The proteinaceous part of maize endosperm is

The correct option is Aleurone layer.

Step-by-step explanation:

1. Maize is a monocotyledonous plant, and its seed is endospermic. The major portion of the maize seed consists of the endosperm, which serves as a food storage tissue for the developing embryo.
2. The endosperm is surrounded by a special outermost layer called the aleurone layer.
3. This aleurone layer is highly proteinaceous in nature and plays a crucial role during seed germination by secreting amylase and other hydrolytic enzymes to break down stored starches in the endosperm.
4. Let's briefly look at why the other options are incorrect:
- Peripheral layer: A general term, not the specific protein-rich layer of the maize endosperm.
- Scutellum: This is the shield-shaped cotyledon of the embryo, not a part of the endosperm.
- Apophysis: A structure found in moss capsules and some pine cone scales, unrelated to maize seeds.
Therefore, the proteinaceous part of the maize endosperm is the aleurone layer.