大麦和玉米叶片叶绿体中Rubisco及其活化酶的免疫金标记定位

运用免疫金标记电镜技术研究了禾本科C3植物大麦(Hordeum vulgare L.)和C4植物玉米(Zea mays L.)叶片中Rubisoo及其活化酶(RCA)的细胞定位,结果表明:两种植物叶片解剖结构及叶绿体超微结构差别明显.在大麦叶细胞中,只有一种叶肉细胞叶绿体,Rubisoo和RCA主要分布于叶绿体的间质中.在玉米叶细胞中,存在着维管束鞘细胞和叶肉细胞两种类型叶绿体,Rubisco主要分布于鞘细胞叶绿体的基质中,但在叶肉细胞叶绿体中亦有少量特异性标记;RCA在鞘细胞叶绿体和叶肉细胞叶绿体的基质中都有分布.两种植物叶绿体结构及光合作用关键酶定位的不同,体现了C3植物和C4植物在光合器结构与功能上的差异.

The Immunogold Localization of Rubisco and Its Activase in Chloroplasts of Barley and Maize Leaves

Cellular localization of Rubisco and Rubisco activase (RCA) in the C_3 plant barley (Hordeum vulgare L.) and the C_4 plant maize (Zea mays L.) leaves was investigated using immunogold-labeling electron microscopy. The results showed that the leaf anatomy and the immunolocalization of the two photosynthetic enzymes were markedly different between barley and maize. In barley, the mesophyll chloroplasts had well-developed grana (Fig.2) and their stroma was densely labeled with immunogold particles for Rubisco (Figs.3, 4) and for RCA (Figs.5, 6). In maize, the mesophyll chloroplasts had well-developed grana (Fig.10) but their stroma was scarcely labeled with immunogold particles, indicating a low Rubisco content (Fig. 14). But the chloroplasts of the bundle sheath cells had only few rudimentary grana (Fig.9) and their stroma was densely labeled with immunogold particles for Rubisco (Figs. 12, 13). A higher density of immunogold particles for RCA was located both in chloroplast stroma of the bundle sheath cells (Figs. 15,16) and the mesophyll cells (Fig.17). These results showed that the structure and function of chloroplasts are different between C_3 plants and C_4 plants.