Abstract:

Shrub and semi-shrub plants are important vegetation type for maintaining ecosystem stability in arid and semiarid zones.In this study,we collected organ samples of stems,branches,and leaves of 15 species of shrubs and semi-shrubs from the desert zone on the north slope of eastern Tianshan Mountain and determined their calorific values,ash contents and carbon contents to explore the effects of shrub species,organs,AC,and CC on the CV of shrubs and their correlations.The related research can provide a theoretical basis for gaining a through understanding of the study of material and energy cycles in typical desert environments in the arid region.The results showed:1)The whole plant CV (above-ground) of the 15 plants ranged from 14.21 KJ/g (Anabasis brevifolia) to 19.87 KJ/g (Berberidaceae),with an average of 18.38 KJ/g,which was higher than of the global average calorific value of terrestrial plants;2) Differences in calorific values and carbon contents existed between families of shrub species.We found that Leguminosae and Compositae had higher calorific values and carbon contents compared to Chenopodiaceae and Polygonaceae species;3)The calorific values,ash contents,carbon contents of the stem,branches,and leaves of the 15 plants differed.The order of the average calorific value of each organ was stem>branch>leaf,the order of the average ash content was leaf>branch>stem,and the order of the average carbon content was branch>stem>leaf;4)Calorific value was negatively correlated with ash content (P<0.01) and was positively correlated with carbon content (P<0.01).

Key words: calorific value, ash content, carbon content, north slope of eastern Tianshan Mountain