Magnetophoretic Characterization of the Plant Gravity Receptor
Magnetophoretic Characterization of the Plant Gravity Receptor
复制标题
植物重力受体的磁泳表征
DOI：
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发表时间：
1997
期刊：
影响因子：
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通讯作者：
K. Hasenstein
中科院分区：
文献类型：
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作者：
O. Kuznetsov;K. Hasenstein
采用磁重分析法研究了淀粉体的物理特性（密度p和磁化率x）。在存在和不存在高梯度磁场（HGMF）的情况下，单个淀粉体的速度之比允许确定参数Δ x/Δ p。淀粉体的密度通过在甲泛葡胺溶液中等密度离心来测量，范围为1.36至1.38 g/cm 3。磁化率x在-8.0 ~-8.2 × 10 ~（-7）emu之间，与淀粉的磁化率接近。磁重力电泳是足够敏感的检测淀粉含量的减少，在光剥夺幼苗。亚麻根的显微镜观察表明，由于磁泳作用，柱状细胞中的淀粉体发生了细胞内位移。继续施加HGMF导致根弯曲远离HGMF，胚芽鞘朝向HGMF，类似于灰度刺激后的弯曲。均匀磁场既不会引起曲率，也不会改变生长速率。HGMF诱导的弯曲依赖于淀粉含量的淀粉体，因为野生型拟南芥弯曲，但无淀粉突变体没有。这些数据表明，淀粉体作为重力受体和磁有质动力可以取代重力条件下的是重力。
Physical characteristics (density p and magnetic susceptibility x) of amyloplasts were studied by magnetograviphoresis. The ratio of the velocities of individual amyloplasts in the presence and absence of a high gradient magnetic field (HGMF) permits the determination of the parameter Δ x/Δ p. The density of amyloplasts was measured by isopycnic centrifugation in metrizamide solutions and ranged from 1.36 to 1.38 g/cm3. The magnetic susceptibility x varied between -8.0 to -8.2x10−7emu and is close to that of starch. Magnetograviphoresis was sensitive enough to detect the reduction in the starch content of amyloplasts in light-deprived seedlings. Microscopy of flax roots showed intracellular displacement of amyloplasts in columella cells due to magnetophoresis. Continued application of HGMF resulted in curvature of roots away from HGMF, and coleoptiles toward the HGMF, similar to curvature after grayistimulation. Uniform magnetic fields caused neither curvature nor changes in growth rate. HGMF-induced curvature depended on the starch content of amyloplasts since wildtype of Arabidopsis curved but a starchless mutant did not. These data suggest that amyloplasts serve as the gravity receptor and that magnetic ponderomotive forces could substitute for gravity under is-gravity conditions.