The residual persistent part which forms the perisperm in the seeds of beet is 

In the seeds of beet and black pepper, the residual persistent part that forms the perisperm is the nucellus.
(1) The calyx is the outermost whorl of the flower, composed of sepals. It protects the developing flower bud.

(2) The endosperm is a tissue formed in the seeds of many plants, primarily in angiosperms. It serves as a nutritive tissue to provide nutrients to the developing embryo.

(4) The integument is the outer protective layer(s) of the ovule, which later becomes the seed coat after fertilisation. The seed coat protects the developing embryo and the endosperm (if present) within the seed.