(d)Plant
Adaptation to Water and Heat (xerophytes)
They are plants of dry habitats where the environment favours higher rate of
transpiration than the absorption. Xerophytes plants normally have thick
cuticle on their leaf surface, stomata arranged in deep pits, stomata of
xerophyte plant remain closed during day to reduce the high transpirationXerophytes
are four types(i)
Ephemerals (Drought escapers) The plant live for a brief period during
rain. The rest of year is passed in the form of seed Euphorbia prostrate, Boerhaavia(ii)
Annuals or Drought Evaders They live even after the few weeks of rain.
Their, size are small, leaves have thick waxy, hairy coating with or without
prickles, Echinops, Solanum(iii)
Succulents or Drought Resistants The plants have fleshy organs where
water and mucilage are stored. Opuntia, Aloe, Agave(iv)
Non-succulents or Drought Endurers They are true xerophytes which
actually tolerate drought conditions. They have smaller shoot system. The
root system is very extensive. Many tropical plants of hot and arid regions
perform  -photosynthesis. They uses less
water even at high temperature |