关键词: 古树, 古树, 草坪, 土壤微生物

Abstract:

The aim was to provide the foundation to establish the evaluation indicators system of the drought resistance of the desert shrub and to select the excellent afforestation species. One-year-old seedlings of the six desert shrubs in Ulan Buh Desert, Nitraria tangutorum, Nitraria sibirica, Zygophyllum xanthoxylon, Ammopiptanthus mongolicus, Caragana korshinskii and Reaumuria trigyna were selected as experimental materials. The pot experiment was conducted with the repeated drought method. Many morphological and growth indices and photosynthetic and water physiological indices were measured. After the treatment of PCA, their comprehensive analyses on drought resistance were conducted with the subordination function method. It was showed that eight indices, stomatal conductance, water use efficiency, water potential, branch length, root dry weight, lateral root number, total leaf number and lateral branch number, could be treated as the important indicators of drought-resistant evaluation for the desert shrub. Compared with the water normal treatment, the value of stomatal conductance and water potential of all shrubs decreased in the water stress treatment, but the water use efficiency increased. Among the six shrubs, Reaumuria trigyna was provided with the maximum variation range. Meanwhile the morphological and growth indices presented the different variation differences for the six shrubs. Based on the comprehensive evaluation of the multi-indices analysis, the drought-resistance order of the six desert shrubs was as follows: Reaumuria trigyna > Zygophyllum xanthoxylon > Caragana korshinskii > Nitraria tangutorum > Ammopiptanthus mongolicus > Nitraria sibirica.