(b) during dry periods they lose their leaves and blossoms.

Plants have also evolved a wide variety of means for conserving water, which result in different water use efficiencies (WUE). WUE is defined as the biomass of plant tissue produced per gram of water used, and this value will vary among species. The WUE of a plant depends in part on its leaf area relative to its root area or length. Plants with more leaf surface per length of root tend to lose more water. Compared to plants from moist climates, arid land plants generally have less reduced leaf area:root area ratios, and correspondingly higher water use efficiencies. Many plants reduce leaf area over the short term by dropping leaves in response to drought. Some desert plants produce leaves only in response to soaking rains and then shed them when the desert dries out again. These plants reduce leaf area to zero in times of drought.