Section A: PGR Identifications

1. The only gaseous plant hormone is ________.
2. ABA is called the ________ hormone.
3. Gibberellin was discovered from the fungus ________.
4. Kinetin was isolated from ________ DNA.
5. The synthetic auxin used as a selective herbicide is ________.
6. ________ is the natural auxin in plants.
7. Gibberellin induces ________ enzyme in the ________ layer of barley.
8. The Richmond-Lang effect (delay of senescence) is caused by ________.
9. ________ promotes stomatal closure by causing $K^{+}$ efflux from guard cells.
10. Triple response in seedlings is caused by ________.

Answers: 1. Ethylene 2. Stress 3. Gibberella fujikuroi 4. Herring sperm 5. 2,4-D 6. IAA 7. Alpha-amylase, aleurone 8. Cytokinins 9. ABA 10. Ethylene

Section B: Photoperiodism

11. Rice is a ________ plant.
12. Wheat is a ________ plant.
13. Tomato is a ________ plant.
14. The active form of phytochrome is ________.
15. Pfr ________ flowering in SDP and ________ flowering in LDP.
16. Vernalization temperature range: ________ to ________ °C.
17. In a night-break experiment, a flash of ________ light prevents SDP flowering.

Answers: 11. Short-day 12. Long-day 13. Day-neutral 14. Pfr 15. Inhibits, promotes 16. 0, 5 17. Red

Section C: Growth Mathematics

18. Arithmetic growth formula: ________.
19. Geometric growth formula: ________.
20. The three phases of sigmoid growth: ________, ________, ________.
21. In arithmetic growth, ________ daughter cell(s) continue(s) dividing.
22. In geometric growth, ________ daughter cell(s) continue(s) dividing.

Answers: 18. Lt = $L_{0}$ + rt 19. $W_{1}$ = $W_{0}$eʳᵗ 20. Lag, Log, Stationary 21. One 22. Both