Abstract:

Investigation into whether there is ecological niche separation of nitrogen (N) utilization by the same living type of plants in desert ecosystems can help in elucidating the survival strategies of desert plants and the influence of N on the survival of these plants. In the Gurbantunggut Desert, four short-lived herbaceous plants—Erodium oxyrrhynchum, Hyalea pulchella, Nonea caspica, and Lactuca undulata—are distributed widely. The uptake of different forms of N by these four plants was investigated at different soil depths in different months. The findings revealed that the N uptake rates of all four species in May were higher than were those in April at different soil depths. As for the uptake rates of different forms of N, that of glycine was lower than that of both nitrate and ammonium N. The highest recovery of nitrate N was achieved by N. caspica in April, up to 52.3%. Meanwhile, the highest recovery of ammonium N was achieved by N. caspica in May, reaching 90.7%. The uptake of ¹⁵N by H. pulchella was lower than was that by the other three species. The four short-lived plants could efficiently utilize not only soil inorganic N but also soil organic N, and E. oxyrrhynchum and L. undulata displayed a significant preference for nitrate N uptake. The findings reveal that in the Gurbantunggut Desert ecosystem, short-lived plants have differential and diversified N uptake capacity and can all absorb soluble organic state N sources from the soil.

Key words: eremophytes, isotopic labeling, nitrogen absorption, Gurbantunggut Desert