Graduate Research Course
Flower Biology & Biochemistry
From the ABC model of floral development to scent biochemistry and co-evolutionary arms races with pollinators — the complete biology of flowers in 9 modules.
Key Equations of Flower Biology
ABC Model of Floral Identity
\( A = \text{sepal}, A+B = \text{petal}, B+C = \text{stamen}, C = \text{carpel} \)
Flavonoid Biosynthesis
\( \text{PAL: Phe} \rightarrow \text{cinnamate} \rightarrow \text{chalcone} \rightarrow \text{anthocyanin} \)
Pollination Kinetics
\( V(r) = V_{\max} \cdot e^{-r/\lambda} \)
Nectar Dilution Optimization
\( \eta(c) = \frac{c \cdot \text{energy/mol}}{\mu(c)} \)
Selfing Rate
\( s = \frac{\text{self pollen}}{\text{self + outcross pollen}} \)
Heritability
\( h^2 = V_A / V_P \)
About This Course
Flowers are the reproductive innovation that, within roughly 100 million years, transformed the terrestrial biosphere. The angiosperm flower is simultaneously a developmental marvel — four concentric whorls patterned by a handful of MADS-box transcription factors — a chemical factory producing anthocyanins, terpenoids, and benzenoids, and a signaling interface engaged in a 130-million-year co-evolutionary conversation with pollinators.
This course takes a quantitative, biochemical, and evolutionary approach to floral biology. We derive the ABC(DE) quartet model from first principles, trace the enzymatic cascades of pigment and scent biosynthesis, model pollinator foraging economics, analyze self-incompatibility genetics, and confront the climate-driven phenological mismatches now unraveling plant-pollinator mutualisms worldwide.
Every module includes MathJax derivations, SVG diagrams, and computational models. Cross-links to our Plant Biochemistry, Bee Biophysics, and Ecological Biochemistry courses connect floral form to metabolism, pollinator mechanics, and chemical ecology at the community scale.
Nine Modules
M0
Floral Anatomy & Morphology
The four whorls of the angiosperm flower, floral formulae and diagrams, symmetry (actinomorphic vs zygomorphic), and inflorescence architecture.
M1
Flower Development & ABC Model
The classical ABC(DE) model of floral organ identity, MADS-box transcription factors, quartet model, and the molecular logic of meristem transition.
M2
Pigments & Color
Anthocyanin, carotenoid, and betalain biosynthesis, vacuolar pH control, structural color in petals, and UV nectar guides invisible to human eyes.
M3
Scent & Volatile Biochemistry
Terpenoid, benzenoid, and phenylpropanoid volatile biosynthesis, circadian emission rhythms, and scent as a multi-component pollinator attractant.
M4
Pollination Ecology
Pollinator syndromes, nectar chemistry and reward optimization, buzz pollination biomechanics, and the economics of plant-pollinator mutualism.
M5
Reproduction & Genetics
Self-incompatibility systems (gametophytic and sporophytic), pollen-pistil signaling, double fertilization, and the genetics of mating system evolution.
M6
Phylogeny & Evolution
Angiosperm origins and Darwins abominable mystery, ANA grade to eudicots, co-evolution with pollinators, and the evolution of floral novelty.
M7
Ornamental Horticulture
Breeding for novel colors and forms, cut flower postharvest physiology, ethylene senescence, and the genetic engineering of blue roses and black petunias.
M8
Flowers & Climate Change
Phenological mismatch with pollinators, heat stress on pollen viability, range shifts, and the future of flowering plants in a warming world.
Recommended Textbooks
- [1] Willmer, P. (2011). Pollination and Floral Ecology. Princeton University Press.
- [2] Barrett, S.C.H. (2002). The evolution of plant sexual diversity. Nature Reviews Genetics, 3(4), 274–284.
- [3] Glover, B.J. (2014). Understanding Flowers and Flowering (2nd ed.). Oxford University Press.
- [4] Coen, E.S. & Meyerowitz, E.M. (1991). The war of the whorls: genetic interactions controlling flower development. Nature, 353(6339), 31–37.
- [5] Dudareva, N., Klempien, A., Muhlemann, J.K. & Kaplan, I. (2013). Biosynthesis, function and metabolic engineering of plant volatile organic compounds. New Phytologist, 198(1), 16–32.
- [6] Ollerton, J., Winfree, R. & Tarrant, S. (2011). How many flowering plants are pollinated by animals? Oikos, 120(3), 321–326.