关键词: 盐生植物, 盐节木, 盐爪爪, 根长密度, 根生物量, 离子含量

Abstract:

Halocnemum strobilaceum and Kalidium foliatum are two dominant species in halophytic plant communities in Xinjiang. The strong adaptability to salinity is probably related to the characteristics of their root systems. The field investigation and laboratory analysis were used to examine the distribution patterns of root systems, the water content of different diameter roots, and the ion contents in soil, root xylem and cortex of the two halophytes. Results showed that the roots of H. strobilaceum and K. foliatum vertically distributed as deep as 70 and 80 cm soil layers, and most roots distributed in 30-60 and 20-50 cm depths respectively. Roots horizontal distribution of the two species all exceeded 140 cm. The distribution pattern of root fresh weight in soil was similar to that of root length density. pH value, and the contents of salt and water in different edaphic layers may influence the pattern of root distribution. As for H. strobilaceum, the root length of diameter less than 0.3 cm accounted for only 10.33% of total root length, and the mean water content in root cortex with the root diameter from 0.3 cm to 0.5 cm was highest (78.10%). As for K. foliatum, the root length of diameter less than 0.2 cm was 7.81% of total root length, and the mean water content in root cortex of the root diameter from 0.5 cm to 0.6 cm was highest (68.01%), suggesting that the high water content in root cortex may contribute to the adaptability to saline. In both species, the contents of Cl^-, SO^2-₄, Mg²⁺, and Ca²⁺ in root cortex and xylem were relatively high and positively correlated with these ions in soil. With the exception of Ca²⁺, the contents of other ions were insignificantly different (P>0.05) between root cortex and xylem. It is suggested that the high content of Ca²⁺may promote plants adapting to the saline soil.

Key words: halophyte, Halocnemum strobilaceum, Kalidium foliatum, root length density, root biomass, the content of ions