Let's examine each combination:
- I: H.G. Khorana is known for Artificial gene synthesis and Cell Biology.
- II: P.K.K. Nair is associated with Pollen Science and Pollinology.
- III: Amon is not directly linked to respiration; this option is incorrect.
- IV: Bessey is known for Phylogenetic classification and Taxonomy.
Thus, the correct answer is "I II IV."