非损伤微测技术在植物生长发育研究中的应用

光通过光周期和非光周期过程影响着叶片的展开。选择性微电极能探测到光诱导引起的与叶片生长有关的离子或分子信息。Zivanovic等利用选择性微电极比较了白光(2600µmolm^-2 s^-1)下及结合使用DCMU后的玉米叶片叶基部和叶顶部的H⁺、K⁺ 和Ca²⁺ 流量，选择性微电极探测到的光引起离子流的变化既与叶片生长相联系，也与光合作用有关（Plant Cell Environ）。非损伤微测技术为研究植物根系的生长和吸收营养元素的过程提供了一个极为有效的手段。菌根是土壤中的真菌与植物根的共生联合体。Plassard等用选择性微电极直接置于植物活的外生菌根表面，研究单个菌根对不同离子吸收或释放的情况。为选择在含有不同离子的土壤上种植喜好该土壤中离子的菌根植物，提供了一种方便快捷的方法（Plant Cell Environ）。

Figure 1. Estimation of NO₃^– and K⁺ net fluxes in roots of non-mycorrhizal maritime pines using ion-selective microelectrodes. Threeweek-old seedlings were incubated in a solution containing 0·2 mol m^-3 CaSO₄ and 0·02 mol m^-3  KNO₃ (pH 5.7). (a), (b) Concentration gradients of NO₃^– (a) and K⁺ (b) near the root surface: the ion activity is plotted against ln(r) where r is the radial distance of measurement from the root axis (r in cm). The plain line shows a linear regression drawn using local concentrations probed between the root surface and 700 um from the root surface. As described by Henriksen et al. (1992), the point of intersection of this line with that of 99% bulk ion concentration (horizontal dotted line) can be used to estimate the width of the depleted unstirred layer (vertical dotted line). In this example, the root radius is 1050 um and the width of the unstirred layer is approximately 900um from the root surface for both ions. (c), (d) Longitudinal variation of net NO₃^– (c) and K⁺ (d) fluxes estimated from ion concentrations measured at 1um from the root surface and 400 um from the root surface, corresponding, respectively, to ln (r) values of -2.25 and -1.93 in (a) and (b). Each point represents the average of three independent determinations ± SE.

欢迎试测 登记表