ABSTRACT
NaHCO3 stress and hemp (Cannabis sativa L.) adaptation: Growth physiology-metabolism synergy in saline-alkaline environments

Yunshu Ye1, Zimeng Li1, Haoyu Wang1, and Yuhong Zhang1*
 
Salt and alkaline stress pose major challenges to global agriculture, negatively affecting crop production. It is essential to understand how hemp (Cannabis sativa L.) adapt to these stresses in order to improve cultivation in affected regions. This study investigated the adaptive responses of hemp to sodium bicarbonate (NaHCO3) stress by evaluating growth, photosynthetic performance, physiological characteristics, nutrient distribution, and secondary metabolite accumulation under different NaHCO3 concentrations (0, 100, 200, and 300 mM). Low NaHCO3 concentration (100 mM) had nonsignificant effect on hemp growth (p > 0.05) and even increased root dry weight by 32.31%. However, higher concentrations (200, 300 mM) significantly inhibited growth, reducing plant height by 20.70%-28.87%, stem diameter by 30.40%-52.48%, root length by 23.08%-33.25%, and leaf dry weight by up to 81.60%. Mild stress enhanced photosynthetic performance, with increases in SPAD (6.02%), net photosynthetic rate (20.64%), stomatal conductance (26.94%), transpiration rate (18.99%), and intercellular CO2 concentration (9.61%), whereas severe stress markedly suppressed these parameters. The NaHCO3 stress promoted Na+ accumulation, particularly in roots (up to 630.91%), while reducing the uptake of K+, Ca2+, Mg2+, N, and P. Moderate stress enhanced antioxidant defense and stimulated secondary metabolism, resulting in increases of 86.75% in total flavonoids, 145.92% in total phenolics, and 60.63% in cannabidiol, whereas these metabolites declined under severe stress. These findings could help to optimize hemp cultivation to improve salinity tolerance and contribute to the understanding of salinity stress responses in other important economic crops.
Key words: Antioxidant enzymes, Cannabis sativa, mineral elements, NaHCO3 stress, nutrient uptake, secondary metabolites.
1Northeast Forestry University, Key Laboratory of Forestry Plant Ecology of Ministry of Education, Harbin 150040, Heilongjiang Province, China.
*Corresponding author (pzhangyh@nefu.edu.cn).
Received: 19 April 2026; Accepted: 17 July 2026, Available online: 7 September 2026.