AP BIOLOGY

Detailed explanation-1: -Xerophytes have dense hairs known as trichomes all over the plant including leaves. Trichomes act as a barrier to the wind so as to reduce exposure of stomata to sunlight. Stomata are present sunken in these trichomes.

Detailed explanation-2: -Forming water vapour-rich environment Some xerophytes have tiny hair on their surfaces to provide a wind break and reduce air flow, thereby reducing the rate of evaporation. When a plant surface is covered with tiny hair, it is called tomentose.

Detailed explanation-3: -Trichomes may limit water loss by transpiration through an increase of the leaf–air boundary layer resistance (Palliotti et al., 1994; Guerfel et al., 2009; Mo et al., 2016).

Detailed explanation-4: -In xerophytic plants (cactus), the epidermal layer secretes a thick and waxy layer called the cuticle. This layer closes the stomata and prevents water loss by the transpiration process (water-resistant layer). As the cactus plant lives in a water-deficit area such thick and waxy cuticle is seen.