1. Tardigrade
  2. Question
  3. Biology
  4. The following statements are given about plant growth hormones. I. Kinetin is a degradative substance from DNA molecule. II. ABA is present, in all the plants III. Low ratio of cytpkinins to auxins favours root formation only. IV. ABA is synthesised catabolically through mevalonate pathway. The correct combination is

Q. The following statements are given about plant growth hormones.
I. Kinetin is a degradative substance from DNA molecule.
II. ABA is present, in all the plants
III. Low ratio of cytpkinins to auxins favours root formation only.
IV. ABA is synthesised catabolically through mevalonate pathway.
The correct combination is

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Solution:

Miller et. al, (1955) discovered first cytokinin from degraded sample of yeast DNA and coconut milk and called it kinetin which is a 6 furfuryl amino purine (derivative of purine base-adenine). Auxin and cytokinin are essential for morphogenesis or differentiation of tissue and organ. High ratio of cytokinin to auxin favour bud formation, whereas low ratio of cytokinin to auxin favour root formation. ABA biosynthesis takes place in chloroplast and other plastids. This is formed from mevalonic acid in stress condition, ie, the plants which present in environment which show stress condition.