to repair or replace the organs damaged. As it is often difficult to prevent damage, many alpine plants depend on the replacement of their organs. They help make this possible by placing their meristems below ground, where temperatures are generally warmer. Photosynthesis and respiration rates Photosynthesis and respiration rates are not uniform throughout the growing season. At the start of the growing season, new shoots have low net photosynthesis rates and high respiration rates due to rapid growth of new shoots. As the temperature rises in a plants microclimate, the net photosynthesis rates will increase as long as ample water is available and will peak during flowering. Alpine plants are able to start photosynthesizing and reach maximum photosynthesis rates at lower temperatures compared to plants adapted to lower elevations and warmer climates. This is due to the combined effects of genotype and environmental factors. Avoidance of desiccation In alpine areas, water availability is often variable. Bryophytes and lichens exhibit high desiccation tolerance, which contributes to their abundance throughout all alpine areas habitats. Among higher plants, tissue desiccation is rare at high elevation. If it does occur, it normally happens to plants growing on exposed sites, where wind stress is increased. Alpine plants avoid water loss by deep rooting and increased stomatal control. Plants at low elevation normally reach a maximum stomatal opening in the morning while alpine plants reach maximum opening mid-day when the temperature is greatest. Alpine succulent plants often utilize CAM photosynthesis to avoid water loss. Avoidance of ultraviolet radiation Because ultraviolet radiation tends to increase with elevation, it is often assumed to be a stress factor among alpine plants. In the past, there have been many attempts to research how ultraviolet radiation may influence alpine plant forms. However, it is uncertain if the growth and development of plants are affected by ultraviolet radiation. It is also not clear if the radiation is responsible for promoting genetic differentiation, leading to stunted growth forms. Reproduction Alpine plants use both sexual reproduction and asexual reproduction. Sexual reproduction has limits in high alpine areas, especially in areas with a short growing season in alpine zones at high latitudes. In tropical alpine zones with a year-round growing season, such as the northern Andes, plants can flower year-round. Regardless of when alpine plants flower, pollinators are often scarce. The activity of pollinators decreases with increasing elevation. The most common pollinators in the alpine