番茄果皮与叶片光合细胞超微结构的比较

Ultrastructure comparison of skins cell and leaf photosynthetic cell in tomato

文章对番茄果实不同生长阶段果皮细胞中叶绿素含量进行了测定,并将番茄果皮细胞与成熟叶片光合细胞超微结构进行了比较观察。结果显示,番茄果皮细胞在果实不同生长阶段叶绿素含量、叶绿体结构发生变化,绿熟果期果皮细胞的叶绿素含量最高,果皮细胞含有一定数量的叶绿体,并且具有典型的的基粒片层结构。根据植物光合产物就近运输理论,果皮细胞中叶绿体形成的光合产物,能够及时地转移到果实中,供应果实的生长发育。绿熟果期果皮细胞的叶绿素含量、叶绿体、基粒数量及类囊体垛叠层数明显少于叶肉细胞,说明此时期叶片仍是番茄进行光合作用的主要器官。在果实完熟期,其外观已经由绿色变成红色,果皮细胞中的叶绿体逐步转化为有色体,类囊体基粒片层消失,叶绿体内部含有大量嗜锇颗粒,失去光合能力。

By the application of electron microscope, this study made a comparison between the ultrastructures of tomato skin and of ptotosynthetic cells in leaves of mature tomatoes and measured chlorophyll content of tomato skin at different growth stages. The results showed that changes of chloroplast structure and the chlorophyll content of tomato skin cells varied across stages. The chlorophyll content of tomato skin was the highest at green ripe stage. There were some chloroplasts in several layers pericarp and there were typical structure of grana lamella. According to the theory of nearest transportation of plant photosynthate, the photosynthate produced by chloroplast in the mature-green fruit was timely transformed to fruit for its growth and development. The tomato leaves were the main organs of photosynthesis, because the numbers of chloroplast and granum-thylakoid staeks, and the chlorophyll content were obviously less than those of mesophyll cell. When the tomato was completely ripe, its color changed from green to red and all the chloroplast in flesh cells was turned into chromoplast. Meantime, the thylakoid gradually disappeared, a large amount of heavily strained grains appeared and the fruit lost its photosynthetic capacity.