The response of photosynthesis to the temperature in plants of arid ecosystems of Gobi desert (Mongolia)

摘要

The temperature dependence of potential photosynthesis in plants of Gobi (31 species) desert ecosystems in different altitudes (780-1900 m above sea-level) was investigated by radiometric method. New integral indexes reflecting the response of photosynthesis to sub- and superoptimal temperatures are introduced. Variation of these indexes among different plants is associated with environmental parameters, biological and morphological characteristics, and history of plant species. The evolutionary adaptation of plants in Gobi occurred towards increasing cold-resistance of photosynthesis. As a result the amplitude of thermotolerance of photosynthesis was considerably widened in the dominant species grown under cryo-arid conditions of Gobi. The levle of photosynthesis thermotolerance is usually the highest in the plants of Central Asian origin.