Background And Aims

Root hair emergence is affected by heterogeneities in water availability in the growth medium. Root hairs preferentially emerge into air, whereas their emergence into water is inhibited. Yet, these results were based either on destructive methods or on roots grown on an agar-air interface. Additionally, there is a lack of knowledge about the spatial distribution of root hairs as hairs elongate radially across the rhizosphere. Therefore, root hair growth in soils remains largely unexplored.

Methods

Maize (Zea Mays L.) plants were grown in microcosms which were scanned with a synchrotron-based X-ray \(\mu \)CT. The distribution of root hairs along the root epidermis and radially across the rhizosphere (i.e. as function of distance from the root epidermis) was analysed using spatial point pattern analysis.

Results

While hairs emerged randomly in air-filled pores, their emergence was inhibited where the root was in contact with the soil matrix. As hairs elongated radially into the soil, they were preferentially located in the close proximity of soil particles. In maize, we rarely observed root hairs penetrating into soil aggregates.

Conclusion

We conclude that in maize, root hairs grow in air-filled pores at the root-soil interface, where the flow of nutrients and water is impeded. Across the rhizosphere, hairs establish contact to the soil by growing in the proximity to soil particles. The effect of hairs on uptake processes, plant anchorage and rhizosheath formation might be limited (in maize) as they hardly penetrate into soil aggregates.

中文翻译：

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土壤中根毛图案的观察：基于同步加速器的 X 射线计算机显微断层扫描的见解

背景和目标

根毛的出现受到生长介质中可用水的不均匀性的影响。根毛优先出现在空气中，而它们出现在水中则受到抑制。然而，这些结果要么基于破坏性方法，要么基于在琼脂-空气界面上生长的根。此外，由于根毛在根际呈放射状延伸，因此缺乏对根毛空间分布的了解。因此，土壤中的根毛生长在很大程度上仍未被探索。

方法

玉米 ( Zea Mays L.) 植物在微观世界中生长，并使用基于同步加速器的 X 射线\(\mu \) CT 进行扫描。使用空间点模式分析来分析根毛沿着根表皮和径向穿过根际的分布（即作为距根表皮距离的函数）。

结果

虽然毛发在充满空气的孔隙中随机出现，但在根部与土壤基质接触的地方，它们的出现受到抑制。当毛发径向伸入土壤时，它们优先位于土壤颗粒附近。在玉米中，我们很少观察到根毛渗透到土壤团聚体中。

结论

我们得出的结论是，在玉米中，根毛生长在根-土界面处充满空气的孔隙中，养分和水的流动受到阻碍。在整个根际，毛发通过在土壤颗粒附近生长来与土壤建立接触。毛发对吸收过程、植物固定和根鞘形成的影响可能有限（在玉米中），因为它们很难渗透到土壤团聚体中。