七、实生幼苗的初生维管组织早在萌发后24小时,原形成层就分化出了早期的维管分子。在这个阶段,胚根仅伸出在种皮外几毫米。在此阶段,原形成层组织是很显明的,这是一些成列的着色深的薄壁细胞,具有大的细胞核,较少的细胞内含物,并极少或没有液泡。其纵切面显示出原形成层细胞的长 Seven, primary seedling of young vascular tissue as early as 24 hours after germination, the original formation of the differentiation of the early vascular molecules. At this stage, the radicle extends only a few millimeters beyond the seed coat. At this stage, the protoplasmic layer organization is evident, and is a series of pigmented parenchyma cells with large nuclei, less cellular inclusions, and little or no vacuole. Its longitudinal section shows the length of the primordial layer cells