The cotyledons in some non-endospermic seeds act as a food storage...

In non-endospermic seeds, the endosperm is completely consumed during embryo development. In many of these seeds (like pea and gram), the cotyledons become thick and fleshy as they act as food storage organs to nourish the developing embryo.

However, in some other seeds (like gourd and bean) which show epigeal germination, the cotyledons emerge above the soil, turn green, and act as the first photosynthetic organs (embryonic leaves) to synthesize food for the growing seedling until true leaves develop.

Haustorial cotyledons are typically found in endospermic seeds (like grasses) where they absorb nutrients from the endosperm. Perisperm is the persistent nucellus, and pericarp is the fruit wall.

Answer: photosynthetic organs