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Acta Prataculturae Sinica ›› 2026, Vol. 35 ›› Issue (1): 65-78.DOI: 10.11686/cyxb2025073

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Effects of changes in precipitation on stomatal morphology and photosynthetic and physiological characteristics of major species in desert steppe plant communities

Wen-hui DENG1(), Ke-chen SONG1, Hao ZHANG1, Si-yu GUAN1, Jia-yi YONG1, Tie-na XIE2, Hai-ying HU1()   

  1. 1.College of Forestry and Grassland,Ningxia University,Yinchuan 750021,China
    2.Institute of Science and Technology,Ningxia University,Yinchuan 750021,China
  • Received:2025-03-06 Revised:2025-04-21 Online:2026-01-20 Published:2025-11-13
  • Contact: Hai-ying HU

Abstract:

In this study, we investigated the photosynthetic adaptation mechanisms of five dominant plant species in the desert steppe of Ningxia (Stipa brevifloraLespedeza secalinusLespedeza potaniniiConvolvulus ammannii, and Polygala tenuifolia) under altered precipitation regimes. Three treatments were applied: precipitation increased by 50% (PA), natural precipitation (CK), and precipitation decreased by 50% (PR). We examined changes in leaf photosynthetic parameters, stomatal morphology, and water use efficiency (WUE) to elucidate how these plants adapt to varying water availability. The results show that desert steppe plants were able to enhance their drought tolerance by increasing the stomatal perimeter and area, thereby reducing the transpiration rate and stomatal conductance. These adaptations lowered the net photosynthetic rate (Pn) and increased the WUE. C. ammannii exhibited the highest sensitivity of Pn to changes in precipitation, with the Pn in the PA treatment being 6.65-fold that in the PR treatment, although it had the lowest WUE among the five plants. L. secalinus had the highest WUE, followed by S. breviflora and P. tenuifolia. The specific leaf area (SLA) of all species significantly increased with reduced precipitation (P<0.05). Stomatal shape also influenced drought adaptation; rounder stomata were correlated with higher WUE, whereas elongated stomata were correlated with enhanced Pn. As indicated by changes in photosynthesis and water use, the five plants were ranked from highest ecological adaptability to lowest as follows: S. breviflora>L. secalinus>P. tenuifolia>C. ammannii>L. potaninii. These findings provide theoretical insights into the management of desert steppe ecosystems under the conditions of global climate change.

Key words: desert steppe, precipitation variability, photosynthesis, stomatal characteristics, δ13C, specific leaf area