植物表皮毛细胞响应声波刺激的力-电转导及动力学机制

Plants survive in various stress due to their smart defense system. That is because the plant cells adaptively response to the stresses. The signal transduction is the key process to understand the relationship between multi-scales structures and functions. The model plant Arabidopsis thaliana has recently been shown to accumulate noxious substances caused by caterpillars chewing leaves in response to sound waves. However, the mechanisms for the mechano-electrical transduction remains a mystery. We will characterize the modal shape and frequency spectrum of a trichome in response to acoustic stimulation by a laser Doppler vibrometry system. We will then determine if acoustic vibrations promote the release of protective toxins from papillae of the trichome via an electrochemical testing system. Finally, we will reveal how the Insect chewing sound enhance the synthesis and secretion of defensive toxins in the trichome wall or the migration of toxins through it. This project will help to further understand the mechano-electrical coupling properties of plant cells and plant ears.

植物适应胁迫而生存得益于其巧妙的防御体系。拟南芥能够特异性响应昆虫咀嚼声波刺激并分泌防御性毒素。拟南芥表皮毛细胞具有力敏感特性和捕获声波的能力，然而其触发毒素分泌的力-电转导及动力学响应机制不清楚。本项目拟搭建双轴激光测振实验平台、建立有限元仿真和理论力学模型，分析表皮毛细胞固有频率、模态振型和频谱响应等特征，揭示声波刺激拟南芥表皮毛细胞的动力学响应规律；搭建声波发射与显微电化学检测联合实验平台，检测不同频率声波刺激下pH、钙离子、防御性毒素浓度，揭示声波刺激对表皮毛细胞防御性毒素分泌的影响规律；分析昆虫咀嚼声波的频谱特征与防御性毒素分泌之间的关系，阐明植物对昆虫咀嚼声波刺激的特异性防御响应的动力学机制。本项目有助于理解植物“听觉”产生机理和促进农作物虫害的声波防治应用。

本研究搭建表皮毛细胞的激光多普勒测振实验平台，观测表皮毛细胞的振动响应，并通过快速傅里叶变换（FFT）得到表皮毛细胞的频谱曲线；搭建高速显微成像系统，观测拟南芥表皮毛细胞共振模态振型。发现了拟南芥表皮毛低阶模态固有频率为~10kHz量级，低阶模态振型表现为主干扭转和摇摆振动。根据对拟南芥表皮毛细胞显微三维成像及力学性能表征结果，建立仿真计算模型，并建立了表皮毛细胞振动的简化理论模型，理论分析与有限元仿真、实验结果进行特征可比。发现拟南芥表皮毛细胞前5阶模态振型分别为表皮毛细胞的主干扭转、主干摇摆、主干俯仰、分支横向振动（第四、五阶）。对表皮毛细胞进行振动频谱分析，发现拟南芥表皮毛细胞在可闻声波频率（如Pieris毛虫的声发射频率）范围内可发生共振，且共振频率与表皮毛细胞的大小成反比。发现拟南芥表皮毛细胞的第一阶模态与其他高阶模态形成了两个频率带，Pieris毛虫的声发射频率穿越了这两个频率带，这可能有助于拟南芥对声学信号的选择性转导。研究结果有助于理解植物“听觉”产生机理和促进农作物虫害的声波防治应用。以上研究成果发表Journal of the Mechanics and Physics of Solids、Extreme Mechanics Letters、Physics of Fluids等论文13篇，申请发明专利3项，作学术会议报告6次。培养研究生5人。

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