Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ, UK.
Plant Cell Environ. 2011 Oct;34(10):1630-8. doi: 10.1111/j.1365-3040.2011.02358.x. Epub 2011 Jun 28.
Understanding how root system architecture (RSA) adapts to changing nitrogen and water availability is important for improving acquisition. A sand rhizotron system was developed to study RSA in a porous substrate under tightly regulated nutrient supply. The RSA of Arabidopsis seedlings under differing nitrate (NO₃⁻) and water supplies in agar and sand was described. The hydraulic conductivity of the root environment was manipulated by using altered sand particle size and matric potentials. Ion-selective microelectrodes were used to quantify NO₃⁻ at the surface of growing primary roots in sands of different particle sizes. Differences in RSA were observed between seedlings grown on agar and sand, and the influence of NO₃⁻ (0.1-10.0 mm) and water on RSA was determined. Primary root length (PRL) was a function of water flux and independent of NO₃⁻. The percentage of roots with laterals correlated with water flux, whereas NO₃⁻ supply was important for basal root (BR) growth. In agar and sand, the NO₃⁻ activities at the root surface were higher than those supplied in the nutrient solution. The sand rhizotron system is a useful tool for the study of RSA, providing a porous growth environment that can be used to simulate the effects of hydraulic conductivity on growth.
了解根系结构（RSA）如何适应氮和水供应的变化对于提高获取能力非常重要。开发了一种沙根管系统，以在严格控制养分供应的多孔基质中研究 RSA。描述了在琼脂和沙中不同硝酸盐（NO₃⁻）和水分供应下拟南芥幼苗的 RSA。通过改变沙粒大小和基质势来操纵根环境的水力传导率。使用离子选择性微电极在不同粒径的沙中定量测定生长主根表面的 NO₃⁻。在琼脂和沙上生长的幼苗之间观察到 RSA 存在差异，并确定了 NO₃⁻（0.1-10.0mm）和水对 RSA 的影响。主根长度（PRL）是水通量的函数，与 NO₃⁻无关。侧根的比例与水通量相关，而 NO₃⁻供应对基根（BR）生长很重要。在琼脂和沙中，根表面的 NO₃⁻活性高于营养液中的供应。沙根管系统是研究 RSA 的有用工具，它提供了一种多孔生长环境，可以用来模拟水力传导率对生长的影响。
