The Secondary xylem characteristics were described and compared in details from an ecological perspective in eight xerophytic species grown in arid sandy region in China. All the species showed similar wood structure: obvious growth ring boundaries except sometimes discontinuous in Tetraena mongolica and Zygophyllum xanthoxylum. Ring to semi-ring-porosity; simple perforation plate; alternate intervessel pitting;non-septate fibres; paratracheal confluent axial parenchyma; helical thickenings and heterocellular rays. But there were few quantitative differences of ray and vessel observed among them. Rays are mainly uniseriate in T. mongolica , 2 ～ 5-seriate in Ammopiptanthus mongolicus , Lespedeza bicolor , Nitraria tangutorum and Z. xanthoxylon, commonly 4～10-seriate in other three species. T. mongolica and A. mongolicus had narrower vessels and larger vessel frequency than other six species that had wider and smaller vessel frequency, which could lead to a smaller vulnerability and mesomorphy value. There was significant difference in both fibre length and vessel element length among-tree and within-tree. Thus it was considered that the anatomical features of T. mongolica and A. mongolicus were more likely to suffer from water stress than that of other species.%从生态学角度对8种旱生植物木材的次生木质部结构进行了对比研究.结果表明,8树种次生木质部结构的共同特点为:生长轮分界明显(霸王和四合木的年轮有时不连续),半环孔材,单穿孔,导管壁间纹孔互列,木纤维无横隔膜,联合傍管轴向薄壁组织丰富,导管壁上呈现螺纹加厚,都具有异型射线;它们主要差异在于射线和导管的数量化指标:四合木异型射线1～2列,霸王、白刺、沙冬青和胡枝子射线2～5列,柽柳、柠条和花棒大型射线4～10列;导管分子长度和纤维长度在树种间和同一树种个体间差异较明显.四合木和沙冬青导管频率较大,导管管孔较小,因此Vulnerability和Mesomorphy值也较小,更能适应干旱环境.
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