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水分和氮素是植物生物量积累的重要资源，也是调节植物在荒漠逆境条件下生物量分配的主要因素。本研究以两种荒漠优势植物红砂(Reaumuria soongarica)和珍珠猪毛菜(Salsola passerina)苗木为试验材料，研究了降水[–30% (低水)、0 (中水)、+30% (高水)]与氮素[0 (N0，无氮)、4 g·(m2·a)−1 (N1，中氮)、8 g·(m2·a)−1 (N2，高氮)]交互作用对其不同生长方式(红砂单生、珍珠猪毛菜单生、红砂和珍珠猪毛菜混生)下的生物量分配及相关生长关系的影响。结果表明：1)红砂和珍珠猪毛菜幼苗受水分和氮素影响显著(P 茎 > 叶。混生红砂的根、茎、叶生物量分别在无氮和低水、无氮和中水、低氮和高水条件时有所增加，其分配关系为叶 ≥ 茎 > 根。单生和混生珍珠猪毛菜均在低氮和高水时器官生物量增加，两者生物量分配关系一致，均表现为叶 > 茎 > 根。2)混生方式下的红砂和珍珠猪毛菜叶根重比、叶重比、源汇重比均高于单生方式，而根冠比则较单生分别平均减少了52.63%和37.45%，说明两种植物在混生过程中均能将更多的生物量分配到地上部分。未来在降水格局和氮沉降变化条件下，红砂和珍珠猪毛菜的混生状态将可能比其单生状态更有利于适应全球气候的变化。“,”Water and nitrogen are important resources for plant biomass accumulation, as well as the main factors that regulate biomass allocation in different plants and their growth patterns under adverse conditions. In this study, the seedlings of two dominant desert plants, Reaumuria soongarica and Salsola passerina, were used as test materials to study the synergistic effect of precipitation [–30% (low water), 0 (medium water), +30% (high water)] and nitrogen [0 (N0, no nitrogen, 4 g·(m2·a)−1 (N1, low nitrogen), and 8 g·(m2·a)−1 (N2, high nitrogen)] on biomass distribution and related growth relationships under different growth modes (R. soongarica grown separately, S. passerina grown separately, and R. soongarica and S. passerina grown together). The results showed that: 1) R. soongarica and S. passerina seedlings were significantly affected by water and nitrogen (P stem > leaf. The root, stem, and leaf biomass of mixed R. soongarica increased as the conditions went from no nitrogen and low water, to no nitrogen and medium water, and then to low nitrogen and high water, and the biomass distribution was leaf > stem > root. The organ biomass of both separate and mixed S. passerina increased under low nitrogen and high water, and its distribution remained as leaf > stem > root. 2) The leaf-root weight ratio, leaf weight ratio, and source to sink weight ratio of R. soongarica under the mixed mode were higher than those under the separate mode, whereas, the root-shoot ratios under the mixed mode were reduced compared with the separate mode by 52.63% (R. soongarica) and 37.45% (S. passerina), indicating that both species could allocate more biomass to the above-ground parts when grown combinedly. In the future, under changes in precipitation patterns and nitrogen deposition, mixed communities of R. soongarica and S. passerina may be more conducive to adapting to global climate changes than those grown separately, which will lead to the mixed state having an advantage in the desert ecosystems.