Granum is a basic structural unit of the thylakoid membrane network of plant chloroplasts. It is composed of multiple flattened membranes forming a stacked arrangement of a cylindrical shape. Grana membranes are composed of lipids and tightly packed pigment-protein complexes whose primary role is the catalysis of photosynthetic light reactions. These membranes are highly dynamic structures capable of adapting to changing environmental conditions by fine-tuning photochemical efficiency, manifested by the structural reorganization of grana stacks. Due to a nanometer length scale of the structural granum features, the application of high-resolution electron microscopic techniques is essential for a detailed analysis of the granum architecture. This mini-review overviews recent approaches to quantitative grana structure analyses from electron microscopy data, highlighting the basic manual measurements and semi-automated workflows. We outline and define structural parameters used by different authors, for instance, granum height and diameter, thylakoid thickness, end-membrane length, Stacking Repeat Distance, and Granum Lateral Irregularity. This article also presents insights into efficient and effective measurements of grana stacks visualized on 2D micrographs. The information on how to correctly interpret obtained data, taking into account the 3D nature of grana stacks projected onto 2D space of electron micrograph, is also given. Grana ultrastructural observations reveal key features of this intriguing membrane arrangement, broadening our knowledge of the thylakoid network’s remarkable plasticity.

颗粒是植物叶绿体类囊体膜网络的基本结构单元。它由多个扁平膜组成，形成圆柱形堆叠排列。格拉纳膜由脂质和紧密堆积的色素-蛋白质复合物组成，其主要作用是催化光合光反应。这些膜是高度动态的结构，能够通过微调光化学效率来适应不断变化的环境条件，这体现在谷物堆的结构重组上。由于结构颗粒特征的纳米长度尺度，高分辨率电子显微技术的应用对于颗粒结构的详细分析至关重要。这篇小型综述概述了从电子显微镜数据进行定量颗粒结构分析的最新方法，重点介绍了基本的手动测量和半自动工作流程。我们概述并定义了不同作者使用的结构参数，例如颗粒高度和直径、类囊体厚度、端膜长度、堆叠重复距离和颗粒横向不规则性。本文还介绍了对在 2D 显微照片上可视化的谷物堆的高效和有效测量的见解。还提供了有关如何正确解释获得的数据的信息，同时考虑到投射到电子显微照片 2D 空间的颗粒堆栈的 3D 性质。Grana 超微结构观察揭示了这种有趣的膜排列的关键特征，