中国科学院南京地质古生物研究所机构知识库

Based on sections from both macerated and unmacerated cuticles and, for the extant species, the leaf cuticles from male and female trees, we investigated the leaf cuticle ultrastructure of Ginkgo biloba and Ginkgo yimaensis from the Jurassic of Yima, China. All of the cuticles were cut in two different directions: perpendicular and parallel to the leaf length. The cuticular membranes of both fossil and living species were generally similar, each having a cuticle proper and a fibrillar cuticular layer. The cuticle proper may be divided into an outer peripheral polylamellate layer and an inner, mainly granular, layer. In the upper part of the polylamellate layer, the lamellae were more regularly arranged than in the lower part. Comparisons of macerated and unmacerated cuticles show that the cuticular layer became thinner after treatment with chemical agents. Examining sections in different directions is important for studying leaf cuticular ultrastructure because of the considerable variation. Available evidence shows that taxonomic differences might have more bearing on the cuticle ultrastructure than do environmental differences. Although influences of diagenesis in the geological ages do not appear to be very conspicuous on the leaf cuticular ultrastructure, leaf cuticle ultrastructure might be potentially significant in plant taxonomy.