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Why can pollination and fertilization be separated by a long time in Scots pine?

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Cluster of bright red seeds emerging from the cone-shaped fruit of a magnolia grandiflora, surrounded by large, glossy green leaves. — Seed Fruit and seeds of the southern magnolia (*Magnolia grandiflora*). The fruit is an aggregate of follicles, and each follicle bears a single red seed.

In the Scots pine (Pinus sylvestris), the significant time gap between pollination and fertilization—which spans approximately 14 months—is due to the complex, multi-stage development required for the gametophyte to mature.12

Following pollination in the spring, the pollen tube begins a slow growth process through the nucellus. Simultaneously, the ovule undergoes a lengthy internal development: the megaspore nucleus divides to form a large collection of nuclei, which are then enclosed by walls to create the female gametophyte (or prothallus). Within this structure, archegonia develop to house the egg cells.1

The pollen tube does not reach and penetrate the neck of an archegonium to unite with the egg nucleus until the second growing season. This extended reproductive cycle ensures that the development of the embryo and the surrounding endosperm is carefully synchronized with the maturation of the seed within the cone.12