The effect of potassium and calcium on wood formation and xylem/phloem physology

离子在形成层生长的生理过程中起着重要的作用。为了更好地了解K、Ca和P在木材形成中的作用，我们打算重点研究不同K、Ca和P供应条件下生长的植物以及由P5和/或P3产生的离子转运蛋白表达修饰的转基因植物。两种方法将应用于本项目中所有不同处理的工厂。首先，利用图像分析和高分辨率电子显微镜对茎组织(韧皮部、形成层、木质部)进行结构和超微结构分析。为了将结构变化与生化变化联系起来，第二种方法在所有组织中进行如下分析：K、Ca和P的季节变化将用EDXA测量，而K和Ca也将用原子吸收光谱定量测定。通过产生针对不同钾转运蛋白的抗体，我们将进一步通过荧光和透射电子显微镜显示它们在杨树茎组织中的分布。为了将离子含量的变化与糖浓度相关联，将用酶法测定不同糖和淀粉的季节变化。为了测量细胞壁化学成分的变化，FTIR光谱将被用来定量检测细胞壁中的一系列官能团。

Ions play a fundamental role in the physiology of cambial growth. To gain better knowledge about the role of K, Ca and P in wood formation, we intend to focus on plants grown under different K, Ca and P supply as well as on transgenic plants with modified ion transporter expression produced by P5 and/or P3. Two approaches will be applied on all differently treated plants in this project. First, structural and ultrastructural analysis of stem tissues (phloem, cambium, xylem) will be carried out throughout all seasons by image analysis and high resolution TEM. In order to correlate structural changes to biochemical variations, a second approach deals with the following analysis in all tissues: Seasonal changes of K, Ca and P will be measured by EDXA, whereas K and Ca will also be determined quantitatively by atomic absorption spectrometry. By generating antibodies against different potassium transporters we further will show their distribution in poplar stem tissues throughout all seasons by fluorescence and transmission electron microscopy. In order to correlate changes in ion content to sugar concentrations, seasonal variations of different sugars as well as starch will be determined enzymatically. To measure changes in the chemical composition of cell walls, FTIR-spectroscopy will be used to quantitatively detect a range of functional groups in the cell wall.