Correlation of Soil Properties and Fruit Size of Callgonum mongolicum and Related Species

Calligonum mongolicum Turcz. has complex taxonomic relationships with some species, inter-related distributional areas as well as disputed taxonomic relations with other species. Previous studies suggested that there are variable and overlapping states among fruit morphologies for C. mongolicum as well as other species in the genus, C. pumilum, C. gobicum, C. chinense, C. alashanicum, C. roborowskii and C. zaidamense. There are variable and overlapping states among fruit morphologies for C. mongolicum. The fruit characters can not be used in taxon of the genus. As well, the related species and C. mongolicum have slightly different karyotypes. Dr. SHI Wei examined the relationship between soil physical and chemical properties of the habitats and the taxonomic indices of fruit sizes in arid deserts. The purpose of this experiment is to provide reasons for the differences in fruit sizes in different populations of Calligonum and to overturn the use of fruit size as a taxonomic index.

The results showed that the particle size characteristics of soils for growing C. mongolicum and related species were similar, and the soils belonged to sandyones. The organic matter contents of soils were low (averaging 1.772 to 3.054 g/kg), and the total salt content of soils was low too (averaging 0.471 g/kg). The pH values indicated that the soils were alkaline, varying from pH 7.65 to 10.25. The results of Principal Component Analysis (PCA) and hierarchical cluster showed that 9 habitats could be divided into 6 types according to salt contents and pH values. Fruit sizes of different populations and the soil properties had significant linear correlations (P<0.000). It was concluded that the differences in fruit sizes among the populations of C. mongolicum and related species were related to soil variability, especially the nutrient contents of soils, and fruit size can not be considered as a taxonomic index of C. mongolicum and related species.

The results have been published on Journal of Arid Land, 2011, 4(1): 63-70. The paper is also archived at http://jal.xjegi.com/EN/abstract/abstract125.shtml. This work was supported by the National Natural Science Foundation of China (Grant No 31100150) and the West Light Talents Cultivation Program of Chinese Academy of Sciences (XBBS 201003).