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Researchers Reveal Physiological Sensitivity of Syntrichia caninervis to Snow Cover was Regulated by Freeze–Thaw Cycles

2021-11-08

Researchers from Xinjiang Institute of Ecology and Geography, the Chinese Academy of Sciences, has found that freeze-thaw cycles changed the physiological sensitivity of Syntrichia caninervis to snow cover.

Spring, especially the freeze–thaw season, is considered the key period for the growth and carbon sequestration of desert mosses. It is not clear how the change in environment water and temperature affects the physiological characteristics of desert mosses in freeze–thaw season. In this study, the effects of snow cover and freeze–thaw cycles on the physiological characteristics of S. caninervis were assessed by manipulating the increase or removal of 65% snow and changes in the freeze–thaw cycles.

Our results showed that the changes in snow cover and freeze–thaw cycles in late winter and early spring significantly affected the growth and physiological characteristics of S. caninervis. Along with the decrease in snow depth and freeze–thaw cycles, the contents of free proline, soluble sugar, ASA, GSH, and MDA, as well as SOD, POD, and CAT activities, significantly increased. These results confirmed that S. caninervis can resist environmental stress by regulating the content of osmotic substances and the activity of antioxidant enzymes. However, the sensitivity of physiological characteristics of S. caninervis to snow cover and that to freeze–thaw cycles was different. POD and free proline were the most sensitive, while SOD and CAT were insensitive.
These results provide important reference for the selection of evaluation indexes of stress resistance of desert mosses. However, for the transcript abundance level of antioxidant enzyme related genes, not all transcript abundance levels of related genes increase with the decrease of snow depth. This may indicate that the genes characterizing the same protein in S. caninervis are fully functional at the same time, and high transcript abundance level will not be translated quickly to produce a large number of proteins.
The results indicated that the physiological sensitivity of S. caninervis to snow was regulated by the number of freeze–thaw cycles, and the reduction in freeze–thaw cycles weakened the physiological sensitivity of S. caninervis to snow.
These results are vital for a comprehensive assessment of the maintenance of desert plant diversity under global climate change in the temperate desert.
The findings were published in Journal of Plant Physiology, entitled "Freeze-thaw cycles change the physiological sensitivity of Syntrichia caninervis to snow cover ". 
Fig. 1 The gene relative expression level of associated with the SOD, POD and CAT.
Fig. 2 Sensitivity characteristics of S. caninervis to snow cover under different freeze–thaw cycles.
 
Contact: LIU Jie, Xinjiang Institute of Ecology and Geography