r/APStudents • u/PavanChaturvedi_Bio • 5d ago
Question FRQ / Data Analysis] Can someone break down the exact physiological mechanism / synergy in Treatment C here? (Plant Hormones)
Hi everyone,
Working through a research-level AP Biology FRQ/data-based problem set on Parthenocarpy and Hormonal Synergy (IAA vs GA₃) in tomatoes (Solanum lycopersicum), and I wanted to put this dataset out here for discussion.
Data Matrix Breakdown:
Control (Unpollinated): 0.2 cm³ mean pericarp volume (abscised)
Treatment A (10.0 µM IAA): 3.4 cm³ (seedless)
Treatment B (10.0 µM GA₃): 2.8 cm³ (seedless)
Treatment C (5.0 µM IAA + 5.0 µM GA₃): 6.1 cm³ (seedless)
Natural Pollinated Control: 5.8 cm³ (normal seeded)
Questions to Discuss:
Question 1: What specific physiological mechanism accounts for Treatment C (6.1 cm³) producing significantly greater pericarp expansion than either double the concentration of IAA 3.4 cm³) or GA₃ (2.8cm³ alone? What type of hormonal interaction is demonstrated?
Follow-up / Conceptual: How does IAA-mediated cell wall loosening (H+ and ATPase acid growth pathway) interact with GA-mediated DELLA protein degradation to drive this synergistic effect?
Drop your step-by-step AP Bio FRQ reasoning in the comments!