Ge Sisi, Dupuy Lionel X, MacDonald Michael P
School of Science and Engineering, University of Dundee, Nethergate, Dundee, DD1 4HN UK.
Neiker, Department of Conservation of Natural Resources, Berreaga 1, 48.160, Derio, Spain.
Plant Soil. 2021;468(1-2):475-489. doi: 10.1007/s11104-021-05133-2. Epub 2021 Sep 12.
Laser micromanipulation such as dissection or optical trapping enables remote physical modification of the activity of tissues, cells and organelles. To date, applications of laser manipulation to plant roots grown in soil have been limited. Here, we show laser manipulation can be applied in situ when plant roots are grown in transparent soil.
We have developed a Q-switched laser manipulation and imaging instrument to perform controlled dissection of roots and to study light-induced root growth responses. We performed a detailed characterisation of the properties of the cutting beams through the soil, studying dissection and optical ablation. Furthermore, we also studied the use of low light doses to control the root elongation rate of lettuce seedlings () in air, agar, gel and transparent soil.
We show that whilst soil inhomogeneities affect the thickness and circularity of the beam, those distortions are not inherently limiting. The ability to induce changes in root elongation or complete dissection of microscopic regions of the root is robust to substrate heterogeneity and microscopy set up and is maintained following the limited distortions induced by the transparent soil environment.
Our findings show that controlled in situ laser dissection of root tissues is possible with a simple and low-cost optical set-up. We also show that, in the absence of dissection, a reduced laser light power density can provide reversible control of root growth, achieving a precise "point and shoot" method for root manipulation.
激光显微操作，如解剖或光镊技术，能够对组织、细胞和细胞器的活性进行远程物理修饰。迄今为止，激光操作在土壤中生长的植物根系上的应用一直有限。在此，我们展示了在植物根系生长于透明土壤时，激光操作可原位应用。
我们开发了一种调Q激光操作与成像仪器，用于对根系进行可控解剖，并研究光诱导的根系生长反应。我们对穿过土壤的切割光束的特性进行了详细表征，研究了解剖和光消融。此外，我们还研究了使用低光剂量来控制生菜幼苗在空气、琼脂、凝胶和透明土壤中的根伸长率。
我们表明，虽然土壤不均匀性会影响光束的厚度和圆度，但这些畸变并非本质上的限制因素。诱导根系伸长变化或对根的微观区域进行完全解剖的能力，对基质异质性和显微镜设置具有鲁棒性，并且在透明土壤环境引起的有限畸变之后仍能保持。
我们的研究结果表明，使用简单且低成本的光学装置对根组织进行原位可控激光解剖是可行的。我们还表明，在不进行解剖的情况下，降低的激光光功率密度可以提供对根系生长的可逆控制，实现一种精确的“指向并射击”根系操作方法。
