Abstract: There are currently the inconsistent conclusions about the relationship between ray tissue and non-structural carbohydrate (NSC) content in xylem. In this experiment, Haloxylona mmodendron, adominant species in the Gurbantunggut Desert,was taken as the test material, the ray tissue, NSC, soluble sugar and starch in ecotypes of gravel soil (distributed in Jinghe), sandy soil (distributed in Shihezi) and loam (distributed in Caijiahu) were determined, and the correlations between the ray anatomical features and NSC as well as its components were analyzed. The results showed that the ray proportion of H.ammodendron varied in a range of 3.69%-7.06%, and that of NSC was in a range of 3.55%-5.87% in the three ecotypes. The values were lower compared with those of tropical and subtropical tree species. This may be caused by the limited photosynthetic process of H.ammodendron due to the lack of soil nutrients, severe drought and salinity stress in desert environment. The precipitation in gravel soil was the lowest, which was characterized by the highest values of ray density, ray proportion, NSC and its components, and was in agreement with the lowest values of ray height and wall thickness of ray cell. However, the values of ray density, ray proportion, NSC and its components in loam were the lowest. The ray proportion was positively correlated with NSC (P<0.01) and starch (P<0.05), but the wall thickness of ray cell was negatively correlated with NSC (P<0.01)significantly. These results indicated that H.ammodendron improved the xylem nutrients, water storage and transportation efficiency to cope with the severe conditions by reducing the wall thickness of ray cell, increasing ray proportion and NSC. The results of this paper were of great significance to understanding the adaptation of the plant to the arid desert regions.

Key words: Haloxylon ammodendron, ray proportion, wall thickness of ray cell, starch, soluble sugar, non-structural carbohydrate, Gurbantunggut Desert