Topic 13 - Environmental stresses limit resource capture and use
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Essential elements from Topic 13:
  1. Plants are exposed to multiple environmental stressors, which can occur singly or in combination. These stressors include water, sunlight, edaphic, air pollutants, and temperature.
  2. Adaptive responses to stressors can be broadly categorized as avoidance and tolerance.
  3. Osmotic adjustment is a common response to water deficits.
  4. Stomata are an increasing constraint on productivity, as regional climate gets drier.
  5. Carbon isotope ratios are used as an integrated measure of stomatal function relative to photosynthesis.
  6. The xanthophyll cycle is of advantage to plants in avoidance of damage associated with excess light conditions.
  7. Paraheliotropic leaf movements, changes in leaf spectral characteristics, and adjustments in leaf angle are of advantage to plants in avoidance of damage associated with excess light conditions.
  8. The Arizona monsoon boundary creates a summer moisture gradient in soil water availability that affects plant distributions.