多光子成像阿拉伯芥內短暫性澱粉隨時間的分布和基粒

Abstract

我們利用澱粉的特性來取代染色，施加一激發光使得澱粉產生二次諧波，藉此偵測追蹤阿拉伯芥植株內的澱粉開始發芽後的連續5天和一些較晚期的成長階段。取代用I-KI 溶液去染色澱粉，我們用較自然的方式呈現在一整棵阿拉伯芥植株上澱粉時間上和空間上的分布情形。另外因為在脂質儲存物、暫存性澱粉和葉綠體的成長之間存在一個緊密的關係，這個關係直接反映了碳的流動和碳的來源。因此將這個緊密關係與我們所得到的暫存性澱粉分布情況連結在一起，我們可以更進一步得知植株內每個細胞的發展狀態。最後我們也檢視一些阿拉伯芥發展較晚期的階段來證明積聚的暫存性澱粉只被快速發展中的細胞須要。這裡我們不只提供一個新的方法來追蹤ㄧ活植物中的澱粉，特別是阿拉伯芥，而我們所得到的實驗結果也相當重要，因為對於了解植物生理和儲存物的代謝，阿拉伯芥在植物學中是一個相當重要的模型。 接下來我們利用線偏振光來研究葉綠體的內部結構。因為基粒有著會發二次諧波的自然特性，所以我們將從00 到1800各個不同角度的線偏振光打在阿拉伯芥葉肉細胞上的葉綠體。就我們已經知道的二次諧波是電偶極與極化光源的交互作用結果，一旦分子的電偶極方向平行於光源的極化方向將會有效率的產生二次諧波。因此我們應用這個獨特的性質來探測阿拉伯芥葉綠體內基粒的極化。最後我們發現葉綠體內基粒上分子的電偶極確實有一個特定的排列方式，此外我們也發現微絲的結構也會發出二次諧波。這暗示了我們未來運用二次諧波來研究微絲的可能性。

We took advantage of starch, which emits intense SHG (second harmonic generation) radiation upon the application of optical excitation sources, to noninvasively monitor germination process of starch in Arabidopsis postembryos for the course of 5 days and some later phases of the seedling development. Instead of the traditional staining with I-KI, we presented the temporal and spatial distribution patterns of a whole Arabidopsis seedling in a more natural, noninvasive manner. And since there exists an impartible link between lipid reserves, transient starch, and the progression of growth of chloroplasts that directly reflect the flux of carbon and the sources of carbon. Hence, by associating this link with the patterns of transient starch we obtained, we can further derive the developmental state of every cell in the seedling. At last we also examined some later phases of the evolution of Arabidopsis to demonstrate that accumulated transient starch is only needed for rapidly developing cells. Here, we have provided not only a novel method to tracing starch in a living plant, but also gathered results that are important, particularly, for Arabidopsis which is a major model in botanical studies for the understanding of plant physiology and reservoir metabolism. Next we utilized linearly polarized lights to investigate the interior structure of a chloroplast. With the nature of grana which produces SHG we introduced linearly polarized laser focusing on the chloroplasts in mesophyll cells of Arabidopsis thaliana at different angles of polarization ranging from 00 to 1800. As we have already known that SHG is an interactive result of the electric dipoles and the polarized sources, SHG radiation can be generated efficiently when the direction of an electric dipole in the molecule is parallel to the polarization direction of the laser. Therefore we applied this extraordinary property to explore the polarization of grana in an Arabidopsis chloroplast. Finally, we found that a particular arrangement of electric dipoles of molecules on grana exists in a chloroplast, and the structure of microfilament produces SHG as well, which suggests the possibility of using SHG for to investigate microfilaments in the future exploration of botany.