1.The process of leaf color change. Leaves change color during the autumn because the amounts of pigments change as the leaves prepare to fall from trees. All leaves gradually lose chlorophyll during the growing season, and this loss accelerates before leaf fall.
2.The leaves in hot or dry environments may be adapted to reduce transpiration. For example, their stomata may be open at night and close midday. This is the reverse of what usually happens, and it means that the stomata are closet when the rate of transpiration would be greatest.
A cell can only respond to signals from other cells, not from the physical environment. receptor activation. The ability of a specific tissue or organ to respond to the presence of a hormone is dependent on: the presence of the appropriate receptors on the cells of the target tissue or organ.
