Plant structure

• Guard cells regulate stomatal opening and closing to control gas exchange.
• Water enters through osmosis from the mesophyll cells into the guard cells, causing them to swell and push against one another, resulting in an increase in turgor pressure.
• Stomata are open during the day when photosynthesis occurs, allowing carbon dioxide (CO2) entry into the leaf.
• Guard cells control the opening and closing of stomata based on environmental conditions such as light intensity, humidity, and temperature.
• The epidermis is composed of cells with thick cell walls that have a waxy cuticle layer on the outer surface to prevent water loss.
• The epidermis acts as a protective barrier against environmental stresses such as water loss, damage, and pathogens.
• Stomata are important because they allow gases such as carbon dioxide (CO2) and oxygen (O2) to enter and exit the plant, while also controlling water loss.
• The stomata close at night or under dry conditions to prevent water loss.
• Transpiration is the process by which plants lose water vapor through their leaves.