The prediction of precipitation depends on accurate modeling of terrestrial transpiration. In recent decades, the trait-based plant hydraulic stress scheme has been developed in land surface models, in order to better predict the hydraulic constraint on terrestrial transpiration. However, the role that each plant functional trait plays in the modeling of transpiration remains unknown. The importance of different plant functional traits for modeled transpiration needs to be addressed. Here, the Morris sensitivity analysis method was implemented in the Common Land Model with the plant hydraulic stress scheme (CoLM-PHS). Traits related to drought tolerance (P50), stomata, and photosynthesis were screened as the most critical from all 17 plant traits. Among 12 FLUXNET sites, the importance of P50, measured by normalized sensitivity scores, increased towards lower precipitation, whereas the importance of stomatal traits and photosynthetic traits decreased towards drier climate conditions. P50 was more important than stomatal traits and photosynthetic traits in arid or semi-arid sites, which implies that hydraulic safety strategies are more crucial than plant growth strategies when plants frequently experience drought. Large variation in drought tolerance traits further proved the coexistence of multiple plant strategies of hydraulic safety. Ignoring the variation in drought tolerance traits may potentially bias the modeling of transpiration. More measurements of drought tolerance traits are therefore necessary to help better represent the diversity of plant hydraulic functions.摘要陆面过程蒸腾作用的模拟制约着天气, 气候降水预测的精确度. 近几十年来, 为了更好地描述植被蒸腾的水力约束, 陆面过程模式发展了基于植物性状的植物水力胁迫方案. 然而, 我们对于植物性状在蒸腾模拟中的地位仍然缺乏了解, 植物性状对蒸腾的重要性仍需进一步量化. 本研究利用Morris方法评估植物性状参数在通用陆面模式植物水力胁迫方案(CoLM-PHS)中的重要性, 针对17种植物性状, 筛选出最为重要的: 耐旱性状(P50), 气孔性状, 和光合作用性状. 在12个FLUXNET站点中, 参数的重要性由归一化敏感度来衡量. P50的重要性随着降水的减少而增加, 而气孔性状和光合作用性状的重要性则随着降水的减少而减少. 在干旱或半干旱地区, P50比气孔性状和光合作用性状更重要, 这意味着当植物经常经历干旱时, 水力安全策略比植物生长策略更关键. 而耐旱性状的巨大变异性进一步暗示了多种植物水力安全策略的共存. 忽视P50的变异性可能会对陆面过程模式蒸腾作用的模拟造成严重误差. 因此, 为了更好地表示植物水力功能的变异性, 需要增加对耐旱性状的观测并耦合到陆面模式中.