze the first statement
**Statement:** "Shoot apices that modified themselves into flowering apices cannot perceive photoperiods."
- **Analysis:** This statement is correct. The shoot apices that have modified into flowering apices do not perceive photoperiods; instead, the leaves are responsible for perceiving light and dark durations.

**Hint:** Remember that photoperiod perception primarily occurs in leaves, not in the flowering apices.

### Step 2: Analyze the second statement
**Statement:** "Sugar beet, cabbage, and carrots are monocarpic plants."
- **Analysis:** This statement is also correct. Monocarpic plants flower once, set seeds, and then die. Sugar beet, cabbage, and carrots fit this description.

**Hint:** Monocarpic plants have a single reproductive cycle before they die.

### Step 3: Analyze the third statement
**Statement:** "To initiate flowering, LDP (long day plants) must be exposed to light for a period less than the critical duration."
- **Analysis:** This statement is incorrect. Long day plants require exposure to light for a period longer than the critical duration to initiate flowering. Therefore, this statement contradicts the known requirements for long day plants.

**Hint:** Long day plants thrive with longer daylight hours to trigger flowering.

### Step 4: Analyze the fourth statement
**Statement:** "Ethephon causes thinning of cotton, cherry, and walnut."
- **Analysis:** This statement is correct. Ethephon is a plant growth regulator that releases ethylene and is used commercially to promote thinning in crops like cotton, cherry, and walnut.

**Hint:** Ethephon is associated with ethylene production, which influences plant growth and development.

### Conclusion
After analyzing all the statements, we find that the third statement is the incorrect one.

**Final Answer:** The incorrect statement is: "To initiate flowering, LDP must be exposed to light for a period less than the critical duration."