Water deficit response
Soil drying triggers ABA (abscisic acid) accumulation, closing stomata and inducing stress-protective proteins (dehydrins, LEA proteins).
Osmotic adjustment
Cells accumulate compatible solutes (proline, glycine betaine, sugars) to maintain turgor without toxic ion levels.
Measurement
- Predawn leaf water potential with pressure chamber
- Stomatal conductance with porometer
- Soil moisture sensors at root zone depth
Agricultural relevance
Irrigation scheduling based on physiological thresholds saves water while maintaining yield.