The Action of Guard Cells

Scattered throughout the leaf epidermis are pairs of bean-shaped cells, called guard cells . These cells contain chloroplasts, which are tiny granules filled with chlorophyll . Chlorophyll gives the leaf its green color. Chloroplasts enable leaves to carry on photosynthesis because they are able to absorb sunlight and carbon dioxide, which are essential for the food making process . In response to heat and light, each pair of guard cells pulls apart, and a tiny pore forms between them which are called stoma . …