Plant Physiology & Development
Gibberellins, Stem Elongation & Development
Gibberellin signaling contributes to stem elongation, developmental transitions, and other growth processes. Observed stretch is the integrated outcome of hormone signaling, light, temperature, genotype, developmental stage, and resource availability.
Key concepts
- Gibberellins can promote cell elongation and growth in many plant tissues
- Internode length is a phenotype produced by several interacting signals
- Temperature and spectral environment can change elongation independently of total light quantity
- Rapid elongation can alter mechanical support and canopy uniformity
- Developmental transitions can change elongation rate even without a management change
What to measure or observe
- Measure internode length at successive nodes
- Record day and night temperature conditions
- Track elongation during transition into flowering
- Compare canopy zones for light and crowding
- Observe stem diameter and support needs as elongation changes
Common mistakes
- Calling all elongation a nutrient problem
- Assuming gibberellin alone explains architecture
- Using one internode as the entire plant's growth-rate indicator
- Ignoring the flowering transition
- Correcting stretch with severe interventions before measuring the environment
Visuals this lesson still needs
- Internode elongation sequence
- Hormone-light-temperature interaction map
- Vegetative-to-flower stretch timeline
- Stem diameter versus elongation comparison