Cell Division Pattern in Plants: Division Plane, Cytoskeleton and Organelle Migration in Selaginella Stomatogenesis

细胞骨架在调节分裂平面、有丝分裂和形态发生中的作用将在蕨类植物卷柏的口腔发生中进行研究。 这个简单的系统利用了植物中已知的精确定义的形态发生途径的两个最引人注目的例子：造口发生和单质体细胞分裂。 在口腔发生过程中，保卫母细胞从表皮起始分化，离开导致形成一对专门保卫细胞的途径。 在单质体分裂中，核和质体分裂通过精确的形态发生质体迁移和质体上纺锤体的组织密切协调。 这项研究的总体目标是利用确定的口腔发生途径和形态发生质体迁移现象来回答植物形态发生中的根本性重要问题。 形态发生质体迁移提供了细胞周期期间极性变化的准确标记。 这种迁移将与卷柏中更为人所知的昼夜节律和光刺激叶绿体迁移进行比较。 叶绿体的运动已得到充分研究，并提供了植物中肌动蛋白驱动运动的更好理解的例子之一。 拟议的研究包括使用光（视频增强微分干涉对比、荧光、共焦激光扫描）和透射电子显微镜对 f-肌动蛋白和微管进行实时观察和直接和间接定位。 药物将用于扰乱细胞骨架蛋白，以确定控制分裂平面、细胞器迁移和分裂的功能，以及细胞成形和细胞壁沉积的功能，从而形成成熟保卫细胞的独特形式。 这些研究将增加我们对单质体细胞分裂中质体极性现象的理解，并将有助于了解细胞骨架在多细胞植物组织模式发育中的作用。

The role of the cytoskeleton in regulation of the division plane, mitosis and morphogenesis will be investigated in stomatogenesis in the fern ally, Selaginella. This simple system takes advantage of two of the most dramatic examples of precisely defined morphogenetic pathways known in plants: stomatogenesis and monoplastidic cell division. In stomatogenesis, the guard mother cell differentiates from epidermal initials to depart on a pathway leading to formation of a pair of specialized guard cells. In monoplastidic division, nuclear and plastid division are intimately coordinated by precise morphogenetic plastid migrations and by organization of the spindle at the plastids. The overall objective of this research is to use the determinated pathway of stomatogenesis and the phenomenon of morphogenetic plastid migration to answer questions of fundamental importance in plant morphogenesis. Morphogenetic plastid migration provides an accurate marker of changes in polarity during the cell cycle. This migration will be compared with the better known circadian and photostimulated chloroplast migration in Selaginella. Movement of chloroplasts has been well studied and provides one of the better understood examples of actin driven motility in plants. Proposed studies include live observations and direct and indirect localization of f-actin and microtubules using light (video enhanced differential interference contrast, fluorescence, confocal laser scanning) and transmission electron microscopy. Drugs will be used to perturb cytoskeletal proteins to determine function in control of division plane, organelle migration, and division, and in cell shaping and wall deposition that leads to the distinctive form of mature guard cells. Such studies will increase our understanding of the phenomenon of plastid polarity in monoplastidic cell division, and will contribute to the general knowledge of the role of the cytoskeleton in patterned development in a multicellular plant tissue.