sentence: Plants lose water through stomates.
sentences_before: Guard cell's are types of cells that surrounds stomates in plants.
sentences_after: Guard cells are able to open and close the stomates to save water. Guard cells are activated by sunlight. When water follows, the cells get hard and they push open. At night, guard cells lose water and close again.
concept_name: plant
headings: Guard cell
categories: Plant anatomy Cells