Effects of drip irrigation regimes on leaf structure, photosynthesis, yield, and quality in Atractylodes chinensis (DC.) Koidz

Introduction Atractylodes chinensis (DC.) Koidz, a medicinal herb in the Chinese Pharmacopoeia, is grown in sandy soils. However, water scarcity in the Horqin Sandy Land limits its growth, and the effects of irrigation remain poorly studied. This research aimed to determine how irrigation levels affect its yield and quality through leaf structure, physiology, and secondary metabolism. Methods A field experiment tested five irrigation rates (4500–2500 m 3 ·hm −2 ). We measured leaf anatomy, photosynthetic parameters, yield, and quality indicators. Results and discussion Irrigation altered leaf anatomy (palisade and spongy tissue thickness). Photosynthetic pigment content showed a initial increase then decrease with reduced irrigation. An irrigation rate of 3500 m 3 ·hm −2 maintained high electron transfer efficiency, carbon assimilation, and key enzyme activity for alkaloid synthesis. While yield declined with less water, quality peaked at moderate irrigation. Moderate irrigation (3500 m 3 ·hm −2 ) best balances yield and quality by supporting both physiological function and secondary metabolism. These findings offer a theoretical basis and practical guidance for cultivating A. chinensis in water-limited sandy lands under climate change.