乌兰布和荒漠生态系统12种沙生灌木苗期的抗旱性

目的]建立沙生灌木抗旱性评价指标体系,为沙区优良树种的筛选提供科学依据。方法]以乌兰布和荒漠生态系统12种沙生灌木的2年生幼苗为材料,测定了7项水分生理指标,采用主成分分析和聚类分析对灌木抗旱性进行了研究。结果](1)麻黄(Ephedra distachyaLinn.)、白刺(Nitraia tangutorum Bobr)及柠条锦鸡儿(Caragana korshinskii Kom.)的水势低于其他9种灌木;霸王(Zygophyllum xanthoxylon Maxim.)的束缚水含量和束缚水与自由水(Va/Vs)比值较高,分别为64.20%,3.3;沙木蓼(Atraphaxis bracteata A.Los.)、白刺及柽柳(Tamarix chinensis Lour.)的蒸腾速率显著低于其他9种灌木;梭梭(Haloxylon ammodendron(C.A.Mey.)Bunge)与麻黄的恒重时间最长,均为144h;沙冬青(Ammopiptanthus mongolicus(Maxim.ex Kom.)Cheng F.)的残留含水率最高(44.80%)。(2)水势、Va/Vs值、残留含水率、束缚水、恒重时间、蒸腾速率6个指标对植物抗旱性的影响较大,累积方差贡献率达87.59%。结论]依照抗旱性大小将12种植物分为三类,强抗旱灌木为麻黄;中抗旱灌木为梭梭、白刺、霸王;弱抗旱灌木为花棒(Hedysannn scoparium Fisch)、杨柴(Hedysarum mongolicum Turcz.)、柽柳、柠条锦鸡儿、沙冬青、沙木蓼、沙拐枣(Calligonum mongolicum Turcz.)、小叶锦鸡儿(Caragana microphylla Lam.)。

Drought Resistance of Twelve Desert Shrubs at Seedling Stage in Ulan Buh Desert Ecosystem

Objective] The objective of this study is to provide the foundation for selecting the excellent afforestation species in sandy area by establishing the drought resistance evaluation system.Methods] Two-year-old seedlings of the twelve desert shrubs in Ulan Buh desert ecosystem were selected as the experimental materials. Through measuring seven water physiological indexes, the drought resistances of the twelve desert shrub species were studied by the principal component analysis and cluster analysis.Results] (1) The water potential of Ephedra distachya, Nitraia tangutorum and Caragana korshinskii was lower than the other nine shrub species. The bound water content and the ratio value of bound water and free water(V_a/V_s) of Zygophyllum xanthoxylon was relatively higher, which was 64.20% and 3.3, respectively. The transpiration rate of Atraphaxis bracteata, Nitraia tangutorum and Tamarix chinensis was significantly lower than the other nine shrub species. The constant weight time of Haloxylon ammodendron and Ephedra distachya was the longest, and it was 144 h. The residual moisture content of Ammopiptanthus mongolicus was the highest(44.80%).(2) The drought resistance of the twelve desert shrubs in Ulan Buh desert ecosystem was significantly influenced by water potential, V_a/V_s, residual moisture content, bound water, transpiration rate and constant weight time, and the cumulative variance contribution rate reached to 87.59%.Conclosion] According to the drought resistance, twelve desert shrubs can be clustered into 3 categories. Ephedra distachya belongs to the strong drought-tolerant shrub; Haloxylon ammodendron, Nitraia tangutorum and Zygophyllum xanthoxylon belong to the medium drought-tolerant shrub; Hedysannn scoparium, Hedysarum mongolicum, Tamarix elongate, Caragana korshinskii, Ammopiptanthus mongolicus, Atraphaxis bracteata, Calligonum mongolicum and Caragana microphylla belongs to the weak drought-tolerant shrub.