Ion induced changes in the structure of bordered pit membranes.
Ion induced changes in the structure of bordered pit membranes.
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DOI：
10.3389/fpls.2012.00055
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发表时间：
2012
影响因子：
5.6
通讯作者：
Zwieniecki MA
中科院分区：
文献类型：
--
作者：
Lee J;Holbrook NM;Zwieniecki MA
离子介导的木质部液压阻力的变化被假设为导致从位于相邻的木质部导管分离的有边界的纹孔膜的果胶的水凝胶样性质。尽管离子介导的水力阻力变化的动力学与果胶的膨胀/去膨胀行为一致，但没有这种活性的直接证据。在这份报告中，我们使用原子力显微镜（AFM），以调查与周围溶液的离子浓度的变化相关联的边界坑膜的结构变化。当浸没在去离子水中时，AFM显示有边界的凹坑膜相对光滑、柔软，并且缺乏任何尖锐边缘表面，这与来自扫描电子显微镜（SEM）或在空气干燥材料上进行的AFM的图片形成对比。有界坑膜暴露于50 mM KCl溶液导致表面物理性质和海拔特征的显着变化。具体地说，有边界的纹孔膜变得更硬，纤维边缘清晰可见。此外，由于暴露的微纤维，膜收缩并显得粗糙得多。在这两种溶液中，都没有任何证据表明膜上有离散的孔，其尺寸随周围溶液的离子组成而改变。相反，可变的水力阻力似乎涉及的渗透性和坑膜的厚度的变化。
Ion-mediated changes in xylem hydraulic resistance are hypothesized to result from hydrogel like properties of pectins located in the bordered pit membranes separating adjacent xylem vessels. Although the kinetics of the ion-mediated changes in hydraulic resistance are consistent with the swelling/deswelling behavior of pectins, there is no direct evidence of this activity. In this report we use atomic force microscopy (AFM) to investigate structural changes in bordered pit membranes associated with changes in the ionic concentration of the surrounding solution. When submerged in de-ionized water, AFM revealed bordered pit membranes as relatively smooth, soft, and lacking any sharp edges surface, in contrast to pictures from scanning electron microscope (SEM) or AFM performed on air-dry material. Exposure of the bordered pit membranes to 50 mM KCl solution resulted in significant changes in both surface physical properties and elevation features. Specifically, bordered pit membranes became harder and the fiber edges were clearly visible. In addition, the membrane contracted and appeared much rougher due to exposed microfibers. In neither solution was there any evidence of discrete pores through the membrane whose dimensions were altered in response to the ionic composition of the surrounding solution. Instead the variable hydraulic resistance appears to involve changes in the both the permeability and the thickness of the pit membrane.
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影响因子：
1.9
作者：
Dute, Roland R.;Elder, Thomas
通讯作者：
Elder, Thomas
影响因子：
6.1
作者：
Vyawahare, Saurabh;Sitaula, Suresh;Scherer, Axel
通讯作者：
Scherer, Axel
影响因子：
3
作者：
Liu, LS;Cooke, PH;Hicks, KB
通讯作者：
Hicks, KB
DOI：
10.1073/pnas.0709194105
发表时间：
2008-07-08
影响因子：
11.1
作者：
Noblin, X.;Mahadevan, L.;Zwieniecki, M. A.
通讯作者：
Zwieniecki, M. A.
影响因子：
64.8
作者：
Beebe, DJ;Moore, JS;Jo, BH
通讯作者：
Jo, BH