PJB-2016-121
ECOLOGICAL IMPLICATIONS AND ENVIRONMENT DEPENDENCE OF THE SEED GERMINATION OF COMMON SPECIES IN COLD DESERTS
SUN YUAN-YUAN1, ZHOU JUAN1, LIU TONG1*, LIU ZUN-CHI1, HAO XIAO-RAN1, LIU HUA-FENG1 AND LI RU2
Abstract
Vegetation is increasingly affected by climate change in cold deserts. Nonetheless, research is limited regarding the natural environmental demands of seed germination in such deserts. This study was conducted in Gurbantunggut Desert as a research base and 17 common species as subjects to investigate the moisture and temperature needs of seed germination in artificial settings, as well as the relationship between characteristics of seed germination and the local distribution of dune and shrubs. Results showed：(1) all tested species generally display low germination percentages that range between 2.9% and 79.6%. Winter snow melt dictates seed germination in cold deserts. Moreover, the subsequent spring rainfall can increase the survival rate of seedlings and significantly affect the process of seed germination. (2) seeds start to germinate only two days after snow melts at the average daily temperature (day/night) of 3.5°C (6.7 °C/-0.5°C) and at a soil volumetric water content of 24.2%. Fifteen days after snow melt, all species germinate when the soil volumetric water content is 6.0% and the average daily temperature is 12.9°C (18.3°C/7.1°C). (3) The seed germination of the tested species can be divided into four patterns: rapid, transitional, slow, and low. Low-pattern plants mainly grow on upper dunes and are significantly associated with shrubs. Rapid- and slow-pattern plants distribute in middle and lower dunes. A few of these plants are significantly associated with shrubs. Transitional-pattern plants generally develop in the low land between hills and middle dunes. This study provides a reference for the actual environmental needs of seed germination in cold deserts and for the temperature and moisture requirements of this process in future experimental settings.
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