Question

Which one of the following statements is false?
(A)
(B)
(C)
(D)

• A. Growth regulators stimulate plant cells to undergo cytokinesis
• B. A portion of Ti-plasmid present in Agrobacterium is known as T-DNA
• C. Coconut milk was shown to contain cytokinin, Zeatin
• D. The auxin : cytokinin ratio does not regulate morphogenesis in cultured tissues

Hint:

The Skoog-Miller hypothesis is a core concept in plant biotech.
Morphogenesis = Development of form (Roots/Shoots).
This is always regulated by the balance between Auxin and Cytokinin.

Answer 1

The Correct Option is D

Step 1: Understanding the Question:
The question requires evaluating four statements related to plant biotechnology and physiology to identify the one that is factually incorrect.
Detailed Explanation:

• Evaluating Statement A: "Growth regulators stimulate plant cells to undergo cytokinesis."
This is TRUE. Cytokinins are specifically named for their ability to promote cytokinesis (cell division) in the presence of auxin.

• Evaluating Statement B: "A portion of Ti-plasmid present in Agrobacterium is known as T-DNA."
This is TRUE. The T-DNA (Transfer DNA) is the specific segment of the Tumor-inducing (Ti) plasmid that is transferred and integrated into the host plant genome.

• Evaluating Statement C: "Coconut milk was shown to contain cytokinin, Zeatin."
This is generally considered TRUE in the context of history. Coconut milk (liquid endosperm) was used by van Overbeek to promote embryo growth and was later found to contain various cytokinins, including zeatin and zeatin riboside.

• Evaluating Statement D: "The auxin : cytokinin ratio does not regulate morphogenesis in cultured tissues."
This is FALSE. The work of Skoog and Miller (1957) proved that the ratio of auxin to cytokinin is the primary signal for morphogenesis. High auxin:cytokinin promotes roots, while low auxin:cytokinin promotes shoots.

Step 2: Final Answer:
Statement (D) is false because the hormonal ratio is the fundamental regulator of morphogenesis in tissue culture.