A primary function of the aleurone layer is to provide nourishment to the embryo. Positioned as the outermost cells of the endosperm, it releases enzymes crucial for seed germination. Additionally, the aleurone layer expresses diverse proteins, including PR-4, which offer protection against pathogens. Moreover, it significantly contributes to dietary fiber in grain bran products.
Moreover, the aleurone tissue acts as a repository for vital nutrients, housing protein bodies within its structure. Unlike endosperm cells, aleurone cells maintain their viability in mature grains but undergo programmed cell death when germination is initiated or when exposed to gibberellic acid.
The aleurone layer covers both the starchy endosperm and germ, with interruptions only occurring at the kernel's tip, forming what is known as the hilar layer. This layer is thinnest over the germ and comprises live parenchyma cells organized in three to four layers in barley and rice, while in wheat, oat, and maize, it consists of a single layer.
These cells are distinguished by substantial walls abundant in arabinans and arabinoxylans, with minimal cellulose content. They are interconnected through plasmodesmata, which facilitate communication and nutrient exchange. The aleurone layer's unique structure and functions underscore its indispensable role in seed development and germination, emphasizing its significance in both plant reproduction and human nutrition.
Aleurone Layer Significance
