What are the signs of water stress in plants?

The signs of water stress in plants are commonly indicated by cell elongation that occurs before any visible wilting becomes evident. This phenomenon happens when plants experience drought conditions; they may begin to stretch their cells in an attempt to reach available water sources deeper in the soil. The elongation is a stress response, as the plant is actively trying to adapt to insufficient water availability.

This proactive mechanism can include alterations in the growth patterns of stems and leaves, allowing the plant to optimize its access to moisture. Initially, while the plant may still appear to have some turgor pressure, the changes at the cellular level signal a problem, ultimately leading to wilting as stress continues.

The other options reflect either the absence of signs of water stress or characteristics indicating healthy plant condition. For instance, thickened stems and leaves do suggest a plant that has access to adequate water and nutrients; even distribution of water is a sign of a well-managed irrigation system, not stress, while a healthy green appearance indicates that a plant is thriving and not under duress. Therefore, the correct choice highlights a critical phase in how plants initially react to water scarcity.