Wang Jiaxi, Guo Haiyue, Li Guolei, Gao Fei, Yang Qinsong, Liu Yong
Research Center of Deciduous Oaks, Beijing Forestry University, Beijing, China.
Key Laboratory for Silviculture and Conservation, Ministry of Education, Beijing Forestry University, Beijing, China.
Physiol Plant. 2025 Jul-Aug;177(4):e70413. doi: 10.1111/ppl.70413.
Plant hydraulic performance relies on the coordinated functioning of stomatal, mesophyll, and xylem architecture. However, intraspecific evidence for such integration across climate gradients remains limited. We grew 1-year-old Quercus variabilis seedlings from 15 climatically contrasted provenances in a randomized common garden and quantified 19 anatomical traits across leaves, stems, and taproots. Provenance mean annual temperature, precipitation, and humidity jointly explained most of the observed variations. Seedlings from warmer, wetter origins developed (i) thinner palisade but thicker spongy mesophyll and overall leaves, (ii) smaller, denser stomata, and (iii) wider vessels with thicker walls, higher parenchyma fractions, and reduced fiber content. Root parenchyma covaried with stomatal density, and vessel traits were closely aligned with leaf anatomy, revealing a provenance-scale network that enhances hydraulic conductance, water storage, and stomatal responsiveness while potentially mitigating embolism risk. Although hydraulic vulnerability and conductivity were not directly measured, the convergence of vessel enlargement and wall thickening suggests a functional balance between efficiency and safety. Our findings provide the first intraspecific evidence that Q. variabilis integrates structural adjustments across organs in response to climate, offering new insight into adaptive evolution and informing the selection of drought-resilient provenances.
植物的水力性能依赖于气孔、叶肉和木质部结构的协同作用。然而,关于这种跨气候梯度整合的种内证据仍然有限。我们在一个随机的共同花园中种植了来自15个气候差异显著种源的1年生栓皮栎幼苗,并对叶片、茎和主根的19个解剖学特征进行了量化。种源的年平均温度、降水量和湿度共同解释了大部分观察到的变异。来自温暖、湿润地区的幼苗发育出(i)较薄的栅栏组织但较厚的海绵组织叶肉和整体叶片,(ii)更小、更密集的气孔,以及(iii)更宽的导管,其壁更厚,薄壁组织比例更高,纤维含量更低。根薄壁组织与气孔密度协变,导管特征与叶片解剖结构密切相关,揭示了一个种源尺度的网络,该网络增强了水力传导、水分储存和气孔响应能力,同时可能降低栓塞风险。虽然没有直接测量水力脆弱性和传导性,但导管增大和壁增厚的趋同表明了效率和安全性之间的功能平衡。我们的研究结果提供了首个种内证据,表明栓皮栎会根据气候对各器官的结构调整进行整合,为适应性进化提供了新的见解,并为耐旱种源的选择提供了参考。