含羞草匀浆液流变学行为及其对Maxwell方程的拟合  

Rheological Behavior of Homogenate Suspension of Mimosa pudica L.and its Fitting to Maxwell Equation

作　　者：施永德[1] 陈季武[2] SHI Yong-de;CHEN Ji-wu(Department of Biophysics,Shanghai Medical College,Fudan University,Shanghai 200032,China;School of Life Sciences,East China Normal University,Shanghai 200062,China)

机构地区：[1]复旦大学上海医学院生物物理学教研室,上海200032 [2]华东师范大学生命科学学院,上海200062

出　　处：《中国血液流变学杂志》2022年第1期1-9,共9页Chinese Journal of Hemorheology

摘　　要：目的研究含羞草叶匀浆接受矩形波切变率后的力学反应性及其对Maxwell黏弹性体方程的拟合与修正,揭示含羞草叶匀浆在微弱剪切应力作用下,变为黏弹性体的过程,支持含羞草细胞内有物质在剪切应力下由液体向黏弹性体结构的转变。方法制备无细胞含羞草叶匀浆,采用美国Brookfield公司程序型DVⅡ流变仪,给匀浆施加0.1、1、2、4、8、10、12 s^(-1)等8种切变率的矩形波的作用前、作用中、作用后,在Windows下用该仪器公司提供的软件,编制自动采样程序,做实时数据采集、贮存、回归拟合与数据处理。并与形状相似的植物叶下珠的叶匀浆作了对照。结果(1)含羞草叶匀浆在施加矩形波切变率作用下,其应力-时间上升曲线可用Maxwell黏弹性体方程拟合;下降线形状虽与该方程相似,但在数值上有明显差异,加上“不可逆应力损失项”后则可拟合。(2)从该文所设计的8种切变率矩形波作用下含羞草叶匀浆应力-时间曲线形状可认为均属于黏弹性体类型,尤其在切变率0.1、1、2、4 s^(-1)等4种低切变率的条件更为明显。该文对它们的Maxwell方程松弛时间、应力平衡值和改良后方程的“不可逆应力损失项”的参数进行了计算,并对含羞草、叶下珠叶片匀浆悬浮液进行了比较,前者具有黏弹性体的特有应力-时间曲线形状与明显的方程松弛时间参数值,而后者则无;前者有比后者大20倍的平衡应力数值。结论该文实验支持微弱的剪切应力好像“酶”一样,可驱动含羞草叶匀浆发生类似于Maxwell黏弹性体的力学反应,推测其过程中由于细胞内的某些物质(如蛋白质或细胞骨架)按照时空安排进行三维结构重组并发生运动;而外加的应力撤销后,则慢慢地回复原先状态。认为应用切变率矩形波技术与改良后的Maxwell方程,是研究生物物质的黏弹性的一个定量手段,还认为矩形波的切变率控制在0.1~Objective Through studying the response of homogenate suspension from leaves of Mimosa pudica L.to the rectangular waves of shear rate and its fitting and modifying to Maxwell Equation,the article explains the course how the suspension would change into viscoelastic material under the role of a small shear stress,and support the ideas that some substances in side of cells of leaves from Mimosa pudica transfer viscoelastic structure from liquid state under the shearing stress action.Methods To prepare the homogenate suspension from leaves of the plant,to use the DVⅡtype rheometer made by Brookfield Company,USA,the stress-time data were collected,stored,regressed,fitted and treated by automatic software under Windows condition supplied from the company,before,during and after the suspension accepts the action by the rectangular waves of shear rates such as 0.1,1,2,4,8,10 and 12 s^(-1) respectively.Above experiments were compared with the results from homogenate suspension of Thyllanthus urinaria leaves from another plant whose shape is like Mimosa pudica but without moving function.Results(1)The experimental digital data of stress-time ascending curve could be fitted well by Maxwell equation when the homogenate suspension was accepting the action of a rectangular wave of a shear rate,but the descending curve(when the stress action taking off)had a significant difference between the real experiment data and theoretical calculation values from Maxwell equation,even though the curve shape was similar with each other.After our adding an irreversible stress loss item into the equation,the latter could be fitted as well.(2)According to all curve morphologies,we confirmed that they all belong to viscoelastic bodies when the homogenate suspension from Mimosa pudica was being acted by 8 kinds of rectangular waves of shear rates,among them the ones of shear rates as 0.1,1,2 and 4 s^(-1) were specially significant.(3)Three parameters were calculated from the equation such as relaxation time,equilibrium stress and irreversib

关 键 词：含羞草 矩形波切变率 黏弹性 MAXWELL方程 

分 类 号：Q6[生物学—生物物理学]