Lesson 1 ·Class 10 · Chemical Coordination in Plants · Match Lab
Auxins and Gibberellins
Two hormones with a lot of jobs.
Match each effect to the hormone responsible.
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Nearly every auxin effect traces back to one thing — it makes cells elongate. Ask where the elongation is happening and the effect usually explains itself.
What this lesson covers
Challenges to clear
- Match every effect.
- Connect apical dominance to the hormone effect behind it.
The task
Match each effect to the hormone responsible.
What this lesson covers
- Makes cells elongate, so the shoot grows longer — Auxin — cell elongation (The basic action from which most of its other effects follow.)
- Collects on the shaded side of a shoot, making it bend toward light — Auxin — phototropic bending (More auxin means more elongation on that side, so the stem curves the other way.)
- The tip of the shoot suppresses the side buds below it — Auxin — apical dominance (Remove the tip and the side buds grow. This is exactly why pruning makes a plant bushy.)
- Sprayed on a cutting to make it grow roots — Auxin — root initiation (A standard horticultural use.)
- Used in high concentration as a weedkiller, such as 2,4-D — Auxin — synthetic weedicide (It makes broad-leaved weeds grow uncontrollably until they die, leaving narrow-leaved crops largely unaffected.)
- Makes a dwarf plant shoot up to full height — Gibberellin — stem elongation (The bolting effect. It acts on the internodes.)
- Breaks the dormancy of seeds and buds — Gibberellin — breaking dormancy (Used commercially to get uniform germination.)
- Produces larger fruits, and seedless ones — Gibberellin — fruit development (Familiar from seedless grapes.)
Hint
Nearly every auxin effect traces back to one thing — it makes cells elongate. Ask where the elongation is happening and the effect usually explains itself.