All species of plants pass along DNA to succeeding generations with the goal of surviving. Plants that inherit DNA characteristics that enable them to survive the rigors of a particular climate are said to have adapted; plants that are unable to adapt die out. There is a wide range of adaptations, depending on the climate.
Succulents and cacti store water in their stems or leaves. These may be covered with a waxy coating to prevent the loss of water and with spines to prevent animals from eating the stems or leaves for water. Since leaves lose water during photosynthesis, some plants only grow leaves after it rains or have no leaves and conduct photosynthesis in their green stems. The roots of desert plants go deep or spread wide to collect all possible water. Some plants grow to maturity and die quickly in a short spring growing season.
Temperate Grassland Plants
Temperate grasslands are cold in the winter and hot in the summer with frequent fires. Plants have thick bark and roots that grow back quickly after a fire. Grasses grow from the roots, not the tips, to protect them from fire and grazing animals. Their deep roots are better able to absorb moisture and are not easily pulled out by grazing animals. They have narrow leaves to prevent loss of water; their soft stems bend in the wind.
Plants in Rain Forests
Trees in temperate rain forests, such as firs and redwoods, grow very tall. In their shadow, ferns and mosses grow on other plants to reach sunlight. Seedlings often grow on fallen, decomposing logs.
Plants in tropical rain forests often have smooth bark and waxy flowers and leaves with sharp tips to shed water quickly. Plants living at the bottom of tall canopies receive little or no light; some grow on vines to reach the light. The rapidly growing plants have shallow roots that quickly use decomposing organic material; tall trees may have stilt, prop or buttress roots to hold them erect. Some plants grow on other plants or have aerial roots.
Trees with needles and cones dominate the taiga, which has warm summers and cold winters. Some trees grow above a permanent frozen layer called permafrost. Their needles conduct photosynthesis immediately when temperatures rise. These thin needles shed snow and lose less water than do broad leaves. Their dark color absorbs more heat. Drooping branches also shed snow easily.
Few species are adapted to grow above the year-round permafrost of the tundra. The roots of some small plants are unable to get past the permafrost. Their dark colors help them absorb heat; some are covered with hair to keep them warm. They grow in clumps for mutual protection, and their dishlike flowers follow the warmth of the sun.
Water plants often have flexible stems and leaves that move with the current; their stems often have air spaces to help them float. They absorb dissolved gases directly from the water. Their roots anchor them; they do not absorb water or nutrients. Some plants float on the surface where their leaves conduct photosynthesis. Many plants yield seeds that float.