Below-ground storage organ morphology mediates resource allocation and climate adaptation strategies in ephemeral desert plants

Desert perennials must strategically allocate limited resources between survival and reproduction under highly variable climatic conditions. Below-ground storage organs (BSOs) are critical adaptive structures, but how to influence life-history strategies remains poorly understood. We investigated how contrasting below-ground storage organ (bulb vs. tuber) mediates resource allocation strategies in desert environments.Over a seven-year field experiment (2017–2023) in the Gurbantunggut desert, we compared phenology, biomass allocation, nutrient storage thresholds, and reproductive output between bulb Allium pallasii and tuber Eremurus inderiensis under pronounced climatic fluctuations.A. pallasii demonstrated an opportunistic, ‘fast’ life-history strategy, marked by early reproduction at low nutrient reserves (~0.7 mg N, approximately 3-fold accumulation), moderate seed output (20 –50 seeds/plant), and drought avoidance through early dormancy. In contrast, E. inderiensis adopted a conservative ‘slow’ strategy, characterized by substantial biomass investment in tuber, delayed reproduction at high nutrient thresholds (~20 mg N, approximately 185-fold accumulation), drought tolerance, and high seed production (>300 seeds/plant).These findings confirm that BSO morphology drives distinct bet-hedging strategies in desert perennials, and highlight that BSOs intensify contrasting adaptive strategies, shaping species-specific trade-offs between reproduction timing, resource investment, and drought resilience, with significant implications for understanding perennial plant adaptation under climate variability.