一种自动化的植物细胞壁伸展性能测定仪及其应用

应用实验室常用仪器和电子部件，包括直流稳压电源、等臂双盘天平、记录仪、恒流泵、程控仪、线性可变差动变压器（LVDT）、电磁间等，改装和配置成的植物细胞壁伸展性能测定仪，具有操作简便、测量准确和灵敏度高等优点；对大豆幼苗下胚轴生长区细胞壁的内源伸展活性和重组伸展活性的实测结果与文献报告相符，表明该仪器是一种较为理想的准确测定植物细胞壁伸展性能的自动化仪器。

An Automated Apparatus for Measuring Plant Cell Wall Extensibility and Its Applications

It has been proposed that longterm extension (creep) of islated cell walls frm the growing regin of plant seedlings may be mediated by tw newly discovered prteins, knwn as expansins, thrugh the disruptin of hydrogen bnds in the cell wall. To investigate the role of these proteins in the process of cell elongation during nrmal growth, we cnstructed an automated apparatus fr measuring endogenus and reconstituted wall extension activities by modification of an equal-arm mechanical balance with a linear variable differential transformer (LVDT )and a special sample chamber (Fig. 1 ).Moreover, when equipPed with cmmon laboratory deviees and electronic parts, this apparatus can be used to make wall extensibility measurement by allowing the bathing slution to flow continuusly and by switching from one to the ther automatically (Fig. 1).Preliminary results using this extensometer confirm that long-term extension of isolated cell walls from soybean (Glycine max L. Merr. ) hypocotyls can be induced in acidic buffer (sodium acetate 50 mml/L, pH 4. 5 ) and inhibited in neutral buffer (Hepes 5 mmol/L, pH 6. 8) (Fig. 2) . Furthermore, by adopting a reconstitutin apprach, we found for the first time that a crude protein extract from the cell walls of growing regin of soybean hypoctyl also possessed the expansin activity, l. e., the ability to induce the extensin of heat-inactivated walls (Fig. 3). In summary, this apparatus des nt require any mechanical device which needs to be specially designed and machined for this purpse, and features easy handling, high accuracy and sensitivity, and the results obtuined with it are cnsistent with thse reported previously. Therefore, it is valuable in measuring the extensibility of plant cell walls.