Do all plants have endosperm?

As long as there is double fertilization, there will be endosperm, but in dicotyledonous plants, when they develop into seeds, cotyledons absorb all the nutrients of endosperm, so there is no endosperm in dicotyledonous seeds, while in monocotyledonous plants, endosperm is not absorbed, so there will be endosperm. When seeds germinate, endosperm provides nutrition without photosynthesis.