What you will learn in Growth, hormones and timing in plants

1. 1. Growing and becoming

   Growth as an irreversible increase, the S-shaped curve it draws, and a cut piece of stem that becomes roots or shoots.

2. 2. Hormones, by concentration and tissue

   Auxin at one concentration, read in three tissues — and the five hormone groups taught through what each does where.

3. 3. Moving by growing

   Phototropism and gravitropism as one flank growing faster than the other, and the century-old experiments that found the signal.

4. 4. Knowing what time of year it is

   Photoperiodism, the night break, and why the names short-day and long-day describe the wrong half of the cycle.