Marcel Hubinský, Javier Martín-Gómez José, Emilio Cervantes, Roman Hobza, Jose Luis Rodríguez Lorenzo
Department of Plant Developmental Genetics, Institute of Biophysics of the Czech Academy of Sciences, Brno, Czechia.
National Centre for Biomolecular Research (NCBR), Faculty of Science, Masaryk University, Brno, Czechia.
Front Plant Sci. 2024 Mar 11;15:1297676. doi: 10.3389/fpls.2024.1297676. eCollection 2024.
Plants undergo various natural changes that dramatically modify their genomes. One is polyploidization and the second is hybridization. Both are regarded as key factors in plant evolution and result in phenotypic differences in different plant organs. In , we can find both examples in nature, and this genus has a seed shape diversity that has long been recognized as a valuable source of information for infrageneric classification.
Morphometric analysis is a statistical study of shape and size and their covariations with other variables. Traditionally, seed shape description was limited to an approximate comparison with geometric figures (rounded, globular, reniform, or heart-shaped). Seed shape quantification has been based on direct measurements, such as area, perimeter, length, and width, narrowing statistical analysis. We used seed images and processed them to obtain silhouettes. We performed geometric morphometric analyses, such as similarity to geometric models and elliptic Fourier analysis, to study the hybrid offspring of and .
We generated synthetic tetraploids of and performed controlled crosses between diploid and to analyze seed morphology. After imaging capture and post-processing, statistical analysis revealed differences in seed size, but not in shape, between diploids and tetraploids, as well as some differences in shape among the parentals and hybrids. A detailed inspection using fluorescence microscopy allowed for the identification of shape differences in the cells of the seed coat. In the case of hybrids, differences were found in circularity and solidity. Overal seed shape is maternally regulated for both species, whereas cell shape cannot be associated with any of the sexes.
Our results provide additional tools useful for the combination of morphology with genetics, ecology or taxonomy. Seed shape is a robust indicator that can be used as a complementary tool for the genetic and phylogenetic analyses of hybrid populations.
植物会经历各种显著改变其基因组的自然变化。一种是多倍体化，另一种是杂交。两者都被视为植物进化的关键因素，并导致不同植物器官出现表型差异。在 中，我们在自然界中能找到这两种情况的例子，并且该属具有种子形状多样性，长期以来一直被认为是亚属分类的宝贵信息来源。
形态测量分析是对形状、大小及其与其他变量的协变关系进行的统计研究。传统上，种子形状描述仅限于与几何图形（圆形、球形、肾形或心形）进行大致比较。种子形状量化一直基于直接测量，如面积、周长、长度和宽度，从而限制了统计分析。我们使用种子图像并对其进行处理以获得轮廓。我们进行了几何形态测量分析，如与几何模型的相似度分析和椭圆傅里叶分析，以研究 和 的杂交后代。
我们生成了 的合成四倍体，并在二倍体 和 之间进行了控制杂交以分析种子形态。在图像捕获和后处理之后，统计分析显示 二倍体和四倍体之间种子大小存在差异，但形状无差异，并且亲本和杂种之间在形状上也存在一些差异。使用荧光显微镜进行的详细检查能够识别种皮细胞中的形状差异。在杂种的情况下，发现了圆形度和紧实度方面的差异。两种物种的总体种子形状均由母本调控，而细胞形状与任何一种性别均无关联。
我们的结果提供了有助于将形态学与遗传学、生态学或分类学相结合的额外工具。种子形状是一个可靠的指标，可作为 杂交群体遗传和系统发育分析的补充工具。
