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Download Adaptation - Lycée Romain Rolland
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Adaptation Water uptake Strategy Deep-roots (phreatophytes) How this strategy works Obtain water from a permanent ground supply or from the water table Extensive shallow lateral Absorb surface moisture through root hairs roots Water storage Succulent leaves, stems Specialised water-storage tissues allow plants to take up and water when it is plentiful, tubers and release it during times of drought Ridged stems Allow expansion so the plant balloons rapidly to store water when it rains. The ridges slowly contract as water reserves are used up. Reducing water loss Globe shape Maximises the stem’s water storing capacity, while minimising the surface area Waxy leaves through which water evaporates. Leaves are the main site of water-loss; the waxy coating reduces water loss Few or sunken stomata Reduces transpiration Crassulacean metabolism acid The CAM pathway allows stomata to remain shut during the day, thereby reducing (CAM) transpiration. It is common in plants adapted to arid conditions. Few or no leaves Leaves have evolved into spines, and the plant has green stems for photosynthesis. Hairy or surface spiny Drop leaves periods outer Creates a humid microhabitat around the plant, reduces air movement near the plant surface in dry Reduces transpiration – e.g. Fouquieria splendens only grows leaves after it rains.
