This study investigates the physiological responses of Artemisia absinthium L. seedlings propagated in vitro and acclimatized under arid zone conditions, with a focus on transpiration dynamics and the accumulation of photosynthetic pigments across key phenological stages. Diurnal transpiration rates were monitored during the vegetative, flowering, and seed formation stages, revealing a distinct midday peak in water loss. The highest transpiration rate (903.7 ± 12.4 mg/g·h) was recorded at the vegetative stage, indicating elevated water use during early development. In contrast, chlorophyll a and b contents exhibited a progressive decline from the vegetative to the seed formation stage, suggesting a reduction in photosynthetic efficiency under advancing drought stress. Meanwhile, carotenoid levels increased across the developmental stages, reflecting their role in photoprotection and oxidative stress mitigation. These physiological adjustments demonstrate the adaptive strategies employed by A. absinthium to cope with arid environmental pressures. The results support the potential application of microclonally propagated A. absinthium in ecological restoration of degraded rangelands in water-limited regions.