Journal of Integrative Agriculture ›› 2026, Vol. 25 ›› Issue (3): 965-976.DOI: 10.1016/j.jia.2024.11.012

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不同种植密度下棉花叶脉外水力导度是调节气孔导度和水分利用效率中的关键

  

  • 收稿日期:2024-05-28 修回日期:2024-11-12 接受日期:2024-09-24 出版日期:2026-03-20 发布日期:2026-02-06

Critical role of outside xylem hydraulic conductance in regulating stomatal conductance and water use efficiency in cotton across different planting densities

Yunrui Chen1*, Dayong Fan2*, Ziliang Li1, Yujie Zhang1, Yang He1, Minzhi Chen1, Wangfeng Zhang1, Yali Zhang1#   

  1. 1 Key Laboratory of Oasis Eco-agriculture, Xinjiang Production and Construction Corps, Shihezi University, Shihezi 832003, China

    2 State Key Laboratory of Efficient Production of Forest Resources, Beijing Forestry University, Beijing 100083, China

  • Received:2024-05-28 Revised:2024-11-12 Accepted:2024-09-24 Online:2026-03-20 Published:2026-02-06
  • About author:#Correspondence Yali Zhang, E-mail: zhangyali_cn@foxmail.com, zhangyali_shzu@163.com * These authors contributed equally to this study.
  • Supported by:
    This research was financially supported by the Tianshan Talent Development Program, China for Yali Zhang, the Natural Science Foundation of Xinjiang Production and Construction Corps, China (2024DA002), the Earmarked Fund for XJARS-Cotton, China (XJARS-03).

摘要:

水力理论预测叶片水力导度(Kleaf)与气孔导度(gs)之间存在正相关关系;然而,这一理论并未得到充分的观察支持,其潜在机制仍不清楚。目前,将Kleaf细分为木质部内水力导度(Kx)和木质部外水力导度(Kox)为阐明Kleafgs的调节机制提供了新的视角。最优的种植密度可以通过优化gs来提高水分利用效率(WUE);然而,在这一过程中叶片水力特性的变化及其对gsWUE的调节机制尚不明确。我们研究了KxKoxgs、光合速率(AN)和WUE之间的关系,并调查了在12、18、24、36、48、60、72和84株/平方米的8种种植密度下,影响Kox的结构基础。结果显示,随着种植密度的增加,KleafAN保持一致,而Koxgs显著下降。Kox受叶片厚度和细胞间空气空间体积分数的显著影响。KleafKxANgs没有相关性,但Koxgs表现出显著的正相关。此外,KoxWUE显著负相关。这些发现表明,Kox通过调节gs来减少水分损失,同时维持AN,从而在不同种植密度下提高棉花的WUE


Abstract:

Hydraulic theory predicts a positive coupling between leaf hydraulic conductance (Kleaf) and stomatal conductance (gs); however, this theory has not been fully supported by observations, and underlying mechanisms are poorly understood.  Partitioning Kleaf into inside-xylem (Kx) and outside-xylem (Kox) components offers a refined framework for elucidating the regulation of gs by leaf hydraulics.  While optimal planting density may enhance water use efficiency (WUE) through modulation of gs, corresponding changes in leaf hydraulic properties and their influence on gas exchange remain unclear.  We examined relationships among Kx, Kox, gs, leaf photosynthetic rate (AN), and WUE, and analyzed the structural determinants of Kox in cotton grown under eight planting densities: 12, 18, 24, 36, 48, 60, 72, and 84 plants m–2.  Results showed that as planting density increased, Kleaf and AN remained stable, whereas Kox and gs declined significantly.   Leaf thickness and the volume fraction of inter-cellular air space were key structural factors influencing Kox.  Neither Kleaf nor Kx correlated with AN or gs; however, Kox exhibited a significant positive correlation with gs.  Furthermore, Kox was negatively correlated with WUE.  These findings indicate that Kox modulates gs to minimize water loss without compromising AN, thereby enhancing WUE in cotton across varying planting densities.

Key words: cotton , leaf hydraulic conductance ,  water use efficiency ,  planting density ,  mesophyll structure ,  stomatal conductance