in periods of severe water stress and stomata closure, the cuticle's low water permeability is considered as one of the most vital factor in ensuring the survival of the plant. the rate of transpiration of the cuticles of xerophytes is 25 times lower than that of stomatal transpiration. to give an idea of how low this is, the rate of transpiration of the cuticles of mesophytes is only 2 to 5 times lower than stomatal transpiration.