Environmental and soil characteristics in Ephedra habitats of Uzbekistan.

Abstract

In Uzbekistan, Ephedra distachya L., E. equisetina Bunge, E. foliata Boiss. ex C. A. Mey., E. lomatolepis Schrenk, and E. strobilacea Bunge show species specificity for habitat environments and physical and chemical characteristics of habitat soils. Furthermore, the relationship between soil characteristics and ephedrine and pseudoephedrine contents was examined. E. distachya was found growing from 80 to 200m above sea level (a.s.l) in the Plateau Ustyurt on the desert steppe of cliffs on soil having relatively higher loss on ignition (19.8-33.8%) and water-soluble cations (Ca2+, 5.14-133.13; Mg2+, 0.85-3.18; and Na+, 2.27-8.33mmol/100g dry soil weight) than for other Ephedra habitats. E. strobilacea was found growing on the flat sandy Kyzylkum desert at 94m a.s.l. and had habitat soil that was the driest with the lowest loss on ignition (2.9%) and highest Na+ (9.05mmol/100g dry soil weight) of all the Ephedra habitat soils. On dry steppe from 1054 to 1819m a.s.l., E. foliata, E. lomatolepis, and E. equisetina formed not only a single community but also a complex community on constantly collapsing sandy gravel slope with relatively higher Ca2+ (3.40-17.44mmol/100g dry soil weight) soil content. Notably, E. equisetina grew on the dry steppe of constantly collapsing sandy gravel slopes, in rocky areas, on sandy gravel floodplains of rivers, and on stable humus soil at the base of coniferous trees in a wide range of habitats from dry steppe to coniferous forest zones at altitudes ranging from 1392 to 1819m a.s.l., as reflected in the greater variability than for other Ephedra habitats in the parameters of loss on ignition (1.4-34.8%), pH (7.1-9.6), NO3- (0.08-35.17mmol/100g dry soil weight), Ca2+ (0.24-17.44mmol/100g dry soil weight), Mg2+ (not detected-1.25mmol/100g dry soil weight), and Na+ (0.13-5.19mmol/100g dry soil weight). Ephedrine alkaloids were not detectable in E. strobilacea, E. foliata, and E. lomatolepis. Almost all E. distachya contained only pseudoephedrine (1.25-1.59% of dry weight, %DW), while E. equisetina contained from 1.31 to 2.05%DW ephedrine and from 1.29 to 2.80%DW pseudoephedrine. Ephedrine and pseudoephedrine in E. equisetina showed a statistically significant negative correlation with soil Cl- and Mg2+, respectively.