Explain the structural factors that increase the rate of transpiration

• Some plants with a thick waxy cuticle that is waterproof to lower the rate of transpiration.
• Small leaves, which are needle-like in shape, hence reduced surface area exposed, lowering the rate of transpiration. Broader leaves have a large surface area exposed hence a higher transpiration rate.
• Rolled leaves have reduced surface area exposed for transpiration.
• Rolled leaves also trap moisture reducing saturation deficit hence minimizing transpiration rate.
• Plants with many stomata experience higher transpiration rates compared to those with fewer stomata.
• Plants with more stomata on the upper side than on the lower side experience higher rates of transpiration.
• Some have sunken stomata with sunken pits that trap moisture; reducing saturation deficit and hence minimizing transpiration rate.
• Some have hairy stomata with hairs that trap moisture; reducing saturation deficit hence minimizing transpiration rate.
• Leaves with many and large air spaces will lose more water than a leaf with fewer and smaller air spaces. This is because large air spaces have mesophyll cells from which water evaporates into air spaces. This increases the rate of transpiration.

• Some plants have hairy leaves, hairs trap water vapour hence reducing the saturation deficit hence reduce rate of transpiration.