Accumulation of Trigonelline in the Leaves of Hemp ( Cannabis sativa ) in Response to Water-Deficit Stress

Trigonelline (TRG) has been proposed as a molecular marker of water-deficit stress in plants. This study evaluated whether trigonelline accumulates in hemp ( Cannabis sativa L.) leaves under water-deficit conditions and whether responses differ between cultivars. Two cultivars (‘Jin Ma’ and ‘NWG 2730’) were introduced to water-deficit stress in a controlled greenhouse experiment by withholding irrigation. Trigonel-line was detected in leaves of both cultivars and increased by 451% under water-deficit stress, rising from 0.25 ± 0.08 µmol·g⁻¹ FW to 1.14 ± 0.56 µmol·g⁻¹ FW. Leaf relative water content (RWC) decreased by 58.8%. No significant differences were observed between cultivars for trigonelline concentration or relative water content. These results demonstrate that trigonelline accumulation is a robust physiological response to water-deficit stress in hemp, independent of cultivar. Trigonelline is a reliable and practical biochemical indicator for early drought stress monitoring in commercial hemp production systems.