石英晶体微天平技术用于水稻悬浮细胞重金属毒性与耐性的动态监测与研究

Soil heavy metal (HM) contamination seriously affects the growth and development of plants, resulting in decreased yield and quality, and affecting human health through the food chain. Cell walls are the first barrier of plant cells against HM stress, HMs impede plant growth initially as cell wall hardening and restricting of wall extensibility, namely HMs alter the mechanical properties of plant cell walls. Moreover, HMs may affect the viscoelasticity of cytoskeleton through the plasma-cell wall continuum or after they enter into the protoplast. However, there is currently almost no published reports on the mechanical changes of cell walls and cytoskeletons of living plant cells subjected to HM stress owing to the lack of suitable techniques. This project applies the wide frequency quartz crystal microbalance technique and the surface modification techniques to rice suspension cells to achieve the following goals: 1) establish methods for the measurement of viscoelasticity of living plant cells; 2) explore the dynamic viscoelastic changes of rice suspension cells and the protoplasts subjected to different HMs stresses. This study will further our understanding for the mechanisms of plant toxicity and tolerance subjected to HM stress, and provide new solution for cultivating of new types of hyperaccumulating plants.

土壤重金属污染严重影响植物的生长发育，造成产量和品质下降，还可通过食物链进入人体，影响人类健康。细胞壁是植物细胞应对重金属胁迫的第一道屏障，重金属妨碍植物生长最初表现为细胞壁硬化与伸展性受限，即重金属改变了植物细胞壁的力学性能。此外，重金属也可通过植物细胞壁-质膜-细胞骨架连续体或直接进入原生质影响细胞骨架的粘弹性。然而目前由于缺乏合适的技术，几乎未见关于重金属胁迫下植物活细胞细胞壁及细胞骨架力学性能变化的报道。本项目拟以水稻悬浮细胞为研究对象，采用宽频石英晶体微天平技术及相应界面修饰技术实现如下目标：1)建立植物细胞粘弹性的测定方法; 2)探索水稻悬浮细胞及其原生质体在不同种类重金属胁迫下的动态粘弹性变化规律。该课题的开展有助于加深对植物重金属毒性及其耐性机理的理解，并可为培育新型重金属超积累植物品种提供新的解决途经。

本项目首次建立QCM传感器植物细胞特异的表面修饰技术，通过电化学方法及显微观察术验证植物细胞或原生质体在传感器表面的特异结合；基于宽频范围石英微天平技术对细胞探测深度的差异，确立QCM定量测定植物细胞壁粘弹性及细胞骨架粘弹性的方法；利用细胞骨架或细胞壁特异性药物处理，确立植物细胞粘弹性的动态变化机制；非介入、实时监测了植物细胞在As、Cd等重金属离子胁迫下细胞整体力学性质的变化规律；本项目的开展无论对于植物重金属毒害的基础理论，还是在培育新型超积累植物等实际应用上均具有重要意义。