Definition of razor for English Language Learners. : a tool or device with a sharp edge that is used to shave or cut hair from the face, body, or head.
The pollen grain is the male gametophyte. When pollination occurs and the pollen grain makes contact with the stigma (the apex of the pistil), the tube cell elongates its cytoplasm, forming the pollen tube that grows towards the ovary.The generative cell divides to form two sperm nuclei (male gametes), which then migrate through the pollen tube.3. A typical seed is composed of the embryo, endosperm and shell. Within seeds of angiosperms, there are one or two cotyledons (seed leaves, one in monocots, two in dicots). The endosperm is the tissue within the seed that has the function of nourishing the embryo.
Bryophytes (mosses, liverworts and hornworts) have a dominant gametophyte phase on which the adult sporophyte is dependent for nutrition. The embryo sporophyte develops by cell division of the zygote within the female sex organ or archegonium, and in its early development is therefore nurtured by the gametophyte.