The embryo develops into the sporophyte generative
The antheridial cll divides into a generative cell and a tube cell. The generative cell divides to form 2 male cells or sperms. The sperms are motile in Cycas, but in majority the sperms are non-motile. In the female cones, many megasporophylls are arranged on the central axis. The megasporophylls bear megasporangia or ovules.
The ovule is orthotropous. It consists of nucellus surrounded by one or two integuments. The ovules are naked and are not enclosed by the ovary. The ovule contains the megaspore mother cell which undergoes meiosis to produce a linear row of four megaspores. Of the four megaspores the lowest is functional. The megaspore is haploid. The female gametophyte bears archegonia at the upper end.
The endosperm is a pre-fertilization tissue. It is haploid in gymnosperms. Each archegonium consists of a venter and a neck. The neck canal cells are absent. The pollination is direct, i.e. the pollen grains come in contact with the ovule directly. Embryo development is meroblastic.
Polyembryony is present in many members. eg. Pinus. True fruits are lacking because of the absence of the ovary. The ripened ovule becomes the seed and he inner two layers of the integument become the outer and inner seed coat. A small portion of nucellus may persist in the seed. It is known as perisperm.
The embryo develops into the sporophyte. The sporophyte (diploid) stage in gymnosperms is more dominant and independent, while the gametophyte (haploid) stage is reduced and dependent. Plants show alternation of generations.
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