xerophytes and hydrophytes Flashcards
what are xerophytes ?
-they are plants that are adapted to live in dry conditions
how are xerophyte leaves adapted the reduce water loss?
-their leaves are rolled inward to protect the stomatal surfaces and the reduce surface area exposed to the environment
-by curving the leaves humid air is created which significantly reduces the water potential gradient between the inside and outside of the leaf
how do xerophytes reduce their surface area to reduce transpiration and evaporation?
-a reduction in the surface area to volume ratio of the leaves can be seen in cacti as their leaves are reduced to needles or spines
where does photosynthesis take place in a cacti?
-the stem
how is the cuticle of xerophytes adapted to reduce water loss?
-thick cuticle makes the waterproof layer even more effective in reducing transpiration and evaporation
how are leaf hairs used to reduce water loss in xerophytes?
-epidermal hairs are present on a xerophytes surface to trap moist air and therefore reduces the water potential gradient between the leaf and the atmosphere
-usually found of the lower epidermis
how are the stomata in xerophytes adapted to reduce water loss?
-the stomata are sunken in which builds up humid air immediately outside the stomata which reduces the diffusion gradient out of the leaf
how are the leaves/ tissues adapted to reduce water loss in xerophytes?
-many xerophytes have succulent tissues/ leaves that store large quantities of water which is used in periods of drought
how are the roots of xerophytes adapted to reduce water loss?
-there is an extensive network of deep and shallow roots
-deep roots can penetrate and reach water well below the ground
-shallow roots can quickly absorb any infrequent rain fall before it evaporates off the top layers of the soil
what is a good example of a typical xerophyte?
-marram grass which is well adapted to living in sand dunes and with stand wind
what are hydrophytes?
-aquatic plants e.g. water lilies or lily pads
how are the air spaces in hydrophytes adapted to aquatic environment?
-they have large air cavities called aerenchym that store gases for respiration, they also keep the plant a float
how are hydrophytes chloroplasts adapted to the aquatic environment?
-they have photosynthetic chloroplasts to make use of the less light in the water for photosynthesis
how are hydrophytes leaves adapted to the aquatic environment?
-some hydrophytes have broad leaves to trap maximum light for photosynthesis and to keep them afloat
how are hydrophytes stomata adapted to the aquatic environment?
-the leaves of hydrophytes contain numerous stomata on their upper side to ensure water loos and to allow maximum gas exchange
