plastidium

例句：

1. 1. The plastidium is responsible for the synthesis of chlorophyll in plants.
   质体负责植物中叶绿素的合成。
2. 2.The plastidium plays a crucial role in photosynthesis.
   质体在光合作用中起着至关重要的作用。
3. 3. The plastidium is a small organelle that contains the pigment chlorophyll.
   质体是一个小型的细胞器，包含色素叶绿素。