Abstract: A sand culture pot experiment by using a two-factor completely randomized design was conducted to investigate the growth patterns of Trisetum tibeticum seedlings under nitrogen， phosphorus， potassium deficiency， and water shortage conditions. The experiment included four nutrient treatments： complete nutrition （CN）， nitrogen deficiency （ND）， phosphorus deficiency （PD）， and potassium deficiency （KD）. And four water treatments： 80% field capacity （W₁）， 60% field capacity （W₂）， 40% field capacity （W₃）， and 20% field capacity （W₄）. The results showed that plants of ND treatment exhibited stunted growth with withered leaves， leaves of PD treatment appeared dark green， and leaves of KD treatment showed yellowing and curling at the tips. Water shortage reduced plant height， and growth rates of ND and PD treatments showed declining trends after three weeks. Nutrient-water interactions significantly influenced leaf length， leaf width， root length， root surface area， root volume， above-ground and below-ground biomass， and root-to-shoot ratio （P<0.05）. Under different water conditions， ND treatment consistently resulted in the shortest leaf length， while CN treatment exhibited the greatest leaf width. Water shortage promoted root development in CN treatment， with the largest root surface area and root volume observed at W₄. ND and PD treatments increased the root-to-shoot ratio， with biomass allocation shifting towards below ground parts， while KD had no significant effect on the root-to-shoot ratio. Therefore， the interaction between water shortage and nutrient deficiency synergistically inhibits the growth of Trisetum tibeticum. In seedling cultivation of Trisetum tibeticum， enhanced growth monitoring and timely targeted supplementation should be implemented.

Key words: Trisetum tibeticum, Nutrient deficiency, Water shortage, Seedling growth, Stress interaction

摘要： 为探究西藏三毛草（Trisetum tibeticum）在缺少氮（N）、磷（P）、钾（K）和缺水条件下的幼苗生长规律，本研究采用二因素完全随机组合设计进行砂培盆栽试验，设置完全营养（CN）、缺氮（ND）、缺磷（PD）、缺钾（KD）4个养分处理以及田间持水量的80%（W₁）、60%（W₂）、40%（W₃）、20%（W₄）4个水分处理。结果表明，ND植株矮小叶片干枯，PD叶片暗绿，KD叶尖黄化卷曲。缺水处理的株高减小，ND和PD处理3周后生长速率有下降趋势。养分和水分对叶长、叶宽、根长、根表面积、根体积、地上地下生物量、根冠比具有显著的交互效应（P<0.05）。不同水分条件下ND叶长均最小，CN叶宽均最大。缺水促进CN的根系发育，在W₄时根表面积和根体积最大，ND和PD根冠比增大，生物量向地下转移，KD对根冠比无显著影响。因此，缺水与缺素交互会抑制西藏三毛草的生长，在西藏三毛草幼苗培育中，应加强幼苗生长观测，及时进行针对性地补充。

关键词: 西藏三毛草, 营养缺乏, 水分胁迫, 幼苗生长, 交互效应