科研之友
微信
新浪微博
Facebook
分享链接
摘要
The genus Rhynchospora in the Cyperaceae includes both C-3 and C-4 species. The C-4 species shows two distinct Kranz anatomies: the rhynchosporoid and the fimbristyloid-chlorocyperoid intermediate. This study reports the use of herbarium specimens to obtain the leaf ultrastructure in eight Rhynchospora C-4 species in relation to their C-4 biochemical subtypes, together with carbon isotope ratios. Despite the use of dried materials, electron microscopic observation revealed the structures of chloroplasts and cell walls. In C-4 species with the fimbristyloid-chlorocyperoid intermediate anatomy, Kranz cell chloroplasts had reduced grana and convoluted thylakoids, and suberized lamellae occurred in the mestome sheath cell walls. In C-4 species with the rhynchosporoid anatomy, the Kranz cell chloroplasts also had reduced grana and convoluted thylakoids but with less convolution; suberized lamellae occurred in the Kranz cell walls. These data show that the Rhynchospora C-4 species have ultrastructural features present in the NADP-malic enzyme-type C-4 sedges. The Kranz species had delta C-13 values typical of C-4 plants, as expected, and the values did not differ significantly between the two Kranz anatomies. This study demonstrates that dried herbarium specimens can be used for ultrastructural observation of C-4 leaves and provide valuable information for understanding of the photosynthetic diversity.
- 出版日期2013-5
